1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
|
/* Low-level bidirectional buffer/string-scanning functions for GNU Emacs.
Copyright (C) 2000-2001, 2004-2005, 2009-2014 Free Software
Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Eli Zaretskii <eliz@gnu.org>.
A sequential implementation of the Unicode Bidirectional algorithm,
(UBA) as per UAX#9, a part of the Unicode Standard.
Unlike the Reference Implementation and most other implementations,
this one is designed to be called once for every character in the
buffer or string. That way, we can leave intact the design of the
Emacs display engine, whereby an iterator object is used to
traverse buffer or string text character by character, and generate
the necessary data for displaying each character in 'struct glyph'
objects. (See xdisp.c for the details of that iteration.) The
functions on this file replace the original linear iteration in the
logical order of the text with a non-linear iteration in the visual
order, i.e. in the order characters should be shown on display.
The main entry point is bidi_move_to_visually_next. Each time it
is called, it finds the next character in the visual order, and
returns its information in a special structure. The caller is then
expected to process this character for display or any other
purposes, and call bidi_move_to_visually_next for the next
character. See the comments in bidi_move_to_visually_next for more
details about its algorithm that finds the next visual-order
character by resolving their levels on the fly.
Two other entry points are bidi_paragraph_init and
bidi_mirror_char. The first determines the base direction of a
paragraph, while the second returns the mirrored version of its
argument character.
A few auxiliary entry points are used to initialize the bidi
iterator for iterating an object (buffer or string), push and pop
the bidi iterator state, and save and restore the state of the bidi
cache.
If you want to understand the code, you will have to read it
together with the relevant portions of UAX#9. The comments include
references to UAX#9 rules, for that very reason.
A note about references to UAX#9 rules: if the reference says
something like "X9/Retaining", it means that you need to refer to
rule X9 and to its modifications described in the "Implementation
Notes" section of UAX#9, under "Retaining Format Codes".
Here's the overview of the design of the reordering engine
implemented by this file.
Basic implementation structure
------------------------------
The sequential processing steps described by UAX#9 are implemented
as recursive levels of processing, all of which examine the next
character in the logical order. This hierarchy of processing looks
as follows, from the innermost (deepest) to the outermost level,
omitting some subroutines used by each level:
bidi_fetch_char -- fetch next character
bidi_resolve_explicit -- resolve explicit levels and directions
bidi_resolve_weak -- resolve weak types
bidi_resolve_brackets -- resolve "paired brackets" neutral types
bidi_resolve_neutral -- resolve neutral types
bidi_level_of_next_char -- resolve implicit levels
Each level calls the level below it, and works on the result
returned by the lower level, including all of its sub-levels.
Unlike all the levels below it, bidi_level_of_next_char can return
the information about either the next or previous character in the
logical order, depending on the current direction of scanning the
buffer or string. For the next character, it calls all the levels
below it; for the previous character, it uses the cache, described
below.
Thus, the result of calling bidi_level_of_next_char is the resolved
level of the next or the previous character in the logical order.
Based on this information, the function bidi_move_to_visually_next
finds the next character in the visual order and updates the
direction in which the buffer is scanned, either forward or
backward, to find the next character to be displayed. (Text is
scanned backwards when it needs to be reversed for display, i.e. if
the visual order is the inverse of the logical order.) This
implements the last, reordering steps of the UBA, by successively
calling bidi_level_of_next_char until the character of the required
embedding level is found; the scan direction is dynamically updated
as a side effect. See the commentary before the 'while' loop in
bidi_move_to_visually_next, for the details.
Fetching characters
-------------------
In a nutshell, fetching the next character boils down to calling
STRING_CHAR_AND_LENGTH, passing it the address of a buffer or
string position. See bidi_fetch_char. However, if the next
character is "covered" by a display property of some kind,
bidi_fetch_char returns the u+FFFC "object replacement character"
that represents the entire run of text covered by the display
property. (The ch_len and nchars members of 'struct bidi_it'
reflect the length in bytes and characters of that text.) This is
so we reorder text on both sides of the display property as
appropriate for an image or embedded string. Similarly, text
covered by a display spec of the form '(space ...)', is replaced
with the u+2029 paragraph separator character, so such display
specs produce the same effect as a TAB under UBA. Both these
special characters are not actually displayed -- the display
property is displayed instead -- but just used to compute the
embedding level of the surrounding text so as to produce the
required effect.
Bidi iterator states
--------------------
The UBA is highly context dependent in some of its parts,
i.e. results of processing a character can generally depend on
characters very far away. The UAX#9 description of the UBA
prescribes a stateful processing of each character, whereby the
results of this processing depend on various state variables, such
as the current embedding level, level stack, and directional
override status. In addition, the UAX#9 description includes many
passages like this (from rule W2 in this case):
Search backward from each instance of a European number until the
first strong type (R, L, AL, or sos) is found. If an AL is found,
change the type of the European number to Arabic number.
To support this, we use a bidi iterator object, 'struct bidi_it',
which is a sub-structure of 'struct it' used by xdisp.c (see
dispextern.h for the definition of both of these structures). The
bidi iterator holds the entire state of the iteration required by
the UBA, and is updated as the text is traversed. In particular,
the embedding level of the current character being resolved is
recorded in the iterator state. To avoid costly searches backward
in support of rules like W2 above, the necessary character types
are also recorded in the iterator state as they are found during
the forward scan, and then used when such rules need to be applied.
(Forward scans cannot be avoided in this way; they need to be
performed at least once, and the results recorded in the iterator
state, to be reused until the forward scan oversteps the recorded
position.)
In this manner, the iterator state acts as a mini-cache of
contextual information required for resolving the level of the
current character by various UBA rules.
Caching of bidi iterator states
-------------------------------
As described above, the reordering engine uses the information
recorded in the bidi iterator state in order to resolve the
embedding level of the current character. When the reordering
engine needs to process the next character in the logical order, it
fetches it and applies to it all the UBA levels, updating the
iterator state as it goes. But when the buffer or string is
scanned backwards, i.e. in the reverse order of buffer/string
positions, the scanned characters were already processed during the
preceding forward scan (see bidi_find_other_level_edge). To avoid
costly re-processing of characters that were already processed
during the forward scan, the iterator states computed while
scanning forward are cached.
The cache is just a linear array of 'struct bidi_it' objects, which
is dynamically allocated and reallocated as needed, since the size
of the cache depends on the text being processed. We only need the
cache while processing embedded levels higher than the base
paragraph embedding level, because these higher levels require
changes in scan direction. Therefore, as soon as we are back to
the base embedding level, we can free the cache; see the calls to
bidi_cache_reset and bidi_cache_shrink, for the conditions to do
this.
The cache maintains the index of the next unused cache slot -- this
is where the next iterator state will be cached. The function
bidi_cache_iterator_state saves an instance of the state in the
cache and increments the unused slot index. The companion function
bidi_cache_find looks up a cached state that corresponds to a given
buffer/string position. All of the cached states must correspond
1:1 to the buffer or string region whose processing they reflect;
bidi.c will abort if it finds cache slots that violate this 1:1
correspondence.
When the parent iterator 'struct it' is pushed (see push_it in
xdisp.c) to pause the current iteration and start iterating over a
different object (e.g., a 'display' string that covers some buffer
text), the bidi iterator cache needs to be "pushed" as well, so
that a new empty cache could be used while iterating over the new
object. Later, when the new object is exhausted, and xdisp.c calls
pop_it, we need to "pop" the bidi cache as well and return to the
original cache. See bidi_push_it and bidi_pop_it for how this is
done.
Some functions of the display engine save copies of 'struct it' in
local variables, and restore them later. For examples, see
pos_visible_p and move_it_in_display_line_to in xdisp.c, and
window_scroll_pixel_based in window.c. When this happens, we need
to save and restore the bidi cache as well, because conceptually
the cache is part of the 'struct it' state, and needs to be in
perfect sync with the portion of the buffer/string that is being
processed. This saving and restoring of the cache state is handled
by bidi_shelve_cache and bidi_unshelve_cache, and the helper macros
SAVE_IT and RESTORE_IT defined on xdisp.c.
Note that, because reordering is implemented below the level in
xdisp.c that breaks glyphs into screen lines, we are violating
paragraph 3.4 of UAX#9. which mandates that line breaking shall be
done before reordering each screen line separately. However,
following UAX#9 to the letter in this matter goes against the basic
design of the Emacs display engine, and so we choose here this
minor deviation from the UBA letter in preference to redesign of
the display engine. The effect of this is only seen in continued
lines that are broken into screen lines in the middle of a run
whose direction is opposite to the paragraph's base direction.
Important design and implementation note: when the code needs to
scan far ahead, be sure to avoid such scans as much as possible
when the buffer/string doesn't contain any RTL characters. Users
of left-to-right scripts will never forgive you if you introduce
some slow-down due to bidi in situations that don't involve any
bidirectional text. See the large comment near the beginning of
bidi_resolve_neutral, for one situation where such shortcut was
necessary. */
#include <config.h>
#include <stdio.h>
#include "lisp.h"
#include "character.h"
#include "buffer.h"
#include "dispextern.h"
#include "region-cache.h"
static bool bidi_initialized = 0;
static Lisp_Object bidi_type_table, bidi_mirror_table, bidi_brackets_table;
#define BIDI_EOB (-1)
/* Data type for describing the bidirectional character categories. */
typedef enum {
UNKNOWN_BC,
NEUTRAL,
WEAK,
STRONG,
EXPLICIT_FORMATTING
} bidi_category_t;
static Lisp_Object paragraph_start_re, paragraph_separate_re;
static Lisp_Object Qparagraph_start, Qparagraph_separate;
/***********************************************************************
Utilities
***********************************************************************/
/* Return the bidi type of a character CH, subject to the current
directional OVERRIDE. */
static bidi_type_t
bidi_get_type (int ch, bidi_dir_t override)
{
bidi_type_t default_type;
if (ch == BIDI_EOB)
return NEUTRAL_B;
if (ch < 0 || ch > MAX_CHAR)
emacs_abort ();
default_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch));
/* Every valid character code, even those that are unassigned by the
UCD, have some bidi-class property, according to
DerivedBidiClass.txt file. Therefore, if we ever get UNKNOWN_BT
(= zero) code from CHAR_TABLE_REF, that's a bug. */
if (default_type == UNKNOWN_BT)
emacs_abort ();
switch (default_type)
{
case WEAK_BN:
case NEUTRAL_B:
case LRE:
case LRO:
case RLE:
case RLO:
case PDF:
case LRI:
case RLI:
case FSI:
case PDI:
return default_type;
default:
if (override == L2R)
return STRONG_L;
else if (override == R2L)
return STRONG_R;
else
return default_type;
}
}
static void
bidi_check_type (bidi_type_t type)
{
eassert (UNKNOWN_BT <= type && type <= NEUTRAL_ON);
}
/* Given a bidi TYPE of a character, return its category. */
static bidi_category_t
bidi_get_category (bidi_type_t type)
{
switch (type)
{
case UNKNOWN_BT:
return UNKNOWN_BC;
case STRONG_L:
case STRONG_R:
case STRONG_AL:
return STRONG;
case WEAK_EN:
case WEAK_ES:
case WEAK_ET:
case WEAK_AN:
case WEAK_CS:
case WEAK_NSM:
case WEAK_BN:
return WEAK;
case NEUTRAL_B:
case NEUTRAL_S:
case NEUTRAL_WS:
case NEUTRAL_ON:
return NEUTRAL;
case LRE:
case LRO:
case RLE:
case RLO:
case PDF:
case LRI:
case RLI:
case FSI:
case PDI:
return EXPLICIT_FORMATTING;
default:
emacs_abort ();
}
}
static bool
bidi_isolate_fmt_char (bidi_type_t ch_type)
{
return (ch_type == LRI || ch_type == RLI || ch_type == PDI || ch_type == FSI);
}
/* Return the mirrored character of C, if it has one. If C has no
mirrored counterpart, return C.
Note: The conditions in UAX#9 clause L4 regarding the surrounding
context must be tested by the caller. */
int
bidi_mirror_char (int c)
{
Lisp_Object val;
if (c == BIDI_EOB)
return c;
if (c < 0 || c > MAX_CHAR)
emacs_abort ();
val = CHAR_TABLE_REF (bidi_mirror_table, c);
if (INTEGERP (val))
{
int v;
/* When debugging, check before assigning to V, so that the check
isn't broken by undefined behavior due to int overflow. */
eassert (CHAR_VALID_P (XINT (val)));
v = XINT (val);
/* Minimal test we must do in optimized builds, to prevent weird
crashes further down the road. */
if (v < 0 || v > MAX_CHAR)
emacs_abort ();
return v;
}
return c;
}
/* Return the Bidi_Paired_Bracket_Type property of the character C. */
static bidi_bracket_type_t
bidi_paired_bracket_type (int c)
{
if (c == BIDI_EOB)
return BIDI_BRACKET_NONE;
if (c < 0 || c > MAX_CHAR)
emacs_abort ();
return (bidi_bracket_type_t) XINT (CHAR_TABLE_REF (bidi_brackets_table, c));
}
/* Determine the start-of-sequence (sos) directional type given the two
embedding levels on either side of the run boundary. Also, update
the saved info about previously seen characters, since that info is
generally valid for a single level run. */
static void
bidi_set_sos_type (struct bidi_it *bidi_it, int level_before, int level_after)
{
int higher_level = (level_before > level_after ? level_before : level_after);
/* FIXME: should the default sos direction be user selectable? */
bidi_it->sos = ((higher_level & 1) != 0 ? R2L : L2R); /* X10 */
bidi_it->prev.type = UNKNOWN_BT;
bidi_it->last_strong.type = bidi_it->last_strong.orig_type = UNKNOWN_BT;
bidi_it->prev_for_neutral.type = (bidi_it->sos == R2L ? STRONG_R : STRONG_L);
bidi_it->prev_for_neutral.charpos = bidi_it->charpos;
bidi_it->next_for_neutral.type
= bidi_it->next_for_neutral.orig_type = UNKNOWN_BT;
}
#define ISOLATE_STATUS(BIDI_IT, IDX) ((BIDI_IT)->level_stack[IDX].flags & 1)
#define OVERRIDE(BIDI_IT, IDX) (((BIDI_IT)->level_stack[IDX].flags >> 1) & 3)
/* Push the current embedding level and override status; reset the
current level to LEVEL and the current override status to OVERRIDE. */
static void
bidi_push_embedding_level (struct bidi_it *bidi_it,
int level, bidi_dir_t override, bool isolate_status)
{
struct bidi_stack *st;
int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
bidi_it->stack_idx++;
eassert (bidi_it->stack_idx < BIDI_MAXDEPTH+2+1);
st = &bidi_it->level_stack[bidi_it->stack_idx];
eassert (level <= (1 << 7));
st->level = level;
st->flags = (((override & 3) << 1) | (isolate_status != 0));
if (isolate_status)
{
st->last_strong_type = bidi_it->last_strong.type;
st->prev_for_neutral_type = bidi_it->prev_for_neutral.type;
st->next_for_neutral_type = bidi_it->next_for_neutral.type;
st->next_for_neutral_pos = bidi_it->next_for_neutral.charpos;
st->flags |= ((bidi_it->sos == L2R ? 0 : 1) << 3);
}
/* We've got a new isolating sequence, compute the directional type
of sos and initialize per-sequence variables (UAX#9, clause X10). */
bidi_set_sos_type (bidi_it, prev_level, level);
}
/* Pop from the stack the embedding level, the directional override
status, and optionally saved information for the isolating run
sequence. Return the new level. */
static int
bidi_pop_embedding_level (struct bidi_it *bidi_it)
{
int level;
/* UAX#9 says to ignore invalid PDFs (X7, last bullet)
and PDIs (X6a, 2nd bullet). */
if (bidi_it->stack_idx > 0)
{
bool isolate_status = ISOLATE_STATUS (bidi_it, bidi_it->stack_idx);
int old_level = bidi_it->level_stack[bidi_it->stack_idx].level;
struct bidi_stack st;
st = bidi_it->level_stack[bidi_it->stack_idx];
if (isolate_status)
{
bidi_dir_t sos = ((st.flags >> 3) & 1);
/* PREV is used in W1 for resolving WEAK_NSM. By the time
we get to an NSM, we must have gotten past at least one
character: the PDI that ends the isolate from which we
are popping here. So PREV will have been filled up by
the time we first use it. We initialize it here to
UNKNOWN_BT to be able to catch any blunders in this
logic. */
bidi_it->prev.orig_type = bidi_it->prev.type = UNKNOWN_BT;
bidi_it->last_strong.type = st.last_strong_type;
bidi_it->prev_for_neutral.type = st.prev_for_neutral_type;
bidi_it->next_for_neutral.type = st.next_for_neutral_type;
bidi_it->next_for_neutral.charpos = st.next_for_neutral_pos;
bidi_it->sos = (sos == 0 ? L2R : R2L);
}
else
bidi_set_sos_type (bidi_it, old_level,
bidi_it->level_stack[bidi_it->stack_idx - 1].level);
bidi_it->stack_idx--;
}
level = bidi_it->level_stack[bidi_it->stack_idx].level;
eassert (0 <= level && level <= BIDI_MAXDEPTH + 1);
return level;
}
/* Record in SAVED_INFO the information about the current character. */
static void
bidi_remember_char (struct bidi_saved_info *saved_info,
struct bidi_it *bidi_it, bool from_type)
{
saved_info->charpos = bidi_it->charpos;
if (from_type)
saved_info->type = bidi_it->type;
else
saved_info->type = bidi_it->type_after_wn;
bidi_check_type (saved_info->type);
saved_info->orig_type = bidi_it->orig_type;
bidi_check_type (saved_info->orig_type);
}
/* Copy the bidi iterator from FROM to TO. To save cycles, this only
copies the part of the level stack that is actually in use. */
static void
bidi_copy_it (struct bidi_it *to, struct bidi_it *from)
{
/* Copy everything from the start through the active part of
the level stack. */
memcpy (to, from,
(offsetof (struct bidi_it, level_stack[1])
+ from->stack_idx * sizeof from->level_stack[0]));
}
/***********************************************************************
Caching the bidi iterator states
***********************************************************************/
/* We allocate and de-allocate the cache in chunks of this size (in
characters). 200 was chosen as an upper limit for reasonably-long
lines in a text file/buffer. */
#define BIDI_CACHE_CHUNK 200
/* Maximum size we allow the cache to become, per iterator stack slot,
in units of struct bidi_it size. If we allow unlimited growth, we
could run out of memory for pathologically long bracketed text or
very long text lines that need to be reordered. This is aggravated
when word-wrap is in effect, since then functions display_line and
move_it_in_display_line_to need to keep up to 4 copies of the
cache.
