Add woff2 to src/third_party

third_party/woff2/src/woff2_enc.cc

+// Copyright 2014 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.
+//
+// Library for converting TTF format font files to their WOFF2 versions.
+
+#include "./woff2_enc.h"
+
+#include <stdlib.h>
+#include <complex>
+#include <cstring>
+#include <limits>
+#include <string>
+#include <vector>
+
+#include "./buffer.h"
+#include "./encode.h"
+#include "./font.h"
+#include "./normalize.h"
+#include "./round.h"
+#include "./store_bytes.h"
+#include "./table_tags.h"
+#include "./transform.h"
+#include "./woff2_common.h"
+
+namespace woff2 {
+
+namespace {
+
+using std::string;
+using std::vector;
+
+
+const size_t kWoff2HeaderSize = 48;
+const size_t kWoff2EntrySize = 20;
+
+size_t Base128Size(size_t n) {
+  size_t size = 1;
+  for (; n >= 128; n >>= 7) ++size;
+  return size;
+}
+
+void StoreBase128(size_t len, size_t* offset, uint8_t* dst) {
+  size_t size = Base128Size(len);
+  for (int i = 0; i < size; ++i) {
+    int b = static_cast<int>((len >> (7 * (size - i - 1))) & 0x7f);
+    if (i < size - 1) {
+      b |= 0x80;
+    }
+    dst[(*offset)++] = b;
+  }
+}
+
+bool Compress(const uint8_t* data, const size_t len,
+              uint8_t* result, uint32_t* result_len,
+              brotli::BrotliParams::Mode mode) {
+  size_t compressed_len = *result_len;
+  brotli::BrotliParams params;
+  params.mode = mode;
+  if (brotli::BrotliCompressBuffer(params, len, data, &compressed_len, result)
+      == 0) {
+    return false;
+  }
+  *result_len = compressed_len;
+  return true;
+}
+
+bool Woff2Compress(const uint8_t* data, const size_t len,
+                   uint8_t* result, uint32_t* result_len) {
+  return Compress(data, len, result, result_len,
+                  brotli::BrotliParams::MODE_FONT);
+}
+
+bool TextCompress(const uint8_t* data, const size_t len,
+                   uint8_t* result, uint32_t* result_len) {
+  return Compress(data, len, result, result_len,
+                  brotli::BrotliParams::MODE_TEXT);
+}
+
+bool ReadLongDirectory(Buffer* file, std::vector<Table>* tables,
+    size_t num_tables) {
+  for (size_t i = 0; i < num_tables; ++i) {
+    Table* table = &(*tables)[i];
+    if (!file->ReadU32(&table->tag) ||
+        !file->ReadU32(&table->flags) ||
+        !file->ReadU32(&table->src_length) ||
+        !file->ReadU32(&table->transform_length) ||
+        !file->ReadU32(&table->dst_length)) {
+      return FONT_COMPRESSION_FAILURE();
+    }
+  }
+  return true;
+}
+
+int KnownTableIndex(uint32_t tag) {
+  for (int i = 0; i < 63; ++i) {
+    if (tag == kKnownTags[i]) return i;
+  }
+  return 63;
+}
+
+void StoreTableEntry(const Table& table, size_t* offset, uint8_t* dst) {
+  uint8_t flag_byte = KnownTableIndex(table.tag);
+  dst[(*offset)++] = flag_byte;
+  // The index here is treated as a set of flag bytes because
+  // bits 6 and 7 of the byte are reserved for future use as flags.
+  // 0x3f or 63 means an arbitrary table tag.
