Split out handling of sinhala al-lakuna character from handling of Virama

2005-03-03  Owen Taylor  <otaylor@redhat.com>

        * modules/indic/indic-ot.[ch] modules/indic-ot-class-tables.c:
        Split out handling of sinhala al-lakuna character from
        handling of Virama in the state table to avoid implicit
        formation of conjucts for Sinhala. (Patch from
        Harshula, ##161981)

        * modules/indic/indic-fc.c modules/indic/indic-ot.h:
        Add a new script flag SF_PROCESS_ZWJ indicating
        whether zero width characters should be passed to
        gsub/gpos.

        * modules/indic/indic-ot-class-tables.c: Set SF_PROCESS_ZWJ
        for Sinhala. (#161981, Harshula)

6 files changed, 77 insertions, 27 deletions

diff --git a/ChangeLog b/ChangeLog
index dffaf079..6f87f63d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,21 @@
 2005-03-03  Owen Taylor  <otaylor@redhat.com>
 
+	* modules/indic/indic-ot.[ch] modules/indic-ot-class-tables.c:
+	Split out handling of sinhala al-lakuna character from
+	handling of Virama in the state table to avoid implicit
+	formation of conjucts for Sinhala. (Patch from 
+	Harshula, ##161981)
+
+	* modules/indic/indic-fc.c modules/indic/indic-ot.h:
+	Add a new script flag SF_PROCESS_ZWJ indicating
+	whether zero width characters should be passed to
+	gsub/gpos.
+
+	* modules/indic/indic-ot-class-tables.c: Set SF_PROCESS_ZWJ
+	for Sinhala. (#161981, Harshula)
+
+2005-03-03  Owen Taylor  <otaylor@redhat.com>
+
 	* pango/pango-fontmap.c (pango_font_map_load_font): Add
 	a g_return_if_fail() if desc doesn't have a family.
 	(#165866, Kees Cook)
diff --git a/ChangeLog.pre-1-10 b/ChangeLog.pre-1-10
index dffaf079..6f87f63d 100644
--- a/ChangeLog.pre-1-10
+++ b/ChangeLog.pre-1-10
@@ -1,5 +1,21 @@
 2005-03-03  Owen Taylor  <otaylor@redhat.com>
 
+	* modules/indic/indic-ot.[ch] modules/indic-ot-class-tables.c:
+	Split out handling of sinhala al-lakuna character from
+	handling of Virama in the state table to avoid implicit
+	formation of conjucts for Sinhala. (Patch from 
+	Harshula, ##161981)
+
+	* modules/indic/indic-fc.c modules/indic/indic-ot.h:
+	Add a new script flag SF_PROCESS_ZWJ indicating
+	whether zero width characters should be passed to
+	gsub/gpos.
+
+	* modules/indic/indic-ot-class-tables.c: Set SF_PROCESS_ZWJ
+	for Sinhala. (#161981, Harshula)
+
+2005-03-03  Owen Taylor  <otaylor@redhat.com>
+
 	* pango/pango-fontmap.c (pango_font_map_load_font): Add
 	a g_return_if_fail() if desc doesn't have a family.
 	(#165866, Kees Cook)
diff --git a/modules/indic/indic-fc.c b/modules/indic/indic-fc.c
index 788bc64f..b9816a21 100644
--- a/modules/indic/indic-fc.c
+++ b/modules/indic/indic-fc.c
@@ -250,7 +250,7 @@ get_gpos_ruleset (FT_Face face, PangoIndicInfo *indic_info)
 }
 
 static void
-set_glyphs (PangoFont *font, FT_Face face, const gunichar *wcs, gulong *tags, glong n_glyphs, PangoOTBuffer *buffer)
+set_glyphs (PangoFont *font, FT_Face face, const gunichar *wcs, gulong *tags, glong n_glyphs, PangoOTBuffer *buffer, gboolean process_zwj)
 {
   gint i;
 
@@ -260,7 +260,8 @@ set_glyphs (PangoFont *font, FT_Face face, const gunichar *wcs, gulong *tags, gl
     {
       guint glyph;
 
