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Diffstat (limited to 'woff2/font.cc')
| -rw-r--r-- | woff2/font.cc | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/woff2/font.cc b/woff2/font.cc new file mode 100644 index 0000000..2733708 --- /dev/null +++ b/woff2/font.cc @@ -0,0 +1,176 @@ +// 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 "./ots.h" +#include "./port.h" +#include "./store_bytes.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) { + ots::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 OTS_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 OTS_FAILURE(); + } + if ((table.offset & 3) != 0 || + table.length > len || + len - table.length < table.offset) { + return OTS_FAILURE(); + } + intervals[table.offset] = table.length; + table.data = data + table.offset; + if (font->tables.find(table.tag) != font->tables.end()) { + return OTS_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 OTS_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 OTS_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 OTS_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 OTS_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 OTS_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 OTS_FAILURE(); + } + int index_fmt = head_table->data[51]; + ots::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 OTS_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 OTS_FAILURE(); + } + *glyph_data = glyf_table->data + offset1; + *glyph_size = offset2 - offset1; + } + return true; +} + +} // namespace woff2 |