/gfx/ots/src/ots.cc
C++ | 630 lines | 479 code | 92 blank | 59 comment | 120 complexity | b164c83ede21de31e095e0b38c6e8e2b MD5 | raw file
Possible License(s): AGPL-1.0, MIT, BSD-3-Clause, Apache-2.0, LGPL-2.1, 0BSD, LGPL-3.0, MPL-2.0-no-copyleft-exception, GPL-2.0, JSON
- // 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 "ots.h"
- #include <sys/types.h>
- #include <zlib.h>
- #include <algorithm>
- #include <cstdlib>
- #include <cstring>
- #include <map>
- #include <vector>
- // The OpenType Font File
- // http://www.microsoft.com/typography/otspec/cmap.htm
- namespace {
- bool g_debug_output = true;
- struct OpenTypeTable {
- uint32_t tag;
- uint32_t chksum;
- uint32_t offset;
- uint32_t length;
- uint32_t uncompressed_length;
- };
- // Round a value up to the nearest multiple of 4. Note that this can overflow
- // and return zero.
- template<typename T> T Round4(T value) {
- return (value + 3) & ~3;
- }
- uint32_t Tag(const char *tag_str) {
- uint32_t ret;
- std::memcpy(&ret, tag_str, 4);
- return ret;
- }
- bool CheckTag(uint32_t tag_value) {
- for (unsigned i = 0; i < 4; ++i) {
- const uint32_t check = tag_value & 0xff;
- if (check < 32 || check > 126) {
- return false; // non-ASCII character found.
- }
- tag_value >>= 8;
- }
- return true;
- }
- struct OutputTable {
- uint32_t tag;
- size_t offset;
- size_t length;
- uint32_t chksum;
- static bool SortByTag(const OutputTable& a, const OutputTable& b) {
- const uint32_t atag = ntohl(a.tag);
- const uint32_t btag = ntohl(b.tag);
- return atag < btag;
- }
- };
- struct Arena {
- public:
- ~Arena() {
- for (std::vector<uint8_t*>::iterator
- i = hunks_.begin(); i != hunks_.end(); ++i) {
- delete[] *i;
- }
- }
- uint8_t* Allocate(size_t length) {
- uint8_t* p = new uint8_t[length];
- hunks_.push_back(p);
- return p;
- }
- private:
- std::vector<uint8_t*> hunks_;
- };
- const struct {
- uint32_t tag;
- bool (*parse)(ots::OpenTypeFile *otf, const uint8_t *data, size_t length);
- bool (*serialise)(ots::OTSStream *out, ots::OpenTypeFile *file);
- bool (*should_serialise)(ots::OpenTypeFile *file);
- void (*free)(ots::OpenTypeFile *file);
- bool required;
- } table_parsers[] = {
- { Tag("maxp"), ots::ots_maxp_parse, ots::ots_maxp_serialise,
- ots::ots_maxp_should_serialise, ots::ots_maxp_free, true },
- { Tag("head"), ots::ots_head_parse, ots::ots_head_serialise,
- ots::ots_head_should_serialise, ots::ots_head_free, true },
- { Tag("OS/2"), ots::ots_os2_parse, ots::ots_os2_serialise,
- ots::ots_os2_should_serialise, ots::ots_os2_free, true },
- { Tag("cmap"), ots::ots_cmap_parse, ots::ots_cmap_serialise,
- ots::ots_cmap_should_serialise, ots::ots_cmap_free, true },
- { Tag("hhea"), ots::ots_hhea_parse, ots::ots_hhea_serialise,
- ots::ots_hhea_should_serialise, ots::ots_hhea_free, true },
- { Tag("hmtx"), ots::ots_hmtx_parse, ots::ots_hmtx_serialise,
- ots::ots_hmtx_should_serialise, ots::ots_hmtx_free, true },
- { Tag("name"), ots::ots_name_parse, ots::ots_name_serialise,
- ots::ots_name_should_serialise, ots::ots_name_free, true },
- { Tag("post"), ots::ots_post_parse, ots::ots_post_serialise,
- ots::ots_post_should_serialise, ots::ots_post_free, true },
- { Tag("loca"), ots::ots_loca_parse, ots::ots_loca_serialise,
- ots::ots_loca_should_serialise, ots::ots_loca_free, false },
- { Tag("glyf"), ots::ots_glyf_parse, ots::ots_glyf_serialise,
- ots::ots_glyf_should_serialise, ots::ots_glyf_free, false },
- { Tag("CFF "), ots::ots_cff_parse, ots::ots_cff_serialise,
- ots::ots_cff_should_serialise, ots::ots_cff_free, false },
