| // 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 WOFF2 format font files to their TTF 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 = (int)(len >> (7 * (size - i - 1))) & 0x7f; |
| if (i < size - 1) { |
| b |= 0x80; |
| } |
| dst[(*offset)++] = b; |
| } |
| } |
| |
| bool Woff2Compress(const uint8_t* data, const size_t len, |
| uint8_t* result, uint32_t* result_len) { |
| size_t compressed_len = *result_len; |
| brotli::BrotliParams params; |
| params.mode = brotli::BrotliParams::MODE_FONT; |
| brotli::BrotliCompressBuffer(params, len, data, &compressed_len, result); |
| *result_len = compressed_len; |
| return true; |
| } |
| |
| 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; |
| 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) { |
| size_t size = KnownTableIndex(table.tag) < 31 ? 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 size = kWoff2HeaderSize; |
| for (const auto& table : tables) { |
| size += TableEntrySize(table); |
| } |
| for (const auto& table : tables) { |
| size += table.dst_length; |
| size = Round4(size); |
| } |
| 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) { |
| // 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; |
| } |
| |
| bool ConvertTTFToWOFF2(const uint8_t *data, size_t length, |
| uint8_t *result, size_t *result_length) { |
| 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 = 1.2 * total_transform_length + 10240; |
| 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; |
| } |
| |
| 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); |
| 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 |
| 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); |
| } |
| 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 |