This limitation means there can be no more than that amount of
contiguous RTL text on any single physical line in a LTR paragraph,
and similarly with contiguous LTR + numeric text in a RTL
paragraph. (LTR text in a LTR paragraph and RTL text in a RTL
paragraph are not reordered, and so don't need the cache, and
cannot hit this limit.) More importantly, no single line can have
text longer than this inside paired brackets (because bracket pairs
resolution uses the cache). If the limit is exceeded, the fallback
code will produce visual order that will be incorrect if there are
RTL characters in the offending line of text. */
/* Do we need to allow customization of this limit? */
#define BIDI_CACHE_MAX_ELTS_PER_SLOT 50000
#if BIDI_CACHE_CHUNK >= BIDI_CACHE_MAX_ELTS_PER_SLOT
# error BIDI_CACHE_CHUNK must be less than BIDI_CACHE_MAX_ELTS_PER_SLOT
#endif
static ptrdiff_t bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
static struct bidi_it *bidi_cache;
static ptrdiff_t bidi_cache_size = 0;
enum { elsz = sizeof (struct bidi_it) };
static ptrdiff_t bidi_cache_idx; /* next unused cache slot */
static ptrdiff_t bidi_cache_last_idx; /* slot of last cache hit */
static ptrdiff_t bidi_cache_start = 0; /* start of cache for this
"stack" level */
/* 5-slot stack for saving the start of the previous level of the
cache. xdisp.c maintains a 5-slot stack for its iterator state,
and we need the same size of our stack. */
static ptrdiff_t bidi_cache_start_stack[IT_STACK_SIZE];
static int bidi_cache_sp;
/* Size of header used by bidi_shelve_cache. */
enum
{
bidi_shelve_header_size
= (sizeof (bidi_cache_idx) + sizeof (bidi_cache_start_stack)
+ sizeof (bidi_cache_sp) + sizeof (bidi_cache_start)
+ sizeof (bidi_cache_last_idx) + sizeof (bidi_cache_max_elts))
};
/* Effectively remove the cached states beyond the Nth state from the
part of the cache relevant to iteration of the current object
(buffer or string). */
static void
bidi_cache_reset_to (int n)
{
bidi_cache_idx = bidi_cache_start + n;
bidi_cache_last_idx = -1;
}
/* Reset the cache state to the empty state. We only reset the part
of the cache relevant to iteration of the current object. Previous
objects, which are pushed on the display iterator's stack, are left
intact. This is called when the cached information is no more
useful for the current iteration, e.g. when we were reseated to a
new position on the same object. */
static void
bidi_cache_reset (void)
{
bidi_cache_reset_to (0);
}
/* Shrink the cache to its minimal size. Called when we init the bidi
iterator for reordering a buffer or a string that does not come
from display properties, because that means all the previously
cached info is of no further use. */
static void
bidi_cache_shrink (void)
{
if (bidi_cache_size > BIDI_CACHE_CHUNK)
{
bidi_cache = xrealloc (bidi_cache, BIDI_CACHE_CHUNK * elsz);
bidi_cache_size = BIDI_CACHE_CHUNK;
}
bidi_cache_reset ();
bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
}
static void
bidi_cache_fetch_state (ptrdiff_t idx, struct bidi_it *bidi_it)
{
int current_scan_dir = bidi_it->scan_dir;
if (idx < bidi_cache_start || idx >= bidi_cache_idx)
emacs_abort ();
bidi_copy_it (bidi_it, &bidi_cache[idx]);
bidi_it->scan_dir = current_scan_dir;
bidi_cache_last_idx = idx;
}
/* Find a cached state with a given CHARPOS and resolved embedding
level less or equal to LEVEL. If LEVEL is -1, disregard the
resolved levels in cached states. DIR, if non-zero, means search
in that direction from the last cache hit.
Value is the index of the cached state, or -1 if not found. */
static ptrdiff_t
bidi_cache_search (ptrdiff_t charpos, int level, int dir)
{
ptrdiff_t i, i_start;
if (bidi_cache_idx > bidi_cache_start)
{
if (bidi_cache_last_idx == -1)
bidi_cache_last_idx = bidi_cache_idx - 1;
if (charpos < bidi_cache[bidi_cache_last_idx].charpos)
{
dir = -1;
i_start = bidi_cache_last_idx - 1;
}
else if (charpos > (bidi_cache[bidi_cache_last_idx].charpos
+ bidi_cache[bidi_cache_last_idx].nchars - 1))
{
dir = 1;
i_start = bidi_cache_last_idx + 1;
}
else if (dir)
i_start = bidi_cache_last_idx;
else
{
dir = -1;
i_start = bidi_cache_idx - 1;
}
if (dir < 0)
{
/* Linear search for now; FIXME! */
for (i = i_start; i >= bidi_cache_start; i--)
if (bidi_cache[i].charpos <= charpos
&& charpos < bidi_cache[i].charpos + bidi_cache[i].nchars
&& (level == -1 || bidi_cache[i].resolved_level <= level))
return i;
}
else
{
for (i = i_start; i < bidi_cache_idx; i++)
if (bidi_cache[i].charpos <= charpos
&& charpos < bidi_cache[i].charpos + bidi_cache[i].nchars
&& (level == -1 || bidi_cache[i].resolved_level <= level))
return i;
}
}
return -1;
}
/* Find a cached state where the resolved level changes to a value
that is lower than LEVEL, and return its cache slot index. DIR is
the direction to search, starting with the last used cache slot.
If DIR is zero, we search backwards from the last occupied cache
slot. BEFORE means return the index of the slot that
is ``before'' the level change in the search direction. That is,
given the cached levels like this:
1122333442211
AB C
and assuming we are at the position cached at the slot marked with
C, searching backwards (DIR = -1) for LEVEL = 2 will return the
index of slot B or A, depending whether BEFORE is, respectively,
true or false. */
static ptrdiff_t
bidi_cache_find_level_change (int level, int dir, bool before)
{
if (bidi_cache_idx)
{
ptrdiff_t i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1;
int incr = before ? 1 : 0;
if (i < 0) /* cache overflowed? */
i = 0;
if (!dir)
dir = -1;
else if (!incr)
i += dir;
if (dir < 0)
{
while (i >= bidi_cache_start + incr)
{
if (bidi_cache[i - incr].resolved_level >= 0
&& bidi_cache[i - incr].resolved_level < level)
return i;
i--;
}
}
else
{
while (i < bidi_cache_idx - incr)
{
if (bidi_cache[i + incr].resolved_level >= 0
&& bidi_cache[i + incr].resolved_level < level)
return i;
i++;
}
}
}
return -1;
}
static void
bidi_cache_ensure_space (ptrdiff_t idx)
{
/* Enlarge the cache as needed. */
if (idx >= bidi_cache_size)
{
ptrdiff_t chunk_size = BIDI_CACHE_CHUNK;
if (bidi_cache_size > bidi_cache_max_elts - chunk_size)
chunk_size = bidi_cache_max_elts - bidi_cache_size;
if (max (idx + 1,
bidi_cache_size + chunk_size) <= bidi_cache_max_elts)
{
/* The bidi cache cannot be larger than the largest Lisp
string or buffer. */
ptrdiff_t string_or_buffer_bound
= max (BUF_BYTES_MAX, STRING_BYTES_BOUND);
/* Also, it cannot be larger than what C can represent. */
ptrdiff_t c_bound
= (min (PTRDIFF_MAX, SIZE_MAX) - bidi_shelve_header_size) / elsz;
ptrdiff_t max_elts = bidi_cache_max_elts;
max_elts = min (max_elts, min (string_or_buffer_bound, c_bound));
/* Force xpalloc not to over-allocate by passing it MAX_ELTS
as its 4th argument. */
bidi_cache = xpalloc (bidi_cache, &bidi_cache_size,
max (chunk_size, idx - bidi_cache_size + 1),
max_elts, elsz);
eassert (bidi_cache_size > idx);
}
}
}
static int
bidi_cache_iterator_state (struct bidi_it *bidi_it, bool resolved,
bool update_only)
{
ptrdiff_t idx;
/* We should never cache on backward scans. */
if (bidi_it->scan_dir == -1)
emacs_abort ();
idx = bidi_cache_search (bidi_it->charpos, -1, 1);
if (idx < 0 && update_only)
return 0;
if (idx < 0)
{
idx = bidi_cache_idx;
bidi_cache_ensure_space (idx);
/* Character positions should correspond to cache positions 1:1.
If we are outside the range of cached positions, the cache is
useless and must be reset. */
if (bidi_cache_start < idx && idx < bidi_cache_size
&& (bidi_it->charpos > (bidi_cache[idx - 1].charpos
+ bidi_cache[idx - 1].nchars)
|| bidi_it->charpos < bidi_cache[bidi_cache_start].charpos))
{
bidi_cache_reset ();
idx = bidi_cache_start;
}
if (bidi_it->nchars <= 0)
emacs_abort ();
/* Don't cache if no available space in the cache. */
if (bidi_cache_size > idx)
{
bidi_copy_it (&bidi_cache[idx], bidi_it);
if (!resolved)
bidi_cache[idx].resolved_level = -1;
}
}
else
{
/* Copy only the members which could have changed, to avoid
costly copying of the entire struct. */
bidi_cache[idx].type = bidi_it->type;
bidi_check_type (bidi_it->type);
bidi_cache[idx].type_after_wn = bidi_it->type_after_wn;
bidi_check_type (bidi_it->type_after_wn);
if (resolved)
bidi_cache[idx].resolved_level = bidi_it->resolved_level;
else
bidi_cache[idx].resolved_level = -1;
bidi_cache[idx].invalid_levels = bidi_it->invalid_levels;
bidi_cache[idx].next_for_neutral = bidi_it->next_for_neutral;
bidi_cache[idx].next_for_ws = bidi_it->next_for_ws;
bidi_cache[idx].disp_pos = bidi_it->disp_pos;
bidi_cache[idx].disp_prop = bidi_it->disp_prop;
bidi_cache[idx].bracket_pairing_pos = bidi_it->bracket_pairing_pos;
bidi_cache[idx].bracket_enclosed_type = bidi_it->bracket_enclosed_type;
}
if (bidi_cache_size > idx)
{
bidi_cache_last_idx = idx;
if (idx >= bidi_cache_idx)
bidi_cache_idx = idx + 1;
return 1;
}
else
{
/* The cache overflowed. */
bidi_cache_last_idx = -1;
return 0;
}
}
/* Look for a cached iterator state that corresponds to CHARPOS. If
found, copy the cached state into BIDI_IT and return the type of
the cached entry. If not found, return UNKNOWN_BT. RESOLVED_ONLY
zero means it is OK to return cached states that were not fully
resolved yet. This can happen if the state was cached before it
was resolved in bidi_resolve_neutral. */
static bidi_type_t
bidi_cache_find (ptrdiff_t charpos, bool resolved_only, struct bidi_it *bidi_it)
{
ptrdiff_t i = bidi_cache_search (charpos, -1, bidi_it->scan_dir);
if (i >= bidi_cache_start
&& (!resolved_only
/* Callers that want only fully resolved states (and set
resolved_only = true) need to be sure that there's enough
info in the cached state to return the state as final,
and if not, they don't want the cached state. */
|| bidi_cache[i].resolved_level >= 0))
{
bidi_dir_t current_scan_dir = bidi_it->scan_dir;
bidi_copy_it (bidi_it, &bidi_cache[i]);
bidi_cache_last_idx = i;
/* Don't let scan direction from the cached state override
the current scan direction. */
bidi_it->scan_dir = current_scan_dir;
return bidi_it->type;
}
return UNKNOWN_BT;
}
static int
bidi_peek_at_next_level (struct bidi_it *bidi_it)
{
if (bidi_cache_idx == bidi_cache_start)
emacs_abort ();
/* If the cache overflowed, return the level of the last cached
character. */
if (bidi_cache_last_idx == -1
|| (bidi_cache_last_idx >= bidi_cache_idx - 1 && bidi_it->scan_dir > 0))
return bidi_cache[bidi_cache_idx - 1].resolved_level;
return bidi_cache[bidi_cache_last_idx + bidi_it->scan_dir].resolved_level;
}
/***********************************************************************
Pushing and popping the bidi iterator state
***********************************************************************/
/* Push the bidi iterator state in preparation for reordering a
different object, e.g. display string found at certain buffer
position. Pushing the bidi iterator boils down to saving its
entire state on the cache and starting a new cache "stacked" on top
of the current cache. */
void
bidi_push_it (struct bidi_it *bidi_it)
{
/* Give this stack slot its cache room. */
bidi_cache_max_elts += BIDI_CACHE_MAX_ELTS_PER_SLOT;
/* Save the current iterator state in its entirety after the last
used cache slot. */
bidi_cache_ensure_space (bidi_cache_idx);
bidi_cache[bidi_cache_idx++] = *bidi_it;
/* Push the current cache start onto the stack. */
eassert (bidi_cache_sp < IT_STACK_SIZE);
bidi_cache_start_stack[bidi_cache_sp++] = bidi_cache_start;
/* Start a new level of cache, and make it empty. */
bidi_cache_start = bidi_cache_idx;
bidi_cache_last_idx = -1;
}
/* Restore the iterator state saved by bidi_push_it and return the
cache to the corresponding state. */
void
bidi_pop_it (struct bidi_it *bidi_it)
{
if (bidi_cache_start <= 0)
emacs_abort ();
/* Reset the next free cache slot index to what it was before the
call to bidi_push_it. */
bidi_cache_idx = bidi_cache_start - 1;
/* Restore the bidi iterator state saved in the cache. */
*bidi_it = bidi_cache[bidi_cache_idx];
/* Pop the previous cache start from the stack. */
if (bidi_cache_sp <= 0)
emacs_abort ();
bidi_cache_start = bidi_cache_start_stack[--bidi_cache_sp];
/* Invalidate the last-used cache slot data. */
bidi_cache_last_idx = -1;
bidi_cache_max_elts -= BIDI_CACHE_MAX_ELTS_PER_SLOT;
eassert (bidi_cache_max_elts > 0);
}
static ptrdiff_t bidi_cache_total_alloc;
/* Stash away a copy of the cache and its control variables. */
void *
bidi_shelve_cache (void)
{
unsigned char *databuf;
ptrdiff_t alloc;
/* Empty cache. */
if (bidi_cache_idx == 0)
return NULL;
alloc = (bidi_shelve_header_size
+ bidi_cache_idx * sizeof (struct bidi_it));
databuf = xmalloc (alloc);
bidi_cache_total_alloc += alloc;
memcpy (databuf, &bidi_cache_idx, sizeof (bidi_cache_idx));
memcpy (databuf + sizeof (bidi_cache_idx),
bidi_cache, bidi_cache_idx * sizeof (struct bidi_it));
memcpy (databuf + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it),
bidi_cache_start_stack, sizeof (bidi_cache_start_stack));
memcpy (databuf + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack),
&bidi_cache_sp, sizeof (bidi_cache_sp));
memcpy (databuf + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp),
&bidi_cache_start, sizeof (bidi_cache_start));
memcpy (databuf + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ sizeof (bidi_cache_start),
&bidi_cache_last_idx, sizeof (bidi_cache_last_idx));
memcpy (databuf + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ sizeof (bidi_cache_start) + sizeof (bidi_cache_last_idx),
&bidi_cache_max_elts, sizeof (bidi_cache_max_elts));
return databuf;
}
/* Restore the cache state from a copy stashed away by
bidi_shelve_cache, and free the buffer used to stash that copy.
