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

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

gfx/ots/src/glyf.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 "glyf.h"
 #include <algorithm>
 #include <limits>
 #include "head.h"
 #include "loca.h"
 #include "maxp.h"
 // glyf - Glyph Data
 // http://www.microsoft.com/typography/otspec/glyf.htm
 #define TABLE_NAME "glyf"
 namespace {
 bool ParseFlagsForSimpleGlyph(ots::OpenTypeFile *file,
                               ots::Buffer *table,
                               uint32_t gly_length,
                               uint32_t num_flags,
                               uint32_t *flags_count_logical,
                               uint32_t *flags_count_physical,
                               uint32_t *xy_coordinates_length) {
   uint8_t flag = 0;
   if (!table->ReadU8(&flag)) {
     return OTS_FAILURE_MSG("Can't read flag");
   }
   uint32_t delta = 0;
   if (flag & (1u << 1)) {  // x-Short
     ++delta;
   } else if (!(flag & (1u << 4))) {
     delta += 2;
   }
   if (flag & (1u << 2)) {  // y-Short
     ++delta;
   } else if (!(flag & (1u << 5))) {
     delta += 2;
   }
   if (flag & (1u << 3)) {  // repeat
     if (*flags_count_logical + 1 >= num_flags) {
       return OTS_FAILURE_MSG("Count too high (%d + 1 >= %d)", *flags_count_logical, num_flags);
     }
     uint8_t repeat = 0;
     if (!table->ReadU8(&repeat)) {
       return OTS_FAILURE_MSG("Can't read repeat value");
     }
     if (repeat == 0) {
       return OTS_FAILURE_MSG("Zero repeat");
     }
     delta += (delta * repeat);
     *flags_count_logical += repeat;
     if (*flags_count_logical >= num_flags) {
       return OTS_FAILURE_MSG("Count too high (%d >= %d)", *flags_count_logical, num_flags);
     }
     ++(*flags_count_physical);
   }
   if ((flag & (1u << 6)) || (flag & (1u << 7))) {  // reserved flags
     return OTS_FAILURE_MSG("Bad flag value (%d)", flag);
   }
   *xy_coordinates_length += delta;
   if (gly_length < *xy_coordinates_length) {
     return OTS_FAILURE_MSG("Glyph coordinates length too low (%d < %d)", gly_length, *xy_coordinates_length);
   }
   return true;
 }
 bool ParseSimpleGlyph(ots::OpenTypeFile *file, const uint8_t *data,
                       ots::Buffer *table, int16_t num_contours,
                       uint32_t gly_offset, uint32_t gly_length,
                       uint32_t *new_size) {
   ots::OpenTypeGLYF *glyf = file->glyf;
   // read the end-points array
   uint16_t num_flags = 0;
   for (int i = 0; i < num_contours; ++i) {
     uint16_t tmp_index = 0;
     if (!table->ReadU16(&tmp_index)) {
       return OTS_FAILURE_MSG("Can't read contour index %d", i);
     }
     if (tmp_index == 0xffffu) {
       return OTS_FAILURE_MSG("Bad contour index %d", i);
     }
     // check if the indices are monotonically increasing
     if (i && (tmp_index + 1 <= num_flags)) {
       return OTS_FAILURE_MSG("Decreasing contour index %d + 1 <= %d", tmp_index, num_flags);
     }
     num_flags = tmp_index + 1;
   }
   uint16_t bytecode_length = 0;
   if (!table->ReadU16(&bytecode_length)) {
     return OTS_FAILURE_MSG("Can't read bytecode length");
   }
   if ((file->maxp->version_1) &&
       (file->maxp->max_size_glyf_instructions < bytecode_length)) {
     return OTS_FAILURE_MSG("Bytecode length too high %d", bytecode_length);
   }
   const uint32_t gly_header_length = 10 + num_contours * 2 + 2;
   if (gly_length < (gly_header_length + bytecode_length)) {
     return OTS_FAILURE_MSG("Glyph header length too high %d", gly_header_length);
   }
   if (ots::g_transcode_hints) {
     glyf->iov.push_back(std::make_pair(
         data + gly_offset,
         static_cast<size_t>(gly_header_length + bytecode_length)));
   } else {
     // enqueue two vectors: the glyph data up to the bytecode length, then
     // a pointer to a static uint16_t 0 to overwrite the length.
     glyf->iov.push_back(std::make_pair(
         data + gly_offset,
         static_cast<size_t>(gly_header_length - 2)));
     glyf->iov.push_back(std::make_pair((const uint8_t*) "\x00\x00",
                                        static_cast<size_t>(2)));
   }
   if (!table->Skip(bytecode_length)) {
     return OTS_FAILURE_MSG("Can't skip bytecode of length %d", bytecode_length);
   }
   uint32_t flags_count_physical = 0;  // on memory
   uint32_t xy_coordinates_length = 0;
   for (uint32_t flags_count_logical = 0;
        flags_count_logical < num_flags;
        ++flags_count_logical, ++flags_count_physical) {
     if (!ParseFlagsForSimpleGlyph(file,
                                   table,
                                   gly_length,
                                   num_flags,
                                   &flags_count_logical,
                                   &flags_count_physical,
                                   &xy_coordinates_length)) {
       return OTS_FAILURE_MSG("Failed to parse glyph flags %d", flags_count_logical);
     }
   }
   if (gly_length < (gly_header_length + bytecode_length +
                     flags_count_physical + xy_coordinates_length)) {
     return OTS_FAILURE_MSG("Glyph too short %d", gly_length);
   }
   if (gly_length - (gly_header_length + bytecode_length +
                     flags_count_physical + xy_coordinates_length) > 3) {
