michael@0: // Copyright (c) 2009 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "glyf.h"
michael@0: 
michael@0: #include <algorithm>
michael@0: #include <limits>
michael@0: 
michael@0: #include "head.h"
michael@0: #include "loca.h"
michael@0: #include "maxp.h"
michael@0: 
michael@0: // glyf - Glyph Data
michael@0: // http://www.microsoft.com/typography/otspec/glyf.htm
michael@0: 
michael@0: #define TABLE_NAME "glyf"
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: bool ParseFlagsForSimpleGlyph(ots::OpenTypeFile *file,
michael@0:                               ots::Buffer *table,
michael@0:                               uint32_t gly_length,
michael@0:                               uint32_t num_flags,
michael@0:                               uint32_t *flags_count_logical,
michael@0:                               uint32_t *flags_count_physical,
michael@0:                               uint32_t *xy_coordinates_length) {
michael@0:   uint8_t flag = 0;
michael@0:   if (!table->ReadU8(&flag)) {
michael@0:     return OTS_FAILURE_MSG("Can't read flag");
michael@0:   }
michael@0: 
michael@0:   uint32_t delta = 0;
michael@0:   if (flag & (1u << 1)) {  // x-Short
michael@0:     ++delta;
michael@0:   } else if (!(flag & (1u << 4))) {
michael@0:     delta += 2;
michael@0:   }
michael@0: 
michael@0:   if (flag & (1u << 2)) {  // y-Short
michael@0:     ++delta;
michael@0:   } else if (!(flag & (1u << 5))) {
michael@0:     delta += 2;
michael@0:   }
michael@0: 
michael@0:   if (flag & (1u << 3)) {  // repeat
michael@0:     if (*flags_count_logical + 1 >= num_flags) {
michael@0:       return OTS_FAILURE_MSG("Count too high (%d + 1 >= %d)", *flags_count_logical, num_flags);
michael@0:     }
michael@0:     uint8_t repeat = 0;
michael@0:     if (!table->ReadU8(&repeat)) {
michael@0:       return OTS_FAILURE_MSG("Can't read repeat value");
michael@0:     }
michael@0:     if (repeat == 0) {
michael@0:       return OTS_FAILURE_MSG("Zero repeat");
michael@0:     }
michael@0:     delta += (delta * repeat);
michael@0: 
michael@0:     *flags_count_logical += repeat;
michael@0:     if (*flags_count_logical >= num_flags) {
michael@0:       return OTS_FAILURE_MSG("Count too high (%d >= %d)", *flags_count_logical, num_flags);
michael@0:     }
michael@0:     ++(*flags_count_physical);
michael@0:   }
michael@0: 
michael@0:   if ((flag & (1u << 6)) || (flag & (1u << 7))) {  // reserved flags
michael@0:     return OTS_FAILURE_MSG("Bad flag value (%d)", flag);
michael@0:   }
michael@0: 
michael@0:   *xy_coordinates_length += delta;
michael@0:   if (gly_length < *xy_coordinates_length) {
michael@0:     return OTS_FAILURE_MSG("Glyph coordinates length too low (%d < %d)", gly_length, *xy_coordinates_length);
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ParseSimpleGlyph(ots::OpenTypeFile *file, const uint8_t *data,
michael@0:                       ots::Buffer *table, int16_t num_contours,
michael@0:                       uint32_t gly_offset, uint32_t gly_length,
michael@0:                       uint32_t *new_size) {
michael@0:   ots::OpenTypeGLYF *glyf = file->glyf;
michael@0: 
michael@0:   // read the end-points array
michael@0:   uint16_t num_flags = 0;
michael@0:   for (int i = 0; i < num_contours; ++i) {
michael@0:     uint16_t tmp_index = 0;
michael@0:     if (!table->ReadU16(&tmp_index)) {
michael@0:       return OTS_FAILURE_MSG("Can't read contour index %d", i);
michael@0:     }
michael@0:     if (tmp_index == 0xffffu) {
michael@0:       return OTS_FAILURE_MSG("Bad contour index %d", i);
michael@0:     }
michael@0:     // check if the indices are monotonically increasing
michael@0:     if (i && (tmp_index + 1 <= num_flags)) {
michael@0:       return OTS_FAILURE_MSG("Decreasing contour index %d + 1 <= %d", tmp_index, num_flags);
michael@0:     }
michael@0:     num_flags = tmp_index + 1;
michael@0:   }
michael@0: 
michael@0:   uint16_t bytecode_length = 0;
michael@0:   if (!table->ReadU16(&bytecode_length)) {
michael@0:     return OTS_FAILURE_MSG("Can't read bytecode length");
michael@0:   }
michael@0:   if ((file->maxp->version_1) &&
michael@0:       (file->maxp->max_size_glyf_instructions < bytecode_length)) {
michael@0:     return OTS_FAILURE_MSG("Bytecode length too high %d", bytecode_length);
michael@0:   }
michael@0: 
michael@0:   const uint32_t gly_header_length = 10 + num_contours * 2 + 2;
michael@0:   if (gly_length < (gly_header_length + bytecode_length)) {
michael@0:     return OTS_FAILURE_MSG("Glyph header length too high %d", gly_header_length);
michael@0:   }
michael@0: 
michael@0:   if (ots::g_transcode_hints) {
michael@0:     glyf->iov.push_back(std::make_pair(
michael@0:         data + gly_offset,
michael@0:         static_cast<size_t>(gly_header_length + bytecode_length)));
michael@0:   } else {
michael@0:     // enqueue two vectors: the glyph data up to the bytecode length, then
michael@0:     // a pointer to a static uint16_t 0 to overwrite the length.
