Kenichi Ishibashi | 142d888 | 2014-05-30 09:06:32 +0900 | [diff] [blame] | 1 | // Copyright 2014 Google Inc. All Rights Reserved. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | // |
| 15 | // Library for converting WOFF2 format font files to their TTF versions. |
| 16 | |
| 17 | #include "./woff2_enc.h" |
| 18 | |
| 19 | #include <stdlib.h> |
| 20 | #include <complex> |
| 21 | #include <cstring> |
| 22 | #include <limits> |
| 23 | #include <string> |
| 24 | #include <vector> |
| 25 | |
| 26 | #include "./buffer.h" |
| 27 | #include "./encode.h" |
| 28 | #include "./font.h" |
| 29 | #include "./normalize.h" |
| 30 | #include "./round.h" |
| 31 | #include "./store_bytes.h" |
| 32 | #include "./table_tags.h" |
| 33 | #include "./transform.h" |
| 34 | #include "./woff2_common.h" |
| 35 | |
| 36 | namespace woff2 { |
| 37 | |
| 38 | namespace { |
| 39 | |
| 40 | using std::string; |
| 41 | using std::vector; |
| 42 | |
| 43 | |
| 44 | const size_t kWoff2HeaderSize = 48; |
| 45 | const size_t kWoff2EntrySize = 20; |
| 46 | |
| 47 | size_t Base128Size(size_t n) { |
| 48 | size_t size = 1; |
| 49 | for (; n >= 128; n >>= 7) ++size; |
| 50 | return size; |
| 51 | } |
| 52 | |
| 53 | void StoreBase128(size_t len, size_t* offset, uint8_t* dst) { |
| 54 | size_t size = Base128Size(len); |
| 55 | for (int i = 0; i < size; ++i) { |
| 56 | int b = (int)(len >> (7 * (size - i - 1))) & 0x7f; |
| 57 | if (i < size - 1) { |
| 58 | b |= 0x80; |
| 59 | } |
| 60 | dst[(*offset)++] = b; |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | bool Woff2Compress(const uint8_t* data, const size_t len, |
| 65 | uint8_t* result, uint32_t* result_len) { |
| 66 | size_t compressed_len = *result_len; |
| 67 | brotli::BrotliParams params; |
| 68 | params.mode = brotli::BrotliParams::MODE_FONT; |
| 69 | brotli::BrotliCompressBuffer(params, len, data, &compressed_len, result); |
| 70 | *result_len = compressed_len; |
| 71 | return true; |
| 72 | } |
| 73 | |
| 74 | bool ReadLongDirectory(Buffer* file, std::vector<Table>* tables, |
| 75 | size_t num_tables) { |
| 76 | for (size_t i = 0; i < num_tables; ++i) { |
| 77 | Table* table = &(*tables)[i]; |
| 78 | if (!file->ReadU32(&table->tag) || |
| 79 | !file->ReadU32(&table->flags) || |
| 80 | !file->ReadU32(&table->src_length) || |
| 81 | !file->ReadU32(&table->transform_length) || |
| 82 | !file->ReadU32(&table->dst_length)) { |
| 83 | return FONT_COMPRESSION_FAILURE(); |
| 84 | } |
| 85 | } |
| 86 | return true; |
| 87 | } |
| 88 | |
| 89 | int KnownTableIndex(uint32_t tag) { |
| 90 | for (int i = 0; i < 63; ++i) { |
| 91 | if (tag == kKnownTags[i]) return i; |
| 92 | } |
| 93 | return 63; |
| 94 | } |
| 95 | |
| 96 | void StoreTableEntry(const Table& table, size_t* offset, uint8_t* dst) { |
| 97 | uint8_t flag_byte = KnownTableIndex(table.tag); |
| 98 | dst[(*offset)++] = flag_byte; |
| 99 | if ((flag_byte & 0x3f) == 0x3f) { |
| 100 | StoreU32(table.tag, offset, dst); |
| 101 | } |
| 102 | StoreBase128(table.src_length, offset, dst); |
| 103 | if ((table.flags & kWoff2FlagsTransform) != 0) { |
| 104 | StoreBase128(table.transform_length, offset, dst); |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | size_t TableEntrySize(const Table& table) { |
| 109 | size_t size = KnownTableIndex(table.tag) < 31 ? 1 : 5; |
| 110 | size += Base128Size(table.src_length); |
| 111 | if ((table.flags & kWoff2FlagsTransform) != 0) { |
| 112 | size += Base128Size(table.transform_length); |