JUST_FREE means free the buffer, but don't restore the
cache; used when the corresponding iterator is discarded instead of
being restored. */
void
bidi_unshelve_cache (void *databuf, bool just_free)
{
unsigned char *p = databuf;
if (!p)
{
if (!just_free)
{
/* A NULL pointer means an empty cache. */
bidi_cache_start = 0;
bidi_cache_sp = 0;
bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
bidi_cache_reset ();
}
}
else
{
if (just_free)
{
ptrdiff_t idx;
memcpy (&idx, p, sizeof (bidi_cache_idx));
bidi_cache_total_alloc
-= bidi_shelve_header_size + idx * sizeof (struct bidi_it);
}
else
{
memcpy (&bidi_cache_idx, p, sizeof (bidi_cache_idx));
bidi_cache_ensure_space (bidi_cache_idx);
memcpy (bidi_cache, p + sizeof (bidi_cache_idx),
bidi_cache_idx * sizeof (struct bidi_it));
memcpy (bidi_cache_start_stack,
p + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it),
sizeof (bidi_cache_start_stack));
memcpy (&bidi_cache_sp,
p + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack),
sizeof (bidi_cache_sp));
memcpy (&bidi_cache_start,
p + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp),
sizeof (bidi_cache_start));
memcpy (&bidi_cache_last_idx,
p + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ sizeof (bidi_cache_start),
sizeof (bidi_cache_last_idx));
memcpy (&bidi_cache_max_elts,
p + sizeof (bidi_cache_idx)
+ bidi_cache_idx * sizeof (struct bidi_it)
+ sizeof (bidi_cache_start_stack) + sizeof (bidi_cache_sp)
+ sizeof (bidi_cache_start) + sizeof (bidi_cache_last_idx),
sizeof (bidi_cache_max_elts));
bidi_cache_total_alloc
-= (bidi_shelve_header_size
+ bidi_cache_idx * sizeof (struct bidi_it));
}
xfree (p);
}
}
/***********************************************************************
Initialization
***********************************************************************/
static void
bidi_initialize (void)
{
bidi_type_table = uniprop_table (intern ("bidi-class"));
if (NILP (bidi_type_table))
emacs_abort ();
staticpro (&bidi_type_table);
bidi_mirror_table = uniprop_table (intern ("mirroring"));
if (NILP (bidi_mirror_table))
emacs_abort ();
staticpro (&bidi_mirror_table);
bidi_brackets_table = uniprop_table (intern ("bracket-type"));
if (NILP (bidi_brackets_table))
emacs_abort ();
staticpro (&bidi_brackets_table);
DEFSYM (Qparagraph_start, "paragraph-start");
paragraph_start_re = Fsymbol_value (Qparagraph_start);
if (!STRINGP (paragraph_start_re))
paragraph_start_re = build_string ("\f\\|[ \t]*$");
staticpro (¶graph_start_re);
DEFSYM (Qparagraph_separate, "paragraph-separate");
paragraph_separate_re = Fsymbol_value (Qparagraph_separate);
if (!STRINGP (paragraph_separate_re))
paragraph_separate_re = build_string ("[ \t\f]*$");
staticpro (¶graph_separate_re);
bidi_cache_sp = 0;
bidi_cache_total_alloc = 0;
bidi_cache_max_elts = BIDI_CACHE_MAX_ELTS_PER_SLOT;
bidi_initialized = 1;
}
/* Do whatever UAX#9 clause X8 says should be done at paragraph's
end. */
static void
bidi_set_paragraph_end (struct bidi_it *bidi_it)
{
bidi_it->invalid_levels = 0;
bidi_it->invalid_isolates = 0;
bidi_it->stack_idx = 0;
bidi_it->resolved_level = bidi_it->level_stack[0].level;
}
/* Initialize the bidi iterator from buffer/string position CHARPOS. */
void
bidi_init_it (ptrdiff_t charpos, ptrdiff_t bytepos, bool frame_window_p,
struct bidi_it *bidi_it)
{
if (! bidi_initialized)
bidi_initialize ();
if (charpos >= 0)
bidi_it->charpos = charpos;
if (bytepos >= 0)
bidi_it->bytepos = bytepos;
bidi_it->frame_window_p = frame_window_p;
bidi_it->nchars = -1; /* to be computed in bidi_resolve_explicit */
bidi_it->first_elt = 1;
bidi_set_paragraph_end (bidi_it);
bidi_it->new_paragraph = 1;
bidi_it->separator_limit = -1;
bidi_it->type = NEUTRAL_B;
bidi_it->type_after_wn = NEUTRAL_B;
bidi_it->orig_type = NEUTRAL_B;
/* FIXME: Review this!!! */
bidi_it->prev.type = bidi_it->prev.orig_type = UNKNOWN_BT;
bidi_it->last_strong.type = bidi_it->last_strong.orig_type = UNKNOWN_BT;
bidi_it->next_for_neutral.charpos = -1;
bidi_it->next_for_neutral.type
= bidi_it->next_for_neutral.orig_type = UNKNOWN_BT;
bidi_it->prev_for_neutral.charpos = -1;
bidi_it->prev_for_neutral.type
= bidi_it->prev_for_neutral.orig_type = UNKNOWN_BT;
bidi_it->bracket_pairing_pos = -1;
bidi_it->sos = L2R; /* FIXME: should it be user-selectable? */
bidi_it->disp_pos = -1; /* invalid/unknown */
bidi_it->disp_prop = 0;
/* We can only shrink the cache if we are at the bottom level of its
"stack". */
if (bidi_cache_start == 0)
bidi_cache_shrink ();
else
bidi_cache_reset ();
}
/* Perform initializations for reordering a new line of bidi text. */
static void
bidi_line_init (struct bidi_it *bidi_it)
{
bidi_it->scan_dir = 1; /* FIXME: do we need to have control on this? */
bidi_it->stack_idx = 0;
bidi_it->resolved_level = bidi_it->level_stack[0].level;
bidi_it->level_stack[0].flags = 0; /* NEUTRAL_DIR, false per X1 */
bidi_it->invalid_levels = 0;
bidi_it->isolate_level = 0; /* X1 */
bidi_it->invalid_isolates = 0; /* X1 */
/* Setting this to zero will force its recomputation the first time
we need it for W5. */
bidi_it->next_en_pos = 0;
bidi_it->next_en_type = UNKNOWN_BT;
bidi_it->next_for_ws.charpos = -1;
bidi_it->next_for_ws.type = UNKNOWN_BT;
bidi_it->bracket_pairing_pos = -1;
bidi_set_sos_type (bidi_it,
(bidi_it->paragraph_dir == R2L ? 1 : 0),
bidi_it->level_stack[0].level); /* X10 */
bidi_cache_reset ();
}
/***********************************************************************
Fetching characters
***********************************************************************/
/* Count bytes in string S between BEG/BEGBYTE and END. BEG and END
are zero-based character positions in S, BEGBYTE is byte position
corresponding to BEG. UNIBYTE means S is a unibyte string. */
static ptrdiff_t
bidi_count_bytes (const unsigned char *s, ptrdiff_t beg,
ptrdiff_t begbyte, ptrdiff_t end, bool unibyte)
{
ptrdiff_t pos = beg;
const unsigned char *p = s + begbyte, *start = p;
if (unibyte)
p = s + end;
else
{
if (!CHAR_HEAD_P (*p))
emacs_abort ();
while (pos < end)
{
p += BYTES_BY_CHAR_HEAD (*p);
pos++;
}
}
return p - start;
}
/* Fetch and return the character at byte position BYTEPOS. If S is
non-NULL, fetch the character from string S; otherwise fetch the
character from the current buffer. UNIBYTE means S is a
unibyte string. */
static int
bidi_char_at_pos (ptrdiff_t bytepos, const unsigned char *s, bool unibyte)
{
if (s)
{
s += bytepos;
if (unibyte)
return *s;
}
else
s = BYTE_POS_ADDR (bytepos);
return STRING_CHAR (s);
}
/* Fetch and return the character at CHARPOS/BYTEPOS. If that
character is covered by a display string, treat the entire run of
covered characters as a single character, either u+2029 or u+FFFC,
and return their combined length in CH_LEN and NCHARS. DISP_POS
specifies the character position of the next display string, or -1
if not yet computed. When the next character is at or beyond that
position, the function updates DISP_POS with the position of the
next display string. *DISP_PROP non-zero means that there's really
a display string at DISP_POS, as opposed to when we searched till
DISP_POS without finding one. If *DISP_PROP is 2, it means the
display spec is of the form `(space ...)', which is replaced with
u+2029 to handle it as a paragraph separator. STRING->s is the C
string to iterate, or NULL if iterating over a buffer or a Lisp
string; in the latter case, STRING->lstring is the Lisp string. */
static int
bidi_fetch_char (ptrdiff_t charpos, ptrdiff_t bytepos, ptrdiff_t *disp_pos,
int *disp_prop, struct bidi_string_data *string,
struct window *w,
bool frame_window_p, ptrdiff_t *ch_len, ptrdiff_t *nchars)
{
int ch;
ptrdiff_t endpos
= (string->s || STRINGP (string->lstring)) ? string->schars : ZV;
struct text_pos pos;
int len;
/* If we got past the last known position of display string, compute
the position of the next one. That position could be at CHARPOS. */
if (charpos < endpos && charpos > *disp_pos)
{
SET_TEXT_POS (pos, charpos, bytepos);
*disp_pos = compute_display_string_pos (&pos, string, w, frame_window_p,
disp_prop);
}
/* Fetch the character at BYTEPOS. */
if (charpos >= endpos)
{
ch = BIDI_EOB;
*ch_len = 1;
*nchars = 1;
*disp_pos = endpos;
*disp_prop = 0;
}
else if (charpos >= *disp_pos && *disp_prop)
{
ptrdiff_t disp_end_pos;
/* We don't expect to find ourselves in the middle of a display
property. Hopefully, it will never be needed. */
if (charpos > *disp_pos)
emacs_abort ();
/* Text covered by `display' properties and overlays with
display properties or display strings is handled as a single
character that represents the entire run of characters
covered by the display property. */
if (*disp_prop == 2)
{
/* `(space ...)' display specs are handled as paragraph
separators for the purposes of the reordering; see UAX#9
section 3 and clause HL1 in section 4.3 there. */
ch = 0x2029;
}
else
{
/* All other display specs are handled as the Unicode Object
Replacement Character. */
ch = 0xFFFC;
}
disp_end_pos = compute_display_string_end (*disp_pos, string);
if (disp_end_pos < 0)
{
/* Somebody removed the display string from the buffer
behind our back. Recover by processing this buffer
position as if no display property were present there to
begin with. */
*disp_prop = 0;
goto normal_char;
}
*nchars = disp_end_pos - *disp_pos;
if (*nchars <= 0)
emacs_abort ();
if (string->s)
*ch_len = bidi_count_bytes (string->s, *disp_pos, bytepos,
disp_end_pos, string->unibyte);
else if (STRINGP (string->lstring))
*ch_len = bidi_count_bytes (SDATA (string->lstring), *disp_pos,
bytepos, disp_end_pos, string->unibyte);
else
*ch_len = CHAR_TO_BYTE (disp_end_pos) - bytepos;
}
else
{
normal_char:
if (string->s)
{
if (!string->unibyte)
{
ch = STRING_CHAR_AND_LENGTH (string->s + bytepos, len);
*ch_len = len;
}
else
{
ch = UNIBYTE_TO_CHAR (string->s[bytepos]);
*ch_len = 1;
}
}
else if (STRINGP (string->lstring))
{
if (!string->unibyte)
{
ch = STRING_CHAR_AND_LENGTH (SDATA (string->lstring) + bytepos,
len);
*ch_len = len;
}
else
{
ch = UNIBYTE_TO_CHAR (SREF (string->lstring, bytepos));
*ch_len = 1;
}
}
else
{
ch = STRING_CHAR_AND_LENGTH (BYTE_POS_ADDR (bytepos), len);
*ch_len = len;
}
*nchars = 1;
}
/* If we just entered a run of characters covered by a display
string, compute the position of the next display string. */
if (charpos + *nchars <= endpos && charpos + *nchars > *disp_pos
&& *disp_prop)
{
SET_TEXT_POS (pos, charpos + *nchars, bytepos + *ch_len);
*disp_pos = compute_display_string_pos (&pos, string, w, frame_window_p,
disp_prop);
}
return ch;
}
/* Like bidi_fetch_char, but ignore any text between an isolate
initiator and its matching PDI or, if it has no matching PDI, the
end of the paragraph. If isolates were skipped, CH_LEN and NCHARS
are set to the number of bytes and characters between BYTEPOS/CHARPOS
and the character that was fetched after skipping the isolates. */
static int
bidi_fetch_char_skip_isolates (ptrdiff_t charpos, ptrdiff_t bytepos,
ptrdiff_t *disp_pos, int *disp_prop,
struct bidi_string_data *string,
struct window *w, bool frame_window_p,
ptrdiff_t *ch_len, ptrdiff_t *nchars)
{
ptrdiff_t orig_charpos = charpos, orig_bytepos = bytepos;
int ch = bidi_fetch_char (charpos, bytepos, disp_pos, disp_prop, string, w,
frame_window_p, ch_len, nchars);
bidi_type_t ch_type = bidi_get_type (ch, NEUTRAL_DIR);
ptrdiff_t level = 0;
if (ch_type == LRI || ch_type == RLI || ch_type == FSI)
{
level++;
while (level > 0 && ch_type != NEUTRAL_B)
{
charpos += *nchars;
bytepos += *ch_len;
ch = bidi_fetch_char (charpos, bytepos, disp_pos, disp_prop, string,
w, frame_window_p, ch_len, nchars);
ch_type = bidi_get_type (ch, NEUTRAL_DIR);
/* A Note to P2 says to ignore max_depth limit. */
if (ch_type == LRI || ch_type == RLI || ch_type == FSI)
level++;
else if (ch_type == PDI)
level--;
}
}
/* Communicate to the caller how much did we skip, so it could get
past the last character position we examined. */
*nchars += charpos - orig_charpos;
*ch_len += bytepos - orig_bytepos;
return ch;
}
/***********************************************************************
Determining paragraph direction
***********************************************************************/
/* Check if buffer position CHARPOS/BYTEPOS is the end of a paragraph.
