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Diffstat (limited to 'modules/woff2/src/font.cc')
| -rw-r--r-- | modules/woff2/src/font.cc | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/modules/woff2/src/font.cc b/modules/woff2/src/font.cc new file mode 100644 index 000000000..060673005 --- /dev/null +++ b/modules/woff2/src/font.cc @@ -0,0 +1,396 @@ +// 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" +#include "./woff2_common.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; +} + +std::vector<uint32_t> Font::OutputOrderedTags() const { + std::vector<uint32_t> output_order; + + for (const auto& i : tables) { + const Font::Table& table = i.second; + // This is a transformed table, we will write it together with the + // original version. + if (table.tag & 0x80808080) { + continue; + } + output_order.push_back(table.tag); + } + + // Alphabetize then put loca immediately after glyf + auto glyf_loc = std::find(output_order.begin(), output_order.end(), + kGlyfTableTag); + auto loca_loc = std::find(output_order.begin(), output_order.end(), + kLocaTableTag); + if (glyf_loc != output_order.end() && loca_loc != output_order.end()) { + output_order.erase(loca_loc); + output_order.insert(std::find(output_order.begin(), output_order.end(), + kGlyfTableTag) + 1, kLocaTableTag); + } + + return output_order; +} + +bool ReadTrueTypeFont(Buffer* file, const uint8_t* data, size_t len, + Font* font) { + // 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->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; + table.flag_byte = 0; + table.reuse_of = NULL; + 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; +} + +bool ReadCollectionFont(Buffer* file, const uint8_t* data, size_t len, + Font* font, + std::map<uint32_t, Font::Table*>* all_tables) { + if (!file->ReadU32(&font->flavor)) { + return FONT_COMPRESSION_FAILURE(); + } + if (!ReadTrueTypeFont(file, data, len, font)) { + return FONT_COMPRESSION_FAILURE(); + } + + for (auto& entry : font->tables) { + Font::Table& table = entry.second; + + if (all_tables->find(table.offset) == all_tables->end()) { + (*all_tables)[table.offset] = font->FindTable(table.tag); + } else { + table.reuse_of = (*all_tables)[table.offset]; + } + + } + return true; +} + +bool ReadTrueTypeCollection(Buffer* file, const uint8_t* data, size_t len, + FontCollection* font_collection) { + uint32_t num_fonts; + + if (!file->ReadU32(&font_collection->header_version) || + !file->ReadU32(&num_fonts)) { + return FONT_COMPRESSION_FAILURE(); + } + + std::vector<uint32_t> offsets; + for (size_t i = 0; i < num_fonts; i++) { + uint32_t offset; + if (!file->ReadU32(&offset)) { + return FONT_COMPRESSION_FAILURE(); + } + offsets.push_back(offset); + } + + font_collection->fonts.resize(offsets.size()); + std::vector<Font>::iterator font_it = font_collection->fonts.begin(); + + std::map<uint32_t, Font::Table*> all_tables; + for (const auto offset : offsets) { + file->set_offset(offset); + Font& font = *font_it++; + if (!ReadCollectionFont(file, data, len, &font, &all_tables)) { + return FONT_COMPRESSION_FAILURE(); + } + } + + return true; +} + +bool ReadFont(const uint8_t* data, size_t len, Font* font) { + Buffer file(data, len); + + if (!file.ReadU32(&font->flavor)) { + return FONT_COMPRESSION_FAILURE(); + } + + if (font->flavor == kTtcFontFlavor) { + return FONT_COMPRESSION_FAILURE(); + } + return ReadTrueTypeFont(&file, data, len, font); +} + +bool ReadFontCollection(const uint8_t* data, size_t len, + FontCollection* font_collection) { + Buffer file(data, len); + + if (!file.ReadU32(&font_collection->flavor)) { + return FONT_COMPRESSION_FAILURE(); + } + + if (font_collection->flavor != kTtcFontFlavor) { + font_collection->fonts.resize(1); + Font& font = font_collection->fonts[0]; + font.flavor = font_collection->flavor; + return ReadTrueTypeFont(&file, data, len, &font); + } + return ReadTrueTypeCollection(&file, data, len, font_collection); +} + +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; +} + +size_t FontCollectionFileSize(const FontCollection& font_collection) { + size_t max_offset = 0; + for (auto& font : font_collection.fonts) { + // font file size actually just finds max offset + max_offset = std::max(max_offset, FontFileSize(font)); + } + return max_offset; +} + +bool WriteFont(const Font& font, uint8_t* dst, size_t dst_size) { + size_t offset = 0; + return WriteFont(font, &offset, dst, dst_size); +} + +bool WriteTableRecord(const Font::Table* table, size_t* offset, uint8_t* dst, + size_t dst_size) { + if (dst_size < *offset + kSfntEntrySize) { + return FONT_COMPRESSION_FAILURE(); + } + if (table->IsReused()) { + table = table->reuse_of; + } + StoreU32(table->tag, offset, dst); + StoreU32(table->checksum, offset, dst); + StoreU32(table->offset, offset, dst); + StoreU32(table->length, offset, dst); + return true; +} + +bool WriteTable(const Font::Table& table, size_t* offset, uint8_t* dst, + size_t dst_size) { + if (!WriteTableRecord(&table, offset, dst, dst_size)) { + return false; + } + + // Write the actual table data if it's the first time we've seen it + if (!table.IsReused()) { + 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; +} + +bool WriteFont(const Font& font, size_t* offset, uint8_t* dst, + size_t dst_size) { + if (dst_size < 12ULL + 16ULL * font.num_tables) { + return FONT_COMPRESSION_FAILURE(); + } + 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) { + if (!WriteTable(i.second, offset, dst, dst_size)) { + return false; + } + } + + return true; +} + +bool WriteFontCollection(const FontCollection& font_collection, uint8_t* dst, + size_t dst_size) { + size_t offset = 0; + + // It's simpler if this just a simple sfnt + if (font_collection.flavor != kTtcFontFlavor) { + return WriteFont(font_collection.fonts[0], &offset, dst, dst_size); + } + + // Write TTC header + StoreU32(kTtcFontFlavor, &offset, dst); + StoreU32(font_collection.header_version, &offset, dst); + StoreU32(font_collection.fonts.size(), &offset, dst); + + // Offset Table, zeroed for now + size_t offset_table = offset; // where to write offsets later + for (size_t i = 0; i < font_collection.fonts.size(); i++) { + StoreU32(0, &offset, dst); + } + + if (font_collection.header_version == 0x00020000) { + StoreU32(0, &offset, dst); // ulDsigTag + StoreU32(0, &offset, dst); // ulDsigLength + StoreU32(0, &offset, dst); // ulDsigOffset + } + + // Write fonts and their offsets. + for (size_t i = 0; i < font_collection.fonts.size(); i++) { + const auto& font = font_collection.fonts[i]; + StoreU32(offset, &offset_table, dst); + if (!WriteFont(font, &offset, dst, dst_size)) { + return false; + } + } + + 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 = IndexFormat(font); + int num_glyphs = (loca_table->length / (index_fmt == 0 ? 2 : 4)) - 1; + return num_glyphs; +} + +int IndexFormat(const Font& font) { + const Font::Table* head_table = font.FindTable(kHeadTableTag); + if (head_table == NULL) { + return 0; + } + return head_table->data[51]; +} + +bool Font::Table::IsReused() const { + return this->reuse_of != NULL; +} + +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 = IndexFormat(font); + + 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 |