The Tor Browser: gfx/ots/src/ots.cc@6474c204b198 (annotated)

gfx/ots/src/ots.cc@6474c204b198 (annotated)

gfx/ots/src/ots.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // 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 <limits>
 #include <map>
 #include <vector>
 #ifdef MOZ_OTS_WOFF2
 #include "woff2.h"
 #endif
 // The OpenType Font File
 // http://www.microsoft.com/typography/otspec/cmap.htm
 namespace {
 bool g_debug_output = true;
 #ifdef MOZ_OTS_WOFF2
 bool g_enable_woff2 = false;
 #endif
 ots::MessageFunc  g_message_func = NULL;
 void             *g_message_user_data = NULL;
 ots::TableActionFunc  g_table_action_func = NULL;
 void                 *g_table_action_user_data = NULL;
 // Generate a message with or without a table tag, when 'header' is the OpenTypeFile pointer
 #define OTS_FAILURE_MSG_TAG(msg_,tag_) OTS_FAILURE_MSG_TAG_(header, msg_, tag_)
 #define OTS_FAILURE_MSG_HDR(msg_)      OTS_FAILURE_MSG_(header, msg_)
 struct OpenTypeTable {
   uint32_t tag;
   uint32_t chksum;
   uint32_t offset;
   uint32_t length;
   uint32_t uncompressed_length;
 };
 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;
 }
 uint32_t Tag(const char *tag_str) {
   uint32_t ret;
   std::memcpy(&ret, tag_str, 4);
   return ret;
 }
 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 {
   const char* 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[] = {
   { "maxp", ots::ots_maxp_parse, ots::ots_maxp_serialise,
     ots::ots_maxp_should_serialise, ots::ots_maxp_free, true },
   { "head", ots::ots_head_parse, ots::ots_head_serialise,
     ots::ots_head_should_serialise, ots::ots_head_free, true },
   { "OS/2", ots::ots_os2_parse, ots::ots_os2_serialise,
     ots::ots_os2_should_serialise, ots::ots_os2_free, true },
   { "cmap", ots::ots_cmap_parse, ots::ots_cmap_serialise,
     ots::ots_cmap_should_serialise, ots::ots_cmap_free, true },
   { "hhea", ots::ots_hhea_parse, ots::ots_hhea_serialise,
     ots::ots_hhea_should_serialise, ots::ots_hhea_free, true },
   { "hmtx", ots::ots_hmtx_parse, ots::ots_hmtx_serialise,
     ots::ots_hmtx_should_serialise, ots::ots_hmtx_free, true },
   { "name", ots::ots_name_parse, ots::ots_name_serialise,
     ots::ots_name_should_serialise, ots::ots_name_free, true },
   { "post", ots::ots_post_parse, ots::ots_post_serialise,
     ots::ots_post_should_serialise, ots::ots_post_free, true },
   { "loca", ots::ots_loca_parse, ots::ots_loca_serialise,
     ots::ots_loca_should_serialise, ots::ots_loca_free, false },
   { "glyf", ots::ots_glyf_parse, ots::ots_glyf_serialise,
     ots::ots_glyf_should_serialise, ots::ots_glyf_free, false },
   { "CFF ", ots::ots_cff_parse, ots::ots_cff_serialise,
     ots::ots_cff_should_serialise, ots::ots_cff_free, false },
   { "VDMX", ots::ots_vdmx_parse, ots::ots_vdmx_serialise,
     ots::ots_vdmx_should_serialise, ots::ots_vdmx_free, false },
   { "hdmx", ots::ots_hdmx_parse, ots::ots_hdmx_serialise,
     ots::ots_hdmx_should_serialise, ots::ots_hdmx_free, false },
   { "gasp", ots::ots_gasp_parse, ots::ots_gasp_serialise,
     ots::ots_gasp_should_serialise, ots::ots_gasp_free, false },
   { "cvt ", ots::ots_cvt_parse, ots::ots_cvt_serialise,
     ots::ots_cvt_should_serialise, ots::ots_cvt_free, false },
   { "fpgm", ots::ots_fpgm_parse, ots::ots_fpgm_serialise,
     ots::ots_fpgm_should_serialise, ots::ots_fpgm_free, false },
   { "prep", ots::ots_prep_parse, ots::ots_prep_serialise,
     ots::ots_prep_should_serialise, ots::ots_prep_free, false },
   { "LTSH", ots::ots_ltsh_parse, ots::ots_ltsh_serialise,
     ots::ots_ltsh_should_serialise, ots::ots_ltsh_free, false },
   { "VORG", ots::ots_vorg_parse, ots::ots_vorg_serialise,
     ots::ots_vorg_should_serialise, ots::ots_vorg_free, false },
   { "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.
