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Merge pull request #7066 from Snuffleupagus/Type1-headerBlockLength

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Parse Type1 font files to determine the various `Length{n}` properties, instead of trusting the PDF file (issue 5686, issue 3928)
This commit is contained in:
Brendan Dahl 2016-03-31 09:25:16 -07:00
commit 8910cea7d6
6 changed files with 355 additions and 213 deletions
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2
src/core/evaluator.js
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@ -2197,6 +2197,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
}
var length1 = fontFile.dict.get('Length1');
var length2 = fontFile.dict.get('Length2');
var length3 = fontFile.dict.get('Length3');
}
}
@ -2207,6 +2208,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
file: fontFile,
length1: length1,
length2: length2,
length3: length3,
loadedName: baseDict.loadedName,
composite: composite,
wideChars: composite,

548
src/core/fonts.js
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@ -54,6 +54,7 @@ var shadow = sharedUtil.shadow;
var stringToBytes = sharedUtil.stringToBytes;
var string32 = sharedUtil.string32;
var warn = sharedUtil.warn;
var MissingDataException = sharedUtil.MissingDataException;
var Stream = coreStream.Stream;
var Lexer = coreParser.Lexer;
var getGlyphsUnicode = coreGlyphList.getGlyphsUnicode;
@ -3637,231 +3638,352 @@ var CFFStandardStrings = [
];
// Type1Font is also a CIDFontType0.
var Type1Font = function Type1Font(name, file, properties) {
// Some bad generators embed pfb file as is, we have to strip 6-byte headers.
// Also, length1 and length2 might be off by 6 bytes as well.
// http://www.math.ubc.ca/~cass/piscript/type1.pdf
var PFB_HEADER_SIZE = 6;
var headerBlockLength = properties.length1;
var eexecBlockLength = properties.length2;
var pfbHeader = file.peekBytes(PFB_HEADER_SIZE);
var pfbHeaderPresent = pfbHeader[0] === 0x80 && pfbHeader[1] === 0x01;
if (pfbHeaderPresent) {
file.skip(PFB_HEADER_SIZE);
headerBlockLength = (pfbHeader[5] << 24) | (pfbHeader[4] << 16) |
(pfbHeader[3] << 8) | pfbHeader[2];
}
var Type1Font = (function Type1FontClosure() {
function findBlock(streamBytes, signature, startIndex) {
var streamBytesLength = streamBytes.length;
var signatureLength = signature.length;
var scanLength = streamBytesLength - signatureLength;
// Get the data block containing glyphs and subrs informations
var headerBlock = new Stream(file.getBytes(headerBlockLength));
var headerBlockParser = new Type1Parser(headerBlock);
headerBlockParser.extractFontHeader(properties);
if (pfbHeaderPresent) {
pfbHeader = file.getBytes(PFB_HEADER_SIZE);
eexecBlockLength = (pfbHeader[5] << 24) | (pfbHeader[4] << 16) |
(pfbHeader[3] << 8) | pfbHeader[2];
}
// Decrypt the data blocks and retrieve it's content
var eexecBlock = new Stream(file.getBytes(eexecBlockLength));
var eexecBlockParser = new Type1Parser(eexecBlock, true);
var data = eexecBlockParser.extractFontProgram();
for (var info in data.properties) {
properties[info] = data.properties[info];
}
var charstrings = data.charstrings;
var type2Charstrings = this.getType2Charstrings(charstrings);
var subrs = this.getType2Subrs(data.subrs);
this.charstrings = charstrings;
this.data = this.wrap(name, type2Charstrings, this.charstrings,
subrs, properties);
this.seacs = this.getSeacs(data.charstrings);
};
Type1Font.prototype = {
get numGlyphs() {
return this.charstrings.length + 1;
},
getCharset: function Type1Font_getCharset() {
var charset = ['.notdef'];
var charstrings = this.charstrings;
for (var glyphId = 0; glyphId < charstrings.length; glyphId++) {
charset.push(charstrings[glyphId].glyphName);
var i = startIndex, j, found = false;
while (i < scanLength) {
j = 0;
while (j < signatureLength && streamBytes[i + j] === signature[j]) {
j++;
}
if (j >= signatureLength) { // `signature` found, skip over whitespace.
i += j;
while (i < streamBytesLength && Lexer.isSpace(streamBytes[i])) {
i++;
}
found = true;
break;
}
i++;
}
return charset;
},
return {
found: found,
length: i,
};
}
getGlyphMapping: function Type1Font_getGlyphMapping(properties) {
var charstrings = this.charstrings;
var glyphNames = ['.notdef'], glyphId;
for (glyphId = 0; glyphId < charstrings.length; glyphId++) {
glyphNames.push(charstrings[glyphId].glyphName);
function getHeaderBlock(stream, suggestedLength) {
var EEXEC_SIGNATURE = [0x65, 0x65, 0x78, 0x65, 0x63];
var streamStartPos = stream.pos; // Save the initial stream position.
var headerBytes, headerBytesLength, block;
try {
headerBytes = stream.getBytes(suggestedLength);
headerBytesLength = headerBytes.length;
} catch (ex) {
if (ex instanceof MissingDataException) {
throw ex;
}
// Ignore errors if the `suggestedLength` is huge enough that a Uint8Array
// cannot hold the result of `getBytes`, and fallback to simply checking
// the entire stream (fixes issue3928.pdf).
