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serenity/Userland/Libraries/LibPDF/Fonts/CFF.cpp
Nico Weber c825194fb9 LibPDF: Reject CFFs with more than one font 
The code assumes that there's just one Top DICT, so let's be loud
when that isn't the case.
2023-10-16 08:32:18 +02:00

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/*
* Copyright (c) 2023, Rodrigo Tobar <rtobarc@gmail.com>.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
// CFF spec: https://adobe-type-tools.github.io/font-tech-notes/pdfs/5176.CFF.pdf
#include <AK/Debug.h>
#include <AK/Endian.h>
#include <AK/String.h>
#include <LibGfx/Forward.h>
#include <LibPDF/Encoding.h>
#include <LibPDF/Error.h>
#include <LibPDF/Fonts/CFF.h>
#include <LibPDF/Reader.h>
namespace PDF {
// CFF spec, "Appendix C Predefined Charsets, Expert"
// clang-format off
static constexpr Array s_predefined_charset_expert {
1, 229, 230, 231, 232,
233, 234, 235, 236, 237,
238, 13, 14, 15, 99,
239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 27, 28, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 109, 110,
267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298,
299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 158, 155, 163, 319, 320, 321, 322, 323, 324, 325, 326, 150,
164, 169, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342,
343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360,
361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378,
};
// clang-format on
// CFF spec, "Appendix C Predefined Charsets, Expert Subset"
// clang-format off
static constexpr Array s_predefined_charset_expert_subset {
1, 231, 232, 235, 236, 237, 238, 13, 14, 15, 99,
239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 27,
28, 249, 250, 251, 253, 254, 255, 256, 257, 258, 259,
260, 261, 262, 263, 264, 265, 266, 109, 110, 267, 268, 269, 270, 272, 300, 301, 302, 305,
314, 315, 158, 155, 163, 320, 321, 322, 323, 324, 325, 326, 150, 164, 169, 327, 328, 329,
330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346,
};
// clang-format on
PDFErrorOr<NonnullRefPtr<CFF>> CFF::create(ReadonlyBytes const& cff_bytes, RefPtr<Encoding> encoding)
{
Reader reader(cff_bytes);
// CFF spec, "6 Header"
// skip major, minor version
reader.consume(2);
auto header_size = TRY(reader.try_read<Card8>());
// skip offset size
reader.consume(1);
reader.move_to(header_size);
// CFF spec, "7 Name INDEX"
Vector<String> font_names;
TRY(parse_index(reader, [&](ReadonlyBytes const& data) -> PDFErrorOr<void> {
auto font_name = TRY(String::from_utf8(data));
dbgln_if(CFF_DEBUG, "CFF font name '{}'", font_name);
return TRY(font_names.try_append(font_name));
}));
if (font_names.size() != 1)
return error("CFFs with more than one font not yet implemented");
auto cff = adopt_ref(*new CFF());
cff->set_font_matrix({ 0.001f, 0.0f, 0.0f, 0.001f, 0.0f, 0.0f });
// CFF spec, "8 Top DICT INDEX"
int charset_offset = 0;
Vector<u8> encoding_codes;
auto charstrings_offset = 0;
Vector<ByteBuffer> subroutines;
float defaultWidthX = 0;
float nominalWidthX = 0;
TRY(parse_index(reader, [&](ReadonlyBytes const& element_data) {
Reader element_reader { element_data };
return parse_dict<TopDictOperator>(element_reader, [&](TopDictOperator op, Vector<DictOperand> const& operands) -> PDFErrorOr<void> {
switch (op) {
case TopDictOperator::Encoding: {
auto encoding_offset = 0;
if (!operands.is_empty())
encoding_offset = operands[0].get<int>();
encoding_codes = TRY(parse_encoding(Reader(cff_bytes.slice(encoding_offset))));
break;
}
case TopDictOperator::Charset: {
if (!operands.is_empty())
charset_offset = operands[0].get<int>();
break;
}
case TopDictOperator::CharStrings: {
if (!operands.is_empty())
charstrings_offset = operands[0].get<int>();
break;
}
case TopDictOperator::Private: {
auto private_dict_size = operands[0].get<int>();
auto private_dict_offset = operands[1].get<int>();
Reader priv_dict_reader { cff_bytes.slice(private_dict_offset, private_dict_size) };
TRY(parse_dict<PrivDictOperator>(priv_dict_reader, [&](PrivDictOperator op, Vector<DictOperand> const& operands) -> PDFErrorOr<void> {
switch (op) {
case PrivDictOperator::Subrs: {
// CFF spec, "16 Local/Global Subrs INDEXes"
// "Local subrs are stored in an INDEX structure which is located via the offset operand of the Subrs operator in the Private DICT."