   { "GDEF", ots::ots_gdef_parse, ots::ots_gdef_serialise,
     ots::ots_gdef_should_serialise, ots::ots_gdef_free, false },
   { "GPOS", ots::ots_gpos_parse, ots::ots_gpos_serialise,
     ots::ots_gpos_should_serialise, ots::ots_gpos_free, false },
   { "GSUB", ots::ots_gsub_parse, ots::ots_gsub_serialise,
     ots::ots_gsub_should_serialise, ots::ots_gsub_free, false },
   { "vhea", ots::ots_vhea_parse, ots::ots_vhea_serialise,
     ots::ots_vhea_should_serialise, ots::ots_vhea_free, false },
   { "vmtx", ots::ots_vmtx_parse, ots::ots_vmtx_serialise,
     ots::ots_vmtx_should_serialise, ots::ots_vmtx_free, false },
   { "MATH", ots::ots_math_parse, ots::ots_math_serialise,
     ots::ots_math_should_serialise, ots::ots_math_free, false },
   // TODO(bashi): Support mort, base, and jstf tables.
   { 0, NULL, NULL, NULL, NULL, false },
 };
 bool ProcessGeneric(ots::OpenTypeFile *header,
                     uint32_t signature,
                     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_MSG_HDR("file exceeds 1GB");
   }
   if (!file.ReadTag(&header->version)) {
     return OTS_FAILURE_MSG_HDR("error reading version tag");
   }
   if (!ots::IsValidVersionTag(header->version)) {
       return OTS_FAILURE_MSG_HDR("invalid version tag");
   }
   if (!file.ReadU16(&header->num_tables) ||
       !file.ReadU16(&header->search_range) ||
       !file.ReadU16(&header->entry_selector) ||
       !file.ReadU16(&header->range_shift)) {
     return OTS_FAILURE_MSG_HDR("error reading table directory search header");
   }
   // 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_MSG_HDR("excessive (or zero) number of tables");
   }
   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_MSG_HDR("incorrect entrySelector for table directory");
   }
   // 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_MSG_HDR("error reading table directory");
     }
     table.uncompressed_length = table.length;
     tables.push_back(table);
   }
   return ProcessGeneric(header, header->version, 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_MSG_HDR("file exceeds 1GB");
   }
   uint32_t woff_tag;
   if (!file.ReadTag(&woff_tag)) {
     return OTS_FAILURE_MSG_HDR("error reading WOFF marker");
   }
   if (woff_tag != Tag("wOFF")) {
     return OTS_FAILURE_MSG_HDR("invalid WOFF marker");
   }
   if (!file.ReadTag(&header->version)) {
     return OTS_FAILURE_MSG_HDR("error reading version tag");
   }
   if (!ots::IsValidVersionTag(header->version)) {
     return OTS_FAILURE_MSG_HDR("invalid version tag");
   }
   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_MSG_HDR("incorrect file size in WOFF header");
   }
   if (!file.ReadU16(&header->num_tables) || !header->num_tables) {
     return OTS_FAILURE_MSG_HDR("error reading number of tables");
   }
   uint16_t reserved_value;
   if (!file.ReadU16(&reserved_value) || reserved_value) {
     return OTS_FAILURE_MSG_HDR("error in reserved field of WOFF header");
   }
   uint32_t reported_total_sfnt_size;
   if (!file.ReadU32(&reported_total_sfnt_size)) {
     return OTS_FAILURE_MSG_HDR("error reading total sfnt size");
   }
   // We don't care about these fields of the header:
   //   uint16_t major_version, minor_version
   if (!file.Skip(2 * 2)) {
     return OTS_FAILURE_MSG_HDR("error skipping WOFF header fields");
   }
   // Checks metadata block size.
   uint32_t meta_offset;
   uint32_t meta_length;
   uint32_t meta_length_orig;
   if (!file.ReadU32(&meta_offset) ||
       !file.ReadU32(&meta_length) ||
       !file.ReadU32(&meta_length_orig)) {
     return OTS_FAILURE_MSG_HDR("error reading WOFF header fields");
   }
   if (meta_offset) {
     if (meta_offset >= length || length - meta_offset < meta_length) {
       return OTS_FAILURE_MSG_HDR("invalid metadata block location/size");
     }
   }
   // Checks private data block size.
   uint32_t priv_offset;
   uint32_t priv_length;
   if (!file.ReadU32(&priv_offset) ||
       !file.ReadU32(&priv_length)) {
     return OTS_FAILURE_MSG_HDR("error reading WOFF header fields");
   }
   if (priv_offset) {
     if (priv_offset >= length || length - priv_offset < priv_length) {
       return OTS_FAILURE_MSG_HDR("invalid private block location/size");
     }
   }
   // Next up is the list of tables.