| 113 | } |
| 114 | return size; |
| 115 | } |
| 116 | |
| 117 | size_t ComputeWoff2Length(const std::vector<Table>& tables) { |
| 118 | size_t size = kWoff2HeaderSize; |
| 119 | for (const auto& table : tables) { |
| 120 | size += TableEntrySize(table); |
| 121 | } |
| 122 | for (const auto& table : tables) { |
| 123 | size += table.dst_length; |
| 124 | size = Round4(size); |
| 125 | } |
| 126 | return size; |
| 127 | } |
| 128 | |
| 129 | size_t ComputeTTFLength(const std::vector<Table>& tables) { |
| 130 | size_t size = 12 + 16 * tables.size(); // sfnt header |
| 131 | for (const auto& table : tables) { |
| 132 | size += Round4(table.src_length); |
| 133 | } |
| 134 | return size; |
| 135 | } |
| 136 | |
| 137 | size_t ComputeTotalTransformLength(const Font& font) { |
| 138 | size_t total = 0; |
| 139 | for (const auto& i : font.tables) { |
| 140 | const Font::Table& table = i.second; |
| 141 | if (table.tag & 0x80808080 || !font.FindTable(table.tag ^ 0x80808080)) { |
| 142 | // Count transformed tables and non-transformed tables that do not have |
| 143 | // transformed versions. |
| 144 | total += table.length; |
| 145 | } |
| 146 | } |
| 147 | return total; |
| 148 | } |
| 149 | |
| 150 | } // namespace |
| 151 | |
| 152 | size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length) { |
| 153 | // Except for the header size, which is 32 bytes larger in woff2 format, |
| 154 | // all other parts should be smaller (table header in short format, |
| 155 | // transformations and compression). Just to be sure, we will give some |
| 156 | // headroom anyway. |
| 157 | return length + 1024; |
| 158 | } |
| 159 | |
| 160 | bool ConvertTTFToWOFF2(const uint8_t *data, size_t length, |
| 161 | uint8_t *result, size_t *result_length) { |
| 162 | Font font; |
| 163 | if (!ReadFont(data, length, &font)) { |
| 164 | fprintf(stderr, "Parsing of the input font failed.\n"); |
| 165 | return false; |
| 166 | } |
| 167 | |
| 168 | if (!NormalizeFont(&font)) { |
| 169 | fprintf(stderr, "Font normalization failed.\n"); |
| 170 | return false; |
| 171 | } |
| 172 | |
| 173 | if (!TransformGlyfAndLocaTables(&font)) { |
| 174 | fprintf(stderr, "Font transformation failed.\n"); |
| 175 | return false; |
| 176 | } |
| 177 | |
| 178 | const Font::Table* head_table = font.FindTable(kHeadTableTag); |
| 179 | if (head_table == NULL) { |
| 180 | fprintf(stderr, "Missing head table.\n"); |
| 181 | return false; |
| 182 | } |
| 183 | |
| 184 | // Although the compressed size of each table in the final woff2 file won't |
| 185 | // be larger than its transform_length, we have to allocate a large enough |
| 186 | // buffer for the compressor, since the compressor can potentially increase |
| 187 | // the size. If the compressor overflows this, it should return false and |
| 188 | // then this function will also return false. |
| 189 | size_t total_transform_length = ComputeTotalTransformLength(font); |
| 190 | size_t compression_buffer_size = 1.2 * total_transform_length + 10240; |
| 191 | std::vector<uint8_t> compression_buf(compression_buffer_size); |
| 192 | uint32_t total_compressed_length = compression_buffer_size; |
| 193 | |
| 194 | // Collect all transformed data into one place. |
| 195 | std::vector<uint8_t> transform_buf(total_transform_length); |
| 196 | size_t transform_offset = 0; |
| 197 | for (const auto& i : font.tables) { |
| 198 | if (i.second.tag & 0x80808080) continue; |