+  if ((flag_byte & 0x3f) == 0x3f) {
+    StoreU32(table.tag, offset, dst);
+  }
+  StoreBase128(table.src_length, offset, dst);
+  if ((table.flags & kWoff2FlagsTransform) != 0) {
+    StoreBase128(table.transform_length, offset, dst);
+  }
+}
+
+size_t TableEntrySize(const Table& table) {
+  uint8_t flag_byte = KnownTableIndex(table.tag);
+  size_t size = ((flag_byte & 0x3f) != 0x3f) ? 1 : 5;
+  size += Base128Size(table.src_length);
+  if ((table.flags & kWoff2FlagsTransform) != 0) {
+     size += Base128Size(table.transform_length);
+  }
+  return size;
+}
+
+size_t ComputeWoff2Length(const std::vector<Table>& tables,
+                          size_t extended_metadata_length) {
+  size_t size = kWoff2HeaderSize;
+  for (const auto& table : tables) {
+    size += TableEntrySize(table);
+  }
+  for (const auto& table : tables) {
+    size += table.dst_length;
+    size = Round4(size);
+  }
+  size += extended_metadata_length;
+  return size;
+}
+
+size_t ComputeTTFLength(const std::vector<Table>& tables) {
+  size_t size = 12 + 16 * tables.size();  // sfnt header
+  for (const auto& table : tables) {
+    size += Round4(table.src_length);
+  }
+  return size;
+}
+
+size_t ComputeTotalTransformLength(const Font& font) {
+  size_t total = 0;
+  for (const auto& i : font.tables) {
+    const Font::Table& table = i.second;
+    if (table.tag & 0x80808080 || !font.FindTable(table.tag ^ 0x80808080)) {
+      // Count transformed tables and non-transformed tables that do not have
+      // transformed versions.
+      total += table.length;
+    }
+  }
+  return total;
+}
+
+}  // namespace
+
+size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length) {
+  return MaxWOFF2CompressedSize(data, length, "");
+}
+
+size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length,
+    const string& extended_metadata) {
+  // Except for the header size, which is 32 bytes larger in woff2 format,
+  // all other parts should be smaller (table header in short format,
+  // transformations and compression). Just to be sure, we will give some
+  // headroom anyway.
+  return length + 1024 + extended_metadata.length();
+}
+
+uint32_t CompressedBufferSize(uint32_t original_size) {
+  return 1.2 * original_size + 10240;
+}
+
+bool ConvertTTFToWOFF2(const uint8_t *data, size_t length,
+                       uint8_t *result, size_t *result_length) {
+  return ConvertTTFToWOFF2(data, length, result, result_length, "");
+}
+
+bool ConvertTTFToWOFF2(const uint8_t *data, size_t length,
+                       uint8_t *result, size_t *result_length,
+                       const string& extended_metadata) {
+  Font font;
+  if (!ReadFont(data, length, &font)) {
+    fprintf(stderr, "Parsing of the input font failed.\n");
+    return false;
+  }
+
+  if (!NormalizeFont(&font)) {
+    fprintf(stderr, "Font normalization failed.\n");
+    return false;
+  }
+
+  if (!TransformGlyfAndLocaTables(&font)) {
+    fprintf(stderr, "Font transformation failed.\n");
+    return false;
+  }
+
+  const Font::Table* head_table = font.FindTable(kHeadTableTag);
+  if (head_table == NULL) {
+    fprintf(stderr, "Missing head table.\n");
+    return false;
+  }
+
+  // Although the compressed size of each table in the final woff2 file won't
+  // be larger than its transform_length, we have to allocate a large enough
+  // buffer for the compressor, since the compressor can potentially increase
+  // the size. If the compressor overflows this, it should return false and
+  // then this function will also return false.
+  size_t total_transform_length = ComputeTotalTransformLength(font);
+  size_t compression_buffer_size = CompressedBufferSize(total_transform_length);
+  std::vector<uint8_t> compression_buf(compression_buffer_size);
+  uint32_t total_compressed_length = compression_buffer_size;
+
+  // Collect all transformed data into one place.
+  std::vector<uint8_t> transform_buf(total_transform_length);
+  size_t transform_offset = 0;
+  for (const auto& i : font.tables) {
+    if (i.second.tag & 0x80808080) continue;
+    const Font::Table* table = font.FindTable(i.second.tag ^ 0x80808080);
+    if (table == NULL) table = &i.second;
+    StoreBytes(table->data, table->length,
+               &transform_offset, &transform_buf[0]);
+  }
+  // Compress all transformed data in one stream.
