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-rw-r--r--modules/woff2/src/woff2_enc.cc471
1 files changed, 471 insertions, 0 deletions
diff --git a/modules/woff2/src/woff2_enc.cc b/modules/woff2/src/woff2_enc.cc
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+++ b/modules/woff2/src/woff2_enc.cc
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+// Copyright 2014 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.
+//
+// Library for converting TTF format font files to their WOFF2 versions.
+
+#include "./woff2_enc.h"
+
+#include <stdlib.h>
+#include <complex>
+#include <cstring>
+#include <limits>
+#include <string>
+#include <vector>
+
+#include "./compressor.h"
+#include "./buffer.h"
+#include "./font.h"
+#include "./normalize.h"
+#include "./round.h"
+#include "./store_bytes.h"
+#include "./table_tags.h"
+#include "./transform.h"
+#include "./variable_length.h"
+#include "./woff2_common.h"
+
+
+namespace woff2 {
+
+namespace {
+
+
+using std::string;
+using std::vector;
+
+
+const size_t kWoff2HeaderSize = 48;
+const size_t kWoff2EntrySize = 20;
+
+
+bool Compress(const uint8_t* data, const size_t len,
+ uint8_t* result, uint32_t* result_len,
+ brotli::BrotliParams::Mode mode, int quality) {
+ size_t compressed_len = *result_len;
+ brotli::BrotliParams params;
+ params.mode = mode;
+ params.quality = quality;
+ if (brotli::BrotliCompressBuffer(params, len, data, &compressed_len, result)
+ == 0) {
+ return false;
+ }
+ *result_len = compressed_len;
+ return true;
+}
+
+bool Woff2Compress(const uint8_t* data, const size_t len,
+ uint8_t* result, uint32_t* result_len,
+ int quality) {
+ return Compress(data, len, result, result_len,
+ brotli::BrotliParams::MODE_FONT, quality);
+}
+
+bool TextCompress(const uint8_t* data, const size_t len,
+ uint8_t* result, uint32_t* result_len,
+ int quality) {
+ return Compress(data, len, result, result_len,
+ brotli::BrotliParams::MODE_TEXT, quality);
+}
+
+int KnownTableIndex(uint32_t tag) {
+ for (int i = 0; i < 63; ++i) {
+ if (tag == kKnownTags[i]) return i;
+ }
+ return 63;
+}
+
+void StoreTableEntry(const Table& table, size_t* offset, uint8_t* dst) {
+ uint8_t flag_byte = (table.flags & 0xC0) | KnownTableIndex(table.tag);
+ dst[(*offset)++] = flag_byte;
+ // The index here is treated as a set of flag bytes because
+ // bits 6 and 7 of the byte are reserved for future use as flags.
+ // 0x3f or 63 means an arbitrary table tag.
+ if ((flag_byte & 0x3f) == 0x3f) {
+ StoreU32(table.tag, offset, dst);
+ }
+ StoreBase128(table.src_length, offset, dst);
+ if ((table.flags & kWoff2FlagsTransform) != 0) {
+ StoreBase128(table.transform_length, offset, dst);
+ }
+}
+
+size_t TableEntrySize(const Table& table) {
+ uint8_t flag_byte = KnownTableIndex(table.tag);
+ size_t size = ((flag_byte & 0x3f) != 0x3f) ? 1 : 5;
+ size += Base128Size(table.src_length);
+ if ((table.flags & kWoff2FlagsTransform) != 0) {
+ size += Base128Size(table.transform_length);
+ }
+ return size;
+}
+
+size_t ComputeWoff2Length(const FontCollection& font_collection,
+ const std::vector<Table>& tables,
+ std::map<uint32_t, uint16_t> index_by_offset,
+ size_t compressed_data_length,
+ size_t extended_metadata_length) {
+ size_t size = kWoff2HeaderSize;
+
+ for (const auto& table : tables) {
+ size += TableEntrySize(table);
+ }
+
+ // for collections only, collection tables
+ if (font_collection.flavor == kTtcFontFlavor) {
+ size += 4; // UInt32 Version of TTC Header
+ size += Size255UShort(font_collection.fonts.size()); // 255UInt16 numFonts
+
+ size += 4 * font_collection.fonts.size(); // UInt32 flavor for each
+
+ for (const auto& font : font_collection.fonts) {
+ size += Size255UShort(font.tables.size()); // 255UInt16 numTables
+ for (const auto& entry : font.tables) {
+ const Font::Table& table = entry.second;
+ // no collection entry for xform table
+ if (table.tag & 0x80808080) continue;
+
+ uint16_t table_index = index_by_offset[table.offset];