-      if (ZERO_WIDTH_CHAR (wcs[i]))
+      if (ZERO_WIDTH_CHAR (wcs[i]) &&
+	  (!process_zwj || wcs[i] != 0x200D))
 	glyph = 0;
       else
 	glyph = FT_Get_Char_Index (face, wcs[i]);
@@ -347,7 +348,9 @@ indic_engine_shape (PangoEngineShape *engine,
   
   pango_glyph_string_set_size (glyphs, n_glyphs);
   buffer = pango_ot_buffer_new (fc_font);
-  set_glyphs(font, face, wc_out, tags, n_glyphs, buffer);
+
+  set_glyphs(font, face, wc_out, tags, n_glyphs, buffer,
+	     (indic_info->classTable->scriptFlags & SF_PROCESS_ZWJ) != 0);
 
   /* do gsub processing */
   gsub_ruleset = get_gsub_ruleset (face, indic_info);
diff --git a/modules/indic/indic-ot-class-tables.c b/modules/indic/indic-ot-class-tables.c
index 85fac646..4f9a74b5 100644
--- a/modules/indic/indic-ot-class-tables.c
+++ b/modules/indic/indic-ot-class-tables.c
@@ -40,6 +40,7 @@ enum
     _dr = _dv | CF_MATRA_POST,
     _lm = _dv | CF_LENGTH_MARK,
     _vr = CC_VIRAMA,
+    _al = CC_AL_LAKUNA,
 
     /*
      * Split matras
@@ -198,7 +199,7 @@ static IndicOTCharClass sinhCharClasses[] =
     _iv, _iv, _iv, _iv, _iv, _iv, _iv, _xx, _xx, _xx, _ct, _ct, _ct, _ct, _ct, _ct, /* 0D90 - 0D9F */
     _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, /* 0DA0 - 0DAF */
     _ct, _ct, _xx, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _ct, _xx, _ct, _xx, _xx, /* 0DB0 - 0DBF */
-    _ct, _ct, _ct, _ct, _ct, _ct, _ct, _xx, _xx, _xx, _vr, _xx, _xx, _xx, _xx, _dr, /* 0DC0 - 0DCF */
+    _ct, _ct, _ct, _ct, _ct, _ct, _ct, _xx, _xx, _xx, _al, _xx, _xx, _xx, _xx, _dr, /* 0DC0 - 0DCF */
     _dr, _dr, _da, _da, _db, _xx, _db, _xx, _dr, _dl, _s1, _dl, _s2, _s3, _s4, _dr, /* 0DD0 - 0DDF */
     _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, /* 0DE0 - 0DEF */
     _xx, _xx, _dr, _dr, _xx                                                         /* 0DF0 - 0DF4 */
@@ -243,7 +244,7 @@ static const IndicOTSplitMatra sinhSplitTable[] = {{0x0DD9, 0x0DCA}, {0x0DD9, 0x
 #define TELU_SCRIPT_FLAGS (SF_MATRAS_AFTER_BASE | 3)
 #define KNDA_SCRIPT_FLAGS (SF_MATRAS_AFTER_BASE | 3)
 #define MLYM_SCRIPT_FLAGS (SF_MPRE_FIXUP | SF_NO_POST_BASE_LIMIT)
-#define SINH_SCRIPT_FLAGS (SF_MPRE_FIXUP | SF_NO_POST_BASE_LIMIT)
+#define SINH_SCRIPT_FLAGS (SF_MPRE_FIXUP | SF_NO_POST_BASE_LIMIT | SF_PROCESS_ZWJ)
 
 /*
  * Indic Class Tables
@@ -307,7 +308,14 @@ gboolean indic_ot_is_virama(const IndicOTClassTable *class_table, gunichar ch)
 {
   IndicOTCharClass char_class = indic_ot_get_char_class(class_table, ch);
 