auto subrs_offset = operands[0].get<int>();
Reader subrs_reader { cff_bytes.slice(private_dict_offset + subrs_offset) };
dbgln("Parsing Subrs INDEX");
TRY(parse_index(subrs_reader, [&](ReadonlyBytes const& subroutine_bytes) -> PDFErrorOr<void> {
return TRY(subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
}));
break;
}
case PrivDictOperator::DefaultWidthX:
if (!operands.is_empty())
defaultWidthX = to_number(operands[0]);
break;
case PrivDictOperator::NominalWidthX:
if (!operands.is_empty())
nominalWidthX = to_number(operands[0]);
break;
}
return {};
}));
break;
}
default:;
}
return {};
});
}));
auto strings = TRY(parse_strings(reader));
// FIXME: CFF spec "16 Local/Global Subrs INDEXes"
// "Global subrs are stored in an INDEX structure which follows the String INDEX."
// Create glyphs (now that we have the subroutines) and associate missing information to store them and their encoding
auto glyphs = TRY(parse_charstrings(Reader(cff_bytes.slice(charstrings_offset)), subroutines));
// CFF spec, "Table 22 Charset ID"
Vector<DeprecatedFlyString> charset;
switch (charset_offset) {
case 0:
// CFF spec, "Appendix C Predefined Charsets, ISOAdobe"
for (SID sid = 1; sid <= 228; sid++)
TRY(charset.try_append(resolve_sid(sid, strings)));
break;
case 1:
for (SID sid : s_predefined_charset_expert)
TRY(charset.try_append(resolve_sid(sid, strings)));
break;
case 2:
for (SID sid : s_predefined_charset_expert_subset)
TRY(charset.try_append(resolve_sid(sid, strings)));
break;
default:
charset = TRY(parse_charset(Reader { cff_bytes.slice(charset_offset) }, glyphs.size(), strings));
break;
}
// Adjust glyphs' widths as they are deltas from nominalWidthX
for (auto& glyph : glyphs) {
if (!glyph.has_width())
glyph.set_width(defaultWidthX);
else
glyph.set_width(glyph.width() + nominalWidthX);
}
for (size_t i = 0; i < glyphs.size(); i++) {
if (i == 0) {
TRY(cff->add_glyph(0, move(glyphs[0])));
continue;
}
auto const& name = charset[i - 1];
TRY(cff->add_glyph(name, move(glyphs[i])));
}
cff->consolidate_glyphs();
// Encoding given or read
if (encoding) {
dbgln_if(CFF_DEBUG, "CFF using external encoding");
cff->set_encoding(move(encoding));
} else {
dbgln_if(CFF_DEBUG, "CFF using embedded encoding");
auto encoding = Encoding::create();
for (size_t i = 0; i < glyphs.size(); i++) {
if (i == 0) {
encoding->set(0, ".notdef");
continue;
}
auto code = encoding_codes[i - 1];
