// 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