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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 "hdmx.h"
#include "head.h"
#include "maxp.h"
// hdmx - Horizontal Device Metrics
// http://www.microsoft.com/typography/otspec/hdmx.htm
#define TABLE_NAME "hdmx"
#define DROP_THIS_TABLE(...) \
do { \
OTS_FAILURE_MSG_(font->file, TABLE_NAME ": " __VA_ARGS__); \
OTS_FAILURE_MSG("Table discarded"); \
delete font->hdmx; \
font->hdmx = 0; \
} while (0)
namespace ots {
bool ots_hdmx_parse(Font *font, const uint8_t *data, size_t length) {
Buffer table(data, length);
font->hdmx = new OpenTypeHDMX;
OpenTypeHDMX * const hdmx = font->hdmx;
if (!font->head || !font->maxp) {
return OTS_FAILURE_MSG("Missing maxp or head tables in font, needed by hdmx");
}
if ((font->head->flags & 0x14) == 0) {
// http://www.microsoft.com/typography/otspec/recom.htm
DROP_THIS_TABLE("the table should not be present when bit 2 and 4 of the "
"head->flags are not set");
return true;
}
int16_t num_recs;
if (!table.ReadU16(&hdmx->version) ||
!table.ReadS16(&num_recs) ||
!table.ReadS32(&hdmx->size_device_record)) {
return OTS_FAILURE_MSG("Failed to read hdmx header");
}
if (hdmx->version != 0) {
DROP_THIS_TABLE("bad version: %u", hdmx->version);
return true;
}
if (num_recs <= 0) {
DROP_THIS_TABLE("bad num_recs: %d", num_recs);
return true;
}
const int32_t actual_size_device_record = font->maxp->num_glyphs + 2;
if (hdmx->size_device_record < actual_size_device_record) {
DROP_THIS_TABLE("bad hdmx->size_device_record: %d", hdmx->size_device_record);
return true;
}
hdmx->pad_len = hdmx->size_device_record - actual_size_device_record;
if (hdmx->pad_len > 3) {
return OTS_FAILURE_MSG("Bad padding %d", hdmx->pad_len);
}
uint8_t last_pixel_size = 0;
hdmx->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 OTS_FAILURE_MSG("Failed to read hdmx record %d", i);
}
if ((i != 0) &&
(rec.pixel_size <= last_pixel_size)) {
DROP_THIS_TABLE("records are not sorted");
return true;
}
last_pixel_size = rec.pixel_size;
rec.widths.reserve(font->maxp->num_glyphs);
for (unsigned j = 0; j < font->maxp->num_glyphs; ++j) {
uint8_t width;
if (!table.ReadU8(&width)) {
return OTS_FAILURE_MSG("Failed to read glyph width %d in record %d", j, i);
}
rec.widths.push_back(width);
}
if ((hdmx->pad_len > 0) &&
!table.Skip(hdmx->pad_len)) {
return OTS_FAILURE_MSG("Failed to skip padding %d", hdmx->pad_len);
}
hdmx->records.push_back(rec);
}
return true;
}
bool ots_hdmx_should_serialise(Font *font) {
if (!font->hdmx) return false;
if (!font->glyf) return false; // this table is not for CFF fonts.
return true;
}
bool ots_hdmx_serialise(OTSStream *out, Font *font) {
OpenTypeHDMX * const hdmx = font->hdmx;
const int16_t num_recs = static_cast<int16_t>(hdmx->records.size());
if (hdmx->records.size() >
static_cast<size_t>(std::numeric_limits<int16_t>::max()) ||
!out->WriteU16(hdmx->version) ||
!out->WriteS16(num_recs) ||
!out->WriteS32(hdmx->size_device_record)) {
return OTS_FAILURE_MSG("Failed to write hdmx header");
}
for (int16_t i = 0; i < num_recs; ++i) {
const OpenTypeHDMXDeviceRecord& rec = hdmx->records[i];
if (!out->Write(&rec.pixel_size, 1) ||
!out->Write(&rec.max_width, 1) ||
!out->Write(&rec.widths[0], rec.widths.size())) {
return OTS_FAILURE_MSG("Failed to write hdmx record %d", i);
}
if ((hdmx->pad_len > 0) &&
!out->Write((const uint8_t *)"\x00\x00\x00", hdmx->pad_len)) {
return OTS_FAILURE_MSG("Failed to write hdmx padding of length %d", hdmx->pad_len);
}
}
return true;
}
void ots_hdmx_reuse(Font *font, Font *other) {
font->hdmx = other->hdmx;
font->hdmx_reused = true;
}
void ots_hdmx_free(Font *font) {
delete font->hdmx;
}
} // namespace ots
#undef TABLE_NAME
#undef DROP_THIS_TABLE
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