- { Tag("VDMX"), ots::ots_vdmx_parse, ots::ots_vdmx_serialise,
- ots::ots_vdmx_should_serialise, ots::ots_vdmx_free, false },
- { Tag("hdmx"), ots::ots_hdmx_parse, ots::ots_hdmx_serialise,
- ots::ots_hdmx_should_serialise, ots::ots_hdmx_free, false },
- { Tag("gasp"), ots::ots_gasp_parse, ots::ots_gasp_serialise,
- ots::ots_gasp_should_serialise, ots::ots_gasp_free, false },
- { Tag("cvt "), ots::ots_cvt_parse, ots::ots_cvt_serialise,
- ots::ots_cvt_should_serialise, ots::ots_cvt_free, false },
- { Tag("fpgm"), ots::ots_fpgm_parse, ots::ots_fpgm_serialise,
- ots::ots_fpgm_should_serialise, ots::ots_fpgm_free, false },
- { Tag("prep"), ots::ots_prep_parse, ots::ots_prep_serialise,
- ots::ots_prep_should_serialise, ots::ots_prep_free, false },
- { Tag("LTSH"), ots::ots_ltsh_parse, ots::ots_ltsh_serialise,
- ots::ots_ltsh_should_serialise, ots::ots_ltsh_free, false },
- { Tag("VORG"), ots::ots_vorg_parse, ots::ots_vorg_serialise,
- ots::ots_vorg_should_serialise, ots::ots_vorg_free, false },
- { Tag("kern"), ots::ots_kern_parse, ots::ots_kern_serialise,
- ots::ots_kern_should_serialise, ots::ots_kern_free, false },
- // We need to parse GDEF table in advance of parsing GSUB/GPOS tables
- // because they could refer GDEF table.
- { Tag("GDEF"), ots::ots_gdef_parse, ots::ots_gdef_serialise,
- ots::ots_gdef_should_serialise, ots::ots_gdef_free, false },
- { Tag("GPOS"), ots::ots_gpos_parse, ots::ots_gpos_serialise,
- ots::ots_gpos_should_serialise, ots::ots_gpos_free, false },
- { Tag("GSUB"), ots::ots_gsub_parse, ots::ots_gsub_serialise,
- ots::ots_gsub_should_serialise, ots::ots_gsub_free, false },
- { Tag("vhea"), ots::ots_vhea_parse, ots::ots_vhea_serialise,
- ots::ots_vhea_should_serialise, ots::ots_vhea_free, false },
- { Tag("vmtx"), ots::ots_vmtx_parse, ots::ots_vmtx_serialise,
- ots::ots_vmtx_should_serialise, ots::ots_vmtx_free, false },
- // TODO(bashi): Support mort, base, and jstf tables.
- { 0, NULL, NULL, NULL, NULL, false },
- };
- bool IsValidVersionTag(uint32_t tag) {
- return tag == Tag("\x00\x01\x00\x00") ||
- // OpenType fonts with CFF data have 'OTTO' tag.
- tag == Tag("OTTO") ||
- // Older Mac fonts might have 'true' or 'typ1' tag.
- tag == Tag("true") ||
- tag == Tag("typ1");
- }
- bool ProcessGeneric(ots::OpenTypeFile *header, ots::OTSStream *output,
- const uint8_t *data, size_t length,
- const std::vector<OpenTypeTable>& tables,
- ots::Buffer& file);
- bool ProcessTTF(ots::OpenTypeFile *header,
- ots::OTSStream *output, const uint8_t *data, size_t length) {
- ots::Buffer file(data, length);
- // we disallow all files > 1GB in size for sanity.
- if (length > 1024 * 1024 * 1024) {
- return OTS_FAILURE();
- }
- if (!file.ReadTag(&header->version)) {
- return OTS_FAILURE();
- }
- if (!IsValidVersionTag(header->version)) {
- return OTS_FAILURE();
- }
- if (!file.ReadU16(&header->num_tables) ||
- !file.ReadU16(&header->search_range) ||
- !file.ReadU16(&header->entry_selector) ||
- !file.ReadU16(&header->range_shift)) {
- return OTS_FAILURE();
- }
- // search_range is (Maximum power of 2 <= numTables) x 16. Thus, to avoid
- // overflow num_tables is, at most, 2^16 / 16 = 2^12
- if (header->num_tables >= 4096 || header->num_tables < 1) {
- return OTS_FAILURE();
- }
- unsigned max_pow2 = 0;
- while (1u << (max_pow2 + 1) <= header->num_tables) {
- max_pow2++;
- }
- const uint16_t expected_search_range = (1u << max_pow2) << 4;
- // Don't call ots_failure() here since ~25% of fonts (250+ fonts) in
- // http://www.princexml.com/fonts/ have unexpected search_range value.