   std::vector<OpenTypeTable> tables;
   uint32_t first_index = 0;
   uint32_t last_index = 0;
   // Size of sfnt header plus size of table records.
   uint64_t total_sfnt_size = 12 + 16 * header->num_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_MSG_HDR("error reading table directory");
     }
     total_sfnt_size += ots::Round4(table.uncompressed_length);
     if (total_sfnt_size > std::numeric_limits<uint32_t>::max()) {
       return OTS_FAILURE_MSG_HDR("sfnt size overflow");
     }
     tables.push_back(table);
     if (i == 0 || tables[first_index].offset > table.offset)
       first_index = i;
     if (i == 0 || tables[last_index].offset < table.offset)
       last_index = i;
   }
   if (reported_total_sfnt_size != total_sfnt_size) {
     return OTS_FAILURE_MSG_HDR("uncompressed sfnt size mismatch");
   }
   // Table data must follow immediately after the header.
   if (tables[first_index].offset != ots::Round4(file.offset())) {
     return OTS_FAILURE_MSG_HDR("junk before tables in WOFF file");
   }
   if (tables[last_index].offset >= length ||
       length - tables[last_index].offset < tables[last_index].length) {
     return OTS_FAILURE_MSG_HDR("invalid table location/size");
   }
   // Blocks must follow immediately after the previous block.
   // (Except for padding with a maximum of three null bytes)
   uint64_t block_end = ots::Round4(
       static_cast<uint64_t>(tables[last_index].offset) +
       static_cast<uint64_t>(tables[last_index].length));
   if (block_end > std::numeric_limits<uint32_t>::max()) {
     return OTS_FAILURE_MSG_HDR("invalid table location/size");
   }
   if (meta_offset) {
     if (block_end != meta_offset) {
       return OTS_FAILURE_MSG_HDR("invalid metadata block location");
     }
     block_end = ots::Round4(static_cast<uint64_t>(meta_offset) +
                             static_cast<uint64_t>(meta_length));
     if (block_end > std::numeric_limits<uint32_t>::max()) {
       return OTS_FAILURE_MSG_HDR("invalid metadata block size");
     }
   }
   if (priv_offset) {
     if (block_end != priv_offset) {
       return OTS_FAILURE_MSG_HDR("invalid private block location");
     }
     block_end = ots::Round4(static_cast<uint64_t>(priv_offset) +
                             static_cast<uint64_t>(priv_length));
     if (block_end > std::numeric_limits<uint32_t>::max()) {
       return OTS_FAILURE_MSG_HDR("invalid private block size");
     }
   }
   if (block_end != ots::Round4(length)) {
     return OTS_FAILURE_MSG_HDR("file length mismatch (trailing junk?)");
   }
   return ProcessGeneric(header, woff_tag, output, data, length, tables, file);
 }
 #ifdef MOZ_OTS_WOFF2
 bool ProcessWOFF2(ots::OpenTypeFile *header,
                   ots::OTSStream *output, const uint8_t *data, size_t length) {
   size_t decompressed_size = ots::ComputeWOFF2FinalSize(data, length);
   if (decompressed_size == 0) {
     return OTS_FAILURE();
   }
   // decompressed font must be <= 30MB
   if (decompressed_size > 30 * 1024 * 1024) {
     return OTS_FAILURE();
   }
   std::vector<uint8_t> decompressed_buffer(decompressed_size);
   if (!ots::ConvertWOFF2ToTTF(&decompressed_buffer[0], decompressed_size,
                               data, length)) {
     return OTS_FAILURE();
   }
   return ProcessTTF(header, output, &decompressed_buffer[0], decompressed_size);
 }
 #endif
 ots::TableAction GetTableAction(uint32_t tag) {
   ots::TableAction action = ots::TABLE_ACTION_DEFAULT;
   if (g_table_action_func != NULL) {
     action = g_table_action_func(htonl(tag), g_table_action_user_data);
   }
   if (action == ots::TABLE_ACTION_DEFAULT) {
     action = ots::TABLE_ACTION_DROP;
     for (unsigned i = 0; ; ++i) {
       if (table_parsers[i].parse == NULL) break;
       if (Tag(table_parsers[i].tag) == tag) {
         action = ots::TABLE_ACTION_SANITIZE;
         break;
       }
     }
   }
   assert(action != ots::TABLE_ACTION_DEFAULT); // Should never return this.
   return action;
 }
 bool GetTableData(const uint8_t *data,
                   const OpenTypeTable table,
                   Arena *arena,
                   size_t *table_length,
                   const uint8_t **table_data) {
   if (table.uncompressed_length != table.length) {
     // Compressed table. Need to uncompress into memory first.