Value is the non-negative length of the paragraph separator
following the buffer position, -1 if position is at the beginning
of a new paragraph, or -2 if position is neither at beginning nor
at end of a paragraph. */
static ptrdiff_t
bidi_at_paragraph_end (ptrdiff_t charpos, ptrdiff_t bytepos)
{
Lisp_Object sep_re;
Lisp_Object start_re;
ptrdiff_t val;
sep_re = paragraph_separate_re;
start_re = paragraph_start_re;
val = fast_looking_at (sep_re, charpos, bytepos, ZV, ZV_BYTE, Qnil);
if (val < 0)
{
if (fast_looking_at (start_re, charpos, bytepos, ZV, ZV_BYTE, Qnil) >= 0)
val = -1;
else
val = -2;
}
return val;
}
/* If the user has requested the long scans caching, make sure that
BIDI cache is enabled. Otherwise, make sure it's disabled. */
static struct region_cache *
bidi_paragraph_cache_on_off (void)
{
struct buffer *cache_buffer = current_buffer;
bool indirect_p = false;
/* For indirect buffers, make sure to use the cache of their base
buffer. */
if (cache_buffer->base_buffer)
{
cache_buffer = cache_buffer->base_buffer;
indirect_p = true;
}
/* Don't turn on or off the cache in the base buffer, if the value
of cache-long-scans of the base buffer is inconsistent with that.
This is because doing so will just make the cache pure overhead,
since if we turn it on via indirect buffer, it will be
immediately turned off by its base buffer. */
if (NILP (BVAR (current_buffer, cache_long_scans)))
{
if (!indirect_p
|| NILP (BVAR (cache_buffer, cache_long_scans)))
{
if (cache_buffer->bidi_paragraph_cache)
{
free_region_cache (cache_buffer->bidi_paragraph_cache);
cache_buffer->bidi_paragraph_cache = 0;
}
}
return NULL;
}
else
{
if (!indirect_p
|| !NILP (BVAR (cache_buffer, cache_long_scans)))
{
if (!cache_buffer->bidi_paragraph_cache)
cache_buffer->bidi_paragraph_cache = new_region_cache ();
}
return cache_buffer->bidi_paragraph_cache;
}
}
/* On my 2005-vintage machine, searching back for paragraph start
takes ~1 ms per line. And bidi_paragraph_init is called 4 times
when user types C-p. The number below limits each call to
bidi_paragraph_init to about 10 ms. */
#define MAX_PARAGRAPH_SEARCH 7500
/* Find the beginning of this paragraph by looking back in the buffer.
Value is the byte position of the paragraph's beginning, or
BEGV_BYTE if paragraph_start_re is still not found after looking
back MAX_PARAGRAPH_SEARCH lines in the buffer. */
static ptrdiff_t
bidi_find_paragraph_start (ptrdiff_t pos, ptrdiff_t pos_byte)
{
Lisp_Object re = paragraph_start_re;
ptrdiff_t limit = ZV, limit_byte = ZV_BYTE;
struct region_cache *bpc = bidi_paragraph_cache_on_off ();
ptrdiff_t n = 0, oldpos = pos, next;
struct buffer *cache_buffer = current_buffer;
if (cache_buffer->base_buffer)
cache_buffer = cache_buffer->base_buffer;
while (pos_byte > BEGV_BYTE
&& n++ < MAX_PARAGRAPH_SEARCH
&& fast_looking_at (re, pos, pos_byte, limit, limit_byte, Qnil) < 0)
{
/* FIXME: What if the paragraph beginning is covered by a
display string? And what if a display string covering some
of the text over which we scan back includes
paragraph_start_re? */
DEC_BOTH (pos, pos_byte);
if (bpc && region_cache_backward (cache_buffer, bpc, pos, &next))
{
pos = next, pos_byte = CHAR_TO_BYTE (pos);
break;
}
else
pos = find_newline_no_quit (pos, pos_byte, -1, &pos_byte);
}
if (n >= MAX_PARAGRAPH_SEARCH)
pos = BEGV, pos_byte = BEGV_BYTE;
if (bpc)
know_region_cache (cache_buffer, bpc, pos, oldpos);
/* Positions returned by the region cache are not limited to
BEGV..ZV range, so we limit them here. */
pos_byte = clip_to_bounds (BEGV_BYTE, pos_byte, ZV_BYTE);
return pos_byte;
}
/* On a 3.4 GHz machine, searching forward for a strong directional
character in a long paragraph full of weaks or neutrals takes about
1 ms for each 20K characters. The number below limits each call to
bidi_paragraph_init to less than 10 ms even on slow machines. */
#define MAX_STRONG_CHAR_SEARCH 100000
/* Starting from POS, find the first strong (L, R, or AL) character,
while skipping over any characters between an isolate initiator and
its matching PDI. STOP_AT_PDI non-zero means stop at the PDI that
matches the isolate initiator at POS. Return the bidi type of the
character where the search stopped. Give up if after examining
MAX_STRONG_CHAR_SEARCH buffer or string positions no strong
character was found. */
static bidi_type_t
find_first_strong_char (ptrdiff_t pos, ptrdiff_t bytepos, ptrdiff_t end,
ptrdiff_t *disp_pos, int *disp_prop,
struct bidi_string_data *string, struct window *w,
bool string_p, bool frame_window_p,
ptrdiff_t *ch_len, ptrdiff_t *nchars, bool stop_at_pdi)
{
ptrdiff_t pos1;
bidi_type_t type;
int ch;
if (stop_at_pdi)
{
/* If STOP_AT_PDI is non-zero, we must have been called with FSI
at POS. Get past it. */
#ifdef ENABLE_CHECKING
ch = bidi_fetch_char (pos, bytepos, disp_pos, disp_prop, string, w,
frame_window_p, ch_len, nchars);
type = bidi_get_type (ch, NEUTRAL_DIR);
eassert (type == FSI /* || type == LRI || type == RLI */);
#endif
pos += *nchars;
bytepos += *ch_len;
}
ch = bidi_fetch_char_skip_isolates (pos, bytepos, disp_pos, disp_prop, string,
w, frame_window_p, ch_len, nchars);
type = bidi_get_type (ch, NEUTRAL_DIR);
pos1 = pos;
for (pos += *nchars, bytepos += *ch_len;
bidi_get_category (type) != STRONG
/* If requested to stop at first PDI, stop there. */
&& !(stop_at_pdi && type == PDI)
/* Stop when searched too far into an abnormally large
paragraph full of weak or neutral characters. */
&& pos - pos1 < MAX_STRONG_CHAR_SEARCH;
type = bidi_get_type (ch, NEUTRAL_DIR))
{
if (pos >= end)
{
/* Pretend there's a paragraph separator at end of
buffer/string. */
type = NEUTRAL_B;
break;
}
if (!string_p
&& type == NEUTRAL_B
&& bidi_at_paragraph_end (pos, bytepos) >= -1)
break;
/* Fetch next character and advance to get past it. */
ch = bidi_fetch_char_skip_isolates (pos, bytepos, disp_pos, disp_prop,
string, w, frame_window_p,
ch_len, nchars);
pos += *nchars;
bytepos += *ch_len;
}
return type;
}
/* Determine the base direction, a.k.a. base embedding level, of the
paragraph we are about to iterate through. If DIR is either L2R or
R2L, just use that. Otherwise, determine the paragraph direction
from the first strong directional character of the paragraph.
NO_DEFAULT_P means don't default to L2R if the paragraph
has no strong directional characters and both DIR and
bidi_it->paragraph_dir are NEUTRAL_DIR. In that case, search back
in the buffer until a paragraph is found with a strong character,
or until hitting BEGV. In the latter case, fall back to L2R. This
flag is used in current-bidi-paragraph-direction.
Note that this function gives the paragraph separator the same
direction as the preceding paragraph, even though Emacs generally
views the separator as not belonging to any paragraph. */
void
bidi_paragraph_init (bidi_dir_t dir, struct bidi_it *bidi_it, bool no_default_p)
{
ptrdiff_t bytepos = bidi_it->bytepos;
bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring);
ptrdiff_t pstartbyte;
/* Note that begbyte is a byte position, while end is a character
position. Yes, this is ugly, but we are trying to avoid costly
calls to BYTE_TO_CHAR and its ilk. */
ptrdiff_t begbyte = string_p ? 0 : BEGV_BYTE;
ptrdiff_t end = string_p ? bidi_it->string.schars : ZV;
/* Special case for an empty buffer. */
if (bytepos == begbyte && bidi_it->charpos == end)
dir = L2R;
/* We should never be called at EOB or before BEGV. */
else if (bidi_it->charpos >= end || bytepos < begbyte)
emacs_abort ();
if (dir == L2R)
{
bidi_it->paragraph_dir = L2R;
bidi_it->new_paragraph = 0;
}
else if (dir == R2L)
{
bidi_it->paragraph_dir = R2L;
bidi_it->new_paragraph = 0;
}
else if (dir == NEUTRAL_DIR) /* P2 */
{
ptrdiff_t ch_len, nchars;
ptrdiff_t pos, disp_pos = -1;
int disp_prop = 0;
bidi_type_t type;
const unsigned char *s;
if (!bidi_initialized)
bidi_initialize ();
/* If we are inside a paragraph separator, we are just waiting
for the separator to be exhausted; use the previous paragraph
direction. But don't do that if we have been just reseated,
because we need to reinitialize below in that case. */
if (!bidi_it->first_elt
&& bidi_it->charpos < bidi_it->separator_limit)
return;
/* If we are on a newline, get past it to where the next
paragraph might start. But don't do that at BEGV since then
we are potentially in a new paragraph that doesn't yet
exist. */
pos = bidi_it->charpos;
s = (STRINGP (bidi_it->string.lstring)
? SDATA (bidi_it->string.lstring)
: bidi_it->string.s);
if (bytepos > begbyte
&& bidi_char_at_pos (bytepos, s, bidi_it->string.unibyte) == '\n')
{
bytepos++;
pos++;
}
/* We are either at the beginning of a paragraph or in the
middle of it. Find where this paragraph starts. */
if (string_p)
{
/* We don't support changes of paragraph direction inside a
string. It is treated as a single paragraph. */
pstartbyte = 0;
}
else
pstartbyte = bidi_find_paragraph_start (pos, bytepos);
bidi_it->separator_limit = -1;
bidi_it->new_paragraph = 0;
/* The following loop is run more than once only if NO_DEFAULT_P,
and only if we are iterating on a buffer. */
do {
bytepos = pstartbyte;
if (!string_p)
pos = BYTE_TO_CHAR (bytepos);
type = find_first_strong_char (pos, bytepos, end, &disp_pos, &disp_prop,
&bidi_it->string, bidi_it->w,
string_p, bidi_it->frame_window_p,
&ch_len, &nchars, false);
if (type == STRONG_R || type == STRONG_AL) /* P3 */
bidi_it->paragraph_dir = R2L;
else if (type == STRONG_L)
bidi_it->paragraph_dir = L2R;
if (!string_p
&& no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR)
{
/* If this paragraph is at BEGV, default to L2R. */
if (pstartbyte == BEGV_BYTE)
bidi_it->paragraph_dir = L2R; /* P3 and HL1 */
else
{
ptrdiff_t prevpbyte = pstartbyte;
ptrdiff_t p = BYTE_TO_CHAR (pstartbyte), pbyte = pstartbyte;
/* Find the beginning of the previous paragraph, if any. */
while (pbyte > BEGV_BYTE && prevpbyte >= pstartbyte)
{
/* FXIME: What if p is covered by a display
string? See also a FIXME inside
bidi_find_paragraph_start. */
DEC_BOTH (p, pbyte);
prevpbyte = bidi_find_paragraph_start (p, pbyte);
}
pstartbyte = prevpbyte;
}
}
} while (!string_p
&& no_default_p && bidi_it->paragraph_dir == NEUTRAL_DIR);
}
else
emacs_abort ();
/* Contrary to UAX#9 clause P3, we only default the paragraph
direction to L2R if we have no previous usable paragraph
direction. This is allowed by the HL1 clause. */
if (bidi_it->paragraph_dir != L2R && bidi_it->paragraph_dir != R2L)
bidi_it->paragraph_dir = L2R; /* P3 and HL1 ``higher-level protocols'' */
if (bidi_it->paragraph_dir == R2L)
bidi_it->level_stack[0].level = 1;
else
bidi_it->level_stack[0].level = 0;
bidi_line_init (bidi_it);
}
/***********************************************************************
Resolving explicit and implicit levels.
The rest of this file constitutes the core of the UBA implementation.
