/gfx/ots/src/gdef.cc
C++ | 393 lines | 326 code | 42 blank | 25 comment | 89 complexity | 874b466ed83df5ef336e83aba35cf565 MD5 | raw file
Possible License(s): MPL-2.0-no-copyleft-exception, LGPL-3.0, AGPL-1.0, LGPL-2.1, BSD-3-Clause, GPL-2.0, JSON, Apache-2.0, 0BSD
- // 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
- 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::OpenTypeFile *file, const uint8_t *data,
- size_t length, const uint16_t num_glyphs) {
- return ots::ParseClassDefTable(data, length, num_glyphs,
- kMaxGlyphClassDefValue);
- }
- bool ParseAttachListTable(ots::OpenTypeFile *file, 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();
- }
- 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();
- }
- if (offset_coverage == 0 || offset_coverage >= length ||
- offset_coverage < attach_points_end) {
- return OTS_FAILURE();
- }
- if (glyph_count > num_glyphs) {
- OTS_WARNING("bad glyph count: %u", glyph_count);
- return OTS_FAILURE();
- }
- 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();
- }
- if (attach_points[i] >= length ||
- attach_points[i] < attach_points_end) {
- return OTS_FAILURE();
- }
- }
- // Parse coverage table
- if (!ots::ParseCoverageTable(data + offset_coverage,
- length - offset_coverage, num_glyphs)) {
- return OTS_FAILURE();
- }
- // 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();
- }
- if (point_count == 0) {
- return OTS_FAILURE();
- }
- 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();
- }
- // Contour point indeces are in increasing numerical order
- if (last_point_index != 0 && last_point_index >= point_index) {
- OTS_WARNING("bad contour indeces: %u >= %u",
- last_point_index, point_index);
- return OTS_FAILURE();
- }
- last_point_index = point_index;
- }
- }
- return true;
- }
- bool ParseLigCaretListTable(ots::OpenTypeFile *file, 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();
- }
- 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();
- }
- if (offset_coverage == 0 || offset_coverage >= length ||
- offset_coverage < lig_glyphs_end) {
- return OTS_FAILURE();
- }
- if (lig_glyph_count > num_glyphs) {
- OTS_WARNING("bad ligature glyph count: %u", lig_glyph_count);
- return OTS_FAILURE();
- }
- 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();
- }
- if (lig_glyphs[i] >= length || lig_glyphs[i] < lig_glyphs_end) {
- return OTS_FAILURE();
- }
- }
- // Parse coverage table
- if (!ots::ParseCoverageTable(data + offset_coverage,
- length - offset_coverage, num_glyphs)) {
- return OTS_FAILURE();
- }
- // 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();
- }
- if (caret_count == 0) {
- OTS_WARNING("bad caret value count: %u", caret_count);
- return OTS_FAILURE();
- }
- std::vector<uint16_t> caret_values;
- caret_values.resize(caret_count);
- uint16_t last_offset_caret = 0;
- unsigned caret_values_end = 2 * static_cast<unsigned>(caret_count) + 2;
- for (unsigned j = 0; j < caret_count; ++j) {
- if (!subtable.ReadU16(&caret_values[j])) {
- return OTS_FAILURE();
- }
- if (caret_values[j] >= length || caret_values[j] < caret_values_end) {
- return OTS_FAILURE();
- }
- // Caret offsets are in increasing coordinate order
- if (last_offset_caret != 0 && last_offset_caret >= caret_values[j]) {
- OTS_WARNING("offset isn't in increasing coordinate order: %u >= %u",
- last_offset_caret, caret_values[j]);
- return OTS_FAILURE();
- }
- last_offset_caret = caret_values[j];
- }
- // Parse caret values table
- for (unsigned j = 0; j < caret_count; ++j) {
- subtable.set_offset(lig_glyphs[i] + caret_values[j]);
- uint16_t caret_format = 0;
- if (!subtable.ReadU16(&caret_format)) {
- return OTS_FAILURE();
- }
- // 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) {
- OTS_WARNING("bad caret value format: %u", caret_format);
- return OTS_FAILURE();
- }
- // CaretValueFormats contain a 2-byte field which could be
- // arbitrary value.
