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Diffstat (limited to 'gfx/ots/src/gdef.cc')
| -rw-r--r-- | gfx/ots/src/gdef.cc | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/gfx/ots/src/gdef.cc b/gfx/ots/src/gdef.cc new file mode 100644 index 000000000..71c6fc592 --- /dev/null +++ b/gfx/ots/src/gdef.cc @@ -0,0 +1,373 @@ +// 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 "gdef.h" + +#include <limits> +#include <vector> + +#include "gpos.h" +#include "gsub.h" +#include "layout.h" +#include "maxp.h" + +// GDEF - The Glyph Definition Table +// http://www.microsoft.com/typography/otspec/gdef.htm + +#define TABLE_NAME "GDEF" + +namespace { + +// The maximum class value in class definition tables. +const uint16_t kMaxClassDefValue = 0xFFFF; +// The maximum class value in the glyph class definision table. +const uint16_t kMaxGlyphClassDefValue = 4; +// The maximum format number of caret value tables. +// We don't support format 3 for now. See the comment in +// ParseLigCaretListTable() for the reason. +const uint16_t kMaxCaretValueFormat = 2; + +bool ParseGlyphClassDefTable(ots::Font *font, const uint8_t *data, + size_t length, const uint16_t num_glyphs) { + return ots::ParseClassDefTable(font, data, length, num_glyphs, + kMaxGlyphClassDefValue); +} + +bool ParseAttachListTable(ots::Font *font, const uint8_t *data, + size_t length, const uint16_t num_glyphs) { + ots::Buffer subtable(data, length); + + uint16_t offset_coverage = 0; + uint16_t glyph_count = 0; + if (!subtable.ReadU16(&offset_coverage) || + !subtable.ReadU16(&glyph_count)) { + return OTS_FAILURE_MSG("Failed to read gdef header"); + } + const unsigned attach_points_end = + 2 * static_cast<unsigned>(glyph_count) + 4; + if (attach_points_end > std::numeric_limits<uint16_t>::max()) { + return OTS_FAILURE_MSG("Bad glyph count in gdef"); + } + if (offset_coverage == 0 || offset_coverage >= length || + offset_coverage < attach_points_end) { + return OTS_FAILURE_MSG("Bad coverage offset %d", offset_coverage); + } + if (glyph_count > num_glyphs) { + return OTS_FAILURE_MSG("Bad glyph count %u", glyph_count); + } + + std::vector<uint16_t> attach_points; + attach_points.resize(glyph_count); + for (unsigned i = 0; i < glyph_count; ++i) { + if (!subtable.ReadU16(&attach_points[i])) { + return OTS_FAILURE_MSG("Can't read attachment point %d", i); + } + if (attach_points[i] >= length || + attach_points[i] < attach_points_end) { + return OTS_FAILURE_MSG("Bad attachment point %d of %d", i, attach_points[i]); + } + } + + // Parse coverage table + if (!ots::ParseCoverageTable(font, data + offset_coverage, + length - offset_coverage, num_glyphs)) { + return OTS_FAILURE_MSG("Bad coverage table"); + } + + // Parse attach point table + for (unsigned i = 0; i < attach_points.size(); ++i) { + subtable.set_offset(attach_points[i]); + uint16_t point_count = 0; + if (!subtable.ReadU16(&point_count)) { + return OTS_FAILURE_MSG("Can't read point count %d", i); + } + if (point_count == 0) { + return OTS_FAILURE_MSG("zero point count %d", i); + } + uint16_t last_point_index = 0; + uint16_t point_index = 0; + for (unsigned j = 0; j < point_count; ++j) { + if (!subtable.ReadU16(&point_index)) { + return OTS_FAILURE_MSG("Can't read point index %d in point %d", j, i); + } + // Contour point indeces are in increasing numerical order + if (last_point_index != 0 && last_point_index >= point_index) { + return OTS_FAILURE_MSG("bad contour indeces: %u >= %u", + last_point_index, point_index); + } + last_point_index = point_index; + } + } + return true; +} + +bool ParseLigCaretListTable(ots::Font *font, const uint8_t *data, + size_t length, const uint16_t num_glyphs) { + ots::Buffer subtable(data, length); + uint16_t offset_coverage = 0; + uint16_t lig_glyph_count = 0; + if (!subtable.ReadU16(&offset_coverage) || + !subtable.ReadU16(&lig_glyph_count)) { + return OTS_FAILURE_MSG("Can't read caret structure"); + } + const unsigned lig_glyphs_end = + 2 * static_cast<unsigned>(lig_glyph_count) + 4; + if (lig_glyphs_end > std::numeric_limits<uint16_t>::max()) { + return OTS_FAILURE_MSG("Bad