106 lines
3.2 KiB
C++
106 lines
3.2 KiB
C++
// Copyright (c) 2018 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 "mvar.h"
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#include "variations.h"
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namespace ots {
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// -----------------------------------------------------------------------------
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// OpenTypeMVAR
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// -----------------------------------------------------------------------------
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bool OpenTypeMVAR::Parse(const uint8_t* data, size_t length) {
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Buffer table(data, length);
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uint16_t majorVersion;
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uint16_t minorVersion;
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uint16_t reserved;
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uint16_t valueRecordSize;
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uint16_t valueRecordCount;
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uint16_t itemVariationStoreOffset;
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if (!table.ReadU16(&majorVersion) ||
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!table.ReadU16(&minorVersion) ||
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!table.ReadU16(&reserved) ||
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!table.ReadU16(&valueRecordSize) ||
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!table.ReadU16(&valueRecordCount) ||
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!table.ReadU16(&itemVariationStoreOffset)) {
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return DropVariations("Failed to read table header");
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}
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if (majorVersion != 1) {
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return DropVariations("Unknown table version");
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}
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if (reserved != 0) {
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Warning("Expected reserved=0");
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}
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// The spec says that valueRecordSize "must be greater than zero",
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// but we don't enforce this in the case where valueRecordCount
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// is zero.
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// The minimum size for a valueRecord to be valid is 8, for the
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// three fields currently defined in the record (see below).
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if (valueRecordSize < 8) {
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if (valueRecordCount != 0) {
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return DropVariations("Value record size too small");
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}
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}
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if (valueRecordCount == 0) {
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if (itemVariationStoreOffset != 0) {
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// The spec says "if valueRecordCount is zero, set to zero",
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// but having a variation store even when record count is zero
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// should be harmless -- it just won't be useful for anything.
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// But we don't need to reject altogether.
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Warning("Unexpected item variation store");
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}
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} else {
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if (itemVariationStoreOffset < table.offset() || itemVariationStoreOffset > length) {
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return DropVariations("Invalid item variation store offset");
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}
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if (!ParseItemVariationStore(GetFont(), data + itemVariationStoreOffset,
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length - itemVariationStoreOffset)) {
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return DropVariations("Failed to parse item variation store");
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}
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}
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uint32_t prevTag = 0;
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size_t offset = table.offset();
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for (unsigned i = 0; i < valueRecordCount; i++) {
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uint32_t tag;
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uint16_t deltaSetOuterIndex, deltaSetInnerIndex;
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if (!table.ReadU32(&tag) ||
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!table.ReadU16(&deltaSetOuterIndex) ||
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!table.ReadU16(&deltaSetInnerIndex)) {
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return DropVariations("Failed to read value record");
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}
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if (tag <= prevTag) {
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return DropVariations("Invalid or out-of-order value tag");
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}
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prevTag = tag;
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// Adjust offset in case additional fields have been added to the
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// valueRecord by a new minor version (allowed by spec).
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offset += valueRecordSize;
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table.set_offset(offset);
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}
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this->m_data = data;
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this->m_length = length;
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return true;
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}
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bool OpenTypeMVAR::Serialize(OTSStream* out) {
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if (!out->Write(this->m_data, this->m_length)) {
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return Error("Failed to write MVAR table");
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}
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return true;
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}
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} // namespace ots
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