[OTS] Add support for the MATH table.

src/layout.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "layout.h"
 
 #include <limits>
 #include <vector>
 
 #include "gdef.h"
@@ skipping 318 matching lines @@
       OTS_WARNING("bad class value: %u", class_value);
       return OTS_FAILURE();
     }
     last_end = end;
   }
 
   return true;
 }
 
 bool ParseCoverageFormat1(const uint8_t *data, size_t length,
-                          const uint16_t num_glyphs) {
+                          const uint16_t num_glyphs,
+                          const uint16_t expected_num_glyphs) {
   ots::Buffer subtable(data, length);
 
   // Skip format field.
   if (!subtable.Skip(2)) {
     return OTS_FAILURE();
   }
 
   uint16_t glyph_count = 0;
   if (!subtable.ReadU16(&glyph_count)) {
     return OTS_FAILURE();
   }
   if (glyph_count > num_glyphs) {
     OTS_WARNING("bad glyph count: %u", glyph_count);
     return OTS_FAILURE();
   }
   for (unsigned i = 0; i < glyph_count; ++i) {
     uint16_t glyph = 0;
     if (!subtable.ReadU16(&glyph)) {
       return OTS_FAILURE();
     }
     if (glyph > num_glyphs) {
       OTS_WARNING("bad glyph ID: %u", glyph);
       return OTS_FAILURE();
     }
   }
 
+  if (expected_num_glyphs && expected_num_glyphs != glyph_count) {
+      OTS_WARNING("unexpected number of glyphs: %u", glyph_count);
+      return OTS_FAILURE();
+  }
+
   return true;
 }
 
 bool ParseCoverageFormat2(const uint8_t *data, size_t length,
-                          const uint16_t num_glyphs) {
+                          const uint16_t num_glyphs,
+                          const uint16_t expected_num_glyphs) {
   ots::Buffer subtable(data, length);
 
   // Skip format field.
   if (!subtable.Skip(2)) {
     return OTS_FAILURE();
   }
 
   uint16_t range_count = 0;
   if (!subtable.ReadU16(&range_count)) {
     return OTS_FAILURE();
@@ skipping 23 matching lines @@
       return OTS_FAILURE();
     }
     if (start_coverage_index != last_start_coverage_index) {
       OTS_WARNING("bad start coverage index.");
       return OTS_FAILURE();
     }
     last_end = end;
     last_start_coverage_index += end - start + 1;
   }
 
+  if (expected_num_glyphs &&
+      expected_num_glyphs != last_start_coverage_index) {
+      OTS_WARNING("unexpected number of glyphs: %u", last_start_coverage_index);
+      return OTS_FAILURE();
+  }
+
   return true;
 }
 
 // Parsers for Contextual subtables in GSUB/GPOS tables.
 
 bool ParseLookupRecord(ots::Buffer *subtable, const uint16_t num_glyphs,
                        const uint16_t num_lookups) {
   uint16_t sequence_index = 0;
   uint16_t lookup_list_index = 0;
   if (!subtable->ReadU16(&sequence_index) ||
@@ skipping 904 matching lines @@
   if (format == 1) {
     return ParseClassDefFormat1(data, length, num_glyphs, num_classes);
   } else if (format == 2) {
     return ParseClassDefFormat2(data, length, num_glyphs, num_classes);
   }
 
   return OTS_FAILURE();
 }
 
 bool ParseCoverageTable(const uint8_t *data, size_t length,
-                        const uint16_t num_glyphs) {
+                        const uint16_t num_glyphs,
+                        const uint16_t expected_num_glyphs) {
   Buffer subtable(data, length);
 
   uint16_t format = 0;
   if (!subtable.ReadU16(&format)) {
     return OTS_FAILURE();
   }
   if (format == 1) {
-    return ParseCoverageFormat1(data, length, num_glyphs);
+    return ParseCoverageFormat1(data, length, num_glyphs, expected_num_glyphs);
   } else if (format == 2) {
-    return ParseCoverageFormat2(data, length, num_glyphs);
+    return ParseCoverageFormat2(data, length, num_glyphs, expected_num_glyphs);
   }
 
   return OTS_FAILURE();
 }
 
 bool ParseDeviceTable(const uint8_t *data, size_t length) {
   Buffer subtable(data, length);
 
   uint16_t start_size = 0;
   uint16_t end_size = 0;
@@ skipping 114 matching lines @@
   if (!parser->Parse(file, data + offset_extension, length - offset_extension,
                      lookup_type)) {
     return OTS_FAILURE();
   }
 
   return true;
 }
 
 }  // namespace ots