+  if (!Woff2Compress(transform_buf.data(), total_transform_length,
+                     &compression_buf[0],
+                     &total_compressed_length)) {
+    fprintf(stderr, "Compression of combined table failed.\n");
+    return false;
+  }
+
+  // Compress the extended metadata
+  uint32_t compressed_metadata_buf_length =
+    CompressedBufferSize(extended_metadata.length());
+  std::vector<uint8_t> compressed_metadata_buf(compressed_metadata_buf_length);
+
+  if (extended_metadata.length() > 0) {
+    if (!TextCompress((const uint8_t*)extended_metadata.data(),
+                      extended_metadata.length(),
+                      compressed_metadata_buf.data(),
+                      &compressed_metadata_buf_length)) {
+      fprintf(stderr, "Compression of extended metadata failed.\n");
+      return false;
+    }
+  } else {
+    compressed_metadata_buf_length = 0;
+  }
+
+  std::vector<Table> tables;
+  for (const auto& i : font.tables) {
+    const Font::Table& src_table = i.second;
+    if (src_table.tag & 0x80808080) {
+      // This is a transformed table, we will write it together with the
+      // original version.
+      continue;
+    }
+    Table table;
+    table.tag = src_table.tag;
+    table.flags = 0;
+    table.src_length = src_table.length;
+    table.transform_length = src_table.length;
+    const uint8_t* transformed_data = src_table.data;
+    const Font::Table* transformed_table =
+        font.FindTable(src_table.tag ^ 0x80808080);
+    if (transformed_table != NULL) {
+      table.flags |= kWoff2FlagsTransform;
+      table.transform_length = transformed_table->length;
+      transformed_data = transformed_table->data;
+    }
+    if (tables.empty()) {
+      table.dst_length = total_compressed_length;
+      table.dst_data = &compression_buf[0];
+    } else {
+      table.dst_length = 0;
+      table.dst_data = NULL;
+      table.flags |= kWoff2FlagsContinueStream;
+    }
+    tables.push_back(table);
+  }
+
+  size_t woff2_length =
+    ComputeWoff2Length(tables, compressed_metadata_buf_length);
+  if (woff2_length > *result_length) {
+    fprintf(stderr, "Result allocation was too small (%zd vs %zd bytes).\n",
+           *result_length, woff2_length);
+    return false;
+  }
+  *result_length = woff2_length;
+
+  size_t offset = 0;
+  StoreU32(kWoff2Signature, &offset, result);
+  StoreU32(font.flavor, &offset, result);
+  StoreU32(woff2_length, &offset, result);
+  Store16(tables.size(), &offset, result);
+  Store16(0, &offset, result);  // reserved
+  StoreU32(ComputeTTFLength(tables), &offset, result);
+  StoreU32(total_compressed_length, &offset, result);
+  StoreBytes(head_table->data + 4, 4, &offset, result);  // font revision
+  if (compressed_metadata_buf_length > 0) {
+    StoreU32(woff2_length - compressed_metadata_buf_length,
+             &offset, result);  // metaOffset
+    StoreU32(compressed_metadata_buf_length, &offset, result);  // metaLength
+    StoreU32(extended_metadata.length(), &offset, result);  // metaOrigLength
+  } else {
+    StoreU32(0, &offset, result);  // metaOffset
+    StoreU32(0, &offset, result);  // metaLength
+    StoreU32(0, &offset, result);  // metaOrigLength
+  }
+  StoreU32(0, &offset, result);  // privOffset
+  StoreU32(0, &offset, result);  // privLength
+  for (const auto& table : tables) {
+    StoreTableEntry(table, &offset, result);
+  }
+  for (const auto& table : tables) {
+    StoreBytes(table.dst_data, table.dst_length, &offset, result);
+    offset = Round4(offset);
+  }
+  StoreBytes(compressed_metadata_buf.data(), compressed_metadata_buf_length,
+             &offset, result);
+
+  if (*result_length != offset) {
+    fprintf(stderr, "Mismatch between computed and actual length "
+            "(%zd vs %zd)\n", *result_length, offset);
+    return false;
+  }
+  return true;
+}
+
+} // namespace woff2