michael@0:     glyf->iov.push_back(std::make_pair(
michael@0:         data + gly_offset,
michael@0:         static_cast<size_t>(gly_header_length - 2)));
michael@0:     glyf->iov.push_back(std::make_pair((const uint8_t*) "\x00\x00",
michael@0:                                        static_cast<size_t>(2)));
michael@0:   }
michael@0: 
michael@0:   if (!table->Skip(bytecode_length)) {
michael@0:     return OTS_FAILURE_MSG("Can't skip bytecode of length %d", bytecode_length);
michael@0:   }
michael@0: 
michael@0:   uint32_t flags_count_physical = 0;  // on memory
michael@0:   uint32_t xy_coordinates_length = 0;
michael@0:   for (uint32_t flags_count_logical = 0;
michael@0:        flags_count_logical < num_flags;
michael@0:        ++flags_count_logical, ++flags_count_physical) {
michael@0:     if (!ParseFlagsForSimpleGlyph(file,
michael@0:                                   table,
michael@0:                                   gly_length,
michael@0:                                   num_flags,
michael@0:                                   &flags_count_logical,
michael@0:                                   &flags_count_physical,
michael@0:                                   &xy_coordinates_length)) {
michael@0:       return OTS_FAILURE_MSG("Failed to parse glyph flags %d", flags_count_logical);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (gly_length < (gly_header_length + bytecode_length +
michael@0:                     flags_count_physical + xy_coordinates_length)) {
michael@0:     return OTS_FAILURE_MSG("Glyph too short %d", gly_length);
michael@0:   }
michael@0: 
michael@0:   if (gly_length - (gly_header_length + bytecode_length +
michael@0:                     flags_count_physical + xy_coordinates_length) > 3) {
michael@0:     // We allow 0-3 bytes difference since gly_length is 4-bytes aligned,
michael@0:     // zero-padded length.
michael@0:     return OTS_FAILURE_MSG("Invalid glyph length %d", gly_length);
michael@0:   }
michael@0: 
michael@0:   glyf->iov.push_back(std::make_pair(
michael@0:       data + gly_offset + gly_header_length + bytecode_length,
michael@0:       static_cast<size_t>(flags_count_physical + xy_coordinates_length)));
michael@0: 
michael@0:   *new_size
michael@0:       = gly_header_length + flags_count_physical + xy_coordinates_length;
michael@0:   if (ots::g_transcode_hints) {
michael@0:     *new_size += bytecode_length;
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: namespace ots {
michael@0: 
michael@0: bool ots_glyf_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
michael@0:   Buffer table(data, length);
michael@0: 
michael@0:   if (!file->maxp || !file->loca || !file->head) {
michael@0:     return OTS_FAILURE_MSG("Missing maxp or loca or head table needed by glyf table");
michael@0:   }
michael@0: 
michael@0:   OpenTypeGLYF *glyf = new OpenTypeGLYF;
michael@0:   file->glyf = glyf;
michael@0: 
michael@0:   const unsigned num_glyphs = file->maxp->num_glyphs;
michael@0:   std::vector<uint32_t> &offsets = file->loca->offsets;
michael@0: 
michael@0:   if (offsets.size() != num_glyphs + 1) {
michael@0:     return OTS_FAILURE_MSG("Invalide glyph offsets size %ld != %d", offsets.size(), num_glyphs + 1);
michael@0:   }
michael@0: 
michael@0:   std::vector<uint32_t> resulting_offsets(num_glyphs + 1);
michael@0:   uint32_t current_offset = 0;
michael@0: 
michael@0:   for (unsigned i = 0; i < num_glyphs; ++i) {
michael@0:     const unsigned gly_offset = offsets[i];
michael@0:     // The LOCA parser checks that these values are monotonic
michael@0:     const unsigned gly_length = offsets[i + 1] - offsets[i];
michael@0:     if (!gly_length) {
michael@0:       // this glyph has no outline (e.g. the space charactor)
michael@0:       resulting_offsets[i] = current_offset;
michael@0:       continue;
michael@0:     }
michael@0: 
michael@0:     if (gly_offset >= length) {
michael@0:       return OTS_FAILURE_MSG("Glyph %d offset %d too high %ld", i, gly_offset, length);
michael@0:     }
michael@0:     // Since these are unsigned types, the compiler is not allowed to assume
michael@0:     // that they never overflow.
