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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 "gasp.h"
// gasp - Grid-fitting And Scan-conversion Procedure
namespace ots {
bool OpenTypeGASP::Parse(const uint8_t *data, size_t length) {
Buffer table(data, length);
uint16_t num_ranges = 0;
if (!table.ReadU16(&this->version) ||
!table.ReadU16(&num_ranges)) {
return Error("Failed to read table header");
}
if (this->version > 1) {
// Lots of Linux fonts have bad version numbers...
return Drop("Unsupported version: %u", this->version);
}
if (num_ranges == 0) {
return Drop("numRanges is zero");
}
this->gasp_ranges.reserve(num_ranges);
for (unsigned i = 0; i < num_ranges; ++i) {
uint16_t max_ppem = 0;
uint16_t behavior = 0;
if (!table.ReadU16(&max_ppem) ||
!table.ReadU16(&behavior)) {
return Error("Failed to read GASPRANGE %d", i);
}
if ((i > 0) && (this->gasp_ranges[i - 1].first >= max_ppem)) {
// The records in the gaspRange[] array must be sorted in order of
// increasing rangeMaxPPEM value.
return Drop("Ranges are not sorted");
}
if ((i == num_ranges - 1u) && // never underflow.
(max_ppem != 0xffffu)) {
return Drop("The last record should be 0xFFFF as a sentinel value "
"for rangeMaxPPEM");
}
if (behavior >> 8) {
Warning("Undefined bits are used: %x", behavior);
// mask undefined bits.
behavior &= 0x000fu;
}
if (this->version == 0 && (behavior >> 2) != 0) {
Warning("Changed the version number to 1");
this->version = 1;
}
this->gasp_ranges.push_back(std::make_pair(max_ppem, behavior));
}
return true;
}
bool OpenTypeGASP::Serialize(OTSStream *out) {
const uint16_t num_ranges = static_cast<uint16_t>(this->gasp_ranges.size());
if (num_ranges != this->gasp_ranges.size() ||
!out->WriteU16(this->version) ||
!out->WriteU16(num_ranges)) {
return Error("Failed to write table header");
}
for (uint16_t i = 0; i < num_ranges; ++i) {
if (!out->WriteU16(this->gasp_ranges[i].first) ||
!out->WriteU16(this->gasp_ranges[i].second)) {
return Error("Failed to write GASPRANGE %d", i);
}
}
return true;
}
} // namespace ots