1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/ots/src/loca.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,100 @@
1.4 +// Copyright (c) 2009 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#include "loca.h"
1.9 +
1.10 +#include "head.h"
1.11 +#include "maxp.h"
1.12 +
1.13 +// loca - Index to Location
1.14 +// http://www.microsoft.com/typography/otspec/loca.htm
1.15 +
1.16 +#define TABLE_NAME "loca"
1.17 +
1.18 +namespace ots {
1.19 +
1.20 +bool ots_loca_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
1.21 + Buffer table(data, length);
1.22 +
1.23 + // We can't do anything useful in validating this data except to ensure that
1.24 + // the values are monotonically increasing.
1.25 +
1.26 + OpenTypeLOCA *loca = new OpenTypeLOCA;
1.27 + file->loca = loca;
1.28 +
1.29 + if (!file->maxp || !file->head) {
1.30 + return OTS_FAILURE_MSG("maxp or head tables missing from font, needed by loca");
1.31 + }
1.32 +
1.33 + const unsigned num_glyphs = file->maxp->num_glyphs;
1.34 + unsigned last_offset = 0;
1.35 + loca->offsets.resize(num_glyphs + 1);
1.36 + // maxp->num_glyphs is uint16_t, thus the addition never overflows.
1.37 +
1.38 + if (file->head->index_to_loc_format == 0) {
1.39 + // Note that the <= here (and below) is correct. There is one more offset
1.40 + // than the number of glyphs in order to give the length of the final
1.41 + // glyph.
1.42 + for (unsigned i = 0; i <= num_glyphs; ++i) {
1.43 + uint16_t offset = 0;
1.44 + if (!table.ReadU16(&offset)) {
1.45 + return OTS_FAILURE_MSG("Failed to read offset for glyph %d", i);
1.46 + }
1.47 + if (offset < last_offset) {
1.48 + return OTS_FAILURE_MSG("Out of order offset %d < %d for glyph %d", offset, last_offset, i);
1.49 + }
1.50 + last_offset = offset;
1.51 + loca->offsets[i] = offset * 2;
1.52 + }
1.53 + } else {
1.54 + for (unsigned i = 0; i <= num_glyphs; ++i) {
1.55 + uint32_t offset = 0;
1.56 + if (!table.ReadU32(&offset)) {
1.57 + return OTS_FAILURE_MSG("Failed to read offset for glyph %d", i);
1.58 + }
1.59 + if (offset < last_offset) {
1.60 + return OTS_FAILURE_MSG("Out of order offset %d < %d for glyph %d", offset, last_offset, i);
1.61 + }
1.62 + last_offset = offset;
1.63 + loca->offsets[i] = offset;
1.64 + }
1.65 + }
1.66 +
1.67 + return true;
1.68 +}
1.69 +
1.70 +bool ots_loca_should_serialise(OpenTypeFile *file) {
1.71 + return file->loca != NULL;
1.72 +}
1.73 +
1.74 +bool ots_loca_serialise(OTSStream *out, OpenTypeFile *file) {
1.75 + const OpenTypeLOCA *loca = file->loca;
1.76 + const OpenTypeHEAD *head = file->head;
1.77 +
1.78 + if (!head) {
1.79 + return OTS_FAILURE_MSG("Missing head table in font needed by loca");
1.80 + }
1.81 +
1.82 + if (head->index_to_loc_format == 0) {
1.83 + for (unsigned i = 0; i < loca->offsets.size(); ++i) {
1.84 + if (!out->WriteU16(loca->offsets[i] >> 1)) {
1.85 + return OTS_FAILURE_MSG("Failed to write glyph offset for glyph %d", i);
1.86 + }
1.87 + }
1.88 + } else {
1.89 + for (unsigned i = 0; i < loca->offsets.size(); ++i) {
1.90 + if (!out->WriteU32(loca->offsets[i])) {
1.91 + return OTS_FAILURE_MSG("Failed to write glyph offset for glyph %d", i);
1.92 + }
1.93 + }
1.94 + }
1.95 +
1.96 + return true;
1.97 +}
1.98 +
1.99 +void ots_loca_free(OpenTypeFile *file) {
1.100 + delete file->loca;
1.101 +}
1.102 +
1.103 +} // namespace ots