- if (!subtable.Skip(2)) {
- return OTS_FAILURE();
- }
- }
- }
- return true;
- }
- bool ParseMarkAttachClassDefTable(ots::OpenTypeFile *file, const uint8_t *data,
- size_t length, const uint16_t num_glyphs) {
- return ots::ParseClassDefTable(data, length, num_glyphs, kMaxClassDefValue);
- }
- bool ParseMarkGlyphSetsDefTable(ots::OpenTypeFile *file, 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();
- }
- if (format != 1) {
- OTS_WARNING("bad mark glyph set table format: %u", format);
- return OTS_FAILURE();
- }
- 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();
- }
- for (unsigned i = 0; i < mark_set_count; ++i) {
- uint32_t offset_coverage = 0;
- if (!subtable.ReadU32(&offset_coverage)) {
- return OTS_FAILURE();
- }
- if (offset_coverage >= length ||
- offset_coverage < mark_sets_end) {
- return OTS_FAILURE();
- }
- if (!ots::ParseCoverageTable(data + offset_coverage,
- length - offset_coverage, num_glyphs)) {
- return OTS_FAILURE();
- }
- }
- file->gdef->num_mark_glyph_sets = mark_set_count;
- return true;
- }
- } // namespace
- #define DROP_THIS_TABLE \
- do { file->gdef->data = 0; file->gdef->length = 0; } while (0)
- namespace ots {
- bool ots_gdef_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
- // Grab the number of glyphs in the file from the maxp table to check
- // GlyphIDs in GDEF table.
- if (!file->maxp) {
- return OTS_FAILURE();
- }
- const uint16_t num_glyphs = file->maxp->num_glyphs;
- Buffer table(data, length);
- OpenTypeGDEF *gdef = new OpenTypeGDEF;
- file->gdef = gdef;
- uint32_t version = 0;
- if (!table.ReadU32(&version)) {
- return OTS_FAILURE();
- }
- if (version < 0x00010000 || version == 0x00010001) {
- OTS_WARNING("bad GDEF version");
- DROP_THIS_TABLE;
- return true;
- }
- 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();
- }
- uint16_t offset_mark_glyph_sets_def = 0;
- if (gdef->version_2) {
- if (!table.ReadU16(&offset_mark_glyph_sets_def)) {
- return OTS_FAILURE();
- }
- }
- unsigned gdef_header_end = 8;
- 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();
- }
- if (!ParseGlyphClassDefTable(file, data + offset_glyph_class_def,
- length - offset_glyph_class_def,
- num_glyphs)) {
- DROP_THIS_TABLE;
- return true;
- }
- gdef->has_glyph_class_def = true;
- }
- if (offset_attach_list) {
- if (offset_attach_list >= length ||
- offset_attach_list < gdef_header_end) {
- return OTS_FAILURE();
- }
- if (!ParseAttachListTable(file, data + offset_attach_list,
- length - offset_attach_list,
- num_glyphs)) {
- DROP_THIS_TABLE;
- return true;
- }
- }
- if (offset_lig_caret_list) {
- if (offset_lig_caret_list >= length ||
- offset_lig_caret_list < gdef_header_end) {
- return OTS_FAILURE();
- }
- if (!ParseLigCaretListTable(file, data + offset_lig_caret_list,
- length - offset_lig_caret_list,
- num_glyphs)) {
- DROP_THIS_TABLE;
- return true;
- }
- }
- if (offset_mark_attach_class_def) {
- if (offset_mark_attach_class_def >= length ||
- offset_mark_attach_class_def < gdef_header_end) {
- return OTS_FAILURE();
- }
- if (!ParseMarkAttachClassDefTable(file,
- data + offset_mark_attach_class_def,
- length - offset_mark_attach_class_def,
- num_glyphs)) {
- DROP_THIS_TABLE;
- return true;
- }
- 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();
- }
- if (!ParseMarkGlyphSetsDefTable(file,
- data + offset_mark_glyph_sets_def,
- length - offset_mark_glyph_sets_def,
- num_glyphs)) {
- DROP_THIS_TABLE;
- return true;
- }
- gdef->has_mark_glyph_sets_def = true;
- }
- gdef->data = data;
- gdef->length = length;
- return true;
- }
- bool ots_gdef_should_serialise(OpenTypeFile *file) {
- const bool needed_tables_dropped =
- (file->gsub && file->gsub->data == NULL) ||
- (file->gpos && file->gpos->data == NULL);
- return file->gdef != NULL && file->gdef->data != NULL &&
- !needed_tables_dropped;
- }
- bool ots_gdef_serialise(OTSStream *out, OpenTypeFile *file) {
- if (!out->Write(file->gdef->data, file->gdef->length)) {
- return OTS_FAILURE();
- }
- return true;
- }
- void ots_gdef_free(OpenTypeFile *file) {
- delete file->gdef;
- }
- } // namespace ots