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