-  return IS_VIRAMA(char_class);
+  return (IS_VIRAMA(char_class) || IS_AL_LAKUNA(char_class));
+}
+
+gboolean indic_ot_is_al_lakuna(const IndicOTClassTable *class_table, gunichar ch)
+{
+  IndicOTCharClass char_class = indic_ot_get_char_class(class_table, ch);
+
+  return IS_AL_LAKUNA(char_class);
 }
 
 gboolean indic_ot_is_nukta(const IndicOTClassTable *class_table, gunichar ch)
@@ -413,16 +421,17 @@ IndicOTCharClass indic_ot_get_char_class(const IndicOTClassTable *class_table, g
 
 static const gint8 stateTable[][CC_COUNT] =
 {
-/*   xx  ma  mp  iv  ct  cn  nu  dv  vr  zw */
-    { 1,  1,  1,  5,  3,  2,  1,  1,  1,  1},
-    {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1},
-    {-1,  6,  1, -1, -1, -1, -1,  5,  4, -1},
-    {-1,  6,  1, -1, -1, -1,  2,  5,  4, -1},
-    {-1, -1, -1, -1,  3,  2, -1, -1, -1,  8},
-    {-1,  6,  1, -1, -1, -1, -1,  5, -1, -1},
-    {-1,  7,  1, -1, -1, -1, -1, -1, -1, -1},
-    {-1, -1,  1, -1, -1, -1, -1, -1, -1, -1},
-    {-1, -1, -1, -1,  3,  2, -1, -1, -1, -1}
+/*   xx  ma  mp  iv  ct  cn  nu  dv  vr  zw  al */
+    { 1,  1,  1,  5,  3,  2,  1,  1,  1,  1,  1},
+    {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1},
+    {-1,  6,  1, -1, -1, -1, -1,  5,  4, -1, -1},
+    {-1,  6,  1, -1, -1, -1,  2,  5,  4, -1,  9},
+    {-1, -1, -1, -1,  3,  2, -1, -1, -1,  8, -1},
+    {-1,  6,  1, -1, -1, -1, -1,  5, -1, -1, -1},
+    {-1,  7,  1, -1, -1, -1, -1, -1, -1, -1, -1},
+    {-1, -1,  1, -1, -1, -1, -1, -1, -1, -1, -1},
+    {-1, -1, -1, -1,  3,  2, -1, -1, -1, -1, -1},
+    {-1, -1, -1, -1, -1, -1, -1, -1, -1,  8, -1}
 
 };
 
diff --git a/modules/indic/indic-ot.c b/modules/indic/indic-ot.c
index 159cecdc..6b484f3b 100644
--- a/modules/indic/indic-ot.c
+++ b/modules/indic/indic-ot.c
@@ -29,7 +29,7 @@ struct _Output
     gunichar fMabove;
     gunichar fMpost;
     gunichar fLengthMark;
-    gunichar fVirama; /* to handle virama in sinhala split matras */
+    gunichar fAlLakuna; /* to handle Al-Lakuna in sinhala split matras */
     glong    fMatraIndex;
     gulong   fMatraTags;
     gboolean fMatraWordStart;
@@ -51,7 +51,7 @@ static void initOutput(Output *output, const glong *originalOffsets, gunichar *o
     output->fOutIndex    = 0;
     output->fMatraTags   = 0;
 
-    output->fMpre = output->fMbelow = output->fMabove = output->fMpost = output->fLengthMark = output->fVirama = 0;
+    output->fMpre = output->fMbelow = output->fMabove = output->fMpost = output->fLengthMark = output->fAlLakuna = 0;
 
     output->fMPreOutIndex = -1;
     output->fMPreFixups = mpreFixups;
@@ -70,14 +70,14 @@ static void saveMatra(Output *output, gunichar matra, IndicOTCharClass matraClas
         output->fMpost = matra;
     } else if (IS_LENGTH_MARK(matraClass)) {
         output->fLengthMark = matra;
-    } else if (IS_VIRAMA(matraClass)) {
-        output->fVirama = matra;
+    } else if (IS_AL_LAKUNA(matraClass)) {
+        output->fAlLakuna = matra;
     }
 }
 
 static void initMatra(Output *output, guint32 matraIndex, gulong matraTags, gboolean wordStart)
 {
-    output->fMpre = output->fMbelow = output->fMabove = output->fMpost = output->fLengthMark = output->fVirama = 0;
+    output->fMpre = output->fMbelow = output->fMabove = output->fMpost = output->fLengthMark = output->fAlLakuna = 0;
     output->fMPreOutIndex = -1;
     output->fMatraIndex = matraIndex;
     output->fMatraTags = matraTags;
@@ -165,10 +165,10 @@ static void writeLengthMark(Output *output)
     }
 }
 