caret structure"); + } + if (offset_coverage == 0 || offset_coverage >= length || + offset_coverage < lig_glyphs_end) { + return OTS_FAILURE_MSG("Bad caret coverate offset %d", offset_coverage); + } + if (lig_glyph_count > num_glyphs) { + return OTS_FAILURE_MSG("bad ligature glyph count: %u", lig_glyph_count); + } + + std::vector<uint16_t> lig_glyphs; + lig_glyphs.resize(lig_glyph_count); + for (unsigned i = 0; i < lig_glyph_count; ++i) { + if (!subtable.ReadU16(&lig_glyphs[i])) { + return OTS_FAILURE_MSG("Can't read ligature glyph location %d", i); + } + if (lig_glyphs[i] >= length || lig_glyphs[i] < lig_glyphs_end) { + return OTS_FAILURE_MSG("Bad ligature glyph location %d in glyph %d", lig_glyphs[i], i); + } + } + + // Parse coverage table + if (!ots::ParseCoverageTable(font, data + offset_coverage, + length - offset_coverage, num_glyphs)) { + return OTS_FAILURE_MSG("Can't parse caret coverage table"); + } + + // Parse ligature glyph table + for (unsigned i = 0; i < lig_glyphs.size(); ++i) { + subtable.set_offset(lig_glyphs[i]); + uint16_t caret_count = 0; + if (!subtable.ReadU16(&caret_count)) { + return OTS_FAILURE_MSG("Can't read caret count for glyph %d", i); + } + if (caret_count == 0) { + return OTS_FAILURE_MSG("bad caret value count: %u", caret_count); + } + + std::vector<uint16_t> caret_value_offsets; + caret_value_offsets.resize(caret_count); + unsigned caret_value_offsets_end = 2 * static_cast<unsigned>(caret_count) + 2; + for (unsigned j = 0; j < caret_count; ++j) { + if (!subtable.ReadU16(&caret_value_offsets[j])) { + return OTS_FAILURE_MSG("Can't read caret offset %d for glyph %d", j, i); + } + if (caret_value_offsets[j] >= length || caret_value_offsets[j] < caret_value_offsets_end) { + return OTS_FAILURE_MSG("Bad caret offset %d for caret %d glyph %d", caret_value_offsets[j], j, i); + } + } + + // Parse caret values table + for (unsigned j = 0; j < caret_count; ++j) { + subtable.set_offset(lig_glyphs[i] + caret_value_offsets[j]); + uint16_t caret_format = 0; + if (!subtable.ReadU16(&caret_format)) { + return OTS_FAILURE_MSG("Can't read caret values table %d in glyph %d", j, i); + } + // TODO(bashi): We only support caret value format 1 and 2 for now + // because there are no fonts which contain caret value format 3 + // as far as we investigated. + if (caret_format == 0 || caret_format > kMaxCaretValueFormat) { + return OTS_FAILURE_MSG("bad caret value format: %u", caret_format); + } + // CaretValueFormats contain a 2-byte field which could be + // arbitrary value. + if (!subtable.Skip(2)) { + return OTS_FAILURE_MSG("Bad caret value table structure %d in glyph %d", j, i); + } + } + } + return true; +} + +bool ParseMarkAttachClassDefTable(ots::Font *font, const uint8_t *data, + size_t length, const uint16_t num_glyphs) { + return ots::ParseClassDefTable(font, data, length, num_glyphs, kMaxClassDefValue); +} + +bool ParseMarkGlyphSetsDefTable(ots::Font *font, const uint8_t *data, + size_t length, const uint16_t num_glyphs) { + ots::Buffer subtable(data, length); + uint16_t format = 0; + uint16_t mark_set_count = 0; + if (!subtable.ReadU16(&format) || + !subtable.ReadU16(&mark_set_count)) { + return OTS_FAILURE_MSG("Can' read mark glyph table structure"); + } + if (format != 1) { + return OTS_FAILURE_MSG("bad mark glyph set table format: %u", format); + } + + const unsigned mark_sets_end = 2 * static_cast<unsigned>(mark_set_count) + 4; + if (mark_sets_end > std::numeric_limits<uint16_t>::max()) { + return OTS_FAILURE_MSG("Bad mark_set %d", mark_sets_end); + } + for (unsigned i = 0; i < mark_set_count; ++i) { + uint32_t offset_coverage = 0; + if (!subtable.ReadU32(&offset_coverage)) { + return OTS_FAILURE_MSG("Can't read covrage location for mark set %d", i); + } + if (offset_coverage >= length || + offset_coverage < mark_sets_end) { + return OTS_FAILURE_MSG("Bad coverage location %d for mark set %d", offset_coverage, i); + } + if (!ots::ParseCoverageTable(font, data + offset_coverage, + length - offset_coverage, num_glyphs)) { + return OTS_FAILURE_MSG("Failed to parse coverage table for mark set %d", i); + } + } + font->gdef->num_mark_glyph_sets = mark_set_count; + return true; +} + +} // namespace + +namespace ots { + +bool ots_gdef_parse(Font *font, const uint8_t *data, size_t length) { + // Grab the number of glyphs in the font from the maxp table to check + // GlyphIDs in GDEF table. + if (!font->maxp) { + return OTS_FAILURE_MSG("No maxp table in font, needed by GDEF"); + } + const uint16_t num_glyphs = font->maxp->num_glyphs; + + Buffer table(data, length); + + OpenTypeGDEF *gdef = new OpenTypeGDEF; + font->gdef = gdef; + + uint32_t version = 0; + if (!table.ReadU32(&version)) { + return OTS_FAILURE_MSG("Incomplete table"); + } + if (version < 0x00010000 || version == 0x00010001) { + return OTS_FAILURE_MSG("Bad version"); + } + + if (version >= 0x00010002) { + gdef->version_2 = true; + } + + uint16_t offset_glyph_class_def = 0; + uint16_t offset_attach_list = 0; + uint16_t offset_lig_caret_list = 0; + uint16_t offset_mark_attach_class_def = 0; + if (!table.ReadU16(&offset_glyph_class_def) || + !table.ReadU16(&offset_attach_list) || + !table.ReadU16(&offset_lig_caret_list) || + !table.ReadU16(&offset_mark_attach_class_def)) { + return OTS_FAILURE_MSG("Incomplete table"); + } + uint16_t offset_mark_glyph_sets_def = 0; + if (gdef->version_2) { + if (!table.ReadU16(&offset_mark_glyph_sets_def)) { + return OTS_FAILURE_MSG("Incomplete table"); + } + } + + unsigned gdef_header_end = 4 + 4 * 2; + if (gdef->version_2) + gdef_header_end += 2; + + // Parse subtables + if (offset_glyph_class_def) { + if (offset_glyph_class_def >= length || + offset_glyph_class_def < gdef_header_end) { + return OTS_FAILURE_MSG("Invalid offset to glyph classes"); + } + if (!ParseGlyphClassDefTable(font, data + offset_glyph_class_def, + length - offset_glyph_class_def, + num_glyphs)) { + return OTS_FAILURE_MSG("Invalid glyph classes"); + } + gdef->has_glyph_class_def = true; + } + + if (offset_attach_list) { + if (offset_attach_list >= length || + offset_attach_list < gdef_header_end) { + return OTS_FAILURE_MSG("Invalid offset to attachment list"); + } + if (!ParseAttachListTable(font, data + offset_attach_list, + length - offset_attach_list, + num_glyphs)) { + return OTS_FAILURE_MSG("Invalid attachment list"); + } + } + + if (offset_lig_caret_list) { + if (offset_lig_caret_list >= length || + offset_lig_caret_list < gdef_header_end) { + return OTS_FAILURE_MSG("Invalid offset to ligature caret list"); + } + if (!ParseLigCaretListTable(font, data + offset_lig_caret_list, + length - offset_lig_caret_list, + num_glyphs)) { + return OTS_FAILURE_MSG("Invalid ligature caret list"); + } + } + + if (offset_mark_attach_class_def) { + if (offset_mark_attach_class_def >= length || + offset_mark_attach_class_def < gdef_header_end) { + return OTS_FAILURE_MSG("Invalid offset to mark attachment list"); + } + if (!ParseMarkAttachClassDefTable(font, + data + offset_mark_attach_class_def, + length - offset_mark_attach_class_def, + num_glyphs)) { + return OTS_FAILURE_MSG("Invalid mark attachment list"); + } + gdef->has_mark_attachment_class_def = true; + } + + if (offset_mark_glyph_sets_def) { + if (offset_mark_glyph_sets_def >= length || + offset_mark_glyph_sets_def < gdef_header_end) { + return OTS_FAILURE_MSG("invalid offset to mark glyph sets"); + } + if (!ParseMarkGlyphSetsDefTable(font, + data + offset_mark_glyph_sets_def, + length - offset_mark_glyph_sets_def, + num_glyphs)) { + return OTS_FAILURE_MSG("Invalid mark glyph sets"); + } + gdef->has_mark_glyph_sets_def = true; + } + gdef->data = data; + gdef->length = length; + return true; +} + +bool ots_gdef_should_serialise(Font *font) { + return font->gdef != NULL && font->gdef->data != NULL; +} + +bool ots_gdef_serialise(OTSStream *out, Font *font) { + if (!out->Write(font->gdef->data, font->gdef->length)) { + return OTS_FAILURE_MSG("Failed to write GDEF table"); + } + + return true; +} + +void ots_gdef_reuse(Font *font, Font *other) { + font->gdef = other->gdef; + font->gdef_reused = true; +} + +void ots_gdef_free(Font *font) { + delete font->gdef; +} + +} // namespace ots + +#undef TABLE_NAME |