Add woff2 to src/third_party

third_party/woff2/src/font.cc

+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Font management utilities
+
+#include "./font.h"
+
+#include <algorithm>
+
+#include "./buffer.h"
+#include "./port.h"
+#include "./store_bytes.h"
+#include "./table_tags.h"
+
+namespace woff2 {
+
+Font::Table* Font::FindTable(uint32_t tag) {
+  std::map<uint32_t, Font::Table>::iterator it = tables.find(tag);
+  return it == tables.end() ? 0 : &it->second;
+}
+
+const Font::Table* Font::FindTable(uint32_t tag) const {
+  std::map<uint32_t, Font::Table>::const_iterator it = tables.find(tag);
+  return it == tables.end() ? 0 : &it->second;
+}
+
+bool ReadFont(const uint8_t* data, size_t len, Font* font) {
+  Buffer file(data, len);
+
+  // We don't care about the search_range, entry_selector and range_shift
+  // fields, they will always be computed upon writing the font.
+  if (!file.ReadU32(&font->flavor) ||
+      !file.ReadU16(&font->num_tables) ||
+      !file.Skip(6)) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+
+  std::map<uint32_t, uint32_t> intervals;
+  for (uint16_t i = 0; i < font->num_tables; ++i) {
+    Font::Table table;
+    if (!file.ReadU32(&table.tag) ||
+        !file.ReadU32(&table.checksum) ||
+        !file.ReadU32(&table.offset) ||
+        !file.ReadU32(&table.length)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    if ((table.offset & 3) != 0 ||
+        table.length > len ||
+        len - table.length < table.offset) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    intervals[table.offset] = table.length;
+    table.data = data + table.offset;
+    if (font->tables.find(table.tag) != font->tables.end()) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    font->tables[table.tag] = table;
+  }
+
+  // Check that tables are non-overlapping.
+  uint32_t last_offset = 12UL + 16UL * font->num_tables;
+  for (const auto& i : intervals) {
+    if (i.first < last_offset || i.first + i.second < i.first) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    last_offset = i.first + i.second;
+  }
+  return true;
+}
+
+size_t FontFileSize(const Font& font) {
+  size_t max_offset = 12ULL + 16ULL * font.num_tables;
+  for (const auto& i : font.tables) {
+    const Font::Table& table = i.second;
+    size_t padding_size = (4 - (table.length & 3)) & 3;
+    size_t end_offset = (padding_size + table.offset) + table.length;
+    max_offset = std::max(max_offset, end_offset);
+  }
+  return max_offset;
+}
+
+bool WriteFont(const Font& font, uint8_t* dst, size_t dst_size) {
+  if (dst_size < 12ULL + 16ULL * font.num_tables) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+  size_t offset = 0;
+  StoreU32(font.flavor, &offset, dst);
+  Store16(font.num_tables, &offset, dst);
+  uint16_t max_pow2 = font.num_tables ? Log2Floor(font.num_tables) : 0;
+  uint16_t search_range = max_pow2 ? 1 << (max_pow2 + 4) : 0;
+  uint16_t range_shift = (font.num_tables << 4) - search_range;
+  Store16(search_range, &offset, dst);
+  Store16(max_pow2, &offset, dst);
+  Store16(range_shift, &offset, dst);
+  for (const auto& i : font.tables) {
+    const Font::Table& table = i.second;
+    StoreU32(table.tag, &offset, dst);
+    StoreU32(table.checksum, &offset, dst);
+    StoreU32(table.offset, &offset, dst);
+    StoreU32(table.length, &offset, dst);
+    if (table.offset + table.length < table.offset ||
+        dst_size < table.offset + table.length) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    memcpy(dst + table.offset, table.data, table.length);
+    size_t padding_size = (4 - (table.length & 3)) & 3;
+    if (table.offset + table.length + padding_size < padding_size ||
+        dst_size < table.offset + table.length + padding_size) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    memset(dst + table.offset + table.length, 0, padding_size);
+  }
+  return true;
+}
+
+int NumGlyphs(const Font& font) {
+  const Font::Table* head_table = font.FindTable(kHeadTableTag);
+  const Font::Table* loca_table = font.FindTable(kLocaTableTag);
+  if (head_table == NULL || loca_table == NULL || head_table->length < 52) {
+    return 0;
+  }
+  int index_fmt = IndexFormat(font);
+  int num_glyphs = (loca_table->length / (index_fmt == 0 ? 2 : 4)) - 1;
+  return num_glyphs;
+}
+
+int IndexFormat(const Font& font) {
+  const Font::Table* head_table = font.FindTable(kHeadTableTag);
+  if (head_table == NULL) {
+    return 0;
+  }
+  return head_table->data[51];
+}
+
+bool GetGlyphData(const Font& font, int glyph_index,
+                  const uint8_t** glyph_data, size_t* glyph_size) {
+  if (glyph_index < 0) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+  const Font::Table* head_table = font.FindTable(kHeadTableTag);
+  const Font::Table* loca_table = font.FindTable(kLocaTableTag);
+  const Font::Table* glyf_table = font.FindTable(kGlyfTableTag);
+  if (head_table == NULL || loca_table == NULL || glyf_table == NULL ||
+      head_table->length < 52) {
+    return FONT_COMPRESSION_FAILURE();
+  }
+
+  int index_fmt = IndexFormat(font);
+
+  Buffer loca_buf(loca_table->data, loca_table->length);
+  if (index_fmt == 0) {
+    uint16_t offset1, offset2;
+    if (!loca_buf.Skip(2 * glyph_index) ||
+        !loca_buf.ReadU16(&offset1) ||
+        !loca_buf.ReadU16(&offset2) ||
+        offset2 < offset1 ||
+        2 * offset2 > glyf_table->length) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    *glyph_data = glyf_table->data + 2 * offset1;
+    *glyph_size = 2 * (offset2 - offset1);
+  } else {
+    uint32_t offset1, offset2;
+    if (!loca_buf.Skip(4 * glyph_index) ||
+        !loca_buf.ReadU32(&offset1) ||
+        !loca_buf.ReadU32(&offset2) ||
+        offset2 < offset1 ||
+        offset2 > glyf_table->length) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+    *glyph_data = glyf_table->data + offset1;
+    *glyph_size = offset2 - offset1;
+  }
+  return true;
+}
+
+bool RemoveDigitalSignature(Font* font) {
+  std::map<uint32_t, Font::Table>::iterator it =
+      font->tables.find(kDsigTableTag);
+  if (it != font->tables.end()) {
+    font->tables.erase(it);
+    font->num_tables = font->tables.size();
+  }
+  return true;
+}
+
+} // namespace woff2