| // 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 "gasp.h" |
| |
| // gasp - Grid-fitting And Scan-conversion Procedure |
| // http://www.microsoft.com/typography/otspec/gasp.htm |
| |
| #define TABLE_NAME "gasp" |
| |
| #define DROP_THIS_TABLE(...) \ |
| do { \ |
| OTS_FAILURE_MSG_(file, TABLE_NAME ": " __VA_ARGS__); \ |
| OTS_FAILURE_MSG("Table discarded"); \ |
| delete file->gasp; \ |
| file->gasp = 0; \ |
| } while (0) |
| |
| namespace ots { |
| |
| bool ots_gasp_parse(OpenTypeFile *file, const uint8_t *data, size_t length) { |
| Buffer table(data, length); |
| |
| OpenTypeGASP *gasp = new OpenTypeGASP; |
| file->gasp = gasp; |
| |
| uint16_t num_ranges = 0; |
| if (!table.ReadU16(&gasp->version) || |
| !table.ReadU16(&num_ranges)) { |
| return OTS_FAILURE_MSG("Failed to read table header"); |
| } |
| |
| if (gasp->version > 1) { |
| // Lots of Linux fonts have bad version numbers... |
| DROP_THIS_TABLE("bad version: %u", gasp->version); |
| return true; |
| } |
| |
| if (num_ranges == 0) { |
| DROP_THIS_TABLE("num_ranges is zero"); |
| return true; |
| } |
| |
| gasp->gasp_ranges.reserve(num_ranges); |
| for (unsigned i = 0; i < num_ranges; ++i) { |
| uint16_t max_ppem = 0; |
| uint16_t behavior = 0; |
| if (!table.ReadU16(&max_ppem) || |
| !table.ReadU16(&behavior)) { |
| return OTS_FAILURE_MSG("Failed to read subrange %d", i); |
| } |
| if ((i > 0) && (gasp->gasp_ranges[i - 1].first >= max_ppem)) { |
| // The records in the gaspRange[] array must be sorted in order of |
| // increasing rangeMaxPPEM value. |
| DROP_THIS_TABLE("ranges are not sorted"); |
| return true; |
| } |
| if ((i == num_ranges - 1u) && // never underflow. |
| (max_ppem != 0xffffu)) { |
| DROP_THIS_TABLE("The last record should be 0xFFFF as a sentinel value " |
| "for rangeMaxPPEM"); |
| return true; |
| } |
| |
| if (behavior >> 8) { |
| OTS_WARNING("undefined bits are used: %x", behavior); |
| // mask undefined bits. |
| behavior &= 0x000fu; |
| } |
| |
| if (gasp->version == 0 && (behavior >> 2) != 0) { |
| OTS_WARNING("changed the version number to 1"); |
| gasp->version = 1; |
| } |
| |
| gasp->gasp_ranges.push_back(std::make_pair(max_ppem, behavior)); |
| } |
| |
| return true; |
| } |
| |
| bool ots_gasp_should_serialise(OpenTypeFile *file) { |
| return file->gasp != NULL; |
| } |
| |
| bool ots_gasp_serialise(OTSStream *out, OpenTypeFile *file) { |
| const OpenTypeGASP *gasp = file->gasp; |
| |
| const uint16_t num_ranges = static_cast<uint16_t>(gasp->gasp_ranges.size()); |
| if (num_ranges != gasp->gasp_ranges.size() || |
| !out->WriteU16(gasp->version) || |
| !out->WriteU16(num_ranges)) { |
| return OTS_FAILURE_MSG("failed to write gasp header"); |
| } |
| |
| for (uint16_t i = 0; i < num_ranges; ++i) { |
| if (!out->WriteU16(gasp->gasp_ranges[i].first) || |
| !out->WriteU16(gasp->gasp_ranges[i].second)) { |
| return OTS_FAILURE_MSG("Failed to write gasp subtable %d", i); |
| } |
| } |
| |
| return true; |
| } |
| |
| void ots_gasp_free(OpenTypeFile *file) { |
| delete file->gasp; |
| } |
| |
| } // namespace ots |
| |
| #undef TABLE_NAME |
| #undef DROP_THIS_TABLE |