michael@0: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "gdef.h"
michael@0: 
michael@0: #include <limits>
michael@0: #include <vector>
michael@0: 
michael@0: #include "gpos.h"
michael@0: #include "gsub.h"
michael@0: #include "layout.h"
michael@0: #include "maxp.h"
michael@0: 
michael@0: // GDEF - The Glyph Definition Table
michael@0: // http://www.microsoft.com/typography/otspec/gdef.htm
michael@0: 
michael@0: #define TABLE_NAME "GDEF"
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: // The maximum class value in class definition tables.
michael@0: const uint16_t kMaxClassDefValue = 0xFFFF;
michael@0: // The maximum class value in the glyph class definision table.
michael@0: const uint16_t kMaxGlyphClassDefValue = 4;
michael@0: // The maximum format number of caret value tables.
michael@0: // We don't support format 3 for now. See the comment in
michael@0: // ParseLigCaretListTable() for the reason.
michael@0: const uint16_t kMaxCaretValueFormat = 2;
michael@0: 
michael@0: bool ParseGlyphClassDefTable(ots::OpenTypeFile *file, const uint8_t *data,
michael@0:                              size_t length, const uint16_t num_glyphs) {
michael@0:   return ots::ParseClassDefTable(file, data, length, num_glyphs,
michael@0:                                  kMaxGlyphClassDefValue);
michael@0: }
michael@0: 
michael@0: bool ParseAttachListTable(ots::OpenTypeFile *file, const uint8_t *data,
michael@0:                           size_t length, const uint16_t num_glyphs) {
michael@0:   ots::Buffer subtable(data, length);
michael@0: 
michael@0:   uint16_t offset_coverage = 0;
michael@0:   uint16_t glyph_count = 0;
michael@0:   if (!subtable.ReadU16(&offset_coverage) ||
michael@0:       !subtable.ReadU16(&glyph_count)) {
michael@0:     return OTS_FAILURE_MSG("Failed to read gdef header");
michael@0:   }
michael@0:   const unsigned attach_points_end =
michael@0:       2 * static_cast<unsigned>(glyph_count) + 4;
michael@0:   if (attach_points_end > std::numeric_limits<uint16_t>::max()) {
michael@0:     return OTS_FAILURE_MSG("Bad glyph count in gdef");
michael@0:   }
michael@0:   if (offset_coverage == 0 || offset_coverage >= length ||
michael@0:       offset_coverage < attach_points_end) {
michael@0:     return OTS_FAILURE_MSG("Bad coverage offset %d", offset_coverage);
michael@0:   }
michael@0:   if (glyph_count > num_glyphs) {
michael@0:     return OTS_FAILURE_MSG("Bad glyph count %u", glyph_count);
michael@0:   }
michael@0: 
michael@0:   std::vector<uint16_t> attach_points;
michael@0:   attach_points.resize(glyph_count);
michael@0:   for (unsigned i = 0; i < glyph_count; ++i) {
michael@0:     if (!subtable.ReadU16(&attach_points[i])) {
michael@0:       return OTS_FAILURE_MSG("Can't read attachment point %d", i);
michael@0:     }
michael@0:     if (attach_points[i] >= length ||
michael@0:         attach_points[i] < attach_points_end) {
michael@0:       return OTS_FAILURE_MSG("Bad attachment point %d of %d", i, attach_points[i]);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // Parse coverage table
michael@0:   if (!ots::ParseCoverageTable(file, data + offset_coverage,
michael@0:                                length - offset_coverage, num_glyphs)) {
michael@0:     return OTS_FAILURE_MSG("Bad coverage table");
michael@0:   }
michael@0: 
michael@0:   // Parse attach point table
michael@0:   for (unsigned i = 0; i < attach_points.size(); ++i) {
michael@0:     subtable.set_offset(attach_points[i]);
michael@0:     uint16_t point_count = 0;
michael@0:     if (!subtable.ReadU16(&point_count)) {
michael@0:       return OTS_FAILURE_MSG("Can't read point count %d", i);
michael@0:     }
michael@0:     if (point_count == 0) {
michael@0:       return OTS_FAILURE_MSG("zero point count %d", i);
michael@0:     }
michael@0:     uint16_t last_point_index = 0;
michael@0:     uint16_t point_index = 0;
michael@0:     for (unsigned j = 0; j < point_count; ++j) {
michael@0:       if (!subtable.ReadU16(&point_index)) {
michael@0:         return OTS_FAILURE_MSG("Can't read point index %d in point %d", j, i);
michael@0:       }
michael@0:       // Contour point indeces are in increasing numerical order
