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// Copyright (c) 2009 The Chromium 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 "head.h"
#include <cstring>
// head - Font Header
// http://www.microsoft.com/opentype/otspec/head.htm
namespace ots {
bool ots_head_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
Buffer table(data, length);
file->head = new OpenTypeHEAD;
uint32_t version = 0;
if (!table.ReadU32(&version) ||
!table.ReadU32(&file->head->revision)) {
return OTS_FAILURE();
}
if (version >> 16 != 1) {
return OTS_FAILURE();
}
// Skip the checksum adjustment
if (!table.Skip(4)) {
return OTS_FAILURE();
}
uint32_t magic;
if (!table.ReadTag(&magic) ||
std::memcmp(&magic, "\x5F\x0F\x3C\xF5", 4)) {
return OTS_FAILURE();
}
if (!table.ReadU16(&file->head->flags)) {
return OTS_FAILURE();
}
// We allow bits 0..4, 11..13
file->head->flags &= 0x381f;
if (!table.ReadU16(&file->head->ppem)) {
return OTS_FAILURE();
}
// ppem must be in range
if (file->head->ppem < 16 ||
file->head->ppem > 16384) {
return OTS_FAILURE();
}
// ppem must be a power of two
#if 0
// We don't call ots_failure() for now since lots of TrueType fonts are
// not following this rule. Putting OTS_WARNING here is too noisy.
if ((file->head->ppem - 1) & file->head->ppem) {
return OTS_FAILURE();
}
#endif
if (!table.ReadR64(&file->head->created) ||
!table.ReadR64(&file->head->modified)) {
return OTS_FAILURE();
}
if (!table.ReadS16(&file->head->xmin) ||
!table.ReadS16(&file->head->ymin) ||
!table.ReadS16(&file->head->xmax) ||
!table.ReadS16(&file->head->ymax)) {
return OTS_FAILURE();
}
if (file->head->xmin > file->head->xmax) {
return OTS_FAILURE();
}
if (file->head->ymin > file->head->ymax) {
return OTS_FAILURE();
}
if (!table.ReadU16(&file->head->mac_style)) {
return OTS_FAILURE();
}
// We allow bits 0..6
file->head->mac_style &= 0x7f;
if (!table.ReadU16(&file->head->min_ppem)) {
return OTS_FAILURE();
}
// We don't care about the font direction hint
if (!table.Skip(2)) {
return OTS_FAILURE();
}
if (!table.ReadS16(&file->head->index_to_loc_format)) {
return OTS_FAILURE();
}
if (file->head->index_to_loc_format < 0 ||
file->head->index_to_loc_format > 1) {
return OTS_FAILURE();
}
int16_t glyph_data_format;
if (!table.ReadS16(&glyph_data_format) ||
glyph_data_format) {
return OTS_FAILURE();
}
return true;
}
bool ots_head_should_serialise(OpenTypeFile *file) {
return file->head != NULL;
}
bool ots_head_serialise(OTSStream *out, OpenTypeFile *file) {
if (!out->WriteU32(0x00010000) ||
!out->WriteU32(file->head->revision) ||
!out->WriteU32(0) || // check sum not filled in yet
!out->WriteU32(0x5F0F3CF5) ||
!out->WriteU16(file->head->flags) ||
!out->WriteU16(file->head->ppem) ||
!out->WriteR64(file->head->created) ||
!out->WriteR64(file->head->modified) ||
!out->WriteS16(file->head->xmin) ||
!out->WriteS16(file->head->ymin) ||
!out->WriteS16(file->head->xmax) ||
!out->WriteS16(file->head->ymax) ||
!out->WriteU16(file->head->mac_style) ||
!out->WriteU16(file->head->min_ppem) ||
!out->WriteS16(2) ||
!out->WriteS16(file->head->index_to_loc_format) ||
!out->WriteS16(0)) {
return OTS_FAILURE();
}
return true;
}
void ots_head_free(OpenTypeFile *file) {
delete file->head;
}
} // namespace
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