auto char_name = charset[i - 1];
encoding->set(code, char_name);
}
cff->set_encoding(move(encoding));
}
return cff;
}
/// Appendix A: Standard Strings
static constexpr Array s_cff_builtin_names {
".notdef"sv,
"space"sv,
"exclam"sv,
"quotedbl"sv,
"numbersign"sv,
"dollar"sv,
"percent"sv,
"ampersand"sv,
"quoteright"sv,
"parenleft"sv,
"parenright"sv,
"asterisk"sv,
"plus"sv,
"comma"sv,
"hyphen"sv,
"period"sv,
"slash"sv,
"zero"sv,
"one"sv,
"two"sv,
"three"sv,
"four"sv,
"five"sv,
"six"sv,
"seven"sv,
"eight"sv,
"nine"sv,
"colon"sv,
"semicolon"sv,
"less"sv,
"equal"sv,
"greater"sv,
"question"sv,
"at"sv,
"A"sv,
"B"sv,
"C"sv,
"D"sv,
"E"sv,
"F"sv,
"G"sv,
"H"sv,
"I"sv,
"J"sv,
"K"sv,
"L"sv,
"M"sv,
"N"sv,
"O"sv,
"P"sv,
"Q"sv,
"R"sv,
"S"sv,
"T"sv,
"U"sv,
"V"sv,
"W"sv,
"X"sv,
"Y"sv,
"Z"sv,
"bracketleft"sv,
"backslash"sv,
"bracketright"sv,
"asciicircum"sv,
"underscore"sv,
"quoteleft"sv,
"a"sv,
"b"sv,
"c"sv,
"d"sv,
"e"sv,
"f"sv,
"g"sv,
"h"sv,
"i"sv,
"j"sv,
"k"sv,
"l"sv,
"m"sv,
"n"sv,
"o"sv,
"p"sv,
"q"sv,
"r"sv,
"s"sv,
"t"sv,
"u"sv,
"v"sv,
"w"sv,
"x"sv,
"y"sv,
"z"sv,
"braceleft"sv,
"bar"sv,
"braceright"sv,
"asciitilde"sv,
"exclamdown"sv,
"cent"sv,
"sterling"sv,
"fraction"sv,
"yen"sv,
"florin"sv,
"section"sv,
"currency"sv,
"quotesingle"sv,
"quotedblleft"sv,
"guillemotleft"sv,
"guilsinglleft"sv,
"guilsinglright"sv,
"fi"sv,
"fl"sv,
"endash"sv,
"dagger"sv,
"daggerdbl"sv,
"periodcentered"sv,
"paragraph"sv,
"bullet"sv,
"quotesinglbase"sv,
"quotedblbase"sv,
"quotedblright"sv,
"guillemotright"sv,
"ellipsis"sv,
"perthousand"sv,
"questiondown"sv,
"grave"sv,
"acute"sv,
"circumflex"sv,
"tilde"sv,
"macron"sv,
"breve"sv,
"dotaccent"sv,
"dieresis"sv,
"ring"sv,
"cedilla"sv,
"hungarumlaut"sv,
"ogonek"sv,
"caron"sv,
"emdash"sv,
"AE"sv,
"ordfeminine"sv,
"Lslash"sv,
"Oslash"sv,
"OE"sv,
"ordmasculine"sv,
"ae"sv,
"dotlessi"sv,
"lslash"sv,
"oslash"sv,
"oe"sv,
"germandbls"sv,
"onesuperior"sv,
"logicalnot"sv,
"mu"sv,
"trademark"sv,
"Eth"sv,
"onehalf"sv,
"plusminus"sv,
"Thorn"sv,
"onequarter"sv,
"divide"sv,
"brokenbar"sv,
"degree"sv,
"thorn"sv,
"threequarters"sv,
"twosuperior"sv,
"registered"sv,
"minus"sv,
"eth"sv,
"multiply"sv,
"threesuperior"sv,
"copyright"sv,
"Aacute"sv,
"Acircumflex"sv,
"Adieresis"sv,
"Agrave"sv,
"Aring"sv,
"Atilde"sv,
"Ccedilla"sv,
"Eacute"sv,
"Ecircumflex"sv,
"Edieresis"sv,
"Egrave"sv,
"Iacute"sv,
"Icircumflex"sv,
"Idieresis"sv,
"Igrave"sv,
"Ntilde"sv,
"Oacute"sv,
"Ocircumflex"sv,
