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Diffstat (limited to 'modules/woff2/src/woff2_enc.cc')
| -rw-r--r-- | modules/woff2/src/woff2_enc.cc | 471 |
1 files changed, 471 insertions, 0 deletions
diff --git a/modules/woff2/src/woff2_enc.cc b/modules/woff2/src/woff2_enc.cc new file mode 100644 index 000000000..d100ad51b --- /dev/null +++ b/modules/woff2/src/woff2_enc.cc @@ -0,0 +1,471 @@ +// 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 "./compressor.h" +#include "./buffer.h" +#include "./font.h" +#include "./normalize.h" +#include "./round.h" +#include "./store_bytes.h" +#include "./table_tags.h" +#include "./transform.h" +#include "./variable_length.h" +#include "./woff2_common.h" + + +namespace woff2 { + +namespace { + + +using std::string; +using std::vector; + + +const size_t kWoff2HeaderSize = 48; +const size_t kWoff2EntrySize = 20; + + +bool Compress(const uint8_t* data, const size_t len, + uint8_t* result, uint32_t* result_len, + brotli::BrotliParams::Mode mode, int quality) { + size_t compressed_len = *result_len; + brotli::BrotliParams params; + params.mode = mode; + params.quality = quality; + 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, + int quality) { + return Compress(data, len, result, result_len, + brotli::BrotliParams::MODE_FONT, quality); +} + +bool TextCompress(const uint8_t* data, const size_t len, + uint8_t* result, uint32_t* result_len, + int quality) { + return Compress(data, len, result, result_len, + brotli::BrotliParams::MODE_TEXT, quality); +} + +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 = (table.flags & 0xC0) | 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 FontCollection& font_collection, + const std::vector<Table>& tables, + std::map<uint32_t, uint16_t> index_by_offset, + size_t compressed_data_length, + size_t extended_metadata_length) { + size_t size = kWoff2HeaderSize; + + for (const auto& table : tables) { + size += TableEntrySize(table); + } + + // for collections only, collection tables + if (font_collection.flavor == kTtcFontFlavor) { + size += 4; // UInt32 Version of TTC Header + size += Size255UShort(font_collection.fonts.size()); // 255UInt16 numFonts + + size += 4 * font_collection.fonts.size(); // UInt32 flavor for each + + for (const auto& font : font_collection.fonts) { + size += Size255UShort(font.tables.size()); // 255UInt16 numTables + for (const auto& entry : font.tables) { + const Font::Table& table = entry.second; + // no collection entry for xform table + if (table.tag & 0x80808080) continue; + + uint16_t table_index = index_by_offset[table.offset]; + size += Size255UShort(table_index); // 255UInt16 index entry + } + } + } + + // compressed data + size += compressed_data_length; + size = Round4(size); + + size += extended_metadata_length; + return size; +} + +size_t ComputeUncompressedLength(const Font& font) { + // sfnt header + offset table + size_t size = 12 + 16 * font.num_tables; + for (const auto& entry : font.tables) { + const Font::Table& table = entry.second; + if (table.tag & 0x80808080) continue; // xform tables don't stay + if (table.IsReused()) continue; // don't have to pay twice + size += Round4(table.length); + } + return size; +} + +size_t ComputeUncompressedLength(const FontCollection& font_collection) { + if (font_collection.flavor != kTtcFontFlavor) { + return ComputeUncompressedLength(font_collection.fonts[0]); + } + size_t size = CollectionHeaderSize(font_collection.header_version, + font_collection.fonts.size()); + for (const auto& font : font_collection.fonts) { + size += ComputeUncompressedLength(font); + } + 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.IsReused()) { + continue; + } + 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 TransformFontCollection(FontCollection* font_collection) { + for (auto& font : font_collection->fonts) { + if (!TransformGlyfAndLocaTables(&font)) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "glyf/loca transformation failed.\n"); +#endif + return FONT_COMPRESSION_FAILURE(); + } + } + + return true; +} + +bool ConvertTTFToWOFF2(const uint8_t *data, size_t length, + uint8_t *result, size_t *result_length) { + WOFF2Params params; + return ConvertTTFToWOFF2(data, length, result, result_length, + params); +} + +bool ConvertTTFToWOFF2(const uint8_t *data, size_t length, + uint8_t *result, size_t *result_length, + const WOFF2Params& params) { + FontCollection font_collection; + if (!ReadFontCollection(data, length, &font_collection)) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Parsing of the input font failed.\n"); +#endif + return FONT_COMPRESSION_FAILURE(); + } + + if (!NormalizeFontCollection(&font_collection)) { + return FONT_COMPRESSION_FAILURE(); + } + + if (params.allow_transforms && !TransformFontCollection(&font_collection)) { + return FONT_COMPRESSION_FAILURE(); + } else { + // glyf/loca use 11 to flag "not transformed" + for (auto& font : font_collection.fonts) { + Font::Table* glyf_table = font.FindTable(kGlyfTableTag); + Font::Table* loca_table = font.FindTable(kLocaTableTag); + if (glyf_table) { + glyf_table->flag_byte |= 0xc0; + } + if (loca_table) { + loca_table->flag_byte |= 0xc0; + } + } + } + + // 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 = 0; + for (const auto& font : font_collection.fonts) { + 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 in output order. + std::vector<uint8_t> transform_buf(total_transform_length); + size_t transform_offset = 0; + for (const auto& font : font_collection.fonts) { + for (const auto tag : font.OutputOrderedTags()) { + const Font::Table& original = font.tables.at(tag); + if (original.IsReused()) continue; + if (tag & 0x80808080) continue; + const Font::Table* table_to_store = font.FindTable(tag ^ 0x80808080); + if (table_to_store == NULL) table_to_store = &original; + + StoreBytes(table_to_store->data, table_to_store->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, + params.brotli_quality)) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Compression of combined table failed.