     // We allow 0-3 bytes difference since gly_length is 4-bytes aligned,
     // zero-padded length.
     return OTS_FAILURE_MSG("Invalid glyph length %d", gly_length);
   }
   glyf->iov.push_back(std::make_pair(
       data + gly_offset + gly_header_length + bytecode_length,
       static_cast<size_t>(flags_count_physical + xy_coordinates_length)));
   *new_size
       = gly_header_length + flags_count_physical + xy_coordinates_length;
   if (ots::g_transcode_hints) {
     *new_size += bytecode_length;
   }
   return true;
 }
 }  // namespace
 namespace ots {
 bool ots_glyf_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
   Buffer table(data, length);
   if (!file->maxp || !file->loca || !file->head) {
     return OTS_FAILURE_MSG("Missing maxp or loca or head table needed by glyf table");
   }
   OpenTypeGLYF *glyf = new OpenTypeGLYF;
   file->glyf = glyf;
   const unsigned num_glyphs = file->maxp->num_glyphs;
   std::vector<uint32_t> &offsets = file->loca->offsets;
   if (offsets.size() != num_glyphs + 1) {
     return OTS_FAILURE_MSG("Invalide glyph offsets size %ld != %d", offsets.size(), num_glyphs + 1);
   }
   std::vector<uint32_t> resulting_offsets(num_glyphs + 1);
   uint32_t current_offset = 0;
   for (unsigned i = 0; i < num_glyphs; ++i) {
     const unsigned gly_offset = offsets[i];
     // The LOCA parser checks that these values are monotonic
     const unsigned gly_length = offsets[i + 1] - offsets[i];
     if (!gly_length) {
       // this glyph has no outline (e.g. the space charactor)
       resulting_offsets[i] = current_offset;
       continue;
     }
     if (gly_offset >= length) {
       return OTS_FAILURE_MSG("Glyph %d offset %d too high %ld", i, gly_offset, length);
     }
     // Since these are unsigned types, the compiler is not allowed to assume
     // that they never overflow.
     if (gly_offset + gly_length < gly_offset) {
       return OTS_FAILURE_MSG("Glyph %d length (%d < 0)!", i, gly_length);
     }
     if (gly_offset + gly_length > length) {
       return OTS_FAILURE_MSG("Glyph %d length %d too high", i, gly_length);
     }
     table.set_offset(gly_offset);
     int16_t num_contours, xmin, ymin, xmax, ymax;
     if (!table.ReadS16(&num_contours) ||
         !table.ReadS16(&xmin) ||
         !table.ReadS16(&ymin) ||
         !table.ReadS16(&xmax) ||
         !table.ReadS16(&ymax)) {
       return OTS_FAILURE_MSG("Can't read glyph %d header", i);
     }
     if (num_contours <= -2) {
       // -2, -3, -4, ... are reserved for future use.
       return OTS_FAILURE_MSG("Bad number of contours %d in glyph %d", num_contours, i);
     }
     // workaround for fonts in http://www.princexml.com/fonts/
     if ((xmin == 32767) &&
         (xmax == -32767) &&
         (ymin == 32767) &&
         (ymax == -32767)) {
       OTS_WARNING("bad xmin/xmax/ymin/ymax values");
       xmin = xmax = ymin = ymax = 0;
     }
     if (xmin > xmax || ymin > ymax) {
       return OTS_FAILURE_MSG("Bad bounding box values bl=(%d, %d), tr=(%d, %d) in glyph %d", xmin, ymin, xmax, ymax, i);
     }
     unsigned new_size = 0;
     if (num_contours >= 0) {
       // this is a simple glyph and might contain bytecode
       if (!ParseSimpleGlyph(file, data, &table,
                             num_contours, gly_offset, gly_length, &new_size)) {
         return OTS_FAILURE_MSG("Failed to parse glyph %d", i);
       }
     } else {
       // it's a composite glyph without any bytecode. Enqueue the whole thing
       glyf->iov.push_back(std::make_pair(data + gly_offset,
                                          static_cast<size_t>(gly_length)));
       new_size = gly_length;
     }
     resulting_offsets[i] = current_offset;
     // glyphs must be four byte aligned
     // TODO(yusukes): investigate whether this padding is really necessary.
     //                Which part of the spec requires this?
     const unsigned padding = (4 - (new_size & 3)) % 4;
     if (padding) {
       glyf->iov.push_back(std::make_pair(
           reinterpret_cast<const uint8_t*>("\x00\x00\x00\x00"),
           static_cast<size_t>(padding)));
       new_size += padding;
     }
     current_offset += new_size;
   }
   resulting_offsets[num_glyphs] = current_offset;
   const uint16_t max16 = std::numeric_limits<uint16_t>::max();
   if ((*std::max_element(resulting_offsets.begin(),
                          resulting_offsets.end()) >= (max16 * 2u)) &&
       (file->head->index_to_loc_format != 1)) {
     OTS_WARNING("2-bytes indexing is not possible (due to the padding above)");
     file->head->index_to_loc_format = 1;
   }
   file->loca->offsets = resulting_offsets;
   return true;
 }
 bool ots_glyf_should_serialise(OpenTypeFile *file) {
   return file->glyf != NULL;
 }
 bool ots_glyf_serialise(OTSStream *out, OpenTypeFile *file) {
   const OpenTypeGLYF *glyf = file->glyf;
   for (unsigned i = 0; i < glyf->iov.size(); ++i) {
     if (!out->Write(glyf->iov[i].first, glyf->iov[i].second)) {
       return OTS_FAILURE_MSG("Falied to write glyph %d", i);
     }
   }
   return true;
 }
 void ots_glyf_free(OpenTypeFile *file) {
   delete file->glyf;
 }
 }  // namespace ots

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

gfx/ots/src/glyf.cc