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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 "vdmx.h"
// VDMX - Vertical Device Metrics
// http://www.microsoft.com/opentype/otspec/vdmx.htm
#define DROP_THIS_TABLE \
do { delete file->vdmx; file->vdmx = 0; } while (0)
namespace ots {
bool ots_vdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
Buffer table(data, length);
file->vdmx = new OpenTypeVDMX;
OpenTypeVDMX * const vdmx = file->vdmx;
if (!table.ReadU16(&vdmx->version) ||
!table.ReadU16(&vdmx->num_recs) ||
!table.ReadU16(&vdmx->num_ratios)) {
return OTS_FAILURE();
}
if (vdmx->version > 1) {
OTS_WARNING("bad version: %u", vdmx->version);
DROP_THIS_TABLE;
return true; // continue transcoding
}
vdmx->rat_ranges.reserve(vdmx->num_ratios);
for (unsigned i = 0; i < vdmx->num_ratios; ++i) {
OpenTypeVDMXRatioRecord rec;
if (!table.ReadU8(&rec.charset) ||
!table.ReadU8(&rec.x_ratio) ||
!table.ReadU8(&rec.y_start_ratio) ||
!table.ReadU8(&rec.y_end_ratio)) {
return OTS_FAILURE();
}
if (rec.charset > 1) {
OTS_WARNING("bad charset: %u", rec.charset);
DROP_THIS_TABLE;
return true;
}
if (rec.y_start_ratio < rec.y_end_ratio) {
OTS_WARNING("bad y ratio");
DROP_THIS_TABLE;
return true;
}
// All values set to zero signal the default grouping to use;
// if present, this must be the last Ratio group in the table.
if ((i < vdmx->num_ratios - 1u) &&
(rec.x_ratio == 0) &&
(rec.y_start_ratio == 0) &&
(rec.y_end_ratio == 0)) {
// workaround for fonts which have 2 or more {0, 0, 0} terminators.
OTS_WARNING("superfluous terminator found");
DROP_THIS_TABLE;
return true; // continue transcoding
}
vdmx->rat_ranges.push_back(rec);
}
vdmx->offsets.reserve(vdmx->num_ratios);
const size_t current_offset = table.offset();
// current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k.
for (unsigned i = 0; i < vdmx->num_ratios; ++i) {
uint16_t offset;
if (!table.ReadU16(&offset)) {
return OTS_FAILURE();
}
if (current_offset + offset >= length) { // thus doesn't overflow.
return OTS_FAILURE();
}
vdmx->offsets.push_back(offset);
}
vdmx->groups.reserve(vdmx->num_recs);
for (unsigned i = 0; i < vdmx->num_recs; ++i) {
OpenTypeVDMXGroup group;
if (!table.ReadU16(&group.recs) ||
!table.ReadU8(&group.startsz) ||
!table.ReadU8(&group.endsz)) {
return OTS_FAILURE();
}
group.entries.reserve(group.recs);
for (unsigned j = 0; j < group.recs; ++j) {
OpenTypeVDMXVTable vt;
if (!table.ReadU16(&vt.y_pel_height) ||
!table.ReadS16(&vt.y_max) ||
!table.ReadS16(&vt.y_min)) {
return OTS_FAILURE();
}
if (vt.y_max < vt.y_min) {
OTS_WARNING("bad y min/max");
DROP_THIS_TABLE;
return true;
}
// This table must appear in sorted order (sorted by yPelHeight),
// but need not be continuous.
if ((j != 0) && (group.entries[j - 1].y_pel_height >= vt.y_pel_height)) {
OTS_WARNING("the table is not sorted");
DROP_THIS_TABLE;
return true;
}
group.entries.push_back(vt);
}
vdmx->groups.push_back(group);
}
return true;
}
bool ots_vdmx_should_serialise(OpenTypeFile *file) {
if (!file->glyf) return false; // this table is not for CFF fonts.
return file->vdmx;
}
bool ots_vdmx_serialise(OTSStream *out, OpenTypeFile *file) {
OpenTypeVDMX * const vdmx = file->vdmx;
if (!out->WriteU16(vdmx->version) ||
!out->WriteU16(vdmx->num_recs) ||
!out->WriteU16(vdmx->num_ratios)) {
return OTS_FAILURE();
}
for (unsigned i = 0; i < vdmx->rat_ranges.size(); ++i) {
const OpenTypeVDMXRatioRecord& rec = vdmx->rat_ranges[i];
if (!out->Write(&rec.charset, 1) ||
!out->Write(&rec.x_ratio, 1) ||
!out->Write(&rec.y_start_ratio, 1) ||
!out->Write(&rec.y_end_ratio, 1)) {
return OTS_FAILURE();
}
}
for (unsigned i = 0; i < vdmx->offsets.size(); ++i) {
if (!out->WriteU16(vdmx->offsets[i])) {
return OTS_FAILURE();
}
}
for (unsigned i = 0; i < vdmx->groups.size(); ++i) {
const OpenTypeVDMXGroup& group = vdmx->groups[i];
if (!out->WriteU16(group.recs) ||
!out->Write(&group.startsz, 1) ||
!out->Write(&group.endsz, 1)) {
return OTS_FAILURE();
}
for (unsigned j = 0; j < group.entries.size(); ++j) {
const OpenTypeVDMXVTable& vt = group.entries[j];
if (!out->WriteU16(vt.y_pel_height) ||
!out->WriteS16(vt.y_max) ||
!out->WriteS16(vt.y_min)) {
return OTS_FAILURE();
}
}
}
return true;
}
void ots_vdmx_free(OpenTypeFile *file) {
delete file->vdmx;
}
} // namespace ots
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