***********************************************************************/
static bool
bidi_explicit_dir_char (int ch)
{
bidi_type_t ch_type;
if (!bidi_initialized)
emacs_abort ();
ch_type = (bidi_type_t) XINT (CHAR_TABLE_REF (bidi_type_table, ch));
return (ch_type == LRE || ch_type == LRO
|| ch_type == RLE || ch_type == RLO
|| ch_type == PDF);
}
/* Given an iterator state in BIDI_IT, advance one character position
in the buffer/string to the next character (in the logical order),
resolve any explicit embeddings, directional overrides, and isolate
initiators and terminators, and return the embedding level of the
character after resolving these explicit directives. */
static int
bidi_resolve_explicit (struct bidi_it *bidi_it)
{
int curchar;
bidi_type_t type, typ1, prev_type = UNKNOWN_BT;
int current_level;
int new_level;
bidi_dir_t override;
bool isolate_status;
bool string_p = bidi_it->string.s || STRINGP (bidi_it->string.lstring);
ptrdiff_t ch_len, nchars, disp_pos, end;
int disp_prop;
ptrdiff_t eob
= ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? bidi_it->string.schars : ZV);
/* Record the info about the previous character. */
if (bidi_it->type_after_wn != WEAK_BN /* W1/Retaining */
&& bidi_it->type != WEAK_BN)
{
/* This special case is needed in support of Unicode 8.0
correction to N0, as implemented in bidi_resolve_weak/W1
below. */
if (bidi_it->type_after_wn == NEUTRAL_ON
&& bidi_get_category (bidi_it->type) == STRONG
&& bidi_paired_bracket_type (bidi_it->ch) == BIDI_BRACKET_CLOSE)
bidi_remember_char (&bidi_it->prev, bidi_it, 1);
else
bidi_remember_char (&bidi_it->prev, bidi_it, 0);
}
if (bidi_it->type_after_wn == STRONG_R
|| bidi_it->type_after_wn == STRONG_L
|| bidi_it->type_after_wn == STRONG_AL)
bidi_remember_char (&bidi_it->last_strong, bidi_it, 0);
if (bidi_it->type == STRONG_R || bidi_it->type == STRONG_L
|| bidi_it->type == WEAK_EN || bidi_it->type == WEAK_AN)
bidi_remember_char (&bidi_it->prev_for_neutral, bidi_it, 1);
/* If we overstepped the characters used for resolving neutrals
and whitespace, invalidate their info in the iterator. */
if (bidi_it->charpos >= bidi_it->next_for_neutral.charpos)
{
bidi_it->next_for_neutral.type = UNKNOWN_BT;
/* If needed, reset the "magical" value of pairing bracket
position, so that bidi_resolve_brackets will resume
resolution of brackets according to BPA. */
if (bidi_it->bracket_pairing_pos == eob)
bidi_it->bracket_pairing_pos = -1;
}
if (bidi_it->next_en_pos >= 0
&& bidi_it->charpos >= bidi_it->next_en_pos)
{
bidi_it->next_en_pos = 0;
bidi_it->next_en_type = UNKNOWN_BT;
}
/* Reset the bracket resolution info, unless we previously decided
(in bidi_find_bracket_pairs) that brackets in this level run
should be resolved as neutrals. */
if (bidi_it->bracket_pairing_pos != eob)
{
bidi_it->bracket_pairing_pos = -1;
bidi_it->bracket_enclosed_type = UNKNOWN_BT;
}
/* If reseat()'ed, don't advance, so as to start iteration from the
position where we were reseated. bidi_it->bytepos can be less
than BEGV_BYTE after reseat to BEGV. */
if (bidi_it->bytepos < (string_p ? 0 : BEGV_BYTE)
|| bidi_it->first_elt)
{
bidi_it->first_elt = 0;
if (string_p)
{
const unsigned char *p
= (STRINGP (bidi_it->string.lstring)
? SDATA (bidi_it->string.lstring)
: bidi_it->string.s);
if (bidi_it->charpos < 0)
bidi_it->charpos = bidi_it->bytepos = 0;
eassert (bidi_it->bytepos == bidi_count_bytes (p, 0, 0,
bidi_it->charpos,
bidi_it->string.unibyte));
}
else
{
if (bidi_it->charpos < BEGV)
{
bidi_it->charpos = BEGV;
bidi_it->bytepos = BEGV_BYTE;
}
eassert (bidi_it->bytepos == CHAR_TO_BYTE (bidi_it->charpos));
}
/* Determine the original bidi type of the previous character,
which is needed for handling isolate initiators and PDF. The
type of the previous character will be non-trivial only if
our caller moved through some previous text in
get_visually_first_element, in which case bidi_it->prev holds
the information we want. */
if (bidi_it->first_elt && bidi_it->prev.type != UNKNOWN_BT)
{
eassert (bidi_it->prev.charpos == bidi_it->charpos - 1);
prev_type = bidi_it->prev.orig_type;
if (prev_type == FSI)
prev_type = bidi_it->type_after_wn;
}
}
/* Don't move at end of buffer/string. */
else if (bidi_it->charpos < (string_p ? bidi_it->string.schars : ZV))
{
/* Advance to the next character, skipping characters covered by
display strings (nchars > 1). */
if (bidi_it->nchars <= 0)
emacs_abort ();
bidi_it->charpos += bidi_it->nchars;
if (bidi_it->ch_len == 0)
emacs_abort ();
bidi_it->bytepos += bidi_it->ch_len;
prev_type = bidi_it->orig_type;
if (prev_type == FSI)
prev_type = bidi_it->type_after_wn;
}
else /* EOB or end of string */
prev_type = NEUTRAL_B;
current_level = bidi_it->level_stack[bidi_it->stack_idx].level; /* X1 */
isolate_status = ISOLATE_STATUS (bidi_it, bidi_it->stack_idx);
override = OVERRIDE (bidi_it, bidi_it->stack_idx);
new_level = current_level;
if (bidi_it->charpos >= (string_p ? bidi_it->string.schars : ZV))
{
curchar = BIDI_EOB;
bidi_it->ch_len = 1;
bidi_it->nchars = 1;
bidi_it->disp_pos = (string_p ? bidi_it->string.schars : ZV);
bidi_it->disp_prop = 0;
}
else
{
/* LRI, RLI, and FSI increment, and PDF decrements, the
embedding level of the _following_ characters, so we must
first look at the type of the previous character to support
that. */
switch (prev_type)
{
case RLI: /* X5a */
if (current_level < BIDI_MAXDEPTH
&& bidi_it->invalid_levels == 0
&& bidi_it->invalid_isolates == 0)
{
new_level = ((current_level + 1) & ~1) + 1;
bidi_it->isolate_level++;
bidi_push_embedding_level (bidi_it, new_level,
NEUTRAL_DIR, true);
}
else
bidi_it->invalid_isolates++;
break;
case LRI: /* X5b */
if (current_level < BIDI_MAXDEPTH - 1
&& bidi_it->invalid_levels == 0
&& bidi_it->invalid_isolates == 0)
{
new_level = ((current_level + 2) & ~1);
bidi_it->isolate_level++;
bidi_push_embedding_level (bidi_it, new_level,
NEUTRAL_DIR, true);
}
else
bidi_it->invalid_isolates++;
break;
case PDF: /* X7 */
if (!bidi_it->invalid_isolates)
{
if (bidi_it->invalid_levels)
bidi_it->invalid_levels--;
else if (!isolate_status && bidi_it->stack_idx >= 1)
new_level = bidi_pop_embedding_level (bidi_it);
}
break;
default:
eassert (prev_type != FSI);
/* Nothing. */
break;
}
/* Fetch the character at BYTEPOS. If it is covered by a
display string, treat the entire run of covered characters as
a single character u+FFFC. */
curchar = bidi_fetch_char (bidi_it->charpos, bidi_it->bytepos,
&bidi_it->disp_pos, &bidi_it->disp_prop,
&bidi_it->string, bidi_it->w,
bidi_it->frame_window_p,
&bidi_it->ch_len, &bidi_it->nchars);
}
bidi_it->ch = curchar;
bidi_it->resolved_level = new_level;
/* Don't apply directional override here, as all the types we handle
below will not be affected by the override anyway, and we need
the original type unaltered. The override will be applied in
bidi_resolve_weak. */
type = bidi_get_type (curchar, NEUTRAL_DIR);
bidi_it->orig_type = type;
bidi_check_type (bidi_it->orig_type);
bidi_it->type_after_wn = UNKNOWN_BT;
switch (type)
{
case RLE: /* X2 */
case RLO: /* X4 */
bidi_it->type_after_wn = type;
bidi_check_type (bidi_it->type_after_wn);
type = WEAK_BN; /* X9/Retaining */
if (new_level < BIDI_MAXDEPTH
&& bidi_it->invalid_levels == 0
&& bidi_it->invalid_isolates == 0)
{
/* Compute the least odd embedding level greater than
the current level. */
new_level = ((new_level + 1) & ~1) + 1;
if (bidi_it->type_after_wn == RLE)
override = NEUTRAL_DIR;
else
override = R2L;
bidi_push_embedding_level (bidi_it, new_level, override, false);
bidi_it->resolved_level = new_level;
}
else
{
if (bidi_it->invalid_isolates == 0)
bidi_it->invalid_levels++;
}
break;
case LRE: /* X3 */
case LRO: /* X5 */
bidi_it->type_after_wn = type;
bidi_check_type (bidi_it->type_after_wn);
type = WEAK_BN; /* X9/Retaining */
if (new_level < BIDI_MAXDEPTH - 1
&& bidi_it->invalid_levels == 0
&& bidi_it->invalid_isolates == 0)
{
/* Compute the least even embedding level greater than
the current level. */
new_level = ((new_level + 2) & ~1);
if (bidi_it->type_after_wn == LRE)
override = NEUTRAL_DIR;
else
override = L2R;
bidi_push_embedding_level (bidi_it, new_level, override, false);
bidi_it->resolved_level = new_level;
}
else
{
if (bidi_it->invalid_isolates == 0)
bidi_it->invalid_levels++;
}
break;
case FSI: /* X5c */
end = string_p ? bidi_it->string.schars : ZV;
disp_pos = bidi_it->disp_pos;
disp_prop = bidi_it->disp_prop;
nchars = bidi_it->nchars;
ch_len = bidi_it->ch_len;
typ1 = find_first_strong_char (bidi_it->charpos,
bidi_it->bytepos, end,
&disp_pos, &disp_prop,
&bidi_it->string, bidi_it->w,
string_p, bidi_it->frame_window_p,
&ch_len, &nchars, true);
if (typ1 != STRONG_R && typ1 != STRONG_AL)
{
type = LRI;
goto fsi_as_lri;
}
else
type = RLI;
/* FALLTHROUGH */
case RLI: /* X5a */
if (override == NEUTRAL_DIR)
bidi_it->type_after_wn = type;
else /* Unicode 8.0 correction. */
bidi_it->type_after_wn = (override == L2R ? STRONG_L : STRONG_R);
bidi_check_type (bidi_it->type_after_wn);
break;
case LRI: /* X5b */
fsi_as_lri:
if (override == NEUTRAL_DIR)
bidi_it->type_after_wn = type;
else /* Unicode 8.0 correction. */
bidi_it->type_after_wn = (override == L2R ? STRONG_L : STRONG_R);
bidi_check_type (bidi_it->type_after_wn);
break;
case PDI: /* X6a */
if (bidi_it->invalid_isolates)
bidi_it->invalid_isolates--;
else if (bidi_it->isolate_level > 0)
{
bidi_it->invalid_levels = 0;
while (!ISOLATE_STATUS (bidi_it, bidi_it->stack_idx))
bidi_pop_embedding_level (bidi_it);
eassert (bidi_it->stack_idx > 0);
new_level = bidi_pop_embedding_level (bidi_it);
bidi_it->isolate_level--;
}
bidi_it->resolved_level = new_level;
/* Unicode 8.0 correction. */
{
bidi_dir_t stack_override = OVERRIDE (bidi_it, bidi_it->stack_idx);
if (stack_override == L2R)
bidi_it->type_after_wn = STRONG_L;
else if (stack_override == R2L)
bidi_it->type_after_wn = STRONG_R;
else
bidi_it->type_after_wn = type;
}
break;
case PDF: /* X7 */
bidi_it->type_after_wn = type;
bidi_check_type (bidi_it->type_after_wn);
type = WEAK_BN; /* X9/Retaining */
break;
default:
/* Nothing. */
break;
}
bidi_it->type = type;
bidi_check_type (bidi_it->type);
if (bidi_it->type == NEUTRAL_B) /* X8 */
{
bidi_set_paragraph_end (bidi_it);
/* This is needed by bidi_resolve_weak below, and in L1. */
bidi_it->type_after_wn = bidi_it->type;
}
eassert (bidi_it->resolved_level >= 0);
return bidi_it->resolved_level;
}
/* Advance in the buffer/string, resolve weak types and return the
type of the next character after weak type resolution. */
static bidi_type_t
bidi_resolve_weak (struct bidi_it *bidi_it)
{
bidi_type_t type;
bidi_dir_t override;
int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
int new_level = bidi_resolve_explicit (bidi_it);
int next_char;
bidi_type_t type_of_next;
struct bidi_it saved_it;
ptrdiff_t eob
= ((STRINGP (bidi_it->string.lstring) || bidi_it->string.s)
? bidi_it->string.schars : ZV);
type = bidi_it->type;
override = OVERRIDE (bidi_it, bidi_it->stack_idx);
eassert (!(type == UNKNOWN_BT
|| type == LRE
|| type == LRO
|| type == RLE
|| type == RLO
|| type == PDF));
eassert (prev_level >= 0);
if (bidi_it->type == NEUTRAL_B)
{
/* We've got a new isolating sequence, compute the directional
type of sos and initialize per-run variables (UAX#9, clause
X10). */
bidi_set_sos_type (bidi_it, prev_level, new_level);
}
if (type == NEUTRAL_S || type == NEUTRAL_WS
|| type == WEAK_BN || type == STRONG_AL)
bidi_it->type_after_wn = type; /* needed in L1 */
bidi_check_type (bidi_it->type_after_wn);
/* Level and directional override status are already recorded in
bidi_it, and do not need any change; see X6. */
if (override == R2L) /* X6 */
type = STRONG_R;
else if (override == L2R)
type = STRONG_L;
else
{
if (type == WEAK_NSM) /* W1 */
{
/* Note that we don't need to consider the case where the
prev character has its type overridden by an RLO or LRO,
because then either the type of this NSM would have been
also overridden, or the previous character is outside the
current level run, and thus not relevant to this NSM.