| 199 | const Font::Table* table = font.FindTable(i.second.tag ^ 0x80808080); |
| 200 | if (table == NULL) table = &i.second; |
| 201 | StoreBytes(table->data, table->length, |
| 202 | &transform_offset, &transform_buf[0]); |
| 203 | } |
| 204 | // Compress all transformed data in one stream. |
| 205 | if (!Woff2Compress(transform_buf.data(), total_transform_length, |
| 206 | &compression_buf[0], |
| 207 | &total_compressed_length)) { |
| 208 | fprintf(stderr, "Compression of combined table failed.\n"); |
| 209 | return false; |
| 210 | } |
| 211 | |
| 212 | std::vector<Table> tables; |
| 213 | for (const auto& i : font.tables) { |
| 214 | const Font::Table& src_table = i.second; |
| 215 | if (src_table.tag & 0x80808080) { |
| 216 | // This is a transformed table, we will write it together with the |
| 217 | // original version. |
| 218 | continue; |
| 219 | } |
| 220 | Table table; |
| 221 | table.tag = src_table.tag; |
| 222 | table.flags = 0; |
| 223 | table.src_length = src_table.length; |
| 224 | table.transform_length = src_table.length; |
| 225 | const uint8_t* transformed_data = src_table.data; |
| 226 | const Font::Table* transformed_table = |
| 227 | font.FindTable(src_table.tag ^ 0x80808080); |
| 228 | if (transformed_table != NULL) { |
| 229 | table.flags |= kWoff2FlagsTransform; |
| 230 | table.transform_length = transformed_table->length; |
| 231 | transformed_data = transformed_table->data; |
| 232 | } |
| 233 | if (tables.empty()) { |
| 234 | table.dst_length = total_compressed_length; |
| 235 | table.dst_data = &compression_buf[0]; |
| 236 | } else { |
| 237 | table.dst_length = 0; |
| 238 | table.dst_data = NULL; |
| 239 | table.flags |= kWoff2FlagsContinueStream; |
| 240 | } |
| 241 | tables.push_back(table); |
| 242 | } |
| 243 | |
| 244 | size_t woff2_length = ComputeWoff2Length(tables); |
| 245 | if (woff2_length > *result_length) { |
| 246 | fprintf(stderr, "Result allocation was too small (%zd vs %zd bytes).\n", |
| 247 | *result_length, woff2_length); |
| 248 | return false; |
| 249 | } |
| 250 | *result_length = woff2_length; |
| 251 | |
| 252 | size_t offset = 0; |
| 253 | StoreU32(kWoff2Signature, &offset, result); |
| 254 | StoreU32(font.flavor, &offset, result); |
| 255 | StoreU32(woff2_length, &offset, result); |
| 256 | Store16(tables.size(), &offset, result); |
| 257 | Store16(0, &offset, result); // reserved |
| 258 | StoreU32(ComputeTTFLength(tables), &offset, result); |
| 259 | StoreU32(total_compressed_length, &offset, result); |
| 260 | StoreBytes(head_table->data + 4, 4, &offset, result); // font revision |
| 261 | StoreU32(0, &offset, result); // metaOffset |
| 262 | StoreU32(0, &offset, result); // metaLength |
| 263 | StoreU32(0, &offset, result); // metaOrigLength |
| 264 | StoreU32(0, &offset, result); // privOffset |
| 265 | StoreU32(0, &offset, result); // privLength |
| 266 | for (const auto& table : tables) { |
| 267 | StoreTableEntry(table, &offset, result); |
| 268 | } |
| 269 | for (const auto& table : tables) { |
| 270 | StoreBytes(table.dst_data, table.dst_length, &offset, result); |
| 271 | offset = Round4(offset); |
| 272 | } |
| 273 | if (*result_length != offset) { |
| 274 | fprintf(stderr, "Mismatch between computed and actual length " |
| 275 | "(%zd vs %zd)\n", *result_length, offset); |
| 276 | return false; |
| 277 | } |
| 278 | return true; |
| 279 | } |
| 280 | |
| 281 | } // namespace woff2 |