- if (header->search_range != expected_search_range) {
- OTS_WARNING("bad search range");
- header->search_range = expected_search_range; // Fix the value.
- }
- // entry_selector is Log2(maximum power of 2 <= numTables)
- if (header->entry_selector != max_pow2) {
- return OTS_FAILURE();
- }
- // range_shift is NumTables x 16-searchRange. We know that 16*num_tables
- // doesn't over flow because we range checked it above. Also, we know that
- // it's > header->search_range by construction of search_range.
- const uint32_t expected_range_shift
- = 16 * header->num_tables - header->search_range;
- if (header->range_shift != expected_range_shift) {
- OTS_WARNING("bad range shift");
- header->range_shift = expected_range_shift; // the same as above.
- }
- // Next up is the list of tables.
- std::vector<OpenTypeTable> tables;
- for (unsigned i = 0; i < header->num_tables; ++i) {
- OpenTypeTable table;
- if (!file.ReadTag(&table.tag) ||
- !file.ReadU32(&table.chksum) ||
- !file.ReadU32(&table.offset) ||
- !file.ReadU32(&table.length)) {
- return OTS_FAILURE();
- }
- table.uncompressed_length = table.length;
- tables.push_back(table);
- }
- return ProcessGeneric(header, output, data, length, tables, file);
- }
- bool ProcessWOFF(ots::OpenTypeFile *header,
- ots::OTSStream *output, const uint8_t *data, size_t length) {
- ots::Buffer file(data, length);
- // we disallow all files > 1GB in size for sanity.
- if (length > 1024 * 1024 * 1024) {
- return OTS_FAILURE();
- }
- uint32_t woff_tag;
- if (!file.ReadTag(&woff_tag)) {
- return OTS_FAILURE();
- }
- if (woff_tag != Tag("wOFF")) {
- return OTS_FAILURE();
- }
- if (!file.ReadTag(&header->version)) {
- return OTS_FAILURE();
- }
- if (!IsValidVersionTag(header->version)) {
- return OTS_FAILURE();
- }
- header->search_range = 0;
- header->entry_selector = 0;
- header->range_shift = 0;
- uint32_t reported_length;
- if (!file.ReadU32(&reported_length) || length != reported_length) {
- return OTS_FAILURE();
- }
- if (!file.ReadU16(&header->num_tables)) {
- return OTS_FAILURE();
- }
- uint16_t reserved_value;
- if (!file.ReadU16(&reserved_value) || reserved_value) {
- return OTS_FAILURE();
- }
- // We don't care about these fields of the header:
- // uint32_t uncompressed_size;
- // uint16_t major_version, minor_version
- // uint32_t meta_offset, meta_length, meta_length_orig
- // uint32_t priv_offset, priv_length
- if (!file.Skip(6 * 4 + 2 * 2)) {
- return OTS_FAILURE();
- }
- // Next up is the list of tables.
- std::vector<OpenTypeTable> tables;
- for (unsigned i = 0; i < header->num_tables; ++i) {
- OpenTypeTable table;
- if (!file.ReadTag(&table.tag) ||
- !file.ReadU32(&table.offset) ||
- !file.ReadU32(&table.length) ||
- !file.ReadU32(&table.uncompressed_length) ||
- !file.ReadU32(&table.chksum)) {
- return OTS_FAILURE();
- }
- tables.push_back(table);
- }
- return ProcessGeneric(header, output, data, length, tables, file);
- }
- bool ProcessGeneric(ots::OpenTypeFile *header, ots::OTSStream *output,
- const uint8_t *data, size_t length,
- const std::vector<OpenTypeTable>& tables,
- ots::Buffer& file) {
- const size_t data_offset = file.offset();
- uint32_t uncompressed_sum = 0;
- for (unsigned i = 0; i < header->num_tables; ++i) {
- // the tables must be sorted by tag (when taken as big-endian numbers).
- // This also remove the possibility of duplicate tables.
- if (i) {
- const uint32_t this_tag = ntohl(tables[i].tag);
- const uint32_t prev_tag = ntohl(tables[i - 1].tag);
- if (this_tag <= prev_tag) {
- return OTS_FAILURE();
- }
- }
- // all tag names must be built from printable ASCII characters
- if (!CheckTag(tables[i].tag)) {
- return OTS_FAILURE();
- }
- // tables must be 4-byte aligned
- if (tables[i].offset & 3) {
- return OTS_FAILURE();
- }
- // and must be within the file
- if (tables[i].offset < data_offset || tables[i].offset >= length) {
- return OTS_FAILURE();
- }
- // disallow all tables with a zero length
- if (tables[i].length < 1) {
- // Note: malayalam.ttf has zero length CVT table...