"Odieresis"sv,
"Ograve"sv,
"Otilde"sv,
"Scaron"sv,
"Uacute"sv,
"Ucircumflex"sv,
"Udieresis"sv,
"Ugrave"sv,
"Yacute"sv,
"Ydieresis"sv,
"Zcaron"sv,
"aacute"sv,
"acircumflex"sv,
"adieresis"sv,
"agrave"sv,
"aring"sv,
"atilde"sv,
"ccedilla"sv,
"eacute"sv,
"ecircumflex"sv,
"edieresis"sv,
"egrave"sv,
"iacute"sv,
"icircumflex"sv,
"idieresis"sv,
"igrave"sv,
"ntilde"sv,
"oacute"sv,
"ocircumflex"sv,
"odieresis"sv,
"ograve"sv,
"otilde"sv,
"scaron"sv,
"uacute"sv,
"ucircumflex"sv,
"udieresis"sv,
"ugrave"sv,
"yacute"sv,
"ydieresis"sv,
"zcaron"sv,
"exclamsmall"sv,
"Hungarumlautsmall"sv,
"dollaroldstyle"sv,
"dollarsuperior"sv,
"ampersandsmall"sv,
"Acutesmall"sv,
"parenleftsuperior"sv,
"parenrightsuperior"sv,
"twodotenleader"sv,
"onedotenleader"sv,
"zerooldstyle"sv,
"oneoldstyle"sv,
"twooldstyle"sv,
"threeoldstyle"sv,
"fouroldstyle"sv,
"fiveoldstyle"sv,
"sixoldstyle"sv,
"sevenoldstyle"sv,
"eightoldstyle"sv,
"nineoldstyle"sv,
"commasuperior"sv,
"threequartersemdash"sv,
"periodsuperior"sv,
"questionsmall"sv,
"asuperior"sv,
"bsuperior"sv,
"centsuperior"sv,
"dsuperior"sv,
"esuperior"sv,
"isuperior"sv,
"lsuperior"sv,
"msuperior"sv,
"nsuperior"sv,
"osuperior"sv,
"rsuperior"sv,
"ssuperior"sv,
"tsuperior"sv,
"ff"sv,
"ffi"sv,
"ffl"sv,
"parenleftinferior"sv,
"parenrightinferior"sv,
"Circumflexsmall"sv,
"hyphensuperior"sv,
"Gravesmall"sv,
"Asmall"sv,
"Bsmall"sv,
"Csmall"sv,
"Dsmall"sv,
"Esmall"sv,
"Fsmall"sv,
"Gsmall"sv,
"Hsmall"sv,
"Ismall"sv,
"Jsmall"sv,
"Ksmall"sv,
"Lsmall"sv,
"Msmall"sv,
"Nsmall"sv,
"Osmall"sv,
"Psmall"sv,
"Qsmall"sv,
"Rsmall"sv,
"Ssmall"sv,
"Tsmall"sv,
"Usmall"sv,
"Vsmall"sv,
"Wsmall"sv,
"Xsmall"sv,
"Ysmall"sv,
"Zsmall"sv,
"colonmonetary"sv,
"onefitted"sv,
"rupiah"sv,
"Tildesmall"sv,
"exclamdownsmall"sv,
"centoldstyle"sv,
"Lslashsmall"sv,
"Scaronsmall"sv,
"Zcaronsmall"sv,
"Dieresissmall"sv,
"Brevesmall"sv,
"Caronsmall"sv,
"Dotaccentsmall"sv,
"Macronsmall"sv,
"figuredash"sv,
"hypheninferior"sv,
"Ogoneksmall"sv,
"Ringsmall"sv,
"Cedillasmall"sv,
"questiondownsmall"sv,
"oneeighth"sv,
"threeeighths"sv,
"fiveeighths"sv,
"seveneighths"sv,
"onethird"sv,
"twothirds"sv,
"zerosuperior"sv,
"foursuperior"sv,
"fivesuperior"sv,
"sixsuperior"sv,
"sevensuperior"sv,
"eightsuperior"sv,
"ninesuperior"sv,
"zeroinferior"sv,
"oneinferior"sv,
"twoinferior"sv,
"threeinferior"sv,
"fourinferior"sv,
"fiveinferior"sv,
"sixinferior"sv,
"seveninferior"sv,
"eightinferior"sv,
"nineinferior"sv,