This is why NSM gets the type_after_wn of the previous
character. */
/* bidi_set_sos_type sets type_after_wn to UNKNOWN_BT. */
if (bidi_it->prev.type != UNKNOWN_BT
/* If type_after_wn is NEUTRAL_B, this NSM is at sos. */
&& bidi_it->prev.type != NEUTRAL_B)
{
if (bidi_isolate_fmt_char (bidi_it->prev.type))
{
/* From W1: "Note that in an isolating run sequence,
an isolate initiator followed by an NSM or any
type other than PDI must be an overflow isolate
initiator." */
eassert (bidi_it->invalid_isolates > 0);
type = NEUTRAL_ON;
}
else
{
/* This includes the Unicode 8.0 correction for N0,
due to how we set prev.type in bidi_resolve_explicit,
which see. */
type = bidi_it->prev.type;
}
}
else if (bidi_it->sos == R2L)
type = STRONG_R;
else if (bidi_it->sos == L2R)
type = STRONG_L;
else /* shouldn't happen! */
emacs_abort ();
}
if (type == WEAK_EN /* W2 */
&& bidi_it->last_strong.type == STRONG_AL)
type = WEAK_AN;
else if (type == STRONG_AL) /* W3 */
type = STRONG_R;
else if ((type == WEAK_ES /* W4 */
&& bidi_it->prev.type == WEAK_EN
&& bidi_it->prev.orig_type == WEAK_EN)
|| (type == WEAK_CS
&& ((bidi_it->prev.type == WEAK_EN
&& bidi_it->prev.orig_type == WEAK_EN)
|| bidi_it->prev.type == WEAK_AN)))
{
const unsigned char *s
= (STRINGP (bidi_it->string.lstring)
? SDATA (bidi_it->string.lstring)
: bidi_it->string.s);
next_char = (bidi_it->charpos + bidi_it->nchars >= eob
? BIDI_EOB
: bidi_char_at_pos (bidi_it->bytepos + bidi_it->ch_len,
s, bidi_it->string.unibyte));
type_of_next = bidi_get_type (next_char, override);
if (type_of_next == WEAK_BN
|| bidi_explicit_dir_char (next_char))
{
bidi_copy_it (&saved_it, bidi_it);
while (bidi_resolve_explicit (bidi_it) == new_level
&& bidi_it->type == WEAK_BN)
type_of_next = bidi_it->type;
bidi_copy_it (bidi_it, &saved_it);
}
/* If the next character is EN, but the last strong-type
character is AL, that next EN will be changed to AN when
we process it in W2 above. So in that case, this ES
should not be changed into EN. */
if (type == WEAK_ES
&& type_of_next == WEAK_EN
&& bidi_it->last_strong.type != STRONG_AL)
type = WEAK_EN;
else if (type == WEAK_CS)
{
if (bidi_it->prev.type == WEAK_AN
&& (type_of_next == WEAK_AN
/* If the next character is EN, but the last
strong-type character is AL, EN will be later
changed to AN when we process it in W2 above.
So in that case, this ES should not be
changed into EN. */
|| (type_of_next == WEAK_EN
&& bidi_it->last_strong.type == STRONG_AL)))
type = WEAK_AN;
else if (bidi_it->prev.type == WEAK_EN
&& type_of_next == WEAK_EN
&& bidi_it->last_strong.type != STRONG_AL)
type = WEAK_EN;
}
}
else if (type == WEAK_ET /* W5: ET with EN before or after it */
|| type == WEAK_BN) /* W5/Retaining */
{
if (bidi_it->prev.type == WEAK_EN) /* ET/BN w/EN before it */
type = WEAK_EN;
else if (bidi_it->next_en_pos > bidi_it->charpos
&& bidi_it->next_en_type != WEAK_BN)
{
if (bidi_it->next_en_type == WEAK_EN) /* ET/BN with EN after it */
type = WEAK_EN;
}
else if (bidi_it->next_en_pos >=0)
{
/* We overstepped the last known position for ET
resolution but there could be other such characters
in this paragraph (when we are sure there are no more
such positions, we set next_en_pos to a negative
value). Try to find the next position for ET
resolution. */
ptrdiff_t en_pos = bidi_it->charpos + bidi_it->nchars;
const unsigned char *s = (STRINGP (bidi_it->string.lstring)
? SDATA (bidi_it->string.lstring)
: bidi_it->string.s);
if (bidi_it->nchars <= 0)
emacs_abort ();
next_char
= (bidi_it->charpos + bidi_it->nchars >= eob
? BIDI_EOB
: bidi_char_at_pos (bidi_it->bytepos + bidi_it->ch_len, s,
bidi_it->string.unibyte));
type_of_next = bidi_get_type (next_char, override);
if (type_of_next == WEAK_ET
|| type_of_next == WEAK_BN
|| bidi_explicit_dir_char (next_char))
{
bidi_copy_it (&saved_it, bidi_it);
while (bidi_resolve_explicit (bidi_it) == new_level
&& (bidi_it->type == WEAK_BN
|| bidi_it->type == WEAK_ET))
type_of_next = bidi_it->type;
if (type == WEAK_BN
&& bidi_it->charpos == saved_it.charpos + saved_it.nchars)
{
/* If we entered the above loop with a BN that
changes the level, the type of next
character, which is in a different level, is
not relevant to resolving this series of ET
and BN. */
en_pos = saved_it.charpos;
type_of_next = type;
}
else
en_pos = bidi_it->charpos;
bidi_copy_it (bidi_it, &saved_it);
}
/* Remember this position, to speed up processing of the
next ETs. */
bidi_it->next_en_pos = en_pos;
if (type_of_next == WEAK_EN)
{
/* If the last strong character is AL, the EN we've
found will become AN when we get to it (W2). */
if (bidi_it->last_strong.type == STRONG_AL)
type_of_next = WEAK_AN;
else if (type == WEAK_BN)
type = NEUTRAL_ON; /* W6/Retaining */
else
type = WEAK_EN;
}
else if (type_of_next == NEUTRAL_B)
/* Record the fact that there are no more ENs from
here to the end of paragraph, to avoid entering the
loop above ever again in this paragraph. */
bidi_it->next_en_pos = -1;
/* Record the type of the character where we ended our search. */
bidi_it->next_en_type = type_of_next;
}
}
}
if (type == WEAK_ES || type == WEAK_ET || type == WEAK_CS /* W6 */
|| (type == WEAK_BN
&& (bidi_it->prev.type == WEAK_CS /* W6/Retaining */
|| bidi_it->prev.type == WEAK_ES
|| bidi_it->prev.type == WEAK_ET)))
type = NEUTRAL_ON;
/* Store the type we've got so far, before we clobber it with strong
types in W7 and while resolving neutral types. But leave alone
the original types that were recorded above, because we will need
them for the L1 clause. */
if (bidi_it->type_after_wn == UNKNOWN_BT)
bidi_it->type_after_wn = type;
bidi_check_type (bidi_it->type_after_wn);
if (type == WEAK_EN) /* W7 */
{
if ((bidi_it->last_strong.type == STRONG_L)
|| (bidi_it->last_strong.type == UNKNOWN_BT && bidi_it->sos == L2R))
type = STRONG_L;
}
bidi_it->type = type;
bidi_check_type (bidi_it->type);
return type;
}
/* Resolve the type of a neutral character according to the type of
surrounding strong text and the current embedding level. */
static bidi_type_t
bidi_resolve_neutral_1 (bidi_type_t prev_type, bidi_type_t next_type, int lev)
{
/* N1: "European and Arabic numbers act as if they were R in terms
of their influence on NIs." */
if (next_type == WEAK_EN || next_type == WEAK_AN)
next_type = STRONG_R;
if (prev_type == WEAK_EN || prev_type == WEAK_AN)
prev_type = STRONG_R;
if (next_type == prev_type) /* N1 */
return next_type;
else if ((lev & 1) == 0) /* N2 */
return STRONG_L;
else
return STRONG_R;
}
#define FLAG_EMBEDDING_INSIDE 1
#define FLAG_OPPOSITE_INSIDE 2
/* A data type used in the stack maintained by
bidi_find_bracket_pairs below. */
typedef struct bpa_stack_entry {
int close_bracket_char;
int open_bracket_idx;
#ifdef ENABLE_CHECKING
ptrdiff_t open_bracket_pos;
#endif
unsigned flags : 2;
} bpa_stack_entry;
/* With MAX_ALLOCA of 16KB, this should allow at least 1K slots in the
BPA stack, which should be more than enough for actual bidi text. */
#define MAX_BPA_STACK ((int)max (MAX_ALLOCA / sizeof (bpa_stack_entry), 1))
/* UAX#9 says to match opening brackets with the matching closing
brackets or their canonical equivalents. As of Unicode 7.0, there
are only 2 bracket characters that have canonical equivalence
decompositions: u+2329 and u+232A. So instead of accessing the
table in uni-decomposition.el, we just handle these 2 characters
with this simple macro. Note that ASCII characters don't have
canonical equivalents by definition. */
/* To find all the characters that need to be processed by
CANONICAL_EQU, first find all the characters which have
decompositions in UnicodeData.txt, with this Awk script:
awk -F ";" " {if ($6 != \"\") print $1, $6}" UnicodeData.txt
Then produce a list of all the bracket characters in BidiBrackets.txt:
awk -F "[ ;]" " {if ($1 != \"#\" && $1 != \"\") print $1}" BidiBrackets.txt
And finally, cross-reference these two:
fgrep -w -f brackets.txt decompositions.txt
where "decompositions.txt" was produced by the 1st script, and
"brackets.txt" by the 2nd script. In the output of fgrep, look
only for decompositions that don't begin with some compatibility
formatting tag, such as "<compat>". Only decompositions that
consist solely of character codepoints are relevant to bidi
brackets processing. */
#define CANONICAL_EQU(c) \
( ASCII_CHAR_P (c) ? c \
: (c) == 0x2329 ? 0x3008 \
: (c) == 0x232a ? 0x3009 \
: c )
#ifdef ENABLE_CHECKING
# define STORE_BRACKET_CHARPOS \
bpa_stack[bpa_sp].open_bracket_pos = bidi_it->charpos
#else
# define STORE_BRACKET_CHARPOS /* nothing */
#endif
#define PUSH_BPA_STACK \
do { \
int ch; \
if (bpa_sp < MAX_BPA_STACK - 1) \
{ \
bpa_sp++; \
ch = CANONICAL_EQU (bidi_it->ch); \
bpa_stack[bpa_sp].close_bracket_char = bidi_mirror_char (ch); \
bpa_stack[bpa_sp].open_bracket_idx = bidi_cache_last_idx; \
bpa_stack[bpa_sp].flags = 0; \
STORE_BRACKET_CHARPOS; \
} \
} while (0)
/* This function implements BPA, the Bidi Parenthesis Algorithm,
described in BD16 and N0 of UAX#9. It finds all the bracket pairs
in the current isolating sequence, and records the enclosed type
and the position of the matching bracket in the cache. It returns
non-zero if called with the iterator on the opening bracket which
has a matching closing bracket in the current isolating sequence,
zero otherwise. */
static bool
bidi_find_bracket_pairs (struct bidi_it *bidi_it)
{
bidi_bracket_type_t btype;
bidi_type_t type = bidi_it->type;
bool retval = false;
/* When scanning backwards, we don't expect any unresolved bidi
bracket characters. */
if (bidi_it->scan_dir != 1)
emacs_abort ();
btype = bidi_paired_bracket_type (bidi_it->ch);
if (btype == BIDI_BRACKET_OPEN)
{
bpa_stack_entry bpa_stack[MAX_BPA_STACK];
int bpa_sp = -1;
struct bidi_it saved_it;
int base_level = bidi_it->level_stack[0].level;
int embedding_level = bidi_it->level_stack[bidi_it->stack_idx].level;
int maxlevel = embedding_level;
bidi_type_t embedding_type = (embedding_level & 1) ? STRONG_R : STRONG_L;
struct bidi_it tem_it;
bool l2r_seen = false, r2l_seen = false;
ptrdiff_t pairing_pos;
int idx_at_entry = bidi_cache_idx;
eassert (MAX_BPA_STACK >= 100);
bidi_copy_it (&saved_it, bidi_it);
/* bidi_cache_iterator_state refuses to cache on backward scans,
and bidi_cache_fetch_state doesn't bring scan_dir from the
cache, so we must initialize this explicitly. */
tem_it.scan_dir = 1;
while (1)
{
int old_sidx, new_sidx;
int current_level = bidi_it->level_stack[bidi_it->stack_idx].level;
if (maxlevel < current_level)
maxlevel = current_level;
/* Mark every opening bracket character we've traversed by
putting its own position into bracket_pairing_pos. This
is examined in bidi_resolve_brackets to distinguish
brackets that were already resolved to stay NEUTRAL_ON,
and those that were not yet processed by this function
(because they were skipped when we skip higher embedding
levels below). */
if (btype == BIDI_BRACKET_OPEN && bidi_it->bracket_pairing_pos == -1)
bidi_it->bracket_pairing_pos = bidi_it->charpos;
if (!bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B, 0))
{
/* No more space in cache -- give up and let the opening
bracket that started this be processed as a
NEUTRAL_ON. */
bidi_cache_reset_to (idx_at_entry - bidi_cache_start);
bidi_copy_it (bidi_it, &saved_it);
goto give_up;
}
if (btype == BIDI_BRACKET_OPEN)
PUSH_BPA_STACK;
else if (btype == BIDI_BRACKET_CLOSE)
{
int sp = bpa_sp;
int curchar = CANONICAL_EQU (bidi_it->ch);
eassert (sp >= 0);
while (sp >= 0 && bpa_stack[sp].close_bracket_char != curchar)
sp--;
if (sp >= 0)
{
/* Update and cache the corresponding opening bracket. */
bidi_cache_fetch_state (bpa_stack[sp].open_bracket_idx,
&tem_it);
#ifdef ENABLE_CHECKING
eassert (bpa_stack[sp].open_bracket_pos == tem_it.charpos);
#endif
/* Determine the enclosed type for this bracket
pair's type resolution according to N0. */
if (bpa_stack[sp].flags & FLAG_EMBEDDING_INSIDE)
tem_it.bracket_enclosed_type = embedding_type; /* N0b */
else if (bpa_stack[sp].flags & FLAG_OPPOSITE_INSIDE)
tem_it.bracket_enclosed_type /* N0c */
= (embedding_type == STRONG_L ? STRONG_R : STRONG_L);
else /* N0d */
tem_it.bracket_enclosed_type = UNKNOWN_BT;
/* Record the position of the matching closing
bracket, and update the cache. */
tem_it.bracket_pairing_pos = bidi_it->charpos;
bidi_cache_iterator_state (&tem_it, 0, 1);
/* Pop the BPA stack. */
bpa_sp = sp - 1;
}
if (bpa_sp < 0)
{
retval = true;
break;
}
}
else if (bidi_get_category (bidi_it->type_after_wn) != NEUTRAL)
{
unsigned flag = 0;
int sp;
/* Whenever we see a strong type, update the flags of
all the slots on the stack. */
switch (bidi_it->type)
{
case STRONG_L:
flag = ((embedding_level & 1) == 0
? FLAG_EMBEDDING_INSIDE
: FLAG_OPPOSITE_INSIDE);
l2r_seen = true;
break;
case STRONG_R:
case WEAK_EN:
case WEAK_AN:
flag = ((embedding_level & 1) == 1
? FLAG_EMBEDDING_INSIDE
: FLAG_OPPOSITE_INSIDE);
r2l_seen = true;
break;
default:
break;
}
if (flag)
{
for (sp = bpa_sp; sp >= 0; sp--)
bpa_stack[sp].flags |= flag;
}
}
old_sidx = bidi_it->stack_idx;
type = bidi_resolve_weak (bidi_it);
/* Skip level runs excluded from this isolating run sequence. */
new_sidx = bidi_it->stack_idx;
if (bidi_it->level_stack[new_sidx].level > current_level
&& (ISOLATE_STATUS (bidi_it, new_sidx)
|| (new_sidx > old_sidx + 1
&& ISOLATE_STATUS (bidi_it, new_sidx - 1))))
{
while (bidi_it->level_stack[bidi_it->stack_idx].level
> current_level)
{
if (maxlevel < bidi_it->level_stack[bidi_it->stack_idx].level)
maxlevel = bidi_it->level_stack[bidi_it->stack_idx].level;
if (!bidi_cache_iterator_state (bidi_it,
type == NEUTRAL_B, 0))
{
/* No more space in cache -- give up and let the
opening bracket that started this be
processed as any other NEUTRAL_ON. */
bidi_cache_reset_to (idx_at_entry - bidi_cache_start);
bidi_copy_it (bidi_it, &saved_it);
goto give_up;
}
type = bidi_resolve_weak (bidi_it);
}
}
if (type == NEUTRAL_B
|| (bidi_it->level_stack[bidi_it->stack_idx].level
!= current_level))
{
/* We've marched all the way to the end of this
isolating run sequence, and didn't find matching
closing brackets for some opening brackets. Leave
their type unchanged. */
pairing_pos = bidi_it->charpos;
break;
}
if (bidi_it->type_after_wn == NEUTRAL_ON) /* Unicode 8.0 correction */
btype = bidi_paired_bracket_type (bidi_it->ch);
else
btype = BIDI_BRACKET_NONE;
}
/* Restore bidi_it from the cache, which should have the bracket
resolution members set as determined by the above loop. */
type = bidi_cache_find (saved_it.charpos, 0, bidi_it);
eassert (type == NEUTRAL_ON);
/* The following is an optimization for bracketed text that has
only one level which is equal to the paragraph's base
embedding level. That is, only L2R and weak/neutral
characters in a L2R paragraph, or only R2L and weak/neutral
characters in a R2L paragraph. Such brackets can be resolved
by bidi_resolve_neutral, which has a further shortcut for
this case. So we pretend we did not resolve the brackets in
this case, set up next_for_neutral for the entire bracketed
text, and reset the cache to the character before the opening
bracket. The upshot is to allow bidi_move_to_visually_next
reset the cache when it returns this opening bracket, thus
cutting significantly on the size of the cache, which is
important with long lines, especially if word-wrap is non-nil
(which requires the display engine to copy the cache back and
forth many times). */
if (maxlevel == base_level
&& ((base_level == 0 && !r2l_seen)
|| (base_level == 1 && !l2r_seen)))
{
ptrdiff_t eob
= ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? bidi_it->string.schars : ZV);
if (retval)
pairing_pos = bidi_it->bracket_pairing_pos;
/* This special value (which cannot possibly happen when
brackets are resolved, since there's no character at ZV)
will be noticed by bidi_resolve_explicit, and will be
copied to the following iterator states, instead of being
reset to -1. */
bidi_it->bracket_pairing_pos = eob;
/* This type value will be used for resolving the outermost
closing bracket in bidi_resolve_brackets. */
bidi_it->bracket_enclosed_type = embedding_type;
/* bidi_cache_last_idx is set to the index of the current
state, because we just called bidi_cache_find above.