michael@0:       if (last_point_index != 0 && last_point_index >= point_index) {
michael@0:         return OTS_FAILURE_MSG("bad contour indeces: %u >= %u",
michael@0:                     last_point_index, point_index);
michael@0:       }
michael@0:       last_point_index = point_index;
michael@0:     }
michael@0:   }
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ParseLigCaretListTable(ots::OpenTypeFile *file, const uint8_t *data,
michael@0:                             size_t length, const uint16_t num_glyphs) {
michael@0:   ots::Buffer subtable(data, length);
michael@0:   uint16_t offset_coverage = 0;
michael@0:   uint16_t lig_glyph_count = 0;
michael@0:   if (!subtable.ReadU16(&offset_coverage) ||
michael@0:       !subtable.ReadU16(&lig_glyph_count)) {
michael@0:     return OTS_FAILURE_MSG("Can't read caret structure");
michael@0:   }
michael@0:   const unsigned lig_glyphs_end =
michael@0:       2 * static_cast<unsigned>(lig_glyph_count) + 4;
michael@0:   if (lig_glyphs_end > std::numeric_limits<uint16_t>::max()) {
michael@0:     return OTS_FAILURE_MSG("Bad caret structure");
michael@0:   }
michael@0:   if (offset_coverage == 0 || offset_coverage >= length ||
michael@0:       offset_coverage < lig_glyphs_end) {
michael@0:     return OTS_FAILURE_MSG("Bad caret coverate offset %d", offset_coverage);
michael@0:   }
michael@0:   if (lig_glyph_count > num_glyphs) {
michael@0:     return OTS_FAILURE_MSG("bad ligature glyph count: %u", lig_glyph_count);
michael@0:   }
michael@0: 
michael@0:   std::vector<uint16_t> lig_glyphs;
michael@0:   lig_glyphs.resize(lig_glyph_count);
michael@0:   for (unsigned i = 0; i < lig_glyph_count; ++i) {
michael@0:     if (!subtable.ReadU16(&lig_glyphs[i])) {
michael@0:       return OTS_FAILURE_MSG("Can't read ligature glyph location %d", i);
michael@0:     }
michael@0:     if (lig_glyphs[i] >= length || lig_glyphs[i] < lig_glyphs_end) {
michael@0:       return OTS_FAILURE_MSG("Bad ligature glyph location %d in glyph %d", lig_glyphs[i], i);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // Parse coverage table
michael@0:   if (!ots::ParseCoverageTable(file, data + offset_coverage,
michael@0:                                length - offset_coverage, num_glyphs)) {
michael@0:     return OTS_FAILURE_MSG("Can't parse caret coverage table");
michael@0:   }
michael@0: 
michael@0:   // Parse ligature glyph table
michael@0:   for (unsigned i = 0; i < lig_glyphs.size(); ++i) {
michael@0:     subtable.set_offset(lig_glyphs[i]);
michael@0:     uint16_t caret_count = 0;
michael@0:     if (!subtable.ReadU16(&caret_count)) {
michael@0:       return OTS_FAILURE_MSG("Can't read caret count for glyph %d", i);
michael@0:     }
michael@0:     if (caret_count == 0) {
michael@0:       return OTS_FAILURE_MSG("bad caret value count: %u", caret_count);
michael@0:     }
michael@0: 
michael@0:     std::vector<uint16_t> caret_value_offsets;
michael@0:     caret_value_offsets.resize(caret_count);
michael@0:     unsigned caret_value_offsets_end = 2 * static_cast<unsigned>(caret_count) + 2;
michael@0:     for (unsigned j = 0; j < caret_count; ++j) {
michael@0:       if (!subtable.ReadU16(&caret_value_offsets[j])) {
michael@0:         return OTS_FAILURE_MSG("Can't read caret offset %d for glyph %d", j, i);
michael@0:       }
michael@0:       if (caret_value_offsets[j] >= length || caret_value_offsets[j] < caret_value_offsets_end) {
michael@0:         return OTS_FAILURE_MSG("Bad caret offset %d for caret %d glyph %d", caret_value_offsets[j], j, i);
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     // Parse caret values table
michael@0:     for (unsigned j = 0; j < caret_count; ++j) {
michael@0:       subtable.set_offset(lig_glyphs[i] + caret_value_offsets[j]);
michael@0:       uint16_t caret_format = 0;
michael@0:       if (!subtable.ReadU16(&caret_format)) {
michael@0:         return OTS_FAILURE_MSG("Can't read caret values table %d in glyph %d", j, i);
michael@0:       }
michael@0:       // TODO(bashi): We only support caret value format 1 and 2 for now
michael@0:       // because there are no fonts which contain caret value format 3
michael@0:       // as far as we investigated.