"centinferior"sv,
"dollarinferior"sv,
"periodinferior"sv,
"commainferior"sv,
"Agravesmall"sv,
"Aacutesmall"sv,
"Acircumflexsmall"sv,
"Atildesmall"sv,
"Adieresissmall"sv,
"Aringsmall"sv,
"AEsmall"sv,
"Ccedillasmall"sv,
"Egravesmall"sv,
"Eacutesmall"sv,
"Ecircumflexsmall"sv,
"Edieresissmall"sv,
"Igravesmall"sv,
"Iacutesmall"sv,
"Icircumflexsmall"sv,
"Idieresissmall"sv,
"Ethsmall"sv,
"Ntildesmall"sv,
"Ogravesmall"sv,
"Oacutesmall"sv,
"Ocircumflexsmall"sv,
"Otildesmall"sv,
"Odieresissmall"sv,
"OEsmall"sv,
"Oslashsmall"sv,
"Ugravesmall"sv,
"Uacutesmall"sv,
"Ucircumflexsmall"sv,
"Udieresissmall"sv,
"Yacutesmall"sv,
"Thornsmall"sv,
"Ydieresissmall"sv,
"001.000"sv,
"001.001"sv,
"001.002"sv,
"001.003"sv,
"Black"sv,
"Bold"sv,
"Book"sv,
"Light"sv,
"Medium"sv,
"Regular"sv,
"Roman"sv,
"Semibold"sv,
};
PDFErrorOr<Vector<StringView>> CFF::parse_strings(Reader& reader)
{
// CFF spec "10 String Index"
Vector<StringView> strings;
TRY(parse_index(reader, [&](ReadonlyBytes const& string) -> PDFErrorOr<void> {
return TRY(strings.try_append(string));
}));
return strings;
}
DeprecatedFlyString CFF::resolve_sid(SID sid, Vector<StringView> const& strings)
{
if (sid < s_cff_builtin_names.size())
return DeprecatedFlyString(s_cff_builtin_names[sid]);
if (sid - s_cff_builtin_names.size() < strings.size())
return DeprecatedFlyString(strings[sid - s_cff_builtin_names.size()]);
dbgln("Couldn't find string for SID {}, going with space", sid);
return DeprecatedFlyString("space");
}
PDFErrorOr<Vector<DeprecatedFlyString>> CFF::parse_charset(Reader&& reader, size_t glyph_count, Vector<StringView> const& strings)
{
// CFF spec, "13 Charsets"
Vector<DeprecatedFlyString> names;
auto format = TRY(reader.try_read<Card8>());
if (format == 0) {
// CFF spec, "Table 17 Format 0"
for (u8 i = 0; i < glyph_count - 1; i++) {
SID sid = TRY(reader.try_read<BigEndian<SID>>());
TRY(names.try_append(resolve_sid(sid, strings)));
}
} else if (format == 1) {
// CFF spec, "Table 18 Format 1"
while (names.size() < glyph_count - 1) {
// CFF spec, "Table 19 Range1 Format (Charset)"
auto first_sid = TRY(reader.try_read<BigEndian<SID>>());
int left = TRY(reader.try_read<Card8>());
for (SID sid = first_sid; left >= 0; left--, sid++)
TRY(names.try_append(resolve_sid(sid, strings)));
}
} else if (format == 2) {
// CFF spec, "Table 20 Format 2"
// "Format 2 differs from format 1 only in the size of the Left field in each range."
