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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/typography/otspec/hhea.htm
// http://www.microsoft.com/typography/otspec/vhea.htm
#define TABLE_NAME "metrics" // XXX: use individual table names
namespace ots {
bool ParseMetricsHeader(Font *font, 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_MSG("Failed to read metrics header");
}
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 (!font->head) {
return OTS_FAILURE_MSG("Missing head font table");
}
// if the font is non-slanted, caret_offset should be zero.
if (!(font->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_MSG("Failed to skip reserverd bytes");
}
int16_t data_format;
if (!table->ReadS16(&data_format)) {
return OTS_FAILURE_MSG("Failed to read data format");
}
if (data_format) {
return OTS_FAILURE_MSG("Bad data format %d", data_format);
}
if (!table->ReadU16(&header->num_metrics)) {
return OTS_FAILURE_MSG("Failed to read number of metrics");
}
if (!font->maxp) {
return OTS_FAILURE_MSG("Missing maxp font table");
}
if (header->num_metrics > font->maxp->num_glyphs) {
return OTS_FAILURE_MSG("Bad number of metrics %d", header->num_metrics);
}
return true;
}
bool SerialiseMetricsHeader(const ots::Font *font,
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_MSG("Failed to write metrics");
}
return true;
}
bool ParseMetricsTable(const ots::Font *font,
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_MSG("Bad number of metrics %d", num_metrics);
}
if (!num_metrics) {
return OTS_FAILURE_MSG("No metrics!");
}
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_MSG("Failed to read metric %d", i);
}
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_MSG("Failed to read side bearing %d", i + num_metrics);
}
metrics->sbs.push_back(sb);
}
return true;
}
bool SerialiseMetricsTable(const ots::Font *font,
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_MSG("Failed to write metric %d", i);
}
}
for (unsigned i = 0; i < metrics->sbs.size(); ++i) {
if (!out->WriteS16(metrics->sbs[i])) {
return OTS_FAILURE_MSG("Failed to write side bearing %ld", i + metrics->entries.size());
}
}
return true;
}
} // namespace ots
#undef TABLE_NAME
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