That state describes the outermost opening bracket, the
one with which we entered this function. Force the cache
to "forget" all the cached states starting from that state. */
bidi_cache_reset_to (bidi_cache_last_idx - bidi_cache_start);
/* Set up the next_for_neutral member, to help
bidi_resolve_neutral. */
bidi_it->next_for_neutral.type = embedding_type;
bidi_it->next_for_neutral.charpos = pairing_pos;
/* Pretend we didn't resolve this bracket. */
retval = false;
}
}
give_up:
return retval;
}
static void
bidi_record_type_for_neutral (struct bidi_saved_info *info, int level,
bool nextp)
{
int idx;
for (idx = bidi_cache_last_idx + 1; idx < bidi_cache_idx; idx++)
{
int lev = bidi_cache[idx].level_stack[bidi_cache[idx].stack_idx].level;
if (lev <= level)
{
eassert (lev == level);
if (nextp)
bidi_cache[idx].next_for_neutral = *info;
else
bidi_cache[idx].prev_for_neutral = *info;
break;
}
}
}
static bidi_type_t
bidi_resolve_brackets (struct bidi_it *bidi_it)
{
int prev_level = bidi_it->level_stack[bidi_it->stack_idx].level;
bool resolve_bracket = false;
bidi_type_t type = UNKNOWN_BT;
int ch;
struct bidi_saved_info prev_for_neutral, next_for_neutral;
ptrdiff_t eob
= ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? bidi_it->string.schars : ZV);
/* Record the prev_for_neutral type either from the previous
character, if it was a strong or AN/EN, or from the
prev_for_neutral information recorded previously. */
if (bidi_it->type == STRONG_L || bidi_it->type == STRONG_R
|| bidi_it->type == WEAK_AN || bidi_it->type == WEAK_EN)
bidi_remember_char (&prev_for_neutral, bidi_it, 1);
else
prev_for_neutral = bidi_it->prev_for_neutral;
/* Record the next_for_neutral type information. */
if (bidi_it->next_for_neutral.charpos > bidi_it->charpos)
next_for_neutral = bidi_it->next_for_neutral;
else
next_for_neutral.charpos = -1;
if (!bidi_it->first_elt)
{
type = bidi_cache_find (bidi_it->charpos + bidi_it->nchars, 0, bidi_it);
ch = bidi_it->ch;
}
if (type == UNKNOWN_BT)
{
type = bidi_resolve_weak (bidi_it);
if (type == NEUTRAL_ON)
{
/* bracket_pairing_pos == eob means this bracket does not
need to be resolved as a bracket, but as a neutral, see
the optimization trick we play near the end of
bidi_find_bracket_pairs. */
if (bidi_it->bracket_pairing_pos == eob)
{
/* If this is the outermost closing bracket of a run of
characters in which we decided to resolve brackets as
neutrals, use the embedding level's type, recorded in
bracket_enclosed_type, to resolve the bracket. */
if (bidi_it->next_for_neutral.charpos == bidi_it->charpos
&& bidi_paired_bracket_type (bidi_it->ch) == BIDI_BRACKET_CLOSE)
type = bidi_it->bracket_enclosed_type;
}
else if (bidi_find_bracket_pairs (bidi_it))
resolve_bracket = true;
}
}
else if (bidi_it->bracket_pairing_pos != eob)
{
eassert (bidi_it->resolved_level == -1);
/* If the cached state shows an increase of embedding level due
to an isolate initiator, we need to update the 1st cached
state of the next run of the current isolating sequence with
the prev_for_neutral and next_for_neutral information, so
that it will be picked up when we advance to that next run. */
if (bidi_it->level_stack[bidi_it->stack_idx].level > prev_level
&& ISOLATE_STATUS (bidi_it, bidi_it->stack_idx))
{
bidi_record_type_for_neutral (&prev_for_neutral, prev_level, 0);
bidi_record_type_for_neutral (&next_for_neutral, prev_level, 1);
}
if (type == NEUTRAL_ON
&& bidi_paired_bracket_type (ch) == BIDI_BRACKET_OPEN)
{
if (bidi_it->bracket_pairing_pos > bidi_it->charpos)
{
/* A cached opening bracket that wasn't completely
resolved yet. */
resolve_bracket = true;
}
else if (bidi_it->bracket_pairing_pos == -1)
{
/* Higher levels were not BPA-resolved yet, even if
cached by bidi_find_bracket_pairs. Force application
of BPA to the new level now. */
if (bidi_find_bracket_pairs (bidi_it))
resolve_bracket = true;
}
}
/* Keep track of the prev_for_neutral and next_for_neutral
types, needed for resolving brackets below and for resolving
neutrals in bidi_resolve_neutral. */
if (bidi_it->level_stack[bidi_it->stack_idx].level == prev_level)
{
bidi_it->prev_for_neutral = prev_for_neutral;
if (next_for_neutral.charpos > 0)
bidi_it->next_for_neutral = next_for_neutral;
}
}
/* If needed, resolve the bracket type according to N0. */
if (resolve_bracket)
{
int embedding_level = bidi_it->level_stack[bidi_it->stack_idx].level;
bidi_type_t embedding_type = (embedding_level & 1) ? STRONG_R : STRONG_L;
eassert (bidi_it->prev_for_neutral.type != UNKNOWN_BT);
eassert (bidi_it->bracket_pairing_pos > bidi_it->charpos);
if (bidi_it->bracket_enclosed_type == embedding_type) /* N0b */
type = embedding_type;
else
{
switch (bidi_it->prev_for_neutral.type)
{
case STRONG_R:
case WEAK_EN:
case WEAK_AN:
type =
(bidi_it->bracket_enclosed_type == STRONG_R) /* N0c */
? STRONG_R /* N0c1 */
: embedding_type; /* N0c2 */
break;
case STRONG_L:
type =
(bidi_it->bracket_enclosed_type == STRONG_L) /* N0c */
? STRONG_L /* N0c1 */
: embedding_type; /* N0c2 */
break;
default:
/* N0d: Do not set the type for that bracket pair. */
break;
}
}
eassert (type == STRONG_L || type == STRONG_R || type == NEUTRAL_ON);
/* Update the type of the paired closing bracket to the same
type as for the resolved opening bracket. */
if (type != NEUTRAL_ON)
{
ptrdiff_t idx = bidi_cache_search (bidi_it->bracket_pairing_pos,
-1, 1);
if (idx < bidi_cache_start)
emacs_abort ();
bidi_cache[idx].type = type;
}
}
return type;
}
static bidi_type_t
bidi_resolve_neutral (struct bidi_it *bidi_it)
{
bidi_type_t type = bidi_resolve_brackets (bidi_it);
int current_level;
bool is_neutral;
eassert (type == STRONG_R
|| type == STRONG_L
|| type == WEAK_BN
|| type == WEAK_EN
|| type == WEAK_AN
|| type == NEUTRAL_B
|| type == NEUTRAL_S
|| type == NEUTRAL_WS
|| type == NEUTRAL_ON
|| type == LRI
|| type == RLI
|| type == PDI);
current_level = bidi_it->level_stack[bidi_it->stack_idx].level;
eassert (current_level >= 0);
is_neutral = bidi_get_category (type) == NEUTRAL;
if ((type != NEUTRAL_B /* Don't risk entering the long loop below if
we are already at paragraph end. */
&& (is_neutral || bidi_isolate_fmt_char (type)))
/* N1-N2/Retaining */
|| (type == WEAK_BN && bidi_explicit_dir_char (bidi_it->ch)))
{
if (bidi_it->next_for_neutral.type != UNKNOWN_BT)
{
/* Make sure the data for resolving neutrals we are
about to use is valid. */
eassert (bidi_it->next_for_neutral.charpos > bidi_it->charpos
/* PDI defines an eos, so it's OK for it to
serve as its own next_for_neutral. */
|| (bidi_it->next_for_neutral.charpos == bidi_it->charpos
&& bidi_it->type == PDI));
type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
bidi_it->next_for_neutral.type,
current_level);
}
/* The next two "else if" clauses are shortcuts for the
important special case when we have a long sequence of
neutral or WEAK_BN characters, such as whitespace or nulls or
other control characters, on the base embedding level of the
paragraph, and that sequence goes all the way to the end of
the paragraph and follows a character whose resolved
directionality is identical to the base embedding level.
(This is what happens in a buffer with plain L2R text that
happens to include long sequences of control characters.) By
virtue of N1, the result of examining this long sequence will
always be either STRONG_L or STRONG_R, depending on the base
embedding level. So we use this fact directly instead of
entering the expensive loop in the "else" clause. */
else if (current_level == 0
&& bidi_it->prev_for_neutral.type == STRONG_L
&& !bidi_explicit_dir_char (bidi_it->ch)
&& !bidi_isolate_fmt_char (type))
type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
STRONG_L, current_level);
else if (/* current level is 1 */
current_level == 1
/* base embedding level is also 1 */
&& bidi_it->level_stack[0].level == 1
/* previous character is one of those considered R for
the purposes of W5 */
&& (bidi_it->prev_for_neutral.type == STRONG_R
|| bidi_it->prev_for_neutral.type == WEAK_EN
|| bidi_it->prev_for_neutral.type == WEAK_AN)
&& !bidi_explicit_dir_char (bidi_it->ch)
&& !bidi_isolate_fmt_char (type))
type = bidi_resolve_neutral_1 (bidi_it->prev_for_neutral.type,
STRONG_R, current_level);
else
{
/* Arrrgh!! The UAX#9 algorithm is too deeply entrenched in
the assumption of batch-style processing; see clauses W4,
W5, and especially N1, which require to look far forward
(as well as back) in the buffer/string. May the fleas of
a thousand camels infest the armpits of those who design
supposedly general-purpose algorithms by looking at their
own implementations, and fail to consider other possible
implementations! */
struct bidi_it saved_it;
bidi_type_t next_type;
bool adjacent_to_neutrals = is_neutral;
bidi_copy_it (&saved_it, bidi_it);
/* Scan the text forward until we find the first non-neutral
character, and then use that to resolve the neutral we
are dealing with now. We also cache the scanned iterator
states, to salvage some of the effort later. */
do {
int old_sidx, new_sidx;
/* Paragraph separators have their levels fully resolved
at this point, so cache them as resolved. */
bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B, 0);
old_sidx = bidi_it->stack_idx;
type = bidi_resolve_brackets (bidi_it);
/* Skip level runs excluded from this isolating run sequence. */
new_sidx = bidi_it->stack_idx;
if (bidi_it->level_stack[new_sidx].level > current_level
&& (ISOLATE_STATUS (bidi_it, new_sidx)
/* This is for when we have an isolate initiator
immediately followed by an embedding or
override initiator, in which case we get the
level stack pushed twice by the single call to
bidi_resolve_weak above. */
|| (new_sidx > old_sidx + 1
&& ISOLATE_STATUS (bidi_it, new_sidx - 1))))
{
while (bidi_it->level_stack[bidi_it->stack_idx].level
> current_level)
{
bidi_cache_iterator_state (bidi_it, type == NEUTRAL_B, 0);
type = bidi_resolve_brackets (bidi_it);
}
}
if (!adjacent_to_neutrals
&& (bidi_get_category (type) == NEUTRAL
|| bidi_isolate_fmt_char (type)))
adjacent_to_neutrals = true;
} while (!(type == NEUTRAL_B
|| (type != WEAK_BN
&& bidi_get_category (type) != NEUTRAL
&& !bidi_isolate_fmt_char (type))
/* This is all per level run, so stop when we
reach the end of this level run. */
|| (bidi_it->level_stack[bidi_it->stack_idx].level
!= current_level)));
/* Record the character we stopped at. */
bidi_remember_char (&saved_it.next_for_neutral, bidi_it, 1);
if ((bidi_it->level_stack[bidi_it->stack_idx].level != current_level)
|| type == NEUTRAL_B)
{
/* Marched all the way to the end of this level run. We
need to use the eos type, whose information is stored
by bidi_set_sos_type in the prev_for_neutral
member. */
if (adjacent_to_neutrals)
next_type = bidi_it->prev_for_neutral.type;
else
{
/* This is a BN which does not adjoin neutrals.