while (names.size() < glyph_count - 1) {
// CFF spec, "Table 21 Range2 Format"
auto first_sid = TRY(reader.try_read<BigEndian<SID>>());
int left = TRY(reader.try_read<Card16>());
for (SID sid = first_sid; left >= 0; left--, sid++)
TRY(names.try_append(resolve_sid(sid, strings)));
}
} else {
dbgln("CFF: Unknown charset format {}", format);
}
return names;
}
PDFErrorOr<Vector<CFF::Glyph>> CFF::parse_charstrings(Reader&& reader, Vector<ByteBuffer> const& subroutines)
{
// CFF spec, "14 CharStrings INDEX"
Vector<Glyph> glyphs;
TRY(parse_index(reader, [&](ReadonlyBytes const& charstring_data) -> PDFErrorOr<void> {
GlyphParserState state;
auto glyph = TRY(parse_glyph(charstring_data, subroutines, state, true));
return TRY(glyphs.try_append(glyph));
}));
return glyphs;
}
PDFErrorOr<Vector<u8>> CFF::parse_encoding(Reader&& reader)
{
// CFF spec, "12 Encodings"
Vector<u8> encoding_codes;
auto format_raw = TRY(reader.try_read<Card8>());
// TODO: support encoding supplements when highest bit is set
auto format = format_raw & 0x7f;
if (format == 0) {
auto n_codes = TRY(reader.try_read<Card8>());
for (u8 i = 0; i < n_codes; i++) {
TRY(encoding_codes.try_append(TRY(reader.try_read<Card8>())));
}
} else if (format == 1) {
auto n_ranges = TRY(reader.try_read<Card8>());
for (u8 i = 0; i < n_ranges; i++) {
// CFF spec, "Table 13 Range1 Format (Encoding)"
auto first_code = TRY(reader.try_read<Card8>());
int left = TRY(reader.try_read<Card8>());
for (u8 code = first_code; left >= 0; left--, code++)
TRY(encoding_codes.try_append(code));
}
} else
return error(DeprecatedString::formatted("Invalid encoding format: {}", format));
return encoding_codes;
}
template<typename OperatorT>
PDFErrorOr<void> CFF::parse_dict(Reader& reader, DictEntryHandler<OperatorT>&& handler)
{
// CFF spec, "4 DICT data"
Vector<DictOperand> operands;
while (reader.remaining() > 0) {
auto b0 = reader.read<u8>();
// "Operators and operands may be distinguished by inspection of their first byte: 0-21 specify operators"
if (b0 <= 21) {
auto op = TRY(parse_dict_operator<OperatorT>(b0, reader));
TRY(handler(op, operands));
operands.clear();
continue;
}
// An operand
TRY(operands.try_append(TRY(load_dict_operand(b0, reader))));
}
return {};
}
template PDFErrorOr<void> CFF::parse_dict<CFF::TopDictOperator>(Reader&, DictEntryHandler<TopDictOperator>&&);
template PDFErrorOr<void> CFF::parse_dict<CFF::PrivDictOperator>(Reader&, DictEntryHandler<PrivDictOperator>&&);
template<typename OperatorT>
PDFErrorOr<OperatorT> CFF::parse_dict_operator(u8 b0, Reader& reader)
{
// CFF spec, "4 DICT data"
VERIFY(b0 <= 21);
// "Two-byte operators have an initial escape byte of 12."