- return OTS_FAILURE();
- }
- // disallow all tables with a length > 1GB
- if (tables[i].length > 1024 * 1024 * 1024) {
- return OTS_FAILURE();
- }
- // disallow tables where the uncompressed size is < the compressed size.
- if (tables[i].uncompressed_length < tables[i].length) {
- return OTS_FAILURE();
- }
- if (tables[i].uncompressed_length > tables[i].length) {
- // We'll probably be decompressing this table.
- // disallow all tables which uncompress to > 30 MB
- if (tables[i].uncompressed_length > 30 * 1024 * 1024) {
- return OTS_FAILURE();
- }
- if (uncompressed_sum + tables[i].uncompressed_length < uncompressed_sum) {
- return OTS_FAILURE();
- }
- uncompressed_sum += tables[i].uncompressed_length;
- }
- // since we required that the file be < 1GB in length, and that the table
- // length is < 1GB, the following addtion doesn't overflow
- const uint32_t end_byte = Round4(tables[i].offset + tables[i].length);
- // Some fonts which are automatically generated by a font generator
- // called TTX seems not to add 0-padding to the final table. It might be
- // ok to accept these fonts so we round up the length of the font file.
- if (!end_byte || end_byte > Round4(length)) {
- return OTS_FAILURE();
- }
- }
- // All decompressed tables uncompressed must be <= 30MB.
- if (uncompressed_sum > 30 * 1024 * 1024) {
- return OTS_FAILURE();
- }
- std::map<uint32_t, OpenTypeTable> table_map;
- for (unsigned i = 0; i < header->num_tables; ++i) {
- table_map[tables[i].tag] = tables[i];
- }
- // check that the tables are not overlapping.
- std::vector<std::pair<uint32_t, uint8_t> > overlap_checker;
- for (unsigned i = 0; i < header->num_tables; ++i) {
- overlap_checker.push_back(
- std::make_pair(tables[i].offset, 1 /* start */));
- overlap_checker.push_back(
- std::make_pair(tables[i].offset + tables[i].length, 0 /* end */));
- }
- std::sort(overlap_checker.begin(), overlap_checker.end());
- int overlap_count = 0;
- for (unsigned i = 0; i < overlap_checker.size(); ++i) {
- overlap_count += (overlap_checker[i].second ? 1 : -1);
- if (overlap_count > 1) {
- return OTS_FAILURE();
- }
- }
- Arena arena;
- for (unsigned i = 0; ; ++i) {
- if (table_parsers[i].parse == NULL) break;
- const std::map<uint32_t, OpenTypeTable>::const_iterator it
- = table_map.find(table_parsers[i].tag);
- if (it == table_map.end()) {
- if (table_parsers[i].required) {
- return OTS_FAILURE();
- }
- continue;
- }
- const uint8_t* table_data;
- size_t table_length;
- if (it->second.uncompressed_length != it->second.length) {
- // compressed table. Need to uncompress into memory first.
- table_length = it->second.uncompressed_length;
- table_data = arena.Allocate(table_length);
- uLongf dest_len = table_length;
- int r = uncompress((Bytef*) table_data, &dest_len,
- data + it->second.offset, it->second.length);
- if (r != Z_OK || dest_len != table_length) {
- return OTS_FAILURE();
- }
- } else {
- // uncompressed table. We can process directly from memory.
- table_data = data + it->second.offset;
- table_length = it->second.length;
- }
- if (!table_parsers[i].parse(header, table_data, table_length)) {
- return OTS_FAILURE();
- }
- }
- if (header->cff) {
- // font with PostScript glyph
- if (header->version != Tag("OTTO")) {
- return OTS_FAILURE();
- }
- if (header->glyf || header->loca) {
- // mixing outline formats is not recommended
- return OTS_FAILURE();
- }
- } else {
- if (!header->glyf || !header->loca) {
- // No TrueType glyph found.
- // Note: bitmap-only fonts are not supported.
