blob: aae04c25ab78db23aa5be4e07b28a451a2149068 [file] [log] [blame]
// 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 "loca.h"
#include "head.h"
#include "maxp.h"
// loca - Index to Location
// http://www.microsoft.com/typography/otspec/loca.htm
#define TABLE_NAME "loca"
namespace ots {
bool ots_loca_parse(Font *font, const uint8_t *data, size_t length) {
Buffer table(data, length);
// We can't do anything useful in validating this data except to ensure that
// the values are monotonically increasing.
OpenTypeLOCA *loca = new OpenTypeLOCA;
font->loca = loca;
if (!font->maxp || !font->head) {
return OTS_FAILURE_MSG("maxp or head tables missing from font, needed by loca");
}
const unsigned num_glyphs = font->maxp->num_glyphs;
unsigned last_offset = 0;
loca->offsets.resize(num_glyphs + 1);
// maxp->num_glyphs is uint16_t, thus the addition never overflows.
if (font->head->index_to_loc_format == 0) {
// Note that the <= here (and below) is correct. There is one more offset
// than the number of glyphs in order to give the length of the final
// glyph.
for (unsigned i = 0; i <= num_glyphs; ++i) {
uint16_t offset = 0;
if (!table.ReadU16(&offset)) {
return OTS_FAILURE_MSG("Failed to read offset for glyph %d", i);
}
if (offset < last_offset) {
return OTS_FAILURE_MSG("Out of order offset %d < %d for glyph %d", offset, last_offset, i);
}
last_offset = offset;
loca->offsets[i] = offset * 2;
}
} else {
for (unsigned i = 0; i <= num_glyphs; ++i) {
uint32_t offset = 0;
if (!table.ReadU32(&offset)) {
return OTS_FAILURE_MSG("Failed to read offset for glyph %d", i);
}
if (offset < last_offset) {
return OTS_FAILURE_MSG("Out of order offset %d < %d for glyph %d", offset, last_offset, i);
}
last_offset = offset;
loca->offsets[i] = offset;
}
}
return true;
}
bool ots_loca_should_serialise(Font *font) {
return font->loca != NULL;
}
bool ots_loca_serialise(OTSStream *out, Font *font) {
const OpenTypeLOCA *loca = font->loca;
const OpenTypeHEAD *head = font->head;
if (!head) {
return OTS_FAILURE_MSG("Missing head table in font needed by loca");
}
if (head->index_to_loc_format == 0) {
for (unsigned i = 0; i < loca->offsets.size(); ++i) {
const uint16_t offset = static_cast<uint16_t>(loca->offsets[i] >> 1);
if ((offset != (loca->offsets[i] >> 1)) ||
!out->WriteU16(offset)) {
return OTS_FAILURE_MSG("Failed to write glyph offset for glyph %d", i);
}
}
} else {
for (unsigned i = 0; i < loca->offsets.size(); ++i) {
if (!out->WriteU32(loca->offsets[i])) {
return OTS_FAILURE_MSG("Failed to write glyph offset for glyph %d", i);
}
}
}
return true;
}
void ots_loca_reuse(Font *font, Font *other) {
font->loca = other->loca;
font->loca_reused = true;
}
void ots_loca_free(Font *font) {
delete font->loca;
}
} // namespace ots
#undef TABLE_NAME