Updating OTS repo from https://github.com/khaledhosny/ots.git

third_party/ots/src/glyf.cc

+// 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);
+  }
+
+  glyf->iov.push_back(std::make_pair(
+      data + gly_offset,
+      static_cast<size_t>(gly_header_length + bytecode_length)));
+
+  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 + 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
+
+#undef TABLE_NAME