michael@0:       if (caret_format == 0 || caret_format > kMaxCaretValueFormat) {
michael@0:         return OTS_FAILURE_MSG("bad caret value format: %u", caret_format);
michael@0:       }
michael@0:       // CaretValueFormats contain a 2-byte field which could be
michael@0:       // arbitrary value.
michael@0:       if (!subtable.Skip(2)) {
michael@0:         return OTS_FAILURE_MSG("Bad caret value table structure %d in glyph %d", j, i);
michael@0:       }
michael@0:     }
michael@0:   }
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ParseMarkAttachClassDefTable(ots::OpenTypeFile *file, const uint8_t *data,
michael@0:                                   size_t length, const uint16_t num_glyphs) {
michael@0:   return ots::ParseClassDefTable(file, data, length, num_glyphs, kMaxClassDefValue);
michael@0: }
michael@0: 
michael@0: bool ParseMarkGlyphSetsDefTable(ots::OpenTypeFile *file, const uint8_t *data,
michael@0:                                 size_t length, const uint16_t num_glyphs) {
michael@0:   ots::Buffer subtable(data, length);
michael@0:   uint16_t format = 0;
michael@0:   uint16_t mark_set_count = 0;
michael@0:   if (!subtable.ReadU16(&format) ||
michael@0:       !subtable.ReadU16(&mark_set_count)) {
michael@0:     return OTS_FAILURE_MSG("Can' read mark glyph table structure");
michael@0:   }
michael@0:   if (format != 1) {
michael@0:     return OTS_FAILURE_MSG("bad mark glyph set table format: %u", format);
michael@0:   }
michael@0: 
michael@0:   const unsigned mark_sets_end = 2 * static_cast<unsigned>(mark_set_count) + 4;
michael@0:   if (mark_sets_end > std::numeric_limits<uint16_t>::max()) {
michael@0:     return OTS_FAILURE_MSG("Bad mark_set %d", mark_sets_end);
michael@0:   }
michael@0:   for (unsigned i = 0; i < mark_set_count; ++i) {
michael@0:     uint32_t offset_coverage = 0;
michael@0:     if (!subtable.ReadU32(&offset_coverage)) {
michael@0:       return OTS_FAILURE_MSG("Can't read covrage location for mark set %d", i);
michael@0:     }
michael@0:     if (offset_coverage >= length ||
michael@0:         offset_coverage < mark_sets_end) {
michael@0:       return OTS_FAILURE_MSG("Bad coverage location %d for mark set %d", offset_coverage, i);
michael@0:     }
michael@0:     if (!ots::ParseCoverageTable(file, data + offset_coverage,
michael@0:                                  length - offset_coverage, num_glyphs)) {
michael@0:       return OTS_FAILURE_MSG("Failed to parse coverage table for mark set %d", i);
michael@0:     }
michael@0:   }
michael@0:   file->gdef->num_mark_glyph_sets = mark_set_count;
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: #define DROP_THIS_TABLE(msg_) \
michael@0:   do { \
michael@0:     file->gdef->data = 0; \
michael@0:     file->gdef->length = 0; \
michael@0:     OTS_FAILURE_MSG(msg_ ", table discarded"); \
michael@0:   } while (0)
michael@0: 
michael@0: namespace ots {
michael@0: 
michael@0: bool ots_gdef_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
michael@0:   // Grab the number of glyphs in the file from the maxp table to check
michael@0:   // GlyphIDs in GDEF table.
michael@0:   if (!file->maxp) {
michael@0:     return OTS_FAILURE_MSG("No maxp table in font, needed by GDEF");
michael@0:   }
michael@0:   const uint16_t num_glyphs = file->maxp->num_glyphs;
michael@0: 
michael@0:   Buffer table(data, length);
michael@0: 
michael@0:   OpenTypeGDEF *gdef = new OpenTypeGDEF;
michael@0:   file->gdef = gdef;
michael@0: 
michael@0:   uint32_t version = 0;
michael@0:   if (!table.ReadU32(&version)) {
michael@0:     DROP_THIS_TABLE("Incomplete table");
michael@0:     return true;
michael@0:   }
michael@0:   if (version < 0x00010000 || version == 0x00010001) {
michael@0:     DROP_THIS_TABLE("Bad version");
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   if (version >= 0x00010002) {
michael@0:     gdef->version_2 = true;
michael@0:   }
michael@0: 
michael@0:   uint16_t offset_glyph_class_def = 0;
michael@0:   uint16_t offset_attach_list = 0;
michael@0:   uint16_t offset_lig_caret_list = 0;
michael@0:   uint16_t offset_mark_attach_class_def = 0;
michael@0:   if (!table.ReadU16(&offset_glyph_class_def) ||
michael@0:       !table.ReadU16(&offset_attach_list) ||
michael@0:       !table.ReadU16(&offset_lig_caret_list) ||
michael@0:       !table.ReadU16(&offset_mark_attach_class_def)) {
michael@0:     DROP_THIS_TABLE("Incomplete table");
michael@0:     return true;
michael@0:   }