     *table_length = table.uncompressed_length;
     *table_data = (*arena).Allocate(*table_length);
     uLongf dest_len = *table_length;
     int r = uncompress((Bytef*) *table_data, &dest_len,
                        data + table.offset, table.length);
     if (r != Z_OK || dest_len != *table_length) {
       return false;
     }
   } else {
     // Uncompressed table. We can process directly from memory.
     *table_data = data + table.offset;
     *table_length = table.length;
   }
   return true;
 }
 bool ProcessGeneric(ots::OpenTypeFile *header, uint32_t signature,
                     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_MSG_HDR("table directory not correctly ordered");
       }
     }
     // all tag names must be built from printable ASCII characters
     if (!CheckTag(tables[i].tag)) {
       return OTS_FAILURE_MSG_TAG("invalid table tag", &tables[i].tag);
     }
     // tables must be 4-byte aligned
     if (tables[i].offset & 3) {
       return OTS_FAILURE_MSG_TAG("misaligned table", &tables[i].tag);
     }
     // and must be within the file
     if (tables[i].offset < data_offset || tables[i].offset >= length) {
       return OTS_FAILURE_MSG_TAG("invalid table offset", &tables[i].tag);
     }
     // disallow all tables with a zero length
     if (tables[i].length < 1) {
       // Note: malayalam.ttf has zero length CVT table...
       return OTS_FAILURE_MSG_TAG("zero-length table", &tables[i].tag);
     }
     // disallow all tables with a length > 1GB
     if (tables[i].length > 1024 * 1024 * 1024) {
       return OTS_FAILURE_MSG_TAG("table length exceeds 1GB", &tables[i].tag);
     }
     // disallow tables where the uncompressed size is < the compressed size.
     if (tables[i].uncompressed_length < tables[i].length) {
       return OTS_FAILURE_MSG_TAG("invalid compressed table", &tables[i].tag);
     }
     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_MSG_TAG("uncompressed length exceeds 30MB", &tables[i].tag);
       }
       if (uncompressed_sum + tables[i].uncompressed_length < uncompressed_sum) {
         return OTS_FAILURE_MSG_TAG("overflow of uncompressed sum", &tables[i].tag);
       }
       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
     uint32_t end_byte = tables[i].offset + tables[i].length;
     // Tables in the WOFF file must be aligned 4-byte boundary.
     if (signature == Tag("wOFF")) {
         end_byte = ots::Round4(end_byte);
     }
     if (!end_byte || end_byte > length) {
       return OTS_FAILURE_MSG_TAG("table overruns end of file", &tables[i].tag);
     }
   }
   // All decompressed tables uncompressed must be <= 30MB.
   if (uncompressed_sum > 30 * 1024 * 1024) {
     return OTS_FAILURE_MSG_HDR("uncompressed sum exceeds 30MB");
   }
   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, static_cast<uint8_t>(1) /* start */));
     overlap_checker.push_back(
         std::make_pair(tables[i].offset + tables[i].length,
                        static_cast<uint8_t>(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_MSG_HDR("overlapping tables");
     }
   }
   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(Tag(table_parsers[i].tag));
     ots::TableAction action = GetTableAction(Tag(table_parsers[i].tag));
     if (it == table_map.end()) {
       if (table_parsers[i].required && action == ots::TABLE_ACTION_SANITIZE) {
         return OTS_FAILURE_MSG_TAG("missing required table", table_parsers[i].tag);
       }
       continue;
     }
     const uint8_t* table_data;
     size_t table_length;
     if (!GetTableData(data, it->second, &arena, &table_length, &table_data)) {
       return OTS_FAILURE_MSG_TAG("uncompress failed", table_parsers[i].tag);
     }
     if (action == ots::TABLE_ACTION_SANITIZE &&
         !table_parsers[i].parse(header, table_data, table_length)) {
       // TODO: parsers should generate specific messages detailing the failure;
       // once those are all added, we won't need a generic failure message here
       return OTS_FAILURE_MSG_TAG("failed to parse table", table_parsers[i].tag);
     }
   }
   if (header->cff) {
     // font with PostScript glyph
     if (header->version != Tag("OTTO")) {
       return OTS_FAILURE_MSG_HDR("wrong font version for PostScript glyph data");
     }
     if (header->glyf || header->loca) {
       // mixing outline formats is not recommended
       return OTS_FAILURE_MSG_HDR("font contains both PS and TT glyphs");
     }
   } else {
     if (!header->glyf || !header->loca) {
       // No TrueType glyph found.