}
var encoding = properties.builtInEncoding;
if (encoding) {
var builtInEncoding = Object.create(null);
for (var charCode in encoding) {
glyphId = glyphNames.indexOf(encoding[charCode]);
if (glyphId >= 0) {
builtInEncoding[charCode] = glyphId;
if (headerBytesLength === suggestedLength) {
// Most of the time `suggestedLength` is correct, so to speed things up we
// initially only check the last few bytes to see if the header was found.
// Otherwise we (potentially) check the entire stream to prevent errors in
// `Type1Parser` (fixes issue5686.pdf).
block = findBlock(headerBytes, EEXEC_SIGNATURE,
suggestedLength - 2 * EEXEC_SIGNATURE.length);
if (block.found && block.length === suggestedLength) {
return {
stream: new Stream(headerBytes),
length: suggestedLength,
};
}
}
warn('Invalid "Length1" property in Type1 font -- trying to recover.');
stream.pos = streamStartPos; // Reset the stream position.
var SCAN_BLOCK_LENGTH = 2048;
var actualLength;
while (true) {
var scanBytes = stream.peekBytes(SCAN_BLOCK_LENGTH);
block = findBlock(scanBytes, EEXEC_SIGNATURE, 0);
if (block.length === 0) {
break;
}
stream.pos += block.length; // Update the stream position.
if (block.found) {
actualLength = stream.pos - streamStartPos;
break;
}
}
stream.pos = streamStartPos; // Reset the stream position.
if (actualLength) {
return {
stream: new Stream(stream.getBytes(actualLength)),
length: actualLength,
};
}
warn('Unable to recover "Length1" property in Type1 font -- using as is.');
return {
stream: new Stream(stream.getBytes(suggestedLength)),
length: suggestedLength,
};
}
function getEexecBlock(stream, suggestedLength) {
// We should ideally parse the eexec block to ensure that `suggestedLength`
// is correct, so we don't truncate the block data if it's too small.
// However, this would also require checking if the fixed-content portion
// exists (using the 'Length3' property), and ensuring that it's valid.
//
// Given that `suggestedLength` almost always is correct, all the validation
// would require a great deal of unnecessary parsing for most fonts.
// To save time, we always fetch the entire stream instead, which also avoid
// issues if `suggestedLength` is huge (see comment in `getHeaderBlock`).
//
// NOTE: This means that the function can include the fixed-content portion
// in the returned eexec block. In practice this does *not* seem to matter,
// since `Type1Parser_extractFontProgram` will skip over any non-commands.
var eexecBytes = stream.getBytes();
return {
stream: new Stream(eexecBytes),
length: eexecBytes.length,
};
}
function Type1Font(name, file, properties) {
// Some bad generators embed pfb file as is, we have to strip 6-byte header.
// Also, length1 and length2 might be off by 6 bytes as well.