+ size += Size255UShort(table_index); // 255UInt16 index entry
+ }
+ }
+ }
+
+ // compressed data
+ size += compressed_data_length;
+ size = Round4(size);
+
+ size += extended_metadata_length;
+ return size;
+}
+
+size_t ComputeUncompressedLength(const Font& font) {
+ // sfnt header + offset table
+ size_t size = 12 + 16 * font.num_tables;
+ for (const auto& entry : font.tables) {
+ const Font::Table& table = entry.second;
+ if (table.tag & 0x80808080) continue; // xform tables don't stay
+ if (table.IsReused()) continue; // don't have to pay twice
+ size += Round4(table.length);
+ }
+ return size;
+}
+
+size_t ComputeUncompressedLength(const FontCollection& font_collection) {
+ if (font_collection.flavor != kTtcFontFlavor) {
+ return ComputeUncompressedLength(font_collection.fonts[0]);
+ }
+ size_t size = CollectionHeaderSize(font_collection.header_version,
+ font_collection.fonts.size());
+ for (const auto& font : font_collection.fonts) {
+ size += ComputeUncompressedLength(font);
+ }
+ return size;
+}
+
+size_t ComputeTotalTransformLength(const Font& font) {
+ size_t total = 0;
+ for (const auto& i : font.tables) {
+ const Font::Table& table = i.second;
+ if (table.IsReused()) {
+ continue;
+ }
+ if (table.tag & 0x80808080 || !font.FindTable(table.tag ^ 0x80808080)) {
+ // Count transformed tables and non-transformed tables that do not have
+ // transformed versions.
+ total += table.length;
+ }
+ }
+ return total;
+}
+
+} // namespace
+
+size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length) {
+ return MaxWOFF2CompressedSize(data, length, "");
+}
+
+size_t MaxWOFF2CompressedSize(const uint8_t* data, size_t length,
+ const string& extended_metadata) {
+ // Except for the header size, which is 32 bytes larger in woff2 format,
+ // all other parts should be smaller (table header in short format,
+ // transformations and compression). Just to be sure, we will give some
+ // headroom anyway.
+ return length + 1024 + extended_metadata.length();
+}
+
+uint32_t CompressedBufferSize(uint32_t original_size) {
+ return 1.2 * original_size + 10240;
+}
+
+bool TransformFontCollection(FontCollection* font_collection) {
+ for (auto& font : font_collection->fonts) {
+ if (!TransformGlyfAndLocaTables(&font)) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "glyf/loca transformation failed.\n");
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+ }
+
+ return true;
+}
+
+bool ConvertTTFToWOFF2(const uint8_t *data, size_t length,
+ uint8_t *result, size_t *result_length) {
+ WOFF2Params params;
+ return ConvertTTFToWOFF2(data, length, result, result_length,
+ params);
+}
+
+bool ConvertTTFToWOFF2(const uint8_t *data, size_t length,
+ uint8_t *result, size_t *result_length,
+ const WOFF2Params& params) {
+ FontCollection font_collection;
+ if (!ReadFontCollection(data, length, &font_collection)) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Parsing of the input font failed.\n");
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+
+ if (!NormalizeFontCollection(&font_collection)) {
+ return FONT_COMPRESSION_FAILURE();
+ }
+
+ if (params.allow_transforms && !TransformFontCollection(&font_collection)) {
+ return FONT_COMPRESSION_FAILURE();
+ } else {
+ // glyf/loca use 11 to flag "not transformed"
+ for (auto& font : font_collection.fonts) {
+ Font::Table* glyf_table = font.FindTable(kGlyfTableTag);
+ Font::Table* loca_table = font.FindTable(kLocaTableTag);
+ if (glyf_table) {
+ glyf_table->flag_byte |= 0xc0;
+ }
+ if (loca_table) {
+ loca_table->flag_byte |= 0xc0;
+ }
+ }
+ }
+
+ // Although the compressed size of each table in the final woff2 file won't
+ // be larger than its transform_length, we have to allocate a large enough
+ // buffer for the compressor, since the compressor can potentially increase
+ // the size. If the compressor overflows this, it should return false and
+ // then this function will also return false.
+
+ size_t total_transform_length = 0;
+ for (const auto& font : font_collection.fonts) {
+ total_transform_length += ComputeTotalTransformLength(font);
+ }
+ size_t compression_buffer_size = CompressedBufferSize(total_transform_length);
+ std::vector<uint8_t> compression_buf(compression_buffer_size);
+ uint32_t total_compressed_length = compression_buffer_size;
+
+ // Collect all transformed data into one place in output order.
+ std::vector<uint8_t> transform_buf(total_transform_length);
+ size_t transform_offset = 0;
+ for (const auto& font : font_collection.fonts) {
+ for (const auto tag : font.OutputOrderedTags()) {
+ const Font::Table& original = font.tables.at(tag);
+ if (original.IsReused()) continue;
+ if (tag & 0x80808080) continue;
+ const Font::Table* table_to_store = font.FindTable(tag ^ 0x80808080);
+ if (table_to_store == NULL) table_to_store = &original;
+
+ StoreBytes(table_to_store->data, table_to_store->length,
+ &transform_offset, &transform_buf[0]);
+ }
+ }
+
+ // Compress all transformed data in one stream.
+ if (!Woff2Compress(transform_buf.data(), total_transform_length,
+ &compression_buf[0],
+ &total_compressed_length,
+ params.brotli_quality)) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Compression of combined table failed.\n");
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Compressed %zu to %u.\n", total_transform_length,
+ total_compressed_length);
+#endif
+
+ // Compress the extended metadata
+ // TODO(user): how does this apply to collections
+ uint32_t compressed_metadata_buf_length =
+ CompressedBufferSize(params.extended_metadata.length());
+ std::vector<uint8_t> compressed_metadata_buf(compressed_metadata_buf_length);
+
+ if (params.extended_metadata.length() > 0) {
+ if (!TextCompress((const uint8_t*)params.extended_metadata.data(),
+ params.extended_metadata.length(),
+ compressed_metadata_buf.data(),
+ &compressed_metadata_buf_length,
+ params.brotli_quality)) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Compression of extended metadata failed.\n");
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+ } else {
+ compressed_metadata_buf_length = 0;
+ }
+
+ std::vector<Table> tables;
+ std::map<uint32_t, uint16_t> index_by_offset;
+
+ for (const auto& font : font_collection.fonts) {
+
+ for (const auto tag : font.OutputOrderedTags()) {
+ const Font::Table& src_table = font.tables.at(tag);
+ if (src_table.IsReused()) {
+ continue;
+ }
+
+ if (index_by_offset.find(src_table.offset) == index_by_offset.end()) {
+ index_by_offset[src_table.offset] = tables.size();
+ } else {
+ return false;
+ }
+
+ Table table;
+ table.tag = src_table.tag;
+ table.flags = src_table.flag_byte;
+ table.src_length = src_table.length;
+ table.transform_length = src_table.length;
+ const uint8_t* transformed_data = src_table.data;
+ const Font::Table* transformed_table =
+ font.FindTable(src_table.tag ^ 0x80808080);
+ if (transformed_table != NULL) {
+ table.flags = transformed_table->flag_byte;
+ table.flags |= kWoff2FlagsTransform;
+ table.transform_length = transformed_table->length;
+ transformed_data = transformed_table->data;
+
+ }
+ tables.push_back(table);
+ }
+ }
+
+ size_t woff2_length = ComputeWoff2Length(font_collection, tables,
+ index_by_offset, total_compressed_length, compressed_metadata_buf_length);
+ if (woff2_length > *result_length) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Result allocation was too small (%zd vs %zd bytes).\n",
+ *result_length, woff2_length);
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+ *result_length = woff2_length;
+
+ size_t offset = 0;
+
+ // start of woff2 header (http://www.w3.org/TR/WOFF2/#woff20Header)
+ StoreU32(kWoff2Signature, &offset, result);
+ if (font_collection.flavor != kTtcFontFlavor) {
+ StoreU32(font_collection.fonts[0].flavor, &offset, result);
+ } else {
+ StoreU32(kTtcFontFlavor, &offset, result);
+ }
+ StoreU32(woff2_length, &offset, result);
+ Store16(tables.size(), &offset, result);
+ Store16(0, &offset, result); // reserved
+ // totalSfntSize
+ StoreU32(ComputeUncompressedLength(font_collection), &offset, result);
+ StoreU32(total_compressed_length, &offset, result); // totalCompressedSize
+
+ // Let's just all be v1.0
+ Store16(1, &offset, result); // majorVersion
+ Store16(0, &offset, result); // minorVersion
+ if (compressed_metadata_buf_length > 0) {
+ StoreU32(woff2_length - compressed_metadata_buf_length,
+ &offset, result); // metaOffset
+ StoreU32(compressed_metadata_buf_length, &offset, result); // metaLength
+ StoreU32(params.extended_metadata.length(),
+ &offset, result); // metaOrigLength
+ } else {
+ StoreU32(0, &offset, result); // metaOffset
+ StoreU32(0, &offset, result); // metaLength
+ StoreU32(0, &offset, result); // metaOrigLength
+ }
+ StoreU32(0, &offset, result); // privOffset
+ StoreU32(0, &offset, result); // privLength
+ // end of woff2 header
+
+ // table directory (http://www.w3.org/TR/WOFF2/#table_dir_format)
+ for (const auto& table : tables) {
+ StoreTableEntry(table, &offset, result);
+ }
+
+ // for collections only, collection table directory
+ if (font_collection.flavor == kTtcFontFlavor) {
+ StoreU32(font_collection.header_version, &offset, result);
+ Store255UShort(font_collection.fonts.size(), &offset, result);
+ for (const Font& font : font_collection.fonts) {
+
+ uint16_t num_tables = 0;
+ for (const auto& entry : font.tables) {
+ const Font::Table& table = entry.second;
+ if (table.tag & 0x80808080) continue; // don't write xform tables
+ num_tables++;
+ }
+ Store255UShort(num_tables, &offset, result);
+
+ StoreU32(font.flavor, &offset, result);
+ for (const auto& entry : font.tables) {
+ const Font::Table& table = entry.second;
+ if (table.tag & 0x80808080) continue; // don't write xform tables
+
+ // for reused tables, only the original has an updated offset
+ uint32_t table_offset =
+ table.IsReused() ? table.reuse_of->offset : table.offset;
+ uint32_t table_length =
+ table.IsReused() ? table.reuse_of->length : table.length;
+ if (index_by_offset.find(table_offset) == index_by_offset.end()) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Missing table index for offset 0x%08x\n",
+ table_offset);
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+ uint16_t index = index_by_offset[table_offset];
+ Store255UShort(index, &offset, result);
+
+ }
+
+ }
+ }
+
+ // compressed data format (http://www.w3.org/TR/WOFF2/#table_format)
+
+ StoreBytes(&compression_buf[0], total_compressed_length, &offset, result);
+ offset = Round4(offset);
+
+ StoreBytes(compressed_metadata_buf.data(), compressed_metadata_buf_length,
+ &offset, result);
+
+ if (*result_length != offset) {
+#ifdef FONT_COMPRESSION_BIN
+ fprintf(stderr, "Mismatch between computed and actual length "
+ "(%zd vs %zd)\n", *result_length, offset);
+#endif
+ return FONT_COMPRESSION_FAILURE();
+ }
+ return true;
+}
+
+} // namespace woff2