       // Note: bitmap-only fonts are not supported.
       return OTS_FAILURE_MSG_HDR("neither PS nor TT glyphs present");
     }
   }
   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++;
     }
   }
   for (std::map<uint32_t, OpenTypeTable>::const_iterator it = table_map.begin();
        it != table_map.end(); ++it) {
     ots::TableAction action = GetTableAction(it->first);
     if (action == ots::TABLE_ACTION_PASSTHRU) {
       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;
   // most of the errors here are highly unlikely - they'd only occur if the
   // output stream returns a failure, e.g. lack of space to write
   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_MSG_HDR("error writing output");
   }
   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_MSG_HDR("error writing output");
   }
   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;
     uint32_t tag = Tag(table_parsers[i].tag);
     out.tag = tag;
     out.offset = output->Tell();
     output->ResetChecksum();
     if (tag == Tag("head")) {
       head_table_offset = out.offset;
     }
     if (!table_parsers[i].serialise(output, header)) {
       return OTS_FAILURE_MSG_TAG("failed to serialize table", table_parsers[i].tag);
     }
     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_MSG_HDR("error writing output");
     }
     out.length = end_offset - out.offset;
     // align tables to four bytes
     if (!output->Pad((4 - (end_offset & 3)) % 4)) {
       return OTS_FAILURE_MSG_HDR("error writing output");
     }
     out.chksum = output->chksum();
     out_tables.push_back(out);
   }
   for (std::map<uint32_t, OpenTypeTable>::const_iterator it = table_map.begin();
        it != table_map.end(); ++it) {
     ots::TableAction action = GetTableAction(it->first);
     if (action == ots::TABLE_ACTION_PASSTHRU) {
       OutputTable out;
       out.tag = it->second.tag;
       out.offset = output->Tell();
       output->ResetChecksum();
       if (it->second.tag == Tag("head")) {
         head_table_offset = out.offset;
       }
       const uint8_t* table_data;
       size_t table_length;
       if (!GetTableData(data, it->second, &arena, &table_length, &table_data)) {
         return OTS_FAILURE_MSG_HDR("Failed to uncompress table");
       }
       if (!output->Write(table_data, table_length)) {
         return OTS_FAILURE_MSG_HDR("Failed to serialize table");
       }
       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_MSG_HDR("error writing output");
       }
       out.length = end_offset - out.offset;
       // align tables to four bytes
       if (!output->Pad((4 - (end_offset & 3)) % 4)) {
         return OTS_FAILURE_MSG_HDR("error writing output");
       }
       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_MSG_HDR("error writing output");
   }
   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_MSG_HDR("error writing output");
     }
     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_MSG_HDR("internal error!");
   }
   if (!output->Seek(head_table_offset + 8)) {
     return OTS_FAILURE_MSG_HDR("error writing output");
   }
   if (!output->WriteU32(chksum_magic)) {
     return OTS_FAILURE_MSG_HDR("error writing output");
   }
   if (!output->Seek(end_of_file)) {
     return OTS_FAILURE_MSG_HDR("error writing output");
   }
   return true;
 }
 }  // namespace
 namespace ots {
 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");
 }
 void DisableDebugOutput() {
   g_debug_output = false;
 }
 #ifdef MOZ_OTS_WOFF2
 void EnableWOFF2() {
   g_enable_woff2 = true;
 }
 #endif
 void SetMessageCallback(MessageFunc func, void *user_data) {
   g_message_func = func;
   g_message_user_data = user_data;
 }
 void SetTableActionCallback(TableActionFunc func, void *user_data) {
   g_table_action_func = func;
   g_table_action_user_data = user_data;
 }
 bool Process(OTSStream *output, const uint8_t *data, size_t length) {
   OpenTypeFile header;
   header.message_func = g_message_func;
   header.user_data = g_message_user_data;
   if (length < 4) {
     return OTS_FAILURE_MSG_(&header, "file less than 4 bytes");
   }
   bool result;
   if (data[0] == 'w' && data[1] == 'O' && data[2] == 'F' && data[3] == 'F') {
     result = ProcessWOFF(&header, output, data, length);
 #ifdef MOZ_OTS_WOFF2
   } else if (g_enable_woff2 &&
              data[0] == 'w' && data[1] == 'O' && data[2] == 'F' &&
              data[3] == '2') {
     result = ProcessWOFF2(&header, output, data, length);
 #endif
   } 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

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gfx/ots/src/ots.cc@6474c204b198 (annotated)

gfx/ots/src/ots.cc