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https://github.com/RGBCube/serenity
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LibPDF/CFF: Extract parse_top_dict() function
Pure code move, no behavior change.
This commit is contained in:
Nico Weber
Andreas Kling
parent
1f62984301
commit
9f1cf8babc
2 changed files with 137 additions and 124 deletions
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@ -121,14 +121,122 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
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auto cff = adopt_ref(*new CFF());
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cff->set_font_matrix({ 0.001f, 0.0f, 0.0f, 0.001f, 0.0f, 0.0f });
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// CFF spec, "8 Top DICT INDEX"
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int charset_offset = 0;
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int encoding_offset = 0;
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auto charstrings_offset = 0;
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Vector<ByteBuffer> local_subroutines;
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float defaultWidthX = 0;
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float nominalWidthX = 0;
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int fdselect_offset = 0;
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auto top_dict = TRY(parse_top_dict(reader, cff_bytes));
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auto strings = TRY(parse_strings(reader));
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// CFF spec "16 Local/Global Subrs INDEXes"
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// "Global subrs are stored in an INDEX structure which follows the String INDEX."
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Vector<ByteBuffer> global_subroutines;
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TRY(parse_index(reader, [&](ReadonlyBytes const& subroutine_bytes) -> PDFErrorOr<void> {
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return TRY(global_subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
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}));
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dbgln_if(CFF_DEBUG, "CFF has {} gsubr entries", global_subroutines.size());
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// Create glyphs (now that we have the subroutines) and associate missing information to store them and their encoding
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auto glyphs = TRY(parse_charstrings(Reader(cff_bytes.slice(top_dict.charstrings_offset)), top_dict.local_subroutines, global_subroutines));
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// CFF spec, "Table 16 Encoding ID"
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// FIXME: Only read this if the built-in encoding is actually needed? (ie. `if (!encoding)`)
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Vector<u8> encoding_codes; // Maps GID to its codepoint.
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HashMap<Card8, SID> encoding_supplemental; // Maps codepoint to SID.
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switch (top_dict.encoding_offset) {
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case 0:
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dbgln_if(CFF_DEBUG, "CFF predefined encoding Standard");
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for (size_t i = 1; i < s_predefined_encoding_standard.size(); ++i)
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TRY(encoding_supplemental.try_set(i, s_predefined_encoding_standard[i]));
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break;
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case 1:
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dbgln_if(CFF_DEBUG, "CFF predefined encoding Expert");
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for (size_t i = 1; i < s_predefined_encoding_expert.size(); ++i)
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TRY(encoding_supplemental.try_set(i, s_predefined_encoding_expert[i]));
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break;
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default:
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encoding_codes = TRY(parse_encoding(Reader(cff_bytes.slice(top_dict.encoding_offset)), encoding_supplemental));
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break;
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}
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// CFF spec, "Table 22 Charset ID"
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Vector<DeprecatedFlyString> charset_names;
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switch (top_dict.charset_offset) {
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case 0:
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dbgln_if(CFF_DEBUG, "CFF predefined charset ISOAdobe");
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// CFF spec, "Appendix C Predefined Charsets, ISOAdobe"
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for (SID sid = 1; sid <= 228; sid++)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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case 1:
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dbgln_if(CFF_DEBUG, "CFF predefined charset Expert");
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for (SID sid : s_predefined_charset_expert)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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case 2:
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dbgln_if(CFF_DEBUG, "CFF predefined charset Expert Subset");
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for (SID sid : s_predefined_charset_expert_subset)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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default: {
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auto charset = TRY(parse_charset(Reader { cff_bytes.slice(top_dict.charset_offset) }, glyphs.size()));
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for (SID sid : charset)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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}
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}
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// CFF spec, "19 FDSelect"
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if (top_dict.fdselect_offset != 0) {
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auto fdselect = TRY(parse_fdselect(Reader { cff_bytes.slice(top_dict.fdselect_offset) }, glyphs.size()));
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dbgln_if(CFF_DEBUG, "CFF has {} FDSelect entries", fdselect.size());
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}
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// Adjust glyphs' widths as they are deltas from nominalWidthX
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for (auto& glyph : glyphs) {
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if (!glyph.has_width())
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glyph.set_width(top_dict.defaultWidthX);
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else
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glyph.set_width(glyph.width() + top_dict.nominalWidthX);
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}
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for (size_t i = 0; i < glyphs.size(); i++) {
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if (i == 0) {
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TRY(cff->add_glyph(0, move(glyphs[0])));
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continue;
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}
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auto const& name = charset_names[i - 1];
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TRY(cff->add_glyph(name, move(glyphs[i])));
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}
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cff->consolidate_glyphs();
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// Encoding given or read
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if (encoding) {
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dbgln_if(CFF_DEBUG, "CFF using external encoding");
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cff->set_encoding(move(encoding));
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} else {
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dbgln_if(CFF_DEBUG, "CFF using embedded encoding");