michael@0:     if (gly_offset + gly_length < gly_offset) {
michael@0:       return OTS_FAILURE_MSG("Glyph %d length (%d < 0)!", i, gly_length);
michael@0:     }
michael@0:     if (gly_offset + gly_length > length) {
michael@0:       return OTS_FAILURE_MSG("Glyph %d length %d too high", i, gly_length);
michael@0:     }
michael@0: 
michael@0:     table.set_offset(gly_offset);
michael@0:     int16_t num_contours, xmin, ymin, xmax, ymax;
michael@0:     if (!table.ReadS16(&num_contours) ||
michael@0:         !table.ReadS16(&xmin) ||
michael@0:         !table.ReadS16(&ymin) ||
michael@0:         !table.ReadS16(&xmax) ||
michael@0:         !table.ReadS16(&ymax)) {
michael@0:       return OTS_FAILURE_MSG("Can't read glyph %d header", i);
michael@0:     }
michael@0: 
michael@0:     if (num_contours <= -2) {
michael@0:       // -2, -3, -4, ... are reserved for future use.
michael@0:       return OTS_FAILURE_MSG("Bad number of contours %d in glyph %d", num_contours, i);
michael@0:     }
michael@0: 
michael@0:     // workaround for fonts in http://www.princexml.com/fonts/
michael@0:     if ((xmin == 32767) &&
michael@0:         (xmax == -32767) &&
michael@0:         (ymin == 32767) &&
michael@0:         (ymax == -32767)) {
michael@0:       OTS_WARNING("bad xmin/xmax/ymin/ymax values");
michael@0:       xmin = xmax = ymin = ymax = 0;
michael@0:     }
michael@0: 
michael@0:     if (xmin > xmax || ymin > ymax) {
michael@0:       return OTS_FAILURE_MSG("Bad bounding box values bl=(%d, %d), tr=(%d, %d) in glyph %d", xmin, ymin, xmax, ymax, i);
michael@0:     }
michael@0: 
michael@0:     unsigned new_size = 0;
michael@0:     if (num_contours >= 0) {
michael@0:       // this is a simple glyph and might contain bytecode
michael@0:       if (!ParseSimpleGlyph(file, data, &table,
michael@0:                             num_contours, gly_offset, gly_length, &new_size)) {
michael@0:         return OTS_FAILURE_MSG("Failed to parse glyph %d", i);
michael@0:       }
michael@0:     } else {
michael@0:       // it's a composite glyph without any bytecode. Enqueue the whole thing
michael@0:       glyf->iov.push_back(std::make_pair(data + gly_offset,
michael@0:                                          static_cast<size_t>(gly_length)));
michael@0:       new_size = gly_length;
michael@0:     }
michael@0: 
michael@0:     resulting_offsets[i] = current_offset;
michael@0:     // glyphs must be four byte aligned
michael@0:     // TODO(yusukes): investigate whether this padding is really necessary.
michael@0:     //                Which part of the spec requires this?
michael@0:     const unsigned padding = (4 - (new_size & 3)) % 4;
michael@0:     if (padding) {
michael@0:       glyf->iov.push_back(std::make_pair(
michael@0:           reinterpret_cast<const uint8_t*>("\x00\x00\x00\x00"),
michael@0:           static_cast<size_t>(padding)));
michael@0:       new_size += padding;
michael@0:     }
michael@0:     current_offset += new_size;
michael@0:   }
michael@0:   resulting_offsets[num_glyphs] = current_offset;
michael@0: 
michael@0:   const uint16_t max16 = std::numeric_limits<uint16_t>::max();
michael@0:   if ((*std::max_element(resulting_offsets.begin(),
michael@0:                          resulting_offsets.end()) >= (max16 * 2u)) &&
michael@0:       (file->head->index_to_loc_format != 1)) {
michael@0:     OTS_WARNING("2-bytes indexing is not possible (due to the padding above)");
michael@0:     file->head->index_to_loc_format = 1;
michael@0:   }
michael@0: 
michael@0:   file->loca->offsets = resulting_offsets;
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool ots_glyf_should_serialise(OpenTypeFile *file) {
michael@0:   return file->glyf != NULL;
michael@0: }
michael@0: 
michael@0: bool ots_glyf_serialise(OTSStream *out, OpenTypeFile *file) {
michael@0:   const OpenTypeGLYF *glyf = file->glyf;
michael@0: 
michael@0:   for (unsigned i = 0; i < glyf->iov.size(); ++i) {
michael@0:     if (!out->Write(glyf->iov[i].first, glyf->iov[i].second)) {
michael@0:       return OTS_FAILURE_MSG("Falied to write glyph %d", i);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: void ots_glyf_free(OpenTypeFile *file) {
michael@0:   delete file->glyf;
michael@0: }
michael@0: 
michael@0: }  // namespace ots