Leave its type alone. */
bidi_copy_it (bidi_it, &saved_it);
return bidi_it->type;
}
}
else
{
switch (type)
{
case STRONG_L:
case STRONG_R:
case STRONG_AL:
/* Actually, STRONG_AL cannot happen here, because
bidi_resolve_weak converts it to STRONG_R, per W3. */
eassert (type != STRONG_AL);
next_type = type;
break;
case WEAK_EN:
case WEAK_AN:
/* N1: "European and Arabic numbers act as if they
were R in terms of their influence on NIs." */
next_type = STRONG_R;
break;
default:
emacs_abort ();
break;
}
}
/* Resolve the type of all the NIs found during the above loop. */
type = bidi_resolve_neutral_1 (saved_it.prev_for_neutral.type,
next_type, current_level);
/* Update next_for_neutral with the resolved type, so we
could use it for all the other NIs up to the place where
we exited the loop. */
saved_it.next_for_neutral.type = next_type;
bidi_check_type (type);
/* Update the character which caused us to enter the above loop. */
saved_it.type = type;
bidi_check_type (next_type);
bidi_copy_it (bidi_it, &saved_it);
}
}
return type;
}
/* Given an iterator state in BIDI_IT, advance one character position
in the buffer/string to the next character (in the logical order),
resolve the bidi type of that next character, and return that
type. */
static bidi_type_t
bidi_type_of_next_char (struct bidi_it *bidi_it)
{
bidi_type_t type;
/* This should always be called during a forward scan. */
if (bidi_it->scan_dir != 1)
emacs_abort ();
type = bidi_resolve_neutral (bidi_it);
return type;
}
/* Given an iterator state BIDI_IT, advance one character position in
the buffer/string to the next character (in the current scan
direction), resolve the embedding and implicit levels of that next
character, and return the resulting level. */
static int
bidi_level_of_next_char (struct bidi_it *bidi_it)
{
bidi_type_t type = UNKNOWN_BT;
int level;
ptrdiff_t next_char_pos = -2;
if (bidi_it->scan_dir == 1)
{
ptrdiff_t eob
= ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? bidi_it->string.schars : ZV);
/* There's no sense in trying to advance if we've already hit
the end of text. */
if (bidi_it->charpos >= eob)
{
eassert (bidi_it->resolved_level >= 0);
return bidi_it->resolved_level;
}
}
/* Perhaps the character we want is already cached s fully resolved.
If it is, the call to bidi_cache_find below will return a type
other than UNKNOWN_BT. */
if (bidi_cache_idx > bidi_cache_start && !bidi_it->first_elt)
{
int bob = ((bidi_it->string.s || STRINGP (bidi_it->string.lstring))
? 0 : 1);
if (bidi_it->scan_dir > 0)
{
if (bidi_it->nchars <= 0)
emacs_abort ();
next_char_pos = bidi_it->charpos + bidi_it->nchars;
}
else if (bidi_it->charpos >= bob)
/* Implementation note: we allow next_char_pos to be as low as
0 for buffers or -1 for strings, and that is okay because
that's the "position" of the sentinel iterator state we
cached at the beginning of the iteration. */
next_char_pos = bidi_it->charpos - 1;
if (next_char_pos >= bob - 1)
type = bidi_cache_find (next_char_pos, 1, bidi_it);
if (type != UNKNOWN_BT)
{
/* We asked the cache for fully resolved states. */
eassert (bidi_it->resolved_level >= 0);
return bidi_it->resolved_level;
}
}
if (bidi_it->scan_dir == -1)
/* If we are going backwards, the iterator state is already cached
from previous scans, and should be fully resolved. */
emacs_abort ();
if (type == UNKNOWN_BT)
type = bidi_type_of_next_char (bidi_it);
if (type == NEUTRAL_B)
{
eassert (bidi_it->resolved_level >= 0);
return bidi_it->resolved_level;
}
level = bidi_it->level_stack[bidi_it->stack_idx].level;
eassert ((type == STRONG_R
|| type == STRONG_L
|| type == WEAK_BN
|| type == WEAK_EN
|| type == WEAK_AN));
bidi_it->type = type;
bidi_check_type (bidi_it->type);
/* For L1 below, we need to know, for each WS character, whether
it belongs to a sequence of WS characters preceding a newline
or a TAB or a paragraph separator. */
if ((bidi_it->orig_type == NEUTRAL_WS
|| bidi_isolate_fmt_char (bidi_it->orig_type))
&& bidi_it->next_for_ws.charpos < bidi_it->charpos)
{
int ch;
ptrdiff_t clen = bidi_it->ch_len;
ptrdiff_t bpos = bidi_it->bytepos;
ptrdiff_t cpos = bidi_it->charpos;
ptrdiff_t disp_pos = bidi_it->disp_pos;
ptrdiff_t nc = bidi_it->nchars;
struct bidi_string_data bs = bidi_it->string;
bidi_type_t chtype;
bool fwp = bidi_it->frame_window_p;
int dpp = bidi_it->disp_prop;
if (bidi_it->nchars <= 0)
emacs_abort ();
do {
ch = bidi_fetch_char (cpos += nc, bpos += clen, &disp_pos, &dpp, &bs,
bidi_it->w, fwp, &clen, &nc);
chtype = bidi_get_type (ch, NEUTRAL_DIR);
} while (chtype == NEUTRAL_WS || chtype == WEAK_BN
|| bidi_isolate_fmt_char (chtype)
|| bidi_explicit_dir_char (ch)); /* L1/Retaining */
bidi_it->next_for_ws.type = chtype;
bidi_check_type (bidi_it->next_for_ws.type);
bidi_it->next_for_ws.charpos = cpos;
}
/* Update the cache, but only if this state was already cached. */
bidi_cache_iterator_state (bidi_it, 1, 1);
/* Resolve implicit levels. */
if (bidi_it->orig_type == NEUTRAL_B /* L1 */
|| bidi_it->orig_type == NEUTRAL_S
|| bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB
|| (bidi_it->orig_type == NEUTRAL_WS
&& (bidi_it->next_for_ws.type == NEUTRAL_B
|| bidi_it->next_for_ws.type == NEUTRAL_S)))
level = bidi_it->level_stack[0].level;
else if ((level & 1) == 0) /* I1 */
{
if (type == STRONG_R)
level++;
else if (type == WEAK_EN || type == WEAK_AN)
level += 2;
}
else /* I2 */
{
if (type == STRONG_L || type == WEAK_EN || type == WEAK_AN)
level++;
}
bidi_it->resolved_level = level;
return level;
}
/* Move to the other edge of a level given by LEVEL. If END_FLAG,
we are at the end of a level, and we need to prepare to
resume the scan of the lower level.
If this level's other edge is cached, we simply jump to it, filling
the iterator structure with the iterator state on the other edge.
Otherwise, we walk the buffer or string until we come back to the
same level as LEVEL.
Note: we are not talking here about a ``level run'' in the UAX#9
sense of the term, but rather about a ``level'' which includes
all the levels higher than it. In other words, given the levels
like this:
11111112222222333333334443343222222111111112223322111
A B C
and assuming we are at point A scanning left to right, this
function moves to point C, whereas the UAX#9 ``level 2 run'' ends
at point B. */
static void
bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, bool end_flag)
{
int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir;
ptrdiff_t idx;
/* Try the cache first. */
if ((idx = bidi_cache_find_level_change (level, dir, end_flag))
>= bidi_cache_start)
bidi_cache_fetch_state (idx, bidi_it);
else
{
int new_level;
/* If we are at end of level, its edges must be cached. */
if (end_flag)
emacs_abort ();
if (!bidi_cache_iterator_state (bidi_it, 1, 0))
{
/* Can't happen: if the cache needs to grow, it means we
were at base embedding level, so the cache should have
been either empty or already large enough to cover this
character position. */
emacs_abort ();
}
do {
new_level = bidi_level_of_next_char (bidi_it);
/* If the cache is full, perform an emergency return by
pretending that the level ended. */
if (!bidi_cache_iterator_state (bidi_it, 1, 0))
{
new_level = level - 1;
/* Since the cache should only grow when we are scanning
forward looking for the edge of the level that is one
above the base embedding level, we can only have this
contingency when LEVEL - 1 is the base embedding
level. */
eassert (new_level == bidi_it->level_stack[0].level);
/* Plan B, for when the cache overflows: Back up to the
previous character by fetching the last cached state,
and force the resolved level of that character be the
base embedding level. */
bidi_cache_fetch_state (bidi_cache_idx - 1, bidi_it);
bidi_it->resolved_level = new_level;
bidi_cache_iterator_state (bidi_it, 1, 1);
}
} while (new_level >= level);
}
}
void
bidi_move_to_visually_next (struct bidi_it *bidi_it)
{
int old_level, new_level, next_level;
struct bidi_it sentinel;
struct gcpro gcpro1;
if (bidi_it->charpos < 0 || bidi_it->bytepos < 0)
emacs_abort ();
if (bidi_it->scan_dir == 0)
{
bidi_it->scan_dir = 1; /* default to logical order */
}
/* The code below can call eval, and thus cause GC. If we are
iterating a Lisp string, make sure it won't be GCed. */
if (STRINGP (bidi_it->string.lstring))
GCPRO1 (bidi_it->string.lstring);
/* If we just passed a newline, initialize for the next line. */
if (!bidi_it->first_elt
&& (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB))
bidi_line_init (bidi_it);
/* Prepare the sentinel iterator state, and cache it. When we bump
into it, scanning backwards, we'll know that the last non-base
level is exhausted. */
if (bidi_cache_idx == bidi_cache_start)
{
bidi_copy_it (&sentinel, bidi_it);
if (bidi_it->first_elt)
{
sentinel.charpos--; /* cached charpos needs to be monotonic */
sentinel.bytepos--;
sentinel.ch = '\n'; /* doesn't matter, but why not? */
sentinel.ch_len = 1;
sentinel.nchars = 1;
}
bidi_cache_iterator_state (&sentinel, 1, 0);
}
old_level = bidi_it->resolved_level;
new_level = bidi_level_of_next_char (bidi_it);
/* Reordering of resolved levels (clause L2) is implemented by
jumping to the other edge of the level and flipping direction of
scanning the text whenever we find a level change. */
if (new_level != old_level)
{
bool ascending = new_level > old_level;
int level_to_search = ascending ? old_level + 1 : old_level;
int incr = ascending ? 1 : -1;
int expected_next_level = old_level + incr;
/* Jump (or walk) to the other edge of this level. */
bidi_find_other_level_edge (bidi_it, level_to_search, !ascending);
/* Switch scan direction and peek at the next character in the
new direction. */
bidi_it->scan_dir = -bidi_it->scan_dir;
/* The following loop handles the case where the resolved level
jumps by more than one. This is typical for numbers inside a
run of text with left-to-right embedding direction, but can
also happen in other situations. In those cases the decision
where to continue after a level change, and in what direction,
is tricky. For example, given a text like below:
abcdefgh
11336622
(where the numbers below the text show the resolved levels),
the result of reordering according to UAX#9 should be this:
efdcghba
This is implemented by the loop below which flips direction
and jumps to the other edge of the level each time it finds
the new level not to be the expected one. The expected level
is always one more or one less than the previous one. */
next_level = bidi_peek_at_next_level (bidi_it);
while (next_level != expected_next_level)
{
/* If next_level is -1, it means we have an unresolved level
in the cache, which at this point should not happen. If
it does, we will infloop. */
eassert (next_level >= 0);
/* If next_level is not consistent with incr, we might
infloop. */
eassert (incr > 0
? next_level > expected_next_level
: next_level < expected_next_level);
expected_next_level += incr;
level_to_search += incr;
bidi_find_other_level_edge (bidi_it, level_to_search, !ascending);
bidi_it->scan_dir = -bidi_it->scan_dir;
next_level = bidi_peek_at_next_level (bidi_it);
}
/* Finally, deliver the next character in the new direction. */
next_level = bidi_level_of_next_char (bidi_it);
}
/* Take note when we have just processed the newline that precedes
the end of the paragraph. The next time we are about to be
called, set_iterator_to_next will automatically reinit the
paragraph direction, if needed. We do this at the newline before
the paragraph separator, because the next character might not be
the first character of the next paragraph, due to the bidi
reordering, whereas we _must_ know the paragraph base direction
_before_ we process the paragraph's text, since the base
direction affects the reordering. */
if (bidi_it->scan_dir == 1
&& (bidi_it->ch == '\n' || bidi_it->ch == BIDI_EOB))
{
/* The paragraph direction of the entire string, once
determined, is in effect for the entire string. Setting the
separator limit to the end of the string prevents
bidi_paragraph_init from being called automatically on this
string. */
if (bidi_it->string.s || STRINGP (bidi_it->string.lstring))
bidi_it->separator_limit = bidi_it->string.schars;
else if (bidi_it->bytepos < ZV_BYTE)
{
ptrdiff_t sep_len
= bidi_at_paragraph_end (bidi_it->charpos + bidi_it->nchars,
bidi_it->bytepos + bidi_it->ch_len);
if (bidi_it->nchars <= 0)
emacs_abort ();
if (sep_len >= 0)
{
bidi_it->new_paragraph = 1;
/* Record the buffer position of the last character of the
paragraph separator. */
bidi_it->separator_limit
= bidi_it->charpos + bidi_it->nchars + sep_len;
}
}
}
if (bidi_it->scan_dir == 1 && bidi_cache_idx > bidi_cache_start)
{
/* If we are at paragraph's base embedding level and beyond the
last cached position, the cache's job is done and we can
discard it. */
if (bidi_it->resolved_level == bidi_it->level_stack[0].level
&& bidi_it->charpos > (bidi_cache[bidi_cache_idx - 1].charpos
+ bidi_cache[bidi_cache_idx - 1].nchars - 1))
bidi_cache_reset ();
/* Also reset the cache if it overflowed and we have just
emergency-exited using Plan B. */
else if (bidi_it->resolved_level == bidi_it->level_stack[0].level
&& bidi_cache_idx >= bidi_cache_size
&& bidi_it->charpos == bidi_cache[bidi_cache_idx - 1].charpos)
bidi_cache_reset ();
/* But as long as we are caching during forward scan, we must
cache each state, or else the cache integrity will be
compromised: it assumes cached states correspond to buffer
positions 1:1. */
else
bidi_cache_iterator_state (bidi_it, 1, 0);
}
eassert (bidi_it->resolved_level >= 0
&& bidi_it->resolved_level <= BIDI_MAXDEPTH + 2);
if (STRINGP (bidi_it->string.lstring))
UNGCPRO;
}
/* Utility function for looking for strong directional characters
whose bidi type was overridden by a directional override. */
ptrdiff_t
bidi_find_first_overridden (struct bidi_it *bidi_it)
{
ptrdiff_t found_pos = ZV;
do
{
/* Need to call bidi_resolve_weak, not bidi_resolve_explicit,
because the directional overrides are applied by the
former. */
bidi_type_t type = bidi_resolve_weak (bidi_it);
if ((type == STRONG_R && bidi_it->orig_type == STRONG_L)
|| (type == STRONG_L
&& (bidi_it->orig_type == STRONG_R
|| bidi_it->orig_type == STRONG_AL)))
found_pos = bidi_it->charpos;
} while (found_pos == ZV
&& bidi_it->charpos < ZV
&& bidi_it->ch != BIDI_EOB
&& bidi_it->ch != '\n');
return found_pos;
}
/* This is meant to be called from within the debugger, whenever you
wish to examine the cache contents. */
void bidi_dump_cached_states (void) EXTERNALLY_VISIBLE;
void
bidi_dump_cached_states (void)
{
ptrdiff_t i;
int ndigits = 1;
if (bidi_cache_idx == 0)
{
fprintf (stderr, "The cache is empty.\n");
return;
}
fprintf (stderr, "Total of %"pD"d state%s in cache:\n",
bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s");
for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10)
ndigits++;
fputs ("ch ", stderr);
for (i = 0; i < bidi_cache_idx; i++)
fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch);
fputs ("\n", stderr);
fputs ("lvl ", stderr);
for (i = 0; i < bidi_cache_idx; i++)
fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level);
fputs ("\n", stderr);
fputs ("pos ", stderr);
for (i = 0; i < bidi_cache_idx; i++)
fprintf (stderr, "%*"pD"d", ndigits, bidi_cache[i].charpos);
fputs ("\n", stderr);
}
|