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auto encoding = Encoding::create();
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for (size_t i = 0; i < glyphs.size(); i++) {
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if (i == 0) {
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encoding->set(0, ".notdef");
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continue;
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}
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if (i >= encoding_codes.size() || i >= charset_names.size())
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break;
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auto code = encoding_codes[i - 1];
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auto char_name = charset_names[i - 1];
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encoding->set(code, char_name);
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}
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for (auto const& entry : encoding_supplemental)
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encoding->set(entry.key, resolve_sid(entry.value, strings));
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cff->set_encoding(move(encoding));
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}
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return cff;
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}
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PDFErrorOr<CFF::TopDict> CFF::parse_top_dict(Reader& reader, ReadonlyBytes const& cff_bytes)
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{
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TopDict top_dict;
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TRY(parse_index(reader, [&](ReadonlyBytes const& element_data) {
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Reader element_reader { element_data };
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return parse_dict<TopDictOperator>(element_reader, [&](TopDictOperator op, Vector<DictOperand> const& operands) -> PDFErrorOr<void> {
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@ -166,17 +274,17 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
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break;
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case TopDictOperator::Encoding: {
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if (!operands.is_empty())
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encoding_offset = operands[0].get<int>();
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top_dict.encoding_offset = operands[0].get<int>();
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break;
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}
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case TopDictOperator::Charset: {
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if (!operands.is_empty())
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charset_offset = operands[0].get<int>();
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top_dict.charset_offset = operands[0].get<int>();
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break;
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}
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case TopDictOperator::CharStrings: {
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if (!operands.is_empty())
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charstrings_offset = operands[0].get<int>();
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top_dict.charstrings_offset = operands[0].get<int>();
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break;
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}
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case TopDictOperator::Private: {
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@ -210,18 +318,18 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
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auto subrs_offset = operands[0].get<int>();
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Reader subrs_reader { cff_bytes.slice(private_dict_offset + subrs_offset) };
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TRY(parse_index(subrs_reader, [&](ReadonlyBytes const& subroutine_bytes) -> PDFErrorOr<void> {
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return TRY(local_subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
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return TRY(top_dict.local_subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
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}));
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dbgln_if(CFF_DEBUG, "CFF has {} subr entries", local_subroutines.size());
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dbgln_if(CFF_DEBUG, "CFF has {} subr entries", top_dict.local_subroutines.size());
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break;
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}
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case PrivDictOperator::DefaultWidthX:
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if (!operands.is_empty())
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defaultWidthX = to_number(operands[0]);
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top_dict.defaultWidthX = to_number(operands[0]);
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break;
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case PrivDictOperator::NominalWidthX:
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if (!operands.is_empty())
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nominalWidthX = to_number(operands[0]);
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top_dict.nominalWidthX = to_number(operands[0]);
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break;
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default:
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dbgln("CFF: Unhandled private dict entry {}", static_cast<int>(op));
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@ -232,7 +340,7 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
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}
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case TopDictOperator::FDSelect:
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if (!operands.is_empty())
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fdselect_offset = operands[0].get<int>();
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top_dict.fdselect_offset = operands[0].get<int>();
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break;
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case TopDictOperator::CIDFontVersion:
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case TopDictOperator::CIDFontRevision:
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@ -250,114 +358,7 @@ PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPt
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});
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}));
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auto strings = TRY(parse_strings(reader));
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// CFF spec "16 Local/Global Subrs INDEXes"
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// "Global subrs are stored in an INDEX structure which follows the String INDEX."
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Vector<ByteBuffer> global_subroutines;
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TRY(parse_index(reader, [&](ReadonlyBytes const& subroutine_bytes) -> PDFErrorOr<void> {
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return TRY(global_subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
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}));
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dbgln_if(CFF_DEBUG, "CFF has {} gsubr entries", global_subroutines.size());
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// Create glyphs (now that we have the subroutines) and associate missing information to store them and their encoding
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auto glyphs = TRY(parse_charstrings(Reader(cff_bytes.slice(charstrings_offset)), local_subroutines, global_subroutines));
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// CFF spec, "Table 16 Encoding ID"
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// FIXME: Only read this if the built-in encoding is actually needed? (ie. `if (!encoding)`)
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Vector<u8> encoding_codes; // Maps GID to its codepoint.
