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