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-rw-r--r--modules/woff2/src/font.cc400
1 files changed, 400 insertions, 0 deletions
diff --git a/modules/woff2/src/font.cc b/modules/woff2/src/font.cc
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+++ b/modules/woff2/src/font.cc
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+/* Copyright 2013 Google Inc. All Rights Reserved.
+
+ Distributed under MIT license.
+ See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* 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;
+ }
+
+ // Sanity check key tables
+ const Font::Table* head_table = font->FindTable(kHeadTableTag);
+ if (head_table != NULL && head_table->length < 52) {
+ return FONT_COMPRESSION_FAILURE();
+ }
+
+ 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];
+ if (table.tag != table.reuse_of->tag) {
+ return FONT_COMPRESSION_FAILURE();
+ }
+ }
+
+ }
+ 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 loca_record_size = (index_fmt == 0 ? 2 : 4);
+ if (loca_table->length < loca_record_size) {
+ return 0;
+ }
+ return (loca_table->length / loca_record_size) - 1;
+}
+
+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