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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 "hdmx.h"
#include "head.h"
#include "maxp.h"
// hdmx - Horizontal Device Metrics
// http://www.microsoft.com/typography/otspec/hdmx.htm
namespace ots {
bool OpenTypeHDMX::Parse(const uint8_t *data, size_t length) {
Buffer table(data, length);
OpenTypeMAXP *maxp = static_cast<OpenTypeMAXP*>(
GetFont()->GetTypedTable(OTS_TAG_MAXP));
OpenTypeHEAD *head = static_cast<OpenTypeHEAD*>(
GetFont()->GetTypedTable(OTS_TAG_HEAD));
if (!head || !maxp) {
return Error("Missing maxp or head tables in font, needed by hdmx");
}
if ((head->flags & 0x14) == 0) {
// http://www.microsoft.com/typography/otspec/recom.htm#hdmx
return Drop("the table should not be present when bit 2 and 4 of the "
"head->flags are not set");
}
int16_t num_recs;
if (!table.ReadU16(&this->version) ||
!table.ReadS16(&num_recs) ||
!table.ReadS32(&this->size_device_record)) {
return Error("Failed to read table header");
}
if (this->version != 0) {
return Drop("Unsupported version: %u", this->version);
}
if (num_recs <= 0) {
return Drop("Bad numRecords: %d", num_recs);
}
const int32_t actual_size_device_record = maxp->num_glyphs + 2;
if (this->size_device_record < actual_size_device_record) {
return Drop("Bad sizeDeviceRecord: %d", this->size_device_record);
}
this->pad_len = this->size_device_record - actual_size_device_record;
if (this->pad_len > 3) {
return Error("Bad DeviceRecord padding %d", this->pad_len);
}
uint8_t last_pixel_size = 0;
this->records.reserve(num_recs);
for (int i = 0; i < num_recs; ++i) {
OpenTypeHDMXDeviceRecord rec;
if (!table.ReadU8(&rec.pixel_size) ||
!table.ReadU8(&rec.max_width)) {
return Error("Failed to read DeviceRecord %d", i);
}
if ((i != 0) &&
(rec.pixel_size <= last_pixel_size)) {
return Drop("DeviceRecord's are not sorted");
}
last_pixel_size = rec.pixel_size;
rec.widths.reserve(maxp->num_glyphs);
for (unsigned j = 0; j < maxp->num_glyphs; ++j) {
uint8_t width;
if (!table.ReadU8(&width)) {
return Error("Failed to read glyph width %d in DeviceRecord %d", j, i);
}
rec.widths.push_back(width);
}
if ((this->pad_len > 0) &&
!table.Skip(this->pad_len)) {
return Error("DeviceRecord %d should be padded by %d", i, this->pad_len);
}
this->records.push_back(rec);
}
return true;
}
bool OpenTypeHDMX::ShouldSerialize() {
return Table::ShouldSerialize() &&
// this table is not for CFF fonts.
GetFont()->GetTable(OTS_TAG_GLYF) != NULL;
}
bool OpenTypeHDMX::Serialize(OTSStream *out) {
const int16_t num_recs = static_cast<int16_t>(this->records.size());
if (this->records.size() >
static_cast<size_t>(std::numeric_limits<int16_t>::max()) ||
!out->WriteU16(this->version) ||
!out->WriteS16(num_recs) ||
!out->WriteS32(this->size_device_record)) {
return Error("Failed to write table header");
}
for (int16_t i = 0; i < num_recs; ++i) {
const OpenTypeHDMXDeviceRecord& rec = this->records[i];
if (!out->Write(&rec.pixel_size, 1) ||
!out->Write(&rec.max_width, 1) ||
!out->Write(&rec.widths[0], rec.widths.size())) {
return Error("Failed to write DeviceRecord %d", i);
}
if ((this->pad_len > 0) &&
!out->Write((const uint8_t *)"\x00\x00\x00", this->pad_len)) {
return Error("Failed to write padding of length %d", this->pad_len);
}
}
return true;
}
} // namespace ots
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