160 lines
5.2 KiB
C++
160 lines
5.2 KiB
C++
// Copyright (c) 2009-2017 The OTS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "sill.h"
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#include "feat.h"
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#include <cmath>
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#include <unordered_set>
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namespace ots {
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bool OpenTypeSILL::Parse(const uint8_t* data, size_t length) {
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if (GetFont()->dropped_graphite) {
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return Drop("Skipping Graphite table");
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}
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Buffer table(data, length);
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if (!table.ReadU32(&this->version) || this->version >> 16 != 1) {
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return Drop("Failed to read valid version");
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}
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if (!table.ReadU16(&this->numLangs)) {
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return Drop("Failed to read numLangs");
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}
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// The following three fields are deprecated and ignored. We fix them up here
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// just for internal consistency, but the Graphite engine doesn't care.
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if (!table.ReadU16(&this->searchRange) ||
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!table.ReadU16(&this->entrySelector) ||
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!table.ReadU16(&this->rangeShift)) {
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return Drop("Failed to read searchRange..rangeShift");
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}
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if (this->numLangs == 0) {
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if (this->searchRange != 0 || this->entrySelector != 0 || this->rangeShift != 0) {
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this->searchRange = this->entrySelector = this->rangeShift = 0;
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}
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} else {
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unsigned floorLog2 = std::floor(std::log2(this->numLangs));
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if (this->searchRange != (unsigned)std::pow(2, floorLog2) ||
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this->entrySelector != floorLog2 ||
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this->rangeShift != this->numLangs - this->searchRange) {
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this->searchRange = (unsigned)std::pow(2, floorLog2);
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this->entrySelector = floorLog2;
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this->rangeShift = this->numLangs - this->searchRange;
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}
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}
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std::unordered_set<size_t> unverified;
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//this->entries.resize(static_cast<unsigned long>(this->numLangs) + 1, this);
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for (unsigned long i = 0; i <= this->numLangs; ++i) {
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this->entries.emplace_back(this);
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LanguageEntry& entry = this->entries[i];
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if (!entry.ParsePart(table)) {
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return Drop("Failed to read entries[%u]", i);
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}
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for (unsigned j = 0; j < entry.numSettings; ++j) {
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size_t offset = entry.offset + j * 8;
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if (offset < entry.offset || offset > length) {
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return DropGraphite("Invalid LangFeatureSetting offset %zu/%zu",
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offset, length);
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}
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unverified.insert(offset);
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// need to verify that this LanguageEntry points to valid
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// LangFeatureSetting
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}
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}
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while (table.remaining()) {
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unverified.erase(table.offset());
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LangFeatureSetting setting(this);
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if (!setting.ParsePart(table)) {
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return Drop("Failed to read a LangFeatureSetting");
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}
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settings.push_back(setting);
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}
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if (!unverified.empty()) {
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return Drop("%zu incorrect offsets into settings", unverified.size());
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}
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if (table.remaining()) {
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return Warning("%zu bytes unparsed", table.remaining());
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}
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return true;
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}
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bool OpenTypeSILL::Serialize(OTSStream* out) {
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if (!out->WriteU32(this->version) ||
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!out->WriteU16(this->numLangs) ||
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!out->WriteU16(this->searchRange) ||
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!out->WriteU16(this->entrySelector) ||
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!out->WriteU16(this->rangeShift) ||
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!SerializeParts(this->entries, out) ||
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!SerializeParts(this->settings, out)) {
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return Error("Failed to write table");
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}
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return true;
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}
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bool OpenTypeSILL::LanguageEntry::ParsePart(Buffer& table) {
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if (!table.ReadU8(&this->langcode[0]) ||
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!table.ReadU8(&this->langcode[1]) ||
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!table.ReadU8(&this->langcode[2]) ||
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!table.ReadU8(&this->langcode[3])) {
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return parent->Error("LanguageEntry: Failed to read langcode");
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}
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if (!table.ReadU16(&this->numSettings)) {
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return parent->Error("LanguageEntry: Failed to read numSettings");
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}
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if (!table.ReadU16(&this->offset)) {
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return parent->Error("LanguageEntry: Failed to read offset");
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}
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return true;
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}
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bool OpenTypeSILL::LanguageEntry::SerializePart(OTSStream* out) const {
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if (!out->WriteU8(this->langcode[0]) ||
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!out->WriteU8(this->langcode[1]) ||
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!out->WriteU8(this->langcode[2]) ||
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!out->WriteU8(this->langcode[3]) ||
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!out->WriteU16(this->numSettings) ||
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!out->WriteU16(this->offset)) {
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return parent->Error("LanguageEntry: Failed to write");
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}
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return true;
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}
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bool OpenTypeSILL::LangFeatureSetting::ParsePart(Buffer& table) {
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OpenTypeFEAT* feat = static_cast<OpenTypeFEAT*>(
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parent->GetFont()->GetTypedTable(OTS_TAG_FEAT));
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if (!feat) {
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return parent->Error("FeatureDefn: Required Feat table is missing");
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}
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if (!table.ReadU32(&this->featureId) ||
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!feat->IsValidFeatureId(this->featureId)) {
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return parent->Error("LangFeatureSetting: Failed to read valid featureId");
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}
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if (!table.ReadS16(&this->value)) {
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return parent->Error("LangFeatureSetting: Failed to read value");
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}
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if (!table.ReadU16(&this->reserved)) {
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return parent->Error("LangFeatureSetting: Failed to read reserved");
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}
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if (this->reserved != 0) {
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parent->Warning("LangFeatureSetting: Nonzero reserved");
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}
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return true;
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}
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bool OpenTypeSILL::LangFeatureSetting::SerializePart(OTSStream* out) const {
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if (!out->WriteU32(this->featureId) ||
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!out->WriteS16(this->value) ||
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!out->WriteU16(this->reserved)) {
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return parent->Error("LangFeatureSetting: Failed to read reserved");
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}
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return true;
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}
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} // namespace ots
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