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// Copyright (c) 2011 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 "metrics.h"
#include "head.h"
#include "maxp.h"
// OpenType horizontal and vertical common header format
// http://www.microsoft.com/opentype/otspec/hhea.htm
// http://www.microsoft.com/opentype/otspec/vhea.htm
namespace ots {
bool ParseMetricsHeader(OpenTypeFile *file, Buffer *table,
OpenTypeMetricsHeader *header) {
if (!table->ReadS16(&header->ascent) ||
!table->ReadS16(&header->descent) ||
!table->ReadS16(&header->linegap) ||
!table->ReadU16(&header->adv_width_max) ||
!table->ReadS16(&header->min_sb1) ||
!table->ReadS16(&header->min_sb2) ||
!table->ReadS16(&header->max_extent) ||
!table->ReadS16(&header->caret_slope_rise) ||
!table->ReadS16(&header->caret_slope_run) ||
!table->ReadS16(&header->caret_offset)) {
return OTS_FAILURE();
}
if (header->ascent < 0) {
OTS_WARNING("bad ascent: %d", header->ascent);
header->ascent = 0;
}
if (header->linegap < 0) {
OTS_WARNING("bad linegap: %d", header->linegap);
header->linegap = 0;
}
if (!file->head) {
return OTS_FAILURE();
}
// if the font is non-slanted, caret_offset should be zero.
if (!(file->head->mac_style & 2) &&
(header->caret_offset != 0)) {
OTS_WARNING("bad caret offset: %d", header->caret_offset);
header->caret_offset = 0;
}
// skip the reserved bytes
if (!table->Skip(8)) {
return OTS_FAILURE();
}
int16_t data_format;
if (!table->ReadS16(&data_format)) {
return OTS_FAILURE();
}
if (data_format) {
return OTS_FAILURE();
}
if (!table->ReadU16(&header->num_metrics)) {
return OTS_FAILURE();
}
if (!file->maxp) {
return OTS_FAILURE();
}
if (header->num_metrics > file->maxp->num_glyphs) {
return OTS_FAILURE();
}
return true;
}
bool SerialiseMetricsHeader(OTSStream *out,
const OpenTypeMetricsHeader *header) {
if (!out->WriteU32(header->version) ||
!out->WriteS16(header->ascent) ||
!out->WriteS16(header->descent) ||
!out->WriteS16(header->linegap) ||
!out->WriteU16(header->adv_width_max) ||
!out->WriteS16(header->min_sb1) ||
!out->WriteS16(header->min_sb2) ||
!out->WriteS16(header->max_extent) ||
!out->WriteS16(header->caret_slope_rise) ||
!out->WriteS16(header->caret_slope_run) ||
!out->WriteS16(header->caret_offset) ||
!out->WriteR64(0) || // reserved
!out->WriteS16(0) || // metric data format
!out->WriteU16(header->num_metrics)) {
return OTS_FAILURE();
}
return true;
}
bool ParseMetricsTable(Buffer *table,
const uint16_t num_glyphs,
const OpenTypeMetricsHeader *header,
OpenTypeMetricsTable *metrics) {
// |num_metrics| is a uint16_t, so it's bounded < 65536. This limits that
// amount of memory that we'll allocate for this to a sane amount.
const unsigned num_metrics = header->num_metrics;
if (num_metrics > num_glyphs) {
return OTS_FAILURE();
}
if (!num_metrics) {
return OTS_FAILURE();
}
const unsigned num_sbs = num_glyphs - num_metrics;
metrics->entries.reserve(num_metrics);
for (unsigned i = 0; i < num_metrics; ++i) {
uint16_t adv = 0;
int16_t sb = 0;
if (!table->ReadU16(&adv) || !table->ReadS16(&sb)) {
return OTS_FAILURE();
}
// Since so many fonts don't have proper value on |adv| and |sb|,
// we should not call ots_failure() here. For example, about 20% of fonts
// in http://www.princexml.com/fonts/ (200+ fonts) fails these tests.
if (adv > header->adv_width_max) {
OTS_WARNING("bad adv: %u > %u", adv, header->adv_width_max);
adv = header->adv_width_max;
}
if (sb < header->min_sb1) {
OTS_WARNING("bad sb: %d < %d", sb, header->min_sb1);
sb = header->min_sb1;
}
metrics->entries.push_back(std::make_pair(adv, sb));
}
metrics->sbs.reserve(num_sbs);
for (unsigned i = 0; i < num_sbs; ++i) {
int16_t sb;
if (!table->ReadS16(&sb)) {
// Some Japanese fonts (e.g., mona.ttf) fail this test.
return OTS_FAILURE();
}
if (sb < header->min_sb1) {
// The same as above. Three fonts in http://www.fontsquirrel.com/fontface
// (e.g., Notice2Std.otf) have weird lsb values.
OTS_WARNING("bad lsb: %d < %d", sb, header->min_sb1);
sb = header->min_sb1;
}
metrics->sbs.push_back(sb);
}
return true;
}
bool SerialiseMetricsTable(OTSStream *out,
const OpenTypeMetricsTable *metrics) {
for (unsigned i = 0; i < metrics->entries.size(); ++i) {
if (!out->WriteU16(metrics->entries[i].first) ||
!out->WriteS16(metrics->entries[i].second)) {
return OTS_FAILURE();
}
}
for (unsigned i = 0; i < metrics->sbs.size(); ++i) {
if (!out->WriteS16(metrics->sbs[i])) {
return OTS_FAILURE();
}
}
return true;
}
} // namespace ots
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