\n"); +#endif + return FONT_COMPRESSION_FAILURE(); + } + +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Compressed %zu to %u.\n", total_transform_length, + total_compressed_length); +#endif + + // Compress the extended metadata + // TODO(user): how does this apply to collections + uint32_t compressed_metadata_buf_length = + CompressedBufferSize(params.extended_metadata.length()); + std::vector<uint8_t> compressed_metadata_buf(compressed_metadata_buf_length); + + if (params.extended_metadata.length() > 0) { + if (!TextCompress((const uint8_t*)params.extended_metadata.data(), + params.extended_metadata.length(), + compressed_metadata_buf.data(), + &compressed_metadata_buf_length, + params.brotli_quality)) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Compression of extended metadata failed.\n"); +#endif + return FONT_COMPRESSION_FAILURE(); + } + } else { + compressed_metadata_buf_length = 0; + } + + std::vector<Table> tables; + std::map<uint32_t, uint16_t> index_by_offset; + + for (const auto& font : font_collection.fonts) { + + for (const auto tag : font.OutputOrderedTags()) { + const Font::Table& src_table = font.tables.at(tag); + if (src_table.IsReused()) { + continue; + } + + if (index_by_offset.find(src_table.offset) == index_by_offset.end()) { + index_by_offset[src_table.offset] = tables.size(); + } else { + return false; + } + + Table table; + table.tag = src_table.tag; + table.flags = src_table.flag_byte; + 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 = transformed_table->flag_byte; + table.flags |= kWoff2FlagsTransform; + table.transform_length = transformed_table->length; + transformed_data = transformed_table->data; + + } + tables.push_back(table); + } + } + + size_t woff2_length = ComputeWoff2Length(font_collection, tables, + index_by_offset, total_compressed_length, compressed_metadata_buf_length); + if (woff2_length > *result_length) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Result allocation was too small (%zd vs %zd bytes).\n", + *result_length, woff2_length); +#endif + return FONT_COMPRESSION_FAILURE(); + } + *result_length = woff2_length; + + size_t offset = 0; + + // start of woff2 header (http://www.w3.org/TR/WOFF2/#woff20Header) + StoreU32(kWoff2Signature, &offset, result); + if (font_collection.flavor != kTtcFontFlavor) { + StoreU32(font_collection.fonts[0].flavor, &offset, result); + } else { + StoreU32(kTtcFontFlavor, &offset, result); + } + StoreU32(woff2_length, &offset, result); + Store16(tables.size(), &offset, result); + Store16(0, &offset, result); // reserved + // totalSfntSize + StoreU32(ComputeUncompressedLength(font_collection), &offset, result); + StoreU32(total_compressed_length, &offset, result); // totalCompressedSize + + // Let's just all be v1.0 + Store16(1, &offset, result); // majorVersion + Store16(0, &offset, result); // minorVersion + 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(params.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 + // end of woff2 header + + // table directory (http://www.w3.org/TR/WOFF2/#table_dir_format) + for (const auto& table : tables) { + StoreTableEntry(table, &offset, result); + } + + // for collections only, collection table directory + if (font_collection.flavor == kTtcFontFlavor) { + StoreU32(font_collection.header_version, &offset, result); + Store255UShort(font_collection.fonts.size(), &offset, result); + for (const Font& font : font_collection.fonts) { + + uint16_t num_tables = 0; + for (const auto& entry : font.tables) { + const Font::Table& table = entry.second; + if (table.tag & 0x80808080) continue; // don't write xform tables + num_tables++; + } + Store255UShort(num_tables, &offset, result); + + StoreU32(font.flavor, &offset, result); + for (const auto& entry : font.tables) { + const Font::Table& table = entry.second; + if (table.tag & 0x80808080) continue; // don't write xform tables + + // for reused tables, only the original has an updated offset + uint32_t table_offset = + table.IsReused() ? table.reuse_of->offset : table.offset; + uint32_t table_length = + table.IsReused() ? table.reuse_of->length : table.length; + if (index_by_offset.find(table_offset) == index_by_offset.end()) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Missing table index for offset 0x%08x\n", + table_offset); +#endif + return FONT_COMPRESSION_FAILURE(); + } + uint16_t index = index_by_offset[table_offset]; + Store255UShort(index, &offset, result); + + } + + } + } + + // compressed data format (http://www.w3.org/TR/WOFF2/#table_format) + + StoreBytes(&compression_buf[0], total_compressed_length, &offset, result); + offset = Round4(offset); + + StoreBytes(compressed_metadata_buf.data(), compressed_metadata_buf_length, + &offset, result); + + if (*result_length != offset) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Mismatch between computed and actual length " + "(%zd vs %zd)\n", *result_length, offset); +#endif + return FONT_COMPRESSION_FAILURE(); + } + return true; +} + +} // namespace woff2 |