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HashMap<Card8, SID> encoding_supplemental; // Maps codepoint to SID.
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switch (encoding_offset) {
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case 0:
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dbgln_if(CFF_DEBUG, "CFF predefined encoding Standard");
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for (size_t i = 1; i < s_predefined_encoding_standard.size(); ++i)
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TRY(encoding_supplemental.try_set(i, s_predefined_encoding_standard[i]));
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break;
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case 1:
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dbgln_if(CFF_DEBUG, "CFF predefined encoding Expert");
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for (size_t i = 1; i < s_predefined_encoding_expert.size(); ++i)
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TRY(encoding_supplemental.try_set(i, s_predefined_encoding_expert[i]));
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break;
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default:
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encoding_codes = TRY(parse_encoding(Reader(cff_bytes.slice(encoding_offset)), encoding_supplemental));
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break;
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}
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// CFF spec, "Table 22 Charset ID"
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Vector<DeprecatedFlyString> charset_names;
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switch (charset_offset) {
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case 0:
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dbgln_if(CFF_DEBUG, "CFF predefined charset ISOAdobe");
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// CFF spec, "Appendix C Predefined Charsets, ISOAdobe"
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for (SID sid = 1; sid <= 228; sid++)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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case 1:
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dbgln_if(CFF_DEBUG, "CFF predefined charset Expert");
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for (SID sid : s_predefined_charset_expert)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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case 2:
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dbgln_if(CFF_DEBUG, "CFF predefined charset Expert Subset");
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for (SID sid : s_predefined_charset_expert_subset)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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default: {
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auto charset = TRY(parse_charset(Reader { cff_bytes.slice(charset_offset) }, glyphs.size()));
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for (SID sid : charset)
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TRY(charset_names.try_append(resolve_sid(sid, strings)));
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break;
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}
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}
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// CFF spec, "19 FDSelect"
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if (fdselect_offset != 0) {
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auto fdselect = TRY(parse_fdselect(Reader { cff_bytes.slice(fdselect_offset) }, glyphs.size()));
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dbgln_if(CFF_DEBUG, "CFF has {} FDSelect entries", fdselect.size());
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}
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// Adjust glyphs' widths as they are deltas from nominalWidthX
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for (auto& glyph : glyphs) {
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if (!glyph.has_width())
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glyph.set_width(defaultWidthX);
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else
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glyph.set_width(glyph.width() + nominalWidthX);
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}
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for (size_t i = 0; i < glyphs.size(); i++) {
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if (i == 0) {
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TRY(cff->add_glyph(0, move(glyphs[0])));
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continue;
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}
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auto const& name = charset_names[i - 1];
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TRY(cff->add_glyph(name, move(glyphs[i])));
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}
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cff->consolidate_glyphs();
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// Encoding given or read
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if (encoding) {
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dbgln_if(CFF_DEBUG, "CFF using external encoding");
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cff->set_encoding(move(encoding));
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} else {
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dbgln_if(CFF_DEBUG, "CFF using embedded encoding");
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auto encoding = Encoding::create();
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for (size_t i = 0; i < glyphs.size(); i++) {
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if (i == 0) {
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encoding->set(0, ".notdef");
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continue;
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}
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if (i >= encoding_codes.size() || i >= charset_names.size())
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break;
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auto code = encoding_codes[i - 1];
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auto char_name = charset_names[i - 1];
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encoding->set(code, char_name);
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}
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for (auto const& entry : encoding_supplemental)
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encoding->set(entry.key, resolve_sid(entry.value, strings));
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cff->set_encoding(move(encoding));
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}
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return cff;
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return top_dict;
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}
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/// Appendix A: Standard Strings
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@ -118,6 +118,18 @@ public:
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template<typename OperatorT>
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static PDFErrorOr<OperatorT> parse_dict_operator(u8, Reader&);
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// CFF spec, "8 Top DICT INDEX"
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struct TopDict {
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int charset_offset = 0;
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int encoding_offset = 0;
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int charstrings_offset = 0;
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Vector<ByteBuffer> local_subroutines;
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float defaultWidthX = 0;
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float nominalWidthX = 0;
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int fdselect_offset = 0;
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};
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static PDFErrorOr<TopDict> parse_top_dict(Reader&, ReadonlyBytes const& cff_bytes);
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static PDFErrorOr<Vector<StringView>> parse_strings(Reader&);
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static PDFErrorOr<Vector<CFF::Glyph>> parse_charstrings(Reader&&, Vector<ByteBuffer> const& local_subroutines, Vector<ByteBuffer> const& global_subroutines);
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