| // 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 = head_table->data[51]; |
| return (loca_table->length / (index_fmt == 0 ? 2 : 4)) - 1; |
| } |
| |
| 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 = head_table->data[51]; |
| 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 |