michael@0:   uint16_t offset_mark_glyph_sets_def = 0;
michael@0:   if (gdef->version_2) {
michael@0:     if (!table.ReadU16(&offset_mark_glyph_sets_def)) {
michael@0:       DROP_THIS_TABLE("Incomplete table");
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   unsigned gdef_header_end = 4 + 4 * 2;
michael@0:   if (gdef->version_2)
michael@0:     gdef_header_end += 2;
michael@0: 
michael@0:   // Parse subtables
michael@0:   if (offset_glyph_class_def) {
michael@0:     if (offset_glyph_class_def >= length ||
michael@0:         offset_glyph_class_def < gdef_header_end) {
michael@0:       DROP_THIS_TABLE("Invalid offset to glyph classes");
michael@0:       return true;
michael@0:     }
michael@0:     if (!ParseGlyphClassDefTable(file, data + offset_glyph_class_def,
michael@0:                                  length - offset_glyph_class_def,
michael@0:                                  num_glyphs)) {
michael@0:       DROP_THIS_TABLE("Invalid glyph classes");
michael@0:       return true;
michael@0:     }
michael@0:     gdef->has_glyph_class_def = true;
michael@0:   }
michael@0: 
michael@0:   if (offset_attach_list) {
michael@0:     if (offset_attach_list >= length ||
michael@0:         offset_attach_list < gdef_header_end) {
michael@0:       DROP_THIS_TABLE("Invalid offset to attachment list");
michael@0:       return true;
michael@0:     }
michael@0:     if (!ParseAttachListTable(file, data + offset_attach_list,
michael@0:                               length - offset_attach_list,
michael@0:                               num_glyphs)) {
michael@0:       DROP_THIS_TABLE("Invalid attachment list");
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (offset_lig_caret_list) {
michael@0:     if (offset_lig_caret_list >= length ||
michael@0:         offset_lig_caret_list < gdef_header_end) {
michael@0:       DROP_THIS_TABLE("Invalid offset to ligature caret list");
michael@0:       return true;
michael@0:     }
michael@0:     if (!ParseLigCaretListTable(file, data + offset_lig_caret_list,
michael@0:                               length - offset_lig_caret_list,
michael@0:                               num_glyphs)) {
michael@0:       DROP_THIS_TABLE("Invalid ligature caret list");
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (offset_mark_attach_class_def) {
michael@0:     if (offset_mark_attach_class_def >= length ||
michael@0:         offset_mark_attach_class_def < gdef_header_end) {
michael@0:       return OTS_FAILURE_MSG("Invalid offset to mark attachment list");
michael@0:     }
michael@0:     if (!ParseMarkAttachClassDefTable(file,
michael@0:                                       data + offset_mark_attach_class_def,
michael@0:                                       length - offset_mark_attach_class_def,
michael@0:                                       num_glyphs)) {
michael@0:       DROP_THIS_TABLE("Invalid mark attachment list");
michael@0:       return true;
michael@0:     }
michael@0:     gdef->has_mark_attachment_class_def = true;
michael@0:   }
michael@0: 
michael@0:   if (offset_mark_glyph_sets_def) {
michael@0:     if (offset_mark_glyph_sets_def >= length ||
michael@0:         offset_mark_glyph_sets_def < gdef_header_end) {
michael@0:       return OTS_FAILURE_MSG("invalid offset to mark glyph sets");
michael@0:     }
michael@0:     if (!ParseMarkGlyphSetsDefTable(file,
michael@0:                                     data + offset_mark_glyph_sets_def,
michael@0:                                     length - offset_mark_glyph_sets_def,
michael@0:                                     num_glyphs)) {
michael@0:       DROP_THIS_TABLE("Invalid mark glyph sets");
michael@0:       return true;
michael@0:     }
michael@0:     gdef->has_mark_glyph_sets_def = true;
michael@0:   }
michael@0:   gdef->data = data;
michael@0:   gdef->length = length;
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ots_gdef_should_serialise(OpenTypeFile *file) {
michael@0:   return file->gdef != NULL && file->gdef->data != NULL;
michael@0: }
michael@0: 
michael@0: bool ots_gdef_serialise(OTSStream *out, OpenTypeFile *file) {
michael@0:   if (!out->Write(file->gdef->data, file->gdef->length)) {
michael@0:     return OTS_FAILURE_MSG("Failed to write GDEF table");
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: void ots_gdef_free(OpenTypeFile *file) {
michael@0:   delete file->gdef;
michael@0: }
michael@0: 
michael@0: }  // namespace ots
michael@0: