diff options
Diffstat (limited to 'Source/ThirdParty/woff2/src/woff2_dec.cc')
-rw-r--r-- | Source/ThirdParty/woff2/src/woff2_dec.cc | 1041 |
1 files changed, 499 insertions, 542 deletions
diff --git a/Source/ThirdParty/woff2/src/woff2_dec.cc b/Source/ThirdParty/woff2/src/woff2_dec.cc index 2fa291c3a..ec75775a0 100644 --- a/Source/ThirdParty/woff2/src/woff2_dec.cc +++ b/Source/ThirdParty/woff2/src/woff2_dec.cc @@ -25,6 +25,7 @@ #include <vector> #include <map> #include <memory> +#include <utility> #include "./decode.h" #include "./buffer.h" @@ -65,13 +66,54 @@ const size_t kCheckSumAdjustmentOffset = 8; const size_t kEndPtsOfContoursOffset = 10; const size_t kCompositeGlyphBegin = 10; +// 98% of Google Fonts have no glyph above 5k bytes +// Largest glyph ever observed was 72k bytes +const size_t kDefaultGlyphBuf = 5120; + +// Over 14k test fonts the max compression ratio seen to date was ~20. +// >100 suggests you wrote a bad uncompressed size. +const float kMaxPlausibleCompressionRatio = 100.0; + // metadata for a TTC font entry struct TtcFont { uint32_t flavor; uint32_t dst_offset; + uint32_t header_checksum; std::vector<uint16_t> table_indices; }; +struct WOFF2Header { + uint32_t flavor; + uint32_t header_version; + uint16_t num_tables; + uint64_t compressed_offset; + uint32_t compressed_length; + uint32_t uncompressed_size; + std::vector<Table> tables; // num_tables unique tables + std::vector<TtcFont> ttc_fonts; // metadata to help rebuild font +}; + +/** + * Accumulates data we may need to reconstruct a single font. One per font + * created for a TTC. + */ +struct WOFF2FontInfo { + uint16_t num_glyphs; + uint16_t index_format; + uint16_t num_hmetrics; + std::vector<int16_t> x_mins; + std::map<uint32_t, uint32_t> table_entry_by_tag; +}; + +// Accumulates metadata as we rebuild the font +struct RebuildMetadata { + uint32_t header_checksum; // set by WriteHeaders + std::vector<WOFF2FontInfo> font_infos; + // checksums for tables that have been written. + // (tag, src_offset) => checksum. Need both because 0-length loca. + std::map<std::pair<uint32_t, uint32_t>, uint32_t> checksums; +}; + int WithSign(int flag, int baseval) { // Precondition: 0 <= baseval < 65536 (to avoid integer overflow) return (flag & 1) ? baseval : -baseval; @@ -244,6 +286,7 @@ bool StorePoints(unsigned int n_points, const Point* points, // Compute the bounding box of the coordinates, and store into a glyf buffer. // A precondition is that there are at least 10 bytes available. +// dst should point to the beginning of a 'glyf' record. void ComputeBbox(unsigned int n_points, const Point* points, uint8_t* dst) { int x_min = 0; int y_min = 0; @@ -271,14 +314,15 @@ void ComputeBbox(unsigned int n_points, const Point* points, uint8_t* dst) { offset = Store16(dst, offset, y_max); } -bool ProcessComposite(Buffer* composite_stream, uint8_t* dst, - size_t dst_size, size_t* glyph_size, bool* have_instructions) { - size_t start_offset = composite_stream->offset(); + +bool SizeOfComposite(Buffer composite_stream, size_t* size, + bool* have_instructions) { + size_t start_offset = composite_stream.offset(); bool we_have_instructions = false; uint16_t flags = FLAG_MORE_COMPONENTS; while (flags & FLAG_MORE_COMPONENTS) { - if (PREDICT_FALSE(!composite_stream->ReadU16(&flags))) { + if (PREDICT_FALSE(!composite_stream.ReadU16(&flags))) { return FONT_COMPRESSION_FAILURE(); } we_have_instructions |= (flags & FLAG_WE_HAVE_INSTRUCTIONS) != 0; @@ -295,34 +339,43 @@ bool ProcessComposite(Buffer* composite_stream, uint8_t* dst, } else if (flags & FLAG_WE_HAVE_A_TWO_BY_TWO) { arg_size += 8; } - if (PREDICT_FALSE(!composite_stream->Skip(arg_size))) { + if (PREDICT_FALSE(!composite_stream.Skip(arg_size))) { return FONT_COMPRESSION_FAILURE(); } } - size_t composite_glyph_size = composite_stream->offset() - start_offset; - if (PREDICT_FALSE(composite_glyph_size + kCompositeGlyphBegin > dst_size)) { + + *size = composite_stream.offset() - start_offset; + *have_instructions = we_have_instructions; + + return true; +} + +bool Pad4(WOFF2Out* out) { + uint8_t zeroes[] = {0, 0, 0}; + if (PREDICT_FALSE(out->Size() + 3 < out->Size())) { return FONT_COMPRESSION_FAILURE(); } - Store16(dst, 0, 0xffff); // nContours = -1 for composite glyph - std::memcpy(dst + kCompositeGlyphBegin, - composite_stream->buffer() + start_offset, - composite_glyph_size); - *glyph_size = kCompositeGlyphBegin + composite_glyph_size; - *have_instructions = we_have_instructions; + uint32_t pad_bytes = Round4(out->Size()) - out->Size(); + if (pad_bytes > 0) { + if (PREDICT_FALSE(!out->Write(&zeroes, pad_bytes))) { + return FONT_COMPRESSION_FAILURE(); + } + } return true; } // Build TrueType loca table bool StoreLoca(const std::vector<uint32_t>& loca_values, int index_format, - uint8_t* dst, size_t dst_size) { + uint32_t* checksum, WOFF2Out* out) { + // TODO(user) figure out what index format to use based on whether max + // offset fits into uint16_t or not const uint64_t loca_size = loca_values.size(); const uint64_t offset_size = index_format ? 4 : 2; if (PREDICT_FALSE((loca_size << 2) >> 2 != loca_size)) { return FONT_COMPRESSION_FAILURE(); } - if (PREDICT_FALSE(offset_size * loca_size > dst_size)) { - return FONT_COMPRESSION_FAILURE(); - } + std::vector<uint8_t> loca_content(loca_size * offset_size); + uint8_t* dst = &loca_content[0]; size_t offset = 0; for (size_t i = 0; i < loca_values.size(); ++i) { uint32_t value = loca_values[i]; @@ -332,30 +385,34 @@ bool StoreLoca(const std::vector<uint32_t>& loca_values, int index_format, offset = Store16(dst, offset, value >> 1); } } + *checksum = ComputeULongSum(&loca_content[0], loca_content.size()); + if (PREDICT_FALSE(!out->Write(&loca_content[0], loca_content.size()))) { + return FONT_COMPRESSION_FAILURE(); + } return true; } // Reconstruct entire glyf table based on transformed original -bool ReconstructGlyf(const uint8_t* data, size_t data_size, - uint8_t* dst, size_t dst_size, - uint8_t* loca_buf, size_t loca_size) { +bool ReconstructGlyf(const uint8_t* data, Table* glyf_table, + uint32_t* glyf_checksum, Table * loca_table, + uint32_t* loca_checksum, WOFF2FontInfo* info, + WOFF2Out* out) { static const int kNumSubStreams = 7; - Buffer file(data, data_size); + Buffer file(data, glyf_table->transform_length); uint32_t version; std::vector<std::pair<const uint8_t*, size_t> > substreams(kNumSubStreams); + const size_t glyf_start = out->Size(); if (PREDICT_FALSE(!file.ReadU32(&version))) { return FONT_COMPRESSION_FAILURE(); } - uint16_t num_glyphs; - uint16_t index_format; - if (PREDICT_FALSE(!file.ReadU16(&num_glyphs) || - !file.ReadU16(&index_format))) { + if (PREDICT_FALSE(!file.ReadU16(&info->num_glyphs) || + !file.ReadU16(&info->index_format))) { return FONT_COMPRESSION_FAILURE(); } unsigned int offset = (2 + kNumSubStreams) * 4; - if (PREDICT_FALSE(offset > data_size)) { + if (PREDICT_FALSE(offset > glyf_table->transform_length)) { return FONT_COMPRESSION_FAILURE(); } // Invariant from here on: data_size >= offset @@ -364,7 +421,7 @@ bool ReconstructGlyf(const uint8_t* data, size_t data_size, if (PREDICT_FALSE(!file.ReadU32(&substream_size))) { return FONT_COMPRESSION_FAILURE(); } - if (PREDICT_FALSE(substream_size > data_size - offset)) { + if (PREDICT_FALSE(substream_size > glyf_table->transform_length - offset)) { return FONT_COMPRESSION_FAILURE(); } substreams[i] = std::make_pair(data + offset, substream_size); @@ -378,18 +435,23 @@ bool ReconstructGlyf(const uint8_t* data, size_t data_size, Buffer bbox_stream(substreams[5].first, substreams[5].second); Buffer instruction_stream(substreams[6].first, substreams[6].second); - std::vector<uint32_t> loca_values(num_glyphs + 1); + std::vector<uint32_t> loca_values(info->num_glyphs + 1); std::vector<unsigned int> n_points_vec; std::unique_ptr<Point[]> points; size_t points_size = 0; - uint32_t loca_offset = 0; const uint8_t* bbox_bitmap = bbox_stream.buffer(); // Safe because num_glyphs is bounded - unsigned int bitmap_length = ((num_glyphs + 31) >> 5) << 2; + unsigned int bitmap_length = ((info->num_glyphs + 31) >> 5) << 2; if (!bbox_stream.Skip(bitmap_length)) { return FONT_COMPRESSION_FAILURE(); } - for (unsigned int i = 0; i < num_glyphs; ++i) { + + // Temp buffer for glyph's. + size_t glyph_buf_size = kDefaultGlyphBuf; + std::unique_ptr<uint8_t[]> glyph_buf(new uint8_t[glyph_buf_size]); + + info->x_mins.resize(info->num_glyphs); + for (unsigned int i = 0; i < info->num_glyphs; ++i) { size_t glyph_size = 0; uint16_t n_contours = 0; bool have_bbox = false; @@ -399,8 +461,6 @@ bool ReconstructGlyf(const uint8_t* data, size_t data_size, if (PREDICT_FALSE(!n_contour_stream.ReadU16(&n_contours))) { return FONT_COMPRESSION_FAILURE(); } - uint8_t* glyf_dst = dst + loca_offset; - size_t glyf_dst_size = dst_size - loca_offset; if (n_contours == 0xffff) { // composite glyph @@ -410,26 +470,42 @@ bool ReconstructGlyf(const uint8_t* data, size_t data_size, // composite glyphs must have an explicit bbox return FONT_COMPRESSION_FAILURE(); } - if (PREDICT_FALSE(!ProcessComposite(&composite_stream, glyf_dst, - glyf_dst_size, &glyph_size, &have_instructions))) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(!bbox_stream.Read(glyf_dst + 2, 8))) { + + size_t composite_size; + if (PREDICT_FALSE(!SizeOfComposite(composite_stream, &composite_size, + &have_instructions))) { return FONT_COMPRESSION_FAILURE(); } if (have_instructions) { if (PREDICT_FALSE(!Read255UShort(&glyph_stream, &instruction_size))) { return FONT_COMPRESSION_FAILURE(); } - if (PREDICT_FALSE(instruction_size + 2 > glyf_dst_size - glyph_size)) { - return FONT_COMPRESSION_FAILURE(); - } - Store16(glyf_dst, glyph_size, instruction_size); - if (PREDICT_FALSE(!instruction_stream.Read(glyf_dst + glyph_size + 2, + } + + size_t size_needed = 12 + composite_size + instruction_size; + if (PREDICT_FALSE(glyph_buf_size < size_needed)) { + glyph_buf.reset(new uint8_t[size_needed]); + glyph_buf_size = size_needed; + } + + glyph_size = Store16(glyph_buf.get(), glyph_size, n_contours); + if (PREDICT_FALSE(!bbox_stream.Read(glyph_buf.get() + glyph_size, 8))) { + return FONT_COMPRESSION_FAILURE(); + } + glyph_size += 8; + + if (PREDICT_FALSE(!composite_stream.Read(glyph_buf.get() + glyph_size, + composite_size))) { + return FONT_COMPRESSION_FAILURE(); + } + glyph_size += composite_size; + if (have_instructions) { + glyph_size = Store16(glyph_buf.get(), glyph_size, instruction_size); + if (PREDICT_FALSE(!instruction_stream.Read(glyph_buf.get() + glyph_size, instruction_size))) { return FONT_COMPRESSION_FAILURE(); } - glyph_size += instruction_size + 2; + glyph_size += instruction_size; } } else if (n_contours > 0) { // simple glyph @@ -465,141 +541,110 @@ bool ReconstructGlyf(const uint8_t* data, size_t data_size, total_n_points, points.get(), &triplet_bytes_consumed))) { return FONT_COMPRESSION_FAILURE(); } - const uint32_t header_and_endpts_contours_size = - kEndPtsOfContoursOffset + 2 * n_contours; - if (PREDICT_FALSE(glyf_dst_size < header_and_endpts_contours_size)) { + if (PREDICT_FALSE(!flag_stream.Skip(flag_size))) { return FONT_COMPRESSION_FAILURE(); } - Store16(glyf_dst, 0, n_contours); + if (PREDICT_FALSE(!glyph_stream.Skip(triplet_bytes_consumed))) { + return FONT_COMPRESSION_FAILURE(); + } + unsigned int instruction_size; + if (PREDICT_FALSE(!Read255UShort(&glyph_stream, &instruction_size))) { + return FONT_COMPRESSION_FAILURE(); + } + + if (PREDICT_FALSE(total_n_points >= (1 << 27) + || instruction_size >= (1 << 30))) { + return FONT_COMPRESSION_FAILURE(); + } + size_t size_needed = 12 + 2 * n_contours + 5 * total_n_points + + instruction_size; + if (PREDICT_FALSE(glyph_buf_size < size_needed)) { + glyph_buf.reset(new uint8_t[size_needed]); + glyph_buf_size = size_needed; + } + + glyph_size = Store16(glyph_buf.get(), glyph_size, n_contours); if (have_bbox) { - if (PREDICT_FALSE(!bbox_stream.Read(glyf_dst + 2, 8))) { + if (PREDICT_FALSE(!bbox_stream.Read(glyph_buf.get() + glyph_size, 8))) { return FONT_COMPRESSION_FAILURE(); } } else { - ComputeBbox(total_n_points, points.get(), glyf_dst); + ComputeBbox(total_n_points, points.get(), glyph_buf.get()); } - size_t offset = kEndPtsOfContoursOffset; + glyph_size = kEndPtsOfContoursOffset; int end_point = -1; for (unsigned int contour_ix = 0; contour_ix < n_contours; ++contour_ix) { end_point += n_points_vec[contour_ix]; if (PREDICT_FALSE(end_point >= 65536)) { return FONT_COMPRESSION_FAILURE(); } - offset = Store16(glyf_dst, offset, end_point); - } - if (PREDICT_FALSE(!flag_stream.Skip(flag_size))) { - return FONT_COMPRESSION_FAILURE(); + glyph_size = Store16(glyph_buf.get(), glyph_size, end_point); } - if (PREDICT_FALSE(!glyph_stream.Skip(triplet_bytes_consumed))) { - return FONT_COMPRESSION_FAILURE(); - } - unsigned int instruction_size; - if (PREDICT_FALSE(!Read255UShort(&glyph_stream, &instruction_size))) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(glyf_dst_size - header_and_endpts_contours_size < - instruction_size + 2)) { - return FONT_COMPRESSION_FAILURE(); - } - uint8_t* instruction_dst = glyf_dst + header_and_endpts_contours_size; - Store16(instruction_dst, 0, instruction_size); - if (PREDICT_FALSE( - !instruction_stream.Read(instruction_dst + 2, instruction_size))) { + + glyph_size = Store16(glyph_buf.get(), glyph_size, instruction_size); + if (PREDICT_FALSE(!instruction_stream.Read(glyph_buf.get() + glyph_size, + instruction_size))) { return FONT_COMPRESSION_FAILURE(); } + glyph_size += instruction_size; + if (PREDICT_FALSE(!StorePoints(total_n_points, points.get(), n_contours, - instruction_size, glyf_dst, glyf_dst_size, &glyph_size))) { + instruction_size, glyph_buf.get(), glyph_buf_size, &glyph_size))) { return FONT_COMPRESSION_FAILURE(); } - } else { - glyph_size = 0; } - loca_values[i] = loca_offset; - if (PREDICT_FALSE(glyph_size + 3 < glyph_size)) { + + loca_values[i] = out->Size() - glyf_start; + if (PREDICT_FALSE(!out->Write(glyph_buf.get(), glyph_size))) { return FONT_COMPRESSION_FAILURE(); } - glyph_size = Round4(glyph_size); - if (PREDICT_FALSE(glyph_size > dst_size - loca_offset)) { - // This shouldn't happen, but this test defensively maintains the - // invariant that loca_offset <= dst_size. + + // TODO(user) Old code aligned glyphs ... but do we actually need to? + if (PREDICT_FALSE(!Pad4(out))) { return FONT_COMPRESSION_FAILURE(); } - loca_offset += glyph_size; - } - loca_values[num_glyphs] = loca_offset; - return StoreLoca(loca_values, index_format, loca_buf, loca_size); -} -// This is linear search, but could be changed to binary because we -// do have a guarantee that the tables are sorted by tag. But the total -// cpu time is expected to be very small in any case. -const Table* FindTable(const std::vector<Table>& tables, uint32_t tag) { - size_t n_tables = tables.size(); - for (size_t i = 0; i < n_tables; ++i) { - if (tables[i].tag == tag) { - return &tables[i]; + *glyf_checksum += ComputeULongSum(glyph_buf.get(), glyph_size); + + // We may need x_min to reconstruct 'hmtx' + if (n_contours > 0) { + Buffer x_min_buf(glyph_buf.get() + 2, 2); + if (PREDICT_FALSE(!x_min_buf.ReadS16(&info->x_mins[i]))) { + return FONT_COMPRESSION_FAILURE(); + } } } - return NULL; -} -// https://www.microsoft.com/typography/otspec/maxp.htm -bool ReadNumGlyphs(const Table* maxp_table, - uint8_t* dst, size_t dst_length, uint16_t* num_glyphs) { - if (PREDICT_FALSE(static_cast<uint64_t>(maxp_table->dst_offset + - maxp_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - Buffer buffer(dst + maxp_table->dst_offset, maxp_table->dst_length); - // Skip 4 to reach 'maxp' numGlyphs - if (PREDICT_FALSE(!buffer.Skip(4) || !buffer.ReadU16(num_glyphs))) { + // glyf_table dst_offset was set by ReconstructFont + glyf_table->dst_length = out->Size() - glyf_table->dst_offset; + loca_table->dst_offset = out->Size(); + // loca[n] will be equal the length of the glyph data ('glyf') table + loca_values[info->num_glyphs] = glyf_table->dst_length; + if (PREDICT_FALSE(!StoreLoca(loca_values, info->index_format, loca_checksum, + out))) { return FONT_COMPRESSION_FAILURE(); } - return true; -} + loca_table->dst_length = out->Size() - loca_table->dst_offset; -// Get numberOfHMetrics, https://www.microsoft.com/typography/otspec/hhea.htm -bool ReadNumHMetrics(const Table* hhea_table, - uint8_t* dst, size_t dst_length, uint16_t* num_hmetrics) { - if (PREDICT_FALSE(static_cast<uint64_t>(hhea_table->dst_offset + - hhea_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - // Skip 34 to reach 'hhea' numberOfHMetrics - Buffer buffer(dst + hhea_table->dst_offset, hhea_table->dst_length); - if (PREDICT_FALSE(!buffer.Skip(34) || !buffer.ReadU16(num_hmetrics))) { - return FONT_COMPRESSION_FAILURE(); - } return true; } -// x_min for glyph; https://www.microsoft.com/typography/otspec/glyf.htm -bool ReadGlyphXMin(Buffer* glyf_buff, Buffer* loca_buff, int16_t loca_format, - uint16_t index, int16_t* x_min) { - uint32_t offset1, offset2; - loca_buff->set_offset((loca_format == 0 ? 2 : 4) * index); - if (loca_format == 0) { - uint16_t tmp1, tmp2; - if (PREDICT_FALSE(!loca_buff->ReadU16(&tmp1) || - !loca_buff->ReadU16(&tmp2))) { - return FONT_COMPRESSION_FAILURE(); +Table* FindTable(std::vector<Table*>* tables, uint32_t tag) { + for (Table* table : *tables) { + if (table->tag == tag) { + return table; } - // https://www.microsoft.com/typography/otspec/loca.htm - // "The actual local offset divided by 2 is stored." - offset1 = tmp1 * 2; - offset2 = tmp2 * 2; - } else if (PREDICT_FALSE(!loca_buff->ReadU32(&offset1) || - !loca_buff->ReadU32(&offset2))) { - return FONT_COMPRESSION_FAILURE(); } + return NULL; +} - if (offset1 != offset2) { - glyf_buff->set_offset(offset1 + 2); - if (!glyf_buff->ReadS16(x_min)) { - return FONT_COMPRESSION_FAILURE(); - } - } else { - *x_min = 0; +// Get numberOfHMetrics, https://www.microsoft.com/typography/otspec/hhea.htm +bool ReadNumHMetrics(const uint8_t* data, size_t data_size, + uint16_t* num_hmetrics) { + // Skip 34 to reach 'hhea' numberOfHMetrics + Buffer buffer(data, data_size); + if (PREDICT_FALSE(!buffer.Skip(34) || !buffer.ReadU16(num_hmetrics))) { + return FONT_COMPRESSION_FAILURE(); } return true; } @@ -607,40 +652,11 @@ bool ReadGlyphXMin(Buffer* glyf_buff, Buffer* loca_buff, int16_t loca_format, // http://dev.w3.org/webfonts/WOFF2/spec/Overview.html#hmtx_table_format bool ReconstructTransformedHmtx(const uint8_t* transformed_buf, size_t transformed_size, - const Table* glyf_table, - const Table* hhea_table, - const Table* hmtx_table, - const Table* loca_table, - const Table* maxp_table, - uint8_t* dst, size_t dst_length) { - if (PREDICT_FALSE(!glyf_table)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(!hhea_table)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(!hmtx_table)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(!loca_table)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(!maxp_table)) { - return FONT_COMPRESSION_FAILURE(); - } - - uint16_t num_glyphs, num_hmetrics; - if (!ReadNumGlyphs(maxp_table, dst, dst_length, &num_glyphs)) { - return FONT_COMPRESSION_FAILURE(); - } - if (!ReadNumHMetrics(hhea_table, dst, dst_length, &num_hmetrics)) { - return FONT_COMPRESSION_FAILURE(); - } - - if (PREDICT_FALSE(static_cast<uint64_t>(hmtx_table->dst_offset + - hmtx_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } + uint16_t num_glyphs, + uint16_t num_hmetrics, + const std::vector<int16_t>& x_mins, + uint32_t* checksum, + WOFF2Out* out) { Buffer hmtx_buff_in(transformed_buf, transformed_size); uint8_t hmtx_flags; @@ -658,23 +674,16 @@ bool ReconstructTransformedHmtx(const uint8_t* transformed_buf, return FONT_COMPRESSION_FAILURE(); } - // glyf/loca are done already so we can use them to recover x_min's - if (PREDICT_FALSE(static_cast<uint64_t>(glyf_table->dst_offset + - glyf_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(static_cast<uint64_t>(loca_table->dst_offset + - loca_table->dst_length) > dst_length)) { + assert(x_mins.size() == num_glyphs); + + // num_glyphs 0 is OK if there is no 'glyf' but cannot then xform 'hmtx'. + if (PREDICT_FALSE(num_hmetrics > num_glyphs)) { return FONT_COMPRESSION_FAILURE(); } - Buffer glyf_buff(dst + glyf_table->dst_offset, glyf_table->dst_length); - Buffer loca_buff(dst + loca_table->dst_offset, loca_table->dst_length); - int16_t loca_format; - if (loca_table->dst_length == 2 * (num_glyphs + 1)) { - loca_format = 0; - } else if (loca_table->dst_length == 4 * (num_glyphs + 1)) { - loca_format = 1; - } else { + + // https://www.microsoft.com/typography/otspec/hmtx.htm + // "...only one entry need be in the array, but that entry is required." + if (PREDICT_FALSE(num_hmetrics < 1)) { return FONT_COMPRESSION_FAILURE(); } @@ -693,10 +702,7 @@ bool ReconstructTransformedHmtx(const uint8_t* transformed_buf, return FONT_COMPRESSION_FAILURE(); } } else { - if (PREDICT_FALSE(!ReadGlyphXMin(&glyf_buff, &loca_buff, loca_format, i, - &lsb))) { - return FONT_COMPRESSION_FAILURE(); - } + lsb = x_mins[i]; } lsbs.push_back(lsb); } @@ -708,25 +714,16 @@ bool ReconstructTransformedHmtx(const uint8_t* transformed_buf, return FONT_COMPRESSION_FAILURE(); } } else { - if (PREDICT_FALSE(!ReadGlyphXMin(&glyf_buff, &loca_buff, loca_format, i, - &lsb))) { - return FONT_COMPRESSION_FAILURE(); - } + lsb = x_mins[i]; } lsbs.push_back(lsb); } // bake me a shiny new hmtx table uint32_t hmtx_output_size = 2 * num_glyphs + 2 * num_hmetrics; - if (hmtx_output_size > hmtx_table->dst_length) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(static_cast<uint64_t>(hmtx_table->dst_offset + - hmtx_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - - size_t dst_offset = hmtx_table->dst_offset; + std::vector<uint8_t> hmtx_table(hmtx_output_size); + uint8_t* dst = &hmtx_table[0]; + size_t dst_offset = 0; for (uint32_t i = 0; i < num_glyphs; i++) { if (i < num_hmetrics) { Store16(advance_widths[i], &dst_offset, dst); @@ -734,152 +731,14 @@ bool ReconstructTransformedHmtx(const uint8_t* transformed_buf, Store16(lsbs[i], &dst_offset, dst); } - return true; -} - -bool ReconstructTransformedGlyf(const uint8_t* transformed_buf, - size_t transformed_size, const Table* glyf_table, const Table* loca_table, - uint8_t* dst, size_t dst_length) { - if (PREDICT_FALSE(glyf_table == NULL || loca_table == NULL)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(static_cast<uint64_t>(glyf_table->dst_offset + - glyf_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(static_cast<uint64_t>(loca_table->dst_offset + - loca_table->dst_length) > dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - return ReconstructGlyf(transformed_buf, transformed_size, - dst + glyf_table->dst_offset, glyf_table->dst_length, - dst + loca_table->dst_offset, loca_table->dst_length); -} - -// Reconstructs a single font. tables must not contain duplicates. -bool ReconstructTransformed(const std::vector<Table>& tables, uint32_t tag, - const uint8_t* transformed_buf, size_t transformed_size, - uint8_t* dst, size_t dst_length) { - - if (tag == kGlyfTableTag) { - const Table* glyf_table = FindTable(tables, tag); - const Table* loca_table = FindTable(tables, kLocaTableTag); - return ReconstructTransformedGlyf(transformed_buf, transformed_size, - glyf_table, loca_table, dst, dst_length); - } else if (tag == kLocaTableTag) { - // processing was already done by glyf table, but validate - if (PREDICT_FALSE(!FindTable(tables, kGlyfTableTag))) { - return FONT_COMPRESSION_FAILURE(); - } - } else if (tag == kHmtxTableTag) { - // Tables are sorted for a non-collection. - // glyf is before hmtx and includes loca so all our accesses are safe. - const Table* glyf_table = FindTable(tables, kGlyfTableTag); - const Table* hhea_table = FindTable(tables, kHheaTableTag); - const Table* hmtx_table = FindTable(tables, kHmtxTableTag); - const Table* loca_table = FindTable(tables, kLocaTableTag); - const Table* maxp_table = FindTable(tables, kMaxpTableTag); - - if (PREDICT_FALSE(!ReconstructTransformedHmtx( - transformed_buf, transformed_size, glyf_table, hhea_table, - hmtx_table, loca_table, maxp_table, dst, dst_length))) { - return FONT_COMPRESSION_FAILURE(); - } - } else { - // transform for the tag is not known + *checksum = ComputeULongSum(&hmtx_table[0], hmtx_output_size); + if (PREDICT_FALSE(!out->Write(&hmtx_table[0], hmtx_output_size))) { return FONT_COMPRESSION_FAILURE(); } - return true; -} - -uint32_t ComputeChecksum(const Table* table, const uint8_t* dst) { - return ComputeULongSum(dst + table->dst_offset, table->dst_length); -} - -const Table* FindTable(TtcFont ttc_font, const std::vector<Table>& tables, - uint32_t tag) { - for (const auto i : ttc_font.table_indices) { - if (tables[i].tag == tag) return &tables[i]; - } - return NULL; -} - -bool FixCollectionChecksums(size_t header_version, - const std::vector<Table>& tables, const std::vector<TtcFont>& ttc_fonts, - uint8_t* dst) { - size_t offset = CollectionHeaderSize(header_version, ttc_fonts.size()); - - for (const auto& ttc_font : ttc_fonts) { - offset += 12; // move to start of Offset Table - const std::vector<uint16_t>& table_indices = ttc_font.table_indices; - - const Table* head_table = FindTable(ttc_font, tables, kHeadTableTag); - if (PREDICT_FALSE(head_table == NULL || - head_table->dst_length < kCheckSumAdjustmentOffset + 4)) { - return FONT_COMPRESSION_FAILURE(); - } - - size_t first_table_offset = std::numeric_limits<size_t>::max(); - for (const auto index : table_indices) { - const auto& table = tables[index]; - if (table.dst_offset < first_table_offset) { - first_table_offset = table.dst_offset; - } - } - - size_t adjustment_offset = head_table->dst_offset - + kCheckSumAdjustmentOffset; - StoreU32(dst, adjustment_offset, 0); - - uint32_t file_checksum = 0; - // compute each tables checksum - for (size_t i = 0; i < table_indices.size(); i++) { - const Table& table = tables[table_indices[i]]; - uint32_t table_checksum = ComputeChecksum(&table, dst); - size_t checksum_offset = offset + 4; // skip past tag to checkSum - - // write the checksum for the Table Record - StoreU32(dst, checksum_offset, table_checksum); - file_checksum += table_checksum; - // next Table Record - offset += 16; - } - - size_t header_size = kSfntHeaderSize + - kSfntEntrySize * table_indices.size(); - uint32_t header_checksum = ComputeULongSum(dst + ttc_font.dst_offset, - header_size); - - file_checksum += header_checksum; - uint32_t checksum_adjustment = 0xb1b0afba - file_checksum; - StoreU32(dst, adjustment_offset, checksum_adjustment); - } return true; } -bool FixChecksums(const std::vector<Table>& tables, uint8_t* dst) { - const Table* head_table = FindTable(tables, kHeadTableTag); - if (PREDICT_FALSE(head_table == NULL || - head_table->dst_length < kCheckSumAdjustmentOffset + 4)) { - return FONT_COMPRESSION_FAILURE(); - } - size_t adjustment_offset = head_table->dst_offset + kCheckSumAdjustmentOffset; - StoreU32(dst, adjustment_offset, 0); - size_t n_tables = tables.size(); - uint32_t file_checksum = 0; - for (size_t i = 0; i < n_tables; ++i) { - uint32_t checksum = ComputeChecksum(&tables[i], dst); - StoreU32(dst, kSfntHeaderSize + i * kSfntEntrySize + 4, checksum); - file_checksum += checksum; - } - file_checksum += ComputeULongSum(dst, - kSfntHeaderSize + kSfntEntrySize * n_tables); - uint32_t checksum_adjustment = 0xb1b0afba - file_checksum; - StoreU32(dst, adjustment_offset, checksum_adjustment); - return true; -} - bool Woff2Uncompress(uint8_t* dst_buf, size_t dst_size, const uint8_t* src_buf, size_t src_size) { size_t uncompressed_size = dst_size; @@ -893,6 +752,7 @@ bool Woff2Uncompress(uint8_t* dst_buf, size_t dst_size, bool ReadTableDirectory(Buffer* file, std::vector<Table>* tables, size_t num_tables) { + uint32_t src_offset = 0; for (size_t i = 0; i < num_tables; ++i) { Table* table = &(*tables)[i]; uint8_t flag_byte; @@ -933,6 +793,13 @@ bool ReadTableDirectory(Buffer* file, std::vector<Table>* tables, return FONT_COMPRESSION_FAILURE(); } } + if (PREDICT_FALSE(src_offset + transform_length < src_offset)) { + return FONT_COMPRESSION_FAILURE(); + } + table->src_offset = src_offset; + table->src_length = transform_length; + src_offset += transform_length; + table->tag = tag; table->flags = flags; table->transform_length = transform_length; @@ -941,19 +808,6 @@ bool ReadTableDirectory(Buffer* file, std::vector<Table>* tables, return true; } -} // namespace - -size_t ComputeWOFF2FinalSize(const uint8_t* data, size_t length) { - Buffer file(data, length); - uint32_t total_length; - - if (!file.Skip(16) || - !file.ReadU32(&total_length)) { - return 0; - } - return total_length; -} - // Writes a single Offset Table entry size_t StoreOffsetTable(uint8_t* result, size_t offset, uint32_t flavor, uint16_t num_tables) { @@ -971,62 +825,185 @@ size_t StoreOffsetTable(uint8_t* result, size_t offset, uint32_t flavor, return offset; } -size_t StoreTableEntry(uint8_t* result, const Table& table, size_t offset) { - offset = StoreU32(result, offset, table.tag); - offset = StoreU32(result, offset, 0); // checksum, to fill in later - offset = StoreU32(result, offset, table.dst_offset); - offset = StoreU32(result, offset, table.dst_length); +size_t StoreTableEntry(uint8_t* result, uint32_t offset, uint32_t tag) { + offset = StoreU32(result, offset, tag); + offset = StoreU32(result, offset, 0); + offset = StoreU32(result, offset, 0); + offset = StoreU32(result, offset, 0); return offset; } // First table goes after all the headers, table directory, etc -uint64_t ComputeOffsetToFirstTable(const uint32_t header_version, - const uint16_t num_tables, - const std::vector<TtcFont>& ttc_fonts) { +uint64_t ComputeOffsetToFirstTable(const WOFF2Header& hdr) { uint64_t offset = kSfntHeaderSize + - kSfntEntrySize * static_cast<uint64_t>(num_tables); - if (header_version) { - offset = CollectionHeaderSize(header_version, ttc_fonts.size()) - + kSfntHeaderSize * ttc_fonts.size(); - for (const auto& ttc_font : ttc_fonts) { - offset += - kSfntEntrySize * ttc_font.table_indices.size(); + kSfntEntrySize * static_cast<uint64_t>(hdr.num_tables); + if (hdr.header_version) { + offset = CollectionHeaderSize(hdr.header_version, hdr.ttc_fonts.size()) + + kSfntHeaderSize * hdr.ttc_fonts.size(); + for (const auto& ttc_font : hdr.ttc_fonts) { + offset += kSfntEntrySize * ttc_font.table_indices.size(); } } return offset; } -bool ReconstructTransformedFont(const std::vector<Table>& tables, - std::map<uint32_t, const uint8_t*>* src_by_dest, - uint8_t* result, size_t result_length) { - for (const auto& table : tables) { - if ((table.flags & kWoff2FlagsTransform) != kWoff2FlagsTransform) { - continue; +std::vector<Table*> Tables(WOFF2Header* hdr, size_t font_index) { + std::vector<Table*> tables; + if (PREDICT_FALSE(hdr->header_version)) { + for (auto index : hdr->ttc_fonts[font_index].table_indices) { + tables.push_back(&hdr->tables[index]); + } + } else { + for (auto& table : hdr->tables) { + tables.push_back(&table); + } + } + return tables; +} + +// Offset tables assumed to have been written in with 0's initially. +// WOFF2Header isn't const so we can use [] instead of at() (which upsets FF) +bool ReconstructFont(uint8_t* transformed_buf, + const uint32_t transformed_buf_size, + RebuildMetadata* metadata, + WOFF2Header* hdr, + size_t font_index, + WOFF2Out* out) { + size_t dest_offset = out->Size(); + uint8_t table_entry[12]; + WOFF2FontInfo* info = &metadata->font_infos[font_index]; + std::vector<Table*> tables = Tables(hdr, font_index); + + // 'glyf' without 'loca' doesn't make sense + if (PREDICT_FALSE(static_cast<bool>(FindTable(&tables, kGlyfTableTag)) != + static_cast<bool>(FindTable(&tables, kLocaTableTag)))) { + return FONT_COMPRESSION_FAILURE(); + } + + uint32_t font_checksum = metadata->header_checksum; + if (hdr->header_version) { + font_checksum = hdr->ttc_fonts[font_index].header_checksum; + } + + uint32_t loca_checksum = 0; + for (size_t i = 0; i < tables.size(); i++) { + Table& table = *tables[i]; + + std::pair<uint32_t, uint32_t> checksum_key = {table.tag, table.src_offset}; + bool reused = metadata->checksums.find(checksum_key) + != metadata->checksums.end(); + if (PREDICT_FALSE(font_index == 0 && reused)) { + return FONT_COMPRESSION_FAILURE(); + } + + // TODO(user) a collection with optimized hmtx that reused glyf/loca + // would fail. We don't optimize hmtx for collections yet. + if (PREDICT_FALSE(static_cast<uint64_t>(table.src_offset + table.src_length) + > transformed_buf_size)) { + return FONT_COMPRESSION_FAILURE(); + } + + if (table.tag == kHheaTableTag) { + if (!ReadNumHMetrics(transformed_buf + table.src_offset, + table.src_length, &info->num_hmetrics)) { + return FONT_COMPRESSION_FAILURE(); + } + } + + uint32_t checksum = 0; + if (!reused) { + if ((table.flags & kWoff2FlagsTransform) != kWoff2FlagsTransform) { + if (table.tag == kHeadTableTag) { + if (PREDICT_FALSE(table.src_length < 12)) { + return FONT_COMPRESSION_FAILURE(); + } + // checkSumAdjustment = 0 + StoreU32(transformed_buf + table.src_offset, 8, 0); + } + table.dst_offset = dest_offset; + checksum = ComputeULongSum(transformed_buf + table.src_offset, + table.src_length); + if (PREDICT_FALSE(!out->Write(transformed_buf + table.src_offset, + table.src_length))) { + return FONT_COMPRESSION_FAILURE(); + } + } else { + if (table.tag == kGlyfTableTag) { + table.dst_offset = dest_offset; + + Table* loca_table = FindTable(&tables, kLocaTableTag); + if (PREDICT_FALSE(!ReconstructGlyf(transformed_buf + table.src_offset, + &table, &checksum, loca_table, &loca_checksum, info, out))) { + return FONT_COMPRESSION_FAILURE(); + } + } else if (table.tag == kLocaTableTag) { + // All the work was done by ReconstructGlyf. We already know checksum. + checksum = loca_checksum; + } else if (table.tag == kHmtxTableTag) { + table.dst_offset = dest_offset; + // Tables are sorted so all the info we need has been gathered. + if (PREDICT_FALSE(!ReconstructTransformedHmtx( + transformed_buf + table.src_offset, table.src_length, + info->num_glyphs, info->num_hmetrics, info->x_mins, &checksum, + out))) { + return FONT_COMPRESSION_FAILURE(); + } + } else { + return FONT_COMPRESSION_FAILURE(); // transform unknown + } + } + metadata->checksums[checksum_key] = checksum; + } else { + checksum = metadata->checksums[checksum_key]; + } + font_checksum += checksum; + + // update the table entry with real values. + StoreU32(table_entry, 0, checksum); + StoreU32(table_entry, 4, table.dst_offset); + StoreU32(table_entry, 8, table.dst_length); + if (PREDICT_FALSE(!out->Write(table_entry, + info->table_entry_by_tag[table.tag] + 4, 12))) { + return FONT_COMPRESSION_FAILURE(); + } + + // We replaced 0's. Update overall checksum. + font_checksum += ComputeULongSum(table_entry, 12); + + if (PREDICT_FALSE(!Pad4(out))) { + return FONT_COMPRESSION_FAILURE(); } - const auto it = src_by_dest->find(table.dst_offset); - if (it == src_by_dest->end()) { - continue; + + if (PREDICT_FALSE(static_cast<uint64_t>(table.dst_offset + table.dst_length) + > out->Size())) { + return FONT_COMPRESSION_FAILURE(); } - const uint8_t* transform_buf = (*it).second; - src_by_dest->erase(table.dst_offset); + dest_offset = out->Size(); + } - size_t transform_length = table.transform_length; - if (PREDICT_FALSE(!ReconstructTransformed(tables, table.tag, - transform_buf, transform_length, result, result_length))) { + // Update 'head' checkSumAdjustment. We already set it to 0 and summed font. + Table* head_table = FindTable(&tables, kHeadTableTag); + if (head_table) { + if (PREDICT_FALSE(head_table->dst_length < 12)) { + return FONT_COMPRESSION_FAILURE(); + } + uint8_t checksum_adjustment[4]; + StoreU32(checksum_adjustment, 0, 0xB1B0AFBA - font_checksum); + if (PREDICT_FALSE(!out->Write(checksum_adjustment, + head_table->dst_offset + 8, 4))) { return FONT_COMPRESSION_FAILURE(); } } + return true; } -bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, - const uint8_t* data, size_t length) { +bool ReadWOFF2Header(const uint8_t* data, size_t length, WOFF2Header* hdr) { Buffer file(data, length); uint32_t signature; - uint32_t flavor; if (PREDICT_FALSE(!file.ReadU32(&signature) || signature != kWoff2Signature || - !file.ReadU32(&flavor))) { + !file.ReadU32(&hdr->flavor))) { return FONT_COMPRESSION_FAILURE(); } @@ -1037,18 +1014,17 @@ bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, !file.ReadU32(&reported_length) || length != reported_length)) { return FONT_COMPRESSION_FAILURE(); } - uint16_t num_tables; - if (PREDICT_FALSE(!file.ReadU16(&num_tables) || !num_tables)) { + if (PREDICT_FALSE(!file.ReadU16(&hdr->num_tables) || !hdr->num_tables)) { return FONT_COMPRESSION_FAILURE(); } + // We don't care about these fields of the header: // uint16_t reserved - // uint32_t total_sfnt_size, the caller already passes it as result_length + // uint32_t total_sfnt_size, we don't believe this, will compute later if (PREDICT_FALSE(!file.Skip(6))) { return FONT_COMPRESSION_FAILURE(); } - uint32_t compressed_length; - if (PREDICT_FALSE(!file.ReadU32(&compressed_length))) { + if (PREDICT_FALSE(!file.ReadU32(&hdr->compressed_length))) { return FONT_COMPRESSION_FAILURE(); } // We don't care about these fields of the header: @@ -1082,28 +1058,37 @@ bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, return FONT_COMPRESSION_FAILURE(); } } - std::vector<Table> tables(num_tables); - if (PREDICT_FALSE(!ReadTableDirectory(&file, &tables, num_tables))) { + hdr->tables.resize(hdr->num_tables); + if (PREDICT_FALSE(!ReadTableDirectory( + &file, &hdr->tables, hdr->num_tables))) { + return FONT_COMPRESSION_FAILURE(); + } + + // Before we sort for output the last table end is the uncompressed size. + Table& last_table = hdr->tables.back(); + hdr->uncompressed_size = last_table.src_offset + last_table.src_length; + if (PREDICT_FALSE(hdr->uncompressed_size < last_table.src_offset)) { return FONT_COMPRESSION_FAILURE(); } - uint32_t header_version = 0; - // for each font in a ttc, metadata to use when rebuilding - std::vector<TtcFont> ttc_fonts; - std::map<const Table*, const Table*> loca_by_glyf; + hdr->header_version = 0; - if (flavor == kTtcFontFlavor) { - if (PREDICT_FALSE(!file.ReadU32(&header_version))) { + if (hdr->flavor == kTtcFontFlavor) { + if (PREDICT_FALSE(!file.ReadU32(&hdr->header_version))) { + return FONT_COMPRESSION_FAILURE(); + } + if (PREDICT_FALSE(hdr->header_version != 0x00010000 + && hdr->header_version != 0x00020000)) { return FONT_COMPRESSION_FAILURE(); } uint32_t num_fonts; if (PREDICT_FALSE(!Read255UShort(&file, &num_fonts) || !num_fonts)) { return FONT_COMPRESSION_FAILURE(); } - ttc_fonts.resize(num_fonts); + hdr->ttc_fonts.resize(num_fonts); for (uint32_t i = 0; i < num_fonts; i++) { - TtcFont& ttc_font = ttc_fonts[i]; + TtcFont& ttc_font = hdr->ttc_fonts[i]; uint32_t num_tables; if (PREDICT_FALSE(!Read255UShort(&file, &num_tables) || !num_tables)) { return FONT_COMPRESSION_FAILURE(); @@ -1116,25 +1101,21 @@ bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, const Table* glyf_table = NULL; const Table* loca_table = NULL; - uint16_t glyf_idx; - uint16_t loca_idx; for (uint32_t j = 0; j < num_tables; j++) { unsigned int table_idx; if (PREDICT_FALSE(!Read255UShort(&file, &table_idx)) || - table_idx >= tables.size()) { + table_idx >= hdr->tables.size()) { return FONT_COMPRESSION_FAILURE(); } ttc_font.table_indices[j] = table_idx; - const Table& table = tables[table_idx]; + const Table& table = hdr->tables[table_idx]; if (table.tag == kLocaTableTag) { loca_table = &table; - loca_idx = table_idx; } if (table.tag == kGlyfTableTag) { glyf_table = &table; - glyf_idx = table_idx; } } @@ -1145,65 +1126,28 @@ bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, #endif return FONT_COMPRESSION_FAILURE(); } - - if (glyf_table != NULL && loca_table != NULL) { - loca_by_glyf[glyf_table] = loca_table; - } } } - const uint64_t first_table_offset = - ComputeOffsetToFirstTable(header_version, num_tables, ttc_fonts); - - if (PREDICT_FALSE(first_table_offset > result_length)) { - return FONT_COMPRESSION_FAILURE(); - } + const uint64_t first_table_offset = ComputeOffsetToFirstTable(*hdr); - uint64_t compressed_offset = file.offset(); - if (PREDICT_FALSE(compressed_offset > std::numeric_limits<uint32_t>::max())) { + hdr->compressed_offset = file.offset(); + if (PREDICT_FALSE(hdr->compressed_offset > + std::numeric_limits<uint32_t>::max())) { return FONT_COMPRESSION_FAILURE(); } - uint64_t src_offset = Round4(compressed_offset + compressed_length); + uint64_t src_offset = Round4(hdr->compressed_offset + hdr->compressed_length); uint64_t dst_offset = first_table_offset; - for (uint16_t i = 0; i < num_tables; ++i) { - Table* table = &tables[i]; - table->dst_offset = dst_offset; - dst_offset += table->dst_length; - if (PREDICT_FALSE(dst_offset > std::numeric_limits<uint32_t>::max())) { - return FONT_COMPRESSION_FAILURE(); - } - dst_offset = Round4(dst_offset); - } - if (PREDICT_FALSE(src_offset > length || dst_offset != result_length)) { + if (PREDICT_FALSE(src_offset > length)) { #ifdef FONT_COMPRESSION_BIN fprintf(stderr, "offset fail; src_offset %" PRIu64 " length %lu " - "dst_offset %" PRIu64 " result_length %lu\n", - src_offset, length, dst_offset, result_length); + "dst_offset %" PRIu64 "\n", + src_offset, length, dst_offset); #endif return FONT_COMPRESSION_FAILURE(); } - - // Re-order tables in output (OTSpec) order - std::vector<Table> sorted_tables(tables); - if (header_version) { - // collection; we have to sort the table offset vector in each font - for (auto& ttc_font : ttc_fonts) { - std::map<uint32_t, uint16_t> sorted_index_by_tag; - for (auto table_index : ttc_font.table_indices) { - sorted_index_by_tag[tables[table_index].tag] = table_index; - } - uint16_t index = 0; - for (auto& i : sorted_index_by_tag) { - ttc_font.table_indices[index++] = i.second; - } - } - } else { - // non-collection; we can just sort the tables - std::sort(sorted_tables.begin(), sorted_tables.end()); - } - if (meta_offset) { if (PREDICT_FALSE(src_offset != meta_offset)) { return FONT_COMPRESSION_FAILURE(); @@ -1228,28 +1172,58 @@ bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, return FONT_COMPRESSION_FAILURE(); } + return true; +} + +// Write everything before the actual table data +bool WriteHeaders(const uint8_t* data, size_t length, RebuildMetadata* metadata, + WOFF2Header* hdr, WOFF2Out* out) { + std::vector<uint8_t> output(ComputeOffsetToFirstTable(*hdr), 0); + + // Re-order tables in output (OTSpec) order + std::vector<Table> sorted_tables(hdr->tables); + if (hdr->header_version) { + // collection; we have to sort the table offset vector in each font + for (auto& ttc_font : hdr->ttc_fonts) { + std::map<uint32_t, uint16_t> sorted_index_by_tag; + for (auto table_index : ttc_font.table_indices) { + sorted_index_by_tag[hdr->tables[table_index].tag] = table_index; + } + uint16_t index = 0; + for (auto& i : sorted_index_by_tag) { + ttc_font.table_indices[index++] = i.second; + } + } + } else { + // non-collection; we can just sort the tables + std::sort(sorted_tables.begin(), sorted_tables.end()); + } + // Start building the font + uint8_t* result = &output[0]; size_t offset = 0; - size_t offset_table = 0; - if (header_version) { + if (hdr->header_version) { // TTC header - offset = StoreU32(result, offset, flavor); // TAG TTCTag - offset = StoreU32(result, offset, header_version); // FIXED Version - offset = StoreU32(result, offset, ttc_fonts.size()); // ULONG numFonts + offset = StoreU32(result, offset, hdr->flavor); // TAG TTCTag + offset = StoreU32(result, offset, hdr->header_version); // FIXED Version + offset = StoreU32(result, offset, hdr->ttc_fonts.size()); // ULONG numFonts // Space for ULONG OffsetTable[numFonts] (zeroed initially) - offset_table = offset; // keep start of offset table for later - for (size_t i = 0; i < ttc_fonts.size(); i++) { + size_t offset_table = offset; // keep start of offset table for later + for (size_t i = 0; i < hdr->ttc_fonts.size(); i++) { offset = StoreU32(result, offset, 0); // will fill real values in later } // space for DSIG fields for header v2 - if (header_version == 0x00020000) { + if (hdr->header_version == 0x00020000) { offset = StoreU32(result, offset, 0); // ULONG ulDsigTag offset = StoreU32(result, offset, 0); // ULONG ulDsigLength offset = StoreU32(result, offset, 0); // ULONG ulDsigOffset } // write Offset Tables and store the location of each in TTC Header - for (auto& ttc_font : ttc_fonts) { + metadata->font_infos.resize(hdr->ttc_fonts.size()); + for (size_t i = 0; i < hdr->ttc_fonts.size(); i++) { + TtcFont& ttc_font = hdr->ttc_fonts[i]; + // write Offset Table location into TTC Header offset_table = StoreU32(result, offset_table, offset); @@ -1258,99 +1232,82 @@ bool ConvertWOFF2ToTTF(uint8_t* result, size_t result_length, offset = StoreOffsetTable(result, offset, ttc_font.flavor, ttc_font.table_indices.size()); - // write table entries for (const auto table_index : ttc_font.table_indices) { - offset = StoreTableEntry(result, tables[table_index], offset); + uint32_t tag = hdr->tables[table_index].tag; + metadata->font_infos[i].table_entry_by_tag[tag] = offset; + offset = StoreTableEntry(result, offset, tag); } + + ttc_font.header_checksum = ComputeULongSum(&output[ttc_font.dst_offset], + offset - ttc_font.dst_offset); } } else { - offset = StoreOffsetTable(result, offset, flavor, num_tables); - for (uint16_t i = 0; i < num_tables; ++i) { - offset = StoreTableEntry(result, sorted_tables[i], offset); + metadata->font_infos.resize(1); + offset = StoreOffsetTable(result, offset, hdr->flavor, hdr->num_tables); + for (uint16_t i = 0; i < hdr->num_tables; ++i) { + metadata->font_infos[0].table_entry_by_tag[sorted_tables[i].tag] = offset; + offset = StoreTableEntry(result, offset, sorted_tables[i].tag); } } - std::vector<uint8_t> uncompressed_buf; - const uint8_t* transform_buf = NULL; - uint64_t total_size = 0; - for (uint16_t i = 0; i < num_tables; ++i) { - total_size += tables[i].transform_length; - if (PREDICT_FALSE(total_size > std::numeric_limits<uint32_t>::max())) { - return FONT_COMPRESSION_FAILURE(); - } - } - uncompressed_buf.resize(total_size); - const uint8_t* src_buf = data + compressed_offset; - if (PREDICT_FALSE(!Woff2Uncompress(&uncompressed_buf[0], total_size, - src_buf, compressed_length))) { + if (PREDICT_FALSE(!out->Write(&output[0], output.size()))) { return FONT_COMPRESSION_FAILURE(); } + metadata->header_checksum = ComputeULongSum(&output[0], output.size()); + return true; +} - // round 1, copy across all the unmodified tables - transform_buf = &uncompressed_buf[0]; - const uint8_t* const transform_buf_end = &uncompressed_buf[0] - + uncompressed_buf.size(); +} // namespace - // We wipe out the values as they get written into the final result to dedup - std::map<uint32_t, const uint8_t*> src_by_dest; - for (uint16_t i = 0; i < num_tables; ++i) { - const Table* table = &tables[i]; - size_t transform_length = table->transform_length; +size_t ComputeWOFF2FinalSize(const uint8_t* data, size_t length) { + Buffer file(data, length); + uint32_t total_length; - src_by_dest[table->dst_offset] = transform_buf; + if (!file.Skip(16) || + !file.ReadU32(&total_length)) { + return 0; + } + return total_length; +} - if (PREDICT_FALSE(transform_buf + transform_length > transform_buf_end)) { - return FONT_COMPRESSION_FAILURE(); - } - transform_buf += transform_length; +bool ConvertWOFF2ToTTF(uint8_t *result, size_t result_length, + const uint8_t *data, size_t length) { + WOFF2MemoryOut out(result, result_length); + return ConvertWOFF2ToTTF(data, length, &out); +} + +bool ConvertWOFF2ToTTF(const uint8_t* data, size_t length, + WOFF2Out* out) { + RebuildMetadata metadata; + WOFF2Header hdr; + if (!ReadWOFF2Header(data, length, &hdr)) { + return FONT_COMPRESSION_FAILURE(); } - for (uint16_t i = 0; i < num_tables; ++i) { - const Table* table = &tables[i]; - const size_t transform_length = table->transform_length; + if (!WriteHeaders(data, length, &metadata, &hdr, out)) { + return FONT_COMPRESSION_FAILURE(); + } - if ((table->flags & kWoff2FlagsTransform) != kWoff2FlagsTransform) { - if (PREDICT_FALSE(transform_length != table->dst_length)) { - return FONT_COMPRESSION_FAILURE(); - } - if (PREDICT_FALSE(static_cast<uint64_t>(table->dst_offset + - transform_length) > result_length)) { - return FONT_COMPRESSION_FAILURE(); - } - transform_buf = src_by_dest[table->dst_offset]; - src_by_dest.erase(table->dst_offset); - std::memcpy(result + table->dst_offset, transform_buf, transform_length); - } + const float compression_ratio = (float) hdr.uncompressed_size / length; + if (compression_ratio > kMaxPlausibleCompressionRatio) { +#ifdef FONT_COMPRESSION_BIN + fprintf(stderr, "Implausible compression ratio %.01f\n", compression_ratio); +#endif + return FONT_COMPRESSION_FAILURE(); } - // round 2, reconstruct transformed tables - if (PREDICT_FALSE(header_version)) { - // Rebuild collection font by font. - std::vector<Table> font_tables; - for (const auto& ttc_font : ttc_fonts) { - font_tables.resize(ttc_font.table_indices.size()); - for (auto i = 0; i < ttc_font.table_indices.size(); i++) { - font_tables[i] = tables[ttc_font.table_indices[i]]; - } - if (PREDICT_FALSE(!ReconstructTransformedFont(font_tables, &src_by_dest, - result, result_length))) { - return FONT_COMPRESSION_FAILURE(); - } - } - } else { - if (PREDICT_FALSE(!ReconstructTransformedFont(tables, &src_by_dest, result, - result_length))) { - return FONT_COMPRESSION_FAILURE(); - } + const uint8_t* src_buf = data + hdr.compressed_offset; + std::vector<uint8_t> uncompressed_buf(hdr.uncompressed_size); + if (PREDICT_FALSE(!Woff2Uncompress(&uncompressed_buf[0], + hdr.uncompressed_size, src_buf, + hdr.compressed_length))) { + return FONT_COMPRESSION_FAILURE(); } - if (header_version) { - if (PREDICT_FALSE( - !FixCollectionChecksums(header_version, tables, ttc_fonts, result))) { - return FONT_COMPRESSION_FAILURE(); - } - } else { - if (PREDICT_FALSE(!FixChecksums(sorted_tables, result))) { + for (size_t i = 0; i < metadata.font_infos.size(); i++) { + if (PREDICT_FALSE(!ReconstructFont(&uncompressed_buf[0], + hdr.uncompressed_size, + &metadata, &hdr, i, out))) { return FONT_COMPRESSION_FAILURE(); } } |