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