-static void writeVirama(Output *output)
+static void writeAlLakuna(Output *output)
 {
-    if (output->fVirama != 0) {
-	writeChar(output, output->fVirama, output->fMatraIndex, output->fMatraTags);
+    if (output->fAlLakuna != 0) {
+        writeChar(output, output->fAlLakuna, output->fMatraIndex, output->fMatraTags);
     }
 }
 
@@ -229,6 +229,7 @@ glong indic_ot_reorder(const gunichar *chars, const glong *utf8_offsets, glong c
         case CC_MODIFYING_MARK_POST:
         case CC_NUKTA:
         case CC_VIRAMA:
+        case CC_AL_LAKUNA:
             writeChar(&output, C_DOTTED_CIRCLE, prev, blwf_p);
             writeChar(&output, chars[prev], prev, blwf_p);
             break;
@@ -240,7 +241,7 @@ glong indic_ot_reorder(const gunichar *chars, const glong *utf8_offsets, glong c
             writeMabove(&output);
             writeMpost(&output);
             writeLengthMark(&output);
-	    writeVirama(&output);
+            writeAlLakuna(&output);
             break;
 
         case CC_CONSONANT:
@@ -425,7 +426,7 @@ glong indic_ot_reorder(const gunichar *chars, const glong *utf8_offsets, glong c
 	    }
 
 	    writeLengthMark(&output);
-	    writeVirama(&output);
+	    writeAlLakuna(&output);
 
 	    /* write reph */
 	    if ((class_table->scriptFlags & SF_REPH_AFTER_BELOW) == 0) {
diff --git a/modules/indic/indic-ot.h b/modules/indic/indic-ot.h
index d6b498b3..47ec64e4 100644
--- a/modules/indic/indic-ot.h
+++ b/modules/indic/indic-ot.h
@@ -47,7 +47,8 @@ typedef enum
   CC_DEPENDENT_VOWEL      = 7,
   CC_VIRAMA               = 8,
   CC_ZERO_WIDTH_MARK      = 9,
-  CC_COUNT                = 10
+  CC_AL_LAKUNA            = 10,
+  CC_COUNT                = 11
 } IndicOTCharClassValues;
 
 /*
@@ -89,6 +90,7 @@ typedef enum
   SF_REPH_AFTER_BELOW     = 0x40000000,
   SF_EYELASH_RA           = 0x20000000,
   SF_MPRE_FIXUP           = 0x10000000,
+  SF_PROCESS_ZWJ          = 0x08000000,
 
   SF_POST_BASE_LIMIT_MASK = 0x0000FFFF,
   SF_NO_POST_BASE_LIMIT   = 0x00007FFF
@@ -153,6 +155,8 @@ enum indic_glyph_property_
 
 #define IS_VIRAMA(charClass) ((charClass & CF_CLASS_MASK) == CC_VIRAMA)
 
+#define IS_AL_LAKUNA(charClass) ((charClass & CF_CLASS_MASK) == CC_AL_LAKUNA)
+
 #define IS_VATTU(charClass) ((charClass & CF_VATTU) != 0)
 
 #define IS_MATRA(charClass) ((charClass & CF_CLASS_MASK) == CC_DEPENDENT_VOWEL)
@@ -227,6 +231,7 @@ gboolean indic_ot_is_vm_post(const IndicOTClassTable *class_table, gunichar ch);
 gboolean indic_ot_is_consonant(const IndicOTClassTable *class_table, gunichar ch);
 gboolean indic_ot_is_reph(const IndicOTClassTable *class_table, gunichar ch);
 gboolean indic_ot_is_virama(const IndicOTClassTable *class_table, gunichar ch);
+gboolean indic_ot_is_al_lakuna(const IndicOTClassTable *class_table, gunichar ch);
 gboolean indic_ot_is_nukta(const IndicOTClassTable *class_table, gunichar ch);
 gboolean indic_ot_is_vattu(const IndicOTClassTable *class_table, gunichar ch);
 gboolean indic_ot_is_matra(const IndicOTClassTable *class_table, gunichar ch);