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serenity/Userland/Libraries/LibPDF/Fonts/CFF.cpp
Nico Weber 52afa936c4 LibPDF: Don't over-read in charset formats 1 and 2 
`left` might be a number bigger than there are actually glyphs in the
CFF.

The spec says "The number of ranges is not explicitly specified in the
font. Instead, software utilizing this data simply processes ranges
until all glyphs in the font are covered." Apparently we have to check
for this within each range as well.

Needed for example in 0000054.pdf and 0000354.pdf in 0000.zip in the
pdfa dataset.

Together with the previous commit:

From 21 (7%) to 20 (6%) crashes on the 300 first PDFs, and from
41 (8.2%) to 39 (7.8%) on the 500-random PDFs test.
2023-10-23 09:31:11 -04:00

980 lines
31 KiB
C++
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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 {
// The built-in encodings map codes to SIDs.
// CFF spec, "Appendix B Predefined Encodings, Standard Encoding"
// clang-format off
static constexpr Array s_predefined_encoding_standard {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60,
61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
90, 91, 92, 93, 94, 95, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 0, 111, 112,
113, 114, 0, 115, 116, 117, 118, 119, 120, 121, 122, 0, 123, 0, 124, 125, 126, 127, 128, 129, 130, 131, 0, 132, 133, 0, 134, 135, 136,
137, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 138, 0, 139, 0, 0, 0, 0, 140, 141, 142, 143, 0,
0, 0, 0, 0, 144, 0, 0,
0, 145, 0, 0, 146, 147, 148,
149, 0, 0, 0, 0,
};
static_assert(s_predefined_encoding_standard.size() == 256);
// clang-format on
// CFF spec, "Appendix B Predefined Encodings, Expert Encoding"
// clang-format off
static constexpr Array s_predefined_encoding_expert {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 229, 230, 0,
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, 0, 253, 254, 255, 256, 257, 0, 0, 0, 258, 0, 0, 259, 260, 261, 262, 0, 0, 263,
264, 265, 0, 266, 109, 110, 267, 268, 269, 0, 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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 304, 305, 306, 0, 0, 307, 308, 309, 310,
311, 0, 312, 0, 0, 313, 0, 0, 314, 315, 0, 0, 316, 317, 318, 0, 0, 0, 158, 155, 163, 319, 320, 321, 322, 323, 324, 325, 0,
0, 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,
};
static_assert(s_predefined_encoding_expert.size() == 256);
// clang-format on
// Charsets map GIDs to SIDs.
// 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;
int encoding_offset = 0;
auto charstrings_offset = 0;
Vector<ByteBuffer> local_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::Version:
case TopDictOperator::Notice:
case TopDictOperator::FullName:
case TopDictOperator::FamilyName:
case TopDictOperator::Weight:
case TopDictOperator::FontBBox:
case TopDictOperator::UniqueID:
case TopDictOperator::XUID:
case TopDictOperator::Copyright:
case TopDictOperator::IsFixedPitch:
case TopDictOperator::ItalicAngle:
case TopDictOperator::UnderlinePosition:
case TopDictOperator::UnderlineThickness:
case TopDictOperator::PaintType:
case TopDictOperator::FontMatrix:
case TopDictOperator::StrokeWidth:
case TopDictOperator::PostScript:
case TopDictOperator::BaseFontName:
case TopDictOperator::BaseFontBlend:
break;
case TopDictOperator::CharstringType: {
int charstring_type = 2;
if (!operands.is_empty())
charstring_type = operands[0].get<int>();
if (charstring_type != 2)
dbgln("CFF: has unimplemented CharstringType, might not look right");
break;
}
case TopDictOperator::SyntheticBase:
dbgln("CFF: has unimplemented SyntheticBase, might not look right");
break;
case TopDictOperator::Encoding: {
if (!operands.is_empty())
encoding_offset = operands[0].get<int>();
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) };
TRY(parse_index(subrs_reader, [&](ReadonlyBytes const& subroutine_bytes) -> PDFErrorOr<void> {
return TRY(local_subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
}));
dbgln_if(CFF_DEBUG, "CFF has {} subr entries", local_subroutines.size());
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:
dbgln("CFF: Unhandled top dict entry {}", static_cast<int>(op));
}
return {};
});
}));
auto strings = TRY(parse_strings(reader));
// CFF spec "16 Local/Global Subrs INDEXes"
// "Global subrs are stored in an INDEX structure which follows the String INDEX."
Vector<ByteBuffer> global_subroutines;
TRY(parse_index(reader, [&](ReadonlyBytes const& subroutine_bytes) -> PDFErrorOr<void> {
return TRY(global_subroutines.try_append(TRY(ByteBuffer::copy(subroutine_bytes))));
}));
dbgln_if(CFF_DEBUG, "CFF has {} gsubr entries", global_subroutines.size());