- return OTS_FAILURE();
- }
- }
- unsigned num_output_tables = 0;
- for (unsigned i = 0; ; ++i) {
- if (table_parsers[i].parse == NULL) {
- break;
- }
- if (table_parsers[i].should_serialise(header)) {
- num_output_tables++;
- }
- }
- unsigned max_pow2 = 0;
- while (1u << (max_pow2 + 1) <= num_output_tables) {
- max_pow2++;
- }
- const uint16_t output_search_range = (1u << max_pow2) << 4;
- output->ResetChecksum();
- if (!output->WriteTag(header->version) ||
- !output->WriteU16(num_output_tables) ||
- !output->WriteU16(output_search_range) ||
- !output->WriteU16(max_pow2) ||
- !output->WriteU16((num_output_tables << 4) - output_search_range)) {
- return OTS_FAILURE();
- }
- const uint32_t offset_table_chksum = output->chksum();
- const size_t table_record_offset = output->Tell();
- if (!output->Pad(16 * num_output_tables)) {
- return OTS_FAILURE();
- }
- std::vector<OutputTable> out_tables;
- size_t head_table_offset = 0;
- for (unsigned i = 0; ; ++i) {
- if (table_parsers[i].parse == NULL) {
- break;
- }
- if (!table_parsers[i].should_serialise(header)) {
- continue;
- }
- OutputTable out;
- out.tag = table_parsers[i].tag;
- out.offset = output->Tell();
- output->ResetChecksum();
- if (table_parsers[i].tag == Tag("head")) {
- head_table_offset = out.offset;
- }
- if (!table_parsers[i].serialise(output, header)) {
- return OTS_FAILURE();
- }
- const size_t end_offset = output->Tell();
- if (end_offset <= out.offset) {
- // paranoid check. |end_offset| is supposed to be greater than the offset,
- // as long as the Tell() interface is implemented correctly.
- return OTS_FAILURE();
- }
- out.length = end_offset - out.offset;
- // align tables to four bytes
- if (!output->Pad((4 - (end_offset & 3)) % 4)) {
- return OTS_FAILURE();
- }
- out.chksum = output->chksum();
- out_tables.push_back(out);
- }
- const size_t end_of_file = output->Tell();
- // Need to sort the output tables for inclusion in the file
- std::sort(out_tables.begin(), out_tables.end(), OutputTable::SortByTag);
- if (!output->Seek(table_record_offset)) {
- return OTS_FAILURE();
- }
- output->ResetChecksum();
- uint32_t tables_chksum = 0;
- for (unsigned i = 0; i < out_tables.size(); ++i) {
- if (!output->WriteTag(out_tables[i].tag) ||
- !output->WriteU32(out_tables[i].chksum) ||
- !output->WriteU32(out_tables[i].offset) ||
- !output->WriteU32(out_tables[i].length)) {
- return OTS_FAILURE();
- }
- tables_chksum += out_tables[i].chksum;
- }
- const uint32_t table_record_chksum = output->chksum();
- // http://www.microsoft.com/typography/otspec/otff.htm
- const uint32_t file_chksum
- = offset_table_chksum + tables_chksum + table_record_chksum;
- const uint32_t chksum_magic = static_cast<uint32_t>(0xb1b0afba) - file_chksum;
- // seek into the 'head' table and write in the checksum magic value
- if (!head_table_offset) {
- return OTS_FAILURE(); // not reached.
- }
- if (!output->Seek(head_table_offset + 8)) {
- return OTS_FAILURE();
- }
- if (!output->WriteU32(chksum_magic)) {
- return OTS_FAILURE();
- }
- if (!output->Seek(end_of_file)) {
- return OTS_FAILURE();
- }
- return true;
- }
- } // namespace
- namespace ots {
- void DisableDebugOutput() {
- g_debug_output = false;
- }
- bool Process(OTSStream *output, const uint8_t *data, size_t length) {
- OpenTypeFile header;
- if (length < 4) {
- return OTS_FAILURE();
- }
- bool result;
- if (data[0] == 'w' && data[1] == 'O' && data[2] == 'F' && data[3] == 'F') {
- result = ProcessWOFF(&header, output, data, length);
- } else {
- result = ProcessTTF(&header, output, data, length);
- }
- for (unsigned i = 0; ; ++i) {
- if (table_parsers[i].parse == NULL) break;
- table_parsers[i].free(&header);
- }
- return result;
- }
- #if !defined(_MSC_VER) && defined(OTS_DEBUG)
- bool Failure(const char *f, int l, const char *fn) {
- if (g_debug_output) {
- std::fprintf(stderr, "ERROR at %s:%d (%s)\n", f, l, fn);
- std::fflush(stderr);
- }
- return false;
- }
- void Warning(const char *f, int l, const char *format, ...) {
- if (g_debug_output) {
- std::fprintf(stderr, "WARNING at %s:%d: ", f, l);
- std::va_list va;
- va_start(va, format);
- std::vfprintf(stderr, format, va);
- va_end(va);
- std::fprintf(stderr, "\n");
- std::fflush(stderr);
- }
- }
- #endif
- } // namespace ots