| // 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(OpenTypeFile *file, 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; |
| file->loca = loca; |
| |
| if (!file->maxp || !file->head) { |
| return OTS_FAILURE_MSG("maxp or head tables missing from font, needed by loca"); |
| } |
| |
| const unsigned num_glyphs = file->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 (file->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(OpenTypeFile *file) { |
| return file->loca != NULL; |
| } |
| |
| bool ots_loca_serialise(OTSStream *out, OpenTypeFile *file) { |
| const OpenTypeLOCA *loca = file->loca; |
| const OpenTypeHEAD *head = file->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_free(OpenTypeFile *file) { |
| delete file->loca; |
| } |
| |
| } // namespace ots |
| |
| #undef TABLE_NAME |