// 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)), local_subroutines, global_subroutines));
// CFF spec, "Table 16 Encoding ID"
// FIXME: Only read this if the built-in encoding is actually needed? (ie. `if (!encoding)`)
Vector<u8> encoding_codes; // Maps GID to its codepoint.
HashMap<Card8, SID> encoding_supplemental; // Maps codepoint to SID.
switch (encoding_offset) {
case 0:
dbgln_if(CFF_DEBUG, "CFF predefined encoding Standard");
for (size_t i = 1; i < s_predefined_encoding_standard.size(); ++i)
TRY(encoding_supplemental.try_set(i, s_predefined_encoding_standard[i]));
break;
case 1:
dbgln_if(CFF_DEBUG, "CFF predefined encoding Expert");
for (size_t i = 1; i < s_predefined_encoding_expert.size(); ++i)
TRY(encoding_supplemental.try_set(i, s_predefined_encoding_expert[i]));
break;
default:
encoding_codes = TRY(parse_encoding(Reader(cff_bytes.slice(encoding_offset)), encoding_supplemental));
break;
}
// CFF spec, "Table 22 Charset ID"
Vector<DeprecatedFlyString> charset;
switch (charset_offset) {
case 0:
dbgln_if(CFF_DEBUG, "CFF predefined charset ISOAdobe");
// 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:
dbgln_if(CFF_DEBUG, "CFF predefined charset Expert");
for (SID sid : s_predefined_charset_expert)
TRY(charset.try_append(resolve_sid(sid, strings)));
break;
case 2:
dbgln_if(CFF_DEBUG, "CFF predefined charset Expert Subset");
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;
}
if (i >= encoding_codes.size() || i >= charset.size())
break;
auto code = encoding_codes[i - 1];
auto char_name = charset[i - 1];
encoding->set(code, char_name);
}
for (auto const& entry : encoding_supplemental)
encoding->set(entry.key, resolve_sid(entry.value, strings));
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));
}));
dbgln_if(CFF_DEBUG, "CFF has {} additional strings in string table", strings.size());
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"
dbgln_if(CFF_DEBUG, "CFF charset format 0");
for (size_t 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"
dbgln_if(CFF_DEBUG, "CFF charset 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 && names.size() < glyph_count - 1; 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."
dbgln_if(CFF_DEBUG, "CFF charset format 2");
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 && names.size() < glyph_count - 1; 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& local_subroutines, Vector<ByteBuffer> const& global_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, local_subroutines, global_subroutines, state, true));
return TRY(glyphs.try_append(glyph));
}));
dbgln_if(CFF_DEBUG, "CFF has {} glyphs", glyphs.size());
return glyphs;
}
PDFErrorOr<Vector<u8>> CFF::parse_encoding(Reader&& reader, HashMap<Card8, SID>& supplemental)
{
// CFF spec, "12 Encodings"
Vector<u8> encoding_codes;
auto format_raw = TRY(reader.try_read<Card8>());
auto format = format_raw & 0x7f;
if (format == 0) {
// CFF spec, "Table 11 Format 0"
auto n_codes = TRY(reader.try_read<Card8>());
dbgln_if(CFF_DEBUG, "CFF encoding format 0, {} codes", n_codes);
for (u8 i = 0; i < n_codes; i++) {
TRY(encoding_codes.try_append(TRY(reader.try_read<Card8>())));
}
} else if (format == 1) {
// CFF spec, "Table 12 Format 1"
auto n_ranges = TRY(reader.try_read<Card8>());
dbgln_if(CFF_DEBUG, "CFF encoding format 1, {} ranges", n_ranges);
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));
if (format_raw & 0x80) {
// CFF spec, "Table 14 Supplemental Encoding Data"
auto n_sups = TRY(reader.try_read<Card8>());
dbgln_if(CFF_DEBUG, "CFF encoding, {} supplemental entries", n_sups);
for (u8 i = 0; i < n_sups; i++) {
// CFF spec, "Table 15 Supplement Format"
auto code = TRY(reader.try_read<Card8>());
SID name = TRY(reader.try_read<SID>());
TRY(supplemental.try_set(code, name));
}
}
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 > 4)
return error("CFF INDEX Data offset_size > 4 not supported");
return parse_index_data(offset_size, count, reader, data_handler);
}
PDFErrorOr<void> CFF::parse_index_data(OffSize offset_size, Card16 count, Reader& reader, IndexDataHandler& handler)
{
// CFF spec, "5 INDEX Data"
u32 last_data_end = 1;
auto read_offset = [&]() -> PDFErrorOr<u32> {
u32 offset = 0;
for (OffSize i = 0; i < offset_size; ++i)
offset = (offset << 8) | TRY(reader.try_read<u8>());
return offset;
};
auto offset_refpoint = reader.offset() + offset_size * (count + 1) - 1;
for (u16 i = 0; i < count; i++) {
reader.save();
reader.move_by(offset_size * i);
u32 data_start = TRY(read_offset());
last_data_end = TRY(read_offset());
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 {};
}
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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