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-rw-r--r--gfx/ots/src/gasp.cc84
1 files changed, 84 insertions, 0 deletions
diff --git a/gfx/ots/src/gasp.cc b/gfx/ots/src/gasp.cc
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+++ b/gfx/ots/src/gasp.cc
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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
+// http://www.microsoft.com/typography/otspec/gasp.htm
+
+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