diff options
Diffstat (limited to 'utf8.c')
| -rw-r--r-- | utf8.c | 132 |
1 files changed, 132 insertions, 0 deletions
@@ -2377,6 +2377,138 @@ S_swash_get(pTHX_ SV* swash, UV start, UV span) return swatch; } +HV* +Perl__swash_inversion_hash(pTHX_ SV* swash) +{ + + /* Subject to change or removal. For use only in one place in regexec.c + * + * Returns a hash which is the inversion and closure of a swash mapping. + * For example, consider the input lines: + * 004B 006B + * 004C 006C + * 212A 006B + * + * The returned hash would have two keys, the utf8 for 006B and the utf8 for + * 006C. The value for each key is an array. For 006C, the array would + * have a two elements, the utf8 for itself, and for 004C. For 006B, there + * would be three elements in its array, the utf8 for 006B, 004B and 212A. + * + * Essentially, for any code point, it gives all the code points that map to + * it, or the list of 'froms' for that point. + * + * Currently it only looks at the main body of the swash, and ignores any + * additions or deletions from other swashes */ + + U8 *l, *lend; + STRLEN lcur; + HV *const hv = MUTABLE_HV(SvRV(swash)); + + /* The string containing the main body of the table */ + SV** const listsvp = hv_fetchs(hv, "LIST", FALSE); + + SV** const typesvp = hv_fetchs(hv, "TYPE", FALSE); + SV** const bitssvp = hv_fetchs(hv, "BITS", FALSE); + SV** const nonesvp = hv_fetchs(hv, "NONE", FALSE); + /*SV** const extssvp = hv_fetchs(hv, "EXTRAS", FALSE);*/ + const U8* const typestr = (U8*)SvPV_nolen(*typesvp); + const STRLEN bits = SvUV(*bitssvp); + const STRLEN octets = bits >> 3; /* if bits == 1, then octets == 0 */ + const UV none = SvUV(*nonesvp); + + HV* ret = newHV(); + + PERL_ARGS_ASSERT__SWASH_INVERSION_HASH; + + /* Must have at least 8 bits to get the mappings */ + if (bits != 8 && bits != 16 && bits != 32) { + Perl_croak(aTHX_ "panic: swash_inversion_hash doesn't expect bits %"UVuf, + (UV)bits); + } + + /* read $swash->{LIST} */ + l = (U8*)SvPV(*listsvp, lcur); + lend = l + lcur; + + /* Go through each input line */ + while (l < lend) { + UV min, max, val; + UV inverse; + l = S_swash_scan_list_line(aTHX_ l, lend, &min, &max, &val, + cBOOL(octets), typestr); + if (l > lend) { + break; + } + + /* Each element in the range is to be inverted */ + for (inverse = min; inverse <= max; inverse++) { + AV* list; + SV* element; + SV** listp; + IV i; + bool found_key = FALSE; + + /* The key is the inverse mapping */ + char key[UTF8_MAXBYTES+1]; + char* key_end = (char *) uvuni_to_utf8((U8*) key, val); + STRLEN key_len = key_end - key; + + /* And the value is what the forward mapping is from. */ + char utf8_inverse[UTF8_MAXBYTES+1]; + char *utf8_inverse_end = (char *) uvuni_to_utf8((U8*) utf8_inverse, inverse); + + /* Get the list for the map */ + if ((listp = hv_fetch(ret, key, key_len, FALSE))) { + list = (AV*) *listp; + } + else { /* No entry yet for it: create one */ + list = newAV(); + if (! hv_store(ret, key, key_len, (SV*) list, FALSE)) { + Perl_croak(aTHX_ "panic: hv_store() unexpectedly failed"); + } + } + + for (i = 0; i < av_len(list); i++) { + SV** entryp = av_fetch(list, i, FALSE); + SV* entry; + if (entryp == NULL) { + Perl_croak(aTHX_ "panic: av_fetch() unexpectedly failed"); + } + entry = *entryp; + if (SvCUR(entry) != key_len) { + continue; + } + if (memEQ(key, SvPVX(entry), key_len)) { + found_key = TRUE; + break; + } + } + if (! found_key) { + element = newSVpvn_flags(key, key_len, SVf_UTF8); + av_push(list, element); + } + + + /* Simply add the value to the list */ + element = newSVpvn_flags(utf8_inverse, utf8_inverse_end - utf8_inverse, SVf_UTF8); + av_push(list, element); + + /* swash_get() increments the value of val for each element in the + * range. That makes more compact tables possible. You can + * express the capitalization, for example, of all consecutive + * letters with a single line: 0061\t007A\t0041 This maps 0061 to + * 0041, 0062 to 0042, etc. I (khw) have never understood 'none', + * and it's not documented, and perhaps not even currently used, + * but I copied the semantics from swash_get(), just in case */ + if (!none || val < none) { + ++val; + } + } + } + + return ret; +} + /* =for apidoc uvchr_to_utf8 |