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// 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