if (b0 != 12)
return OperatorT { (int)b0 };
auto b1 = TRY(reader.try_read<u8>());
return OperatorT { b0 << 8 | b1 };
}
template PDFErrorOr<CFF::TopDictOperator> CFF::parse_dict_operator(u8, Reader&);
PDFErrorOr<void> CFF::parse_index(Reader& reader, IndexDataHandler&& data_handler)
{
// CFF spec, "5 INDEX Data"
Card16 count = TRY(reader.try_read<BigEndian<Card16>>());
if (count == 0)
return {};
auto offset_size = TRY(reader.try_read<OffSize>());
if (offset_size == 1)
return parse_index_data<u8>(count, reader, data_handler);
if (offset_size == 2)
return parse_index_data<u16>(count, reader, data_handler);
if (offset_size == 4)
return parse_index_data<u32>(count, reader, data_handler);
VERIFY_NOT_REACHED();
}
template<typename OffsetType>
PDFErrorOr<void> CFF::parse_index_data(Card16 count, Reader& reader, IndexDataHandler& handler)
{
// CFF spec, "5 INDEX Data"
OffsetType last_data_end = 1;
auto offset_refpoint = reader.offset() + sizeof(OffsetType) * (count + 1) - 1;
for (u16 i = 0; i < count; i++) {
reader.save();
reader.move_by(sizeof(OffsetType) * i);
OffsetType data_start = reader.read<BigEndian<OffsetType>>();
last_data_end = reader.read<BigEndian<OffsetType>>();
auto data_size = last_data_end - data_start;
reader.move_to(offset_refpoint + data_start);
TRY(handler(reader.bytes().slice(reader.offset(), data_size)));
reader.load();
}
reader.move_to(offset_refpoint + last_data_end);
return {};
}
template PDFErrorOr<void> CFF::parse_index_data<u8>(Card16, Reader&, IndexDataHandler&);
template PDFErrorOr<void> CFF::parse_index_data<u16>(Card16, Reader&, IndexDataHandler&);
template PDFErrorOr<void> CFF::parse_index_data<u32>(Card16, Reader&, IndexDataHandler&);
int CFF::load_int_dict_operand(u8 b0, Reader& reader)
{
// CFF spec, "Table 3 Operand Encoding"
if (b0 >= 32 && b0 <= 246) {
return b0 - 139;
}
if (b0 >= 247 && b0 <= 250) {
auto b1 = reader.read<u8>();
return (b0 - 247) * 256 + b1 + 108;
}
if (b0 >= 251 && b0 <= 254) {
auto b1 = reader.read<u8>();
return -(b0 - 251) * 256 - b1 - 108;
}
if (b0 == 28) {
auto b1 = reader.read<u8>();
auto b2 = reader.read<u8>();
return b1 << 8 | b2;
}
if (b0 == 29) {
auto b1 = reader.read<u8>();
auto b2 = reader.read<u8>();
auto b3 = reader.read<u8>();
auto b4 = reader.read<u8>();
return b1 << 24 | b2 << 16 | b3 << 8 | b4;
}
VERIFY_NOT_REACHED();
}
float CFF::load_float_dict_operand(Reader& reader)
{
// CFF spec, "Table 5 Nibble Definitions"
StringBuilder sb;
auto add_nibble = [&](char nibble) {
if (nibble < 0xa)
sb.append('0' + nibble);
else if (nibble == 0xa)
sb.append('.');
else if (nibble == 0xb)
sb.append('E');
else if (nibble == 0xc)
sb.append("E-"sv);
else if (nibble == 0xe)
sb.append('-');
};
while (true) {
auto byte = reader.read<u8>();
char nibble1 = (byte & 0xf0) >> 4;
char nibble2 = byte & 0x0f;
if (nibble1 == 0xf)
break;
add_nibble(nibble1);
if (nibble2 == 0xf)
break;
add_nibble(nibble2);
}
auto result = AK::StringUtils::convert_to_floating_point<float>(sb.string_view());
return result.release_value();
}
PDFErrorOr<CFF::DictOperand> CFF::load_dict_operand(u8 b0, Reader& reader)
{
// CFF spec, "4 DICT data"
if (b0 == 30)
return load_float_dict_operand(reader);
if (b0 >= 28)
return load_int_dict_operand(b0, reader);
return Error { Error::Type::MalformedPDF, DeprecatedString::formatted("Unknown CFF dict element prefix: {}", b0) };
}
}
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