[ot] Implement cmap subtable format 0

src/hb-open-type-private.hh

@@ -132,7 +132,7 @@ static inline Type& StructAfter(TObject &X)
 
 /* Global nul-content Null pool.  Enlarge as necessary. */
 /* TODO This really should be a extern HB_INTERNAL and defined somewhere... */
-static const void *_NullPool[64 / sizeof (void *)];
+static const void *_NullPool[(256+8) / sizeof (void *)];
 
 /* Generic nul-content Null objects. */
 template <typename Type>
@@ -572,6 +572,7 @@ struct IntType
   DEFINE_SIZE_STATIC (Size);
 };
 
+typedef		uint8_t	     BYTE;	/* 8-bit unsigned integer. */
 typedef IntType<uint16_t, 2> USHORT;	/* 16-bit unsigned integer. */
 typedef IntType<int16_t,  2> SHORT;	/* 16-bit signed integer. */
 typedef IntType<uint32_t, 4> ULONG;	/* 32-bit unsigned integer. */

src/hb-ot-cmap-table.hh

@@ -40,6 +40,35 @@ namespace OT {
 #define HB_OT_TAG_cmap HB_TAG('c','m','a','p')
 
 
+struct CmapSubtableFormat0
+{
+  friend struct CmapSubtable;
+
+  private:
+  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    hb_codepoint_t gid = codepoint < 256 ? glyphIdArray[codepoint] : 0;
+    if (!gid)
+      return false;
+    *glyph = gid;
+    return true;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this));
+  }
+
+  protected:
+  USHORT	format;		/* Format number is set to 0. */
+  USHORT	length;		/* Byte length of this subtable. */
+  USHORT	language;	/* Ignore. */
+  BYTE		glyphIdArray[256];/* An array that maps character
+				 * code to glyph index values. */
+  public:
+  DEFINE_SIZE_STATIC (6 + 256);
+};
+
 struct CmapSubtableFormat4
 {
   friend struct CmapSubtable;
@@ -246,6 +275,7 @@ struct CmapSubtable
   inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
   {
     switch (u.format) {
+    case  0: return u.format0 .get_glyph(codepoint, glyph);
     case  4: return u.format4 .get_glyph(codepoint, glyph);
     case  6: return u.format6 .get_glyph(codepoint, glyph);
     case 10: return u.format10.get_glyph(codepoint, glyph);
@@ -259,6 +289,7 @@ struct CmapSubtable
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
+    case  0: return TRACE_RETURN (u.format0 .sanitize (c));
     case  4: return TRACE_RETURN (u.format4 .sanitize (c));
     case  6: return TRACE_RETURN (u.format6 .sanitize (c));
     case 10: return TRACE_RETURN (u.format10.sanitize (c));
@@ -271,6 +302,7 @@ struct CmapSubtable
   protected:
   union {
   USHORT		format;		/* Format identifier */
+  CmapSubtableFormat0	format0;
   CmapSubtableFormat4	format4;
   CmapSubtableFormat6	format6;
   CmapSubtableFormat10	format10;