// http://www.math.ubc.ca/~cass/piscript/type1.pdf
var PFB_HEADER_SIZE = 6;
var headerBlockLength = properties.length1;
var eexecBlockLength = properties.length2;
var pfbHeader = file.peekBytes(PFB_HEADER_SIZE);
var pfbHeaderPresent = pfbHeader[0] === 0x80 && pfbHeader[1] === 0x01;
if (pfbHeaderPresent) {
file.skip(PFB_HEADER_SIZE);
headerBlockLength = (pfbHeader[5] << 24) | (pfbHeader[4] << 16) |
(pfbHeader[3] << 8) | pfbHeader[2];
}
// Get the data block containing glyphs and subrs informations
var headerBlock = getHeaderBlock(file, headerBlockLength);
headerBlockLength = headerBlock.length;
var headerBlockParser = new Type1Parser(headerBlock.stream);
headerBlockParser.extractFontHeader(properties);
if (pfbHeaderPresent) {
pfbHeader = file.getBytes(PFB_HEADER_SIZE);
eexecBlockLength = (pfbHeader[5] << 24) | (pfbHeader[4] << 16) |
(pfbHeader[3] << 8) | pfbHeader[2];
}
// Decrypt the data blocks and retrieve it's content
var eexecBlock = getEexecBlock(file, eexecBlockLength);
eexecBlockLength = eexecBlock.length;
var eexecBlockParser = new Type1Parser(eexecBlock.stream, true);
var data = eexecBlockParser.extractFontProgram();
for (var info in data.properties) {
properties[info] = data.properties[info];
}
var charstrings = data.charstrings;
var type2Charstrings = this.getType2Charstrings(charstrings);
var subrs = this.getType2Subrs(data.subrs);
this.charstrings = charstrings;
this.data = this.wrap(name, type2Charstrings, this.charstrings,
subrs, properties);
this.seacs = this.getSeacs(data.charstrings);
}
Type1Font.prototype = {
get numGlyphs() {
return this.charstrings.length + 1;
},
getCharset: function Type1Font_getCharset() {
var charset = ['.notdef'];
var charstrings = this.charstrings;
for (var glyphId = 0; glyphId < charstrings.length; glyphId++) {
charset.push(charstrings[glyphId].glyphName);
}
return charset;
},
getGlyphMapping: function Type1Font_getGlyphMapping(properties) {
var charstrings = this.charstrings;
var glyphNames = ['.notdef'], glyphId;
for (glyphId = 0; glyphId < charstrings.length; glyphId++) {
glyphNames.push(charstrings[glyphId].glyphName);
}
var encoding = properties.builtInEncoding;
if (encoding) {
var builtInEncoding = Object.create(null);
for (var charCode in encoding) {
glyphId = glyphNames.indexOf(encoding[charCode]);
if (glyphId >= 0) {
builtInEncoding[charCode] = glyphId;
}
}
}
}
return type1FontGlyphMapping(properties, builtInEncoding, glyphNames);
},
return type1FontGlyphMapping(properties, builtInEncoding, glyphNames);
},
getSeacs: function Type1Font_getSeacs(charstrings) {
var i, ii;
var seacMap = [];
for (i = 0, ii = charstrings.length; i < ii; i++) {
var charstring = charstrings[i];
if (charstring.seac) {
// Offset by 1 for .notdef
seacMap[i + 1] = charstring.seac;
}
}
return seacMap;
},
getType2Charstrings: function Type1Font_getType2Charstrings(
type1Charstrings) {
var type2Charstrings = [];
for (var i = 0, ii = type1Charstrings.length; i < ii; i++) {
type2Charstrings.push(type1Charstrings[i].charstring);
}
return type2Charstrings;
},
getType2Subrs: function Type1Font_getType2Subrs(type1Subrs) {
var bias = 0;
var count = type1Subrs.length;
if (count < 1133) {
bias = 107;
} else if (count < 33769) {
bias = 1131;
} else {
bias = 32768;
}
// Add a bunch of empty subrs to deal with the Type2 bias
var type2Subrs = [];
var i;
for (i = 0; i < bias; i++) {
type2Subrs.push([0x0B]);
}
for (i = 0; i < count; i++) {
type2Subrs.push(type1Subrs[i]);
}
return type2Subrs;
},
wrap: function Type1Font_wrap(name, glyphs, charstrings, subrs, properties) {
var cff = new CFF();
cff.header = new CFFHeader(1, 0, 4, 4);
cff.names = [name];
var topDict = new CFFTopDict();
// CFF strings IDs 0...390 are predefined names, so refering
// to entries in our own String INDEX starts at SID 391.
topDict.setByName('version', 391);
topDict.setByName('Notice', 392);
topDict.setByName('FullName', 393);
topDict.setByName('FamilyName', 394);
topDict.setByName('Weight', 395);
topDict.setByName('Encoding', null); // placeholder
topDict.setByName('FontMatrix', properties.fontMatrix);
topDict.setByName('FontBBox', properties.bbox);
topDict.setByName('charset', null); // placeholder
topDict.setByName('CharStrings', null); // placeholder
topDict.setByName('Private', null); // placeholder
cff.topDict = topDict;
var strings = new CFFStrings();
strings.add('Version 0.11'); // Version
strings.add('See original notice'); // Notice
strings.add(name); // FullName
strings.add(name); // FamilyName
strings.add('Medium'); // Weight
cff.strings = strings;
cff.globalSubrIndex = new CFFIndex();
var count = glyphs.length;
var charsetArray = [0];
var i, ii;
for (i = 0; i < count; i++) {
var index = CFFStandardStrings.indexOf(charstrings[i].glyphName);
// TODO: Insert the string and correctly map it. Previously it was
// thought mapping names that aren't in the standard strings to .notdef
// was fine, however in issue818 when mapping them all to .notdef the
// adieresis glyph no longer worked.
if (index === -1) {
index = 0;
}
charsetArray.push((index >> 8) & 0xff, index & 0xff);
}
cff.charset = new CFFCharset(false, 0, [], charsetArray);
var charStringsIndex = new CFFIndex();
charStringsIndex.add([0x8B, 0x0E]); // .notdef
for (i = 0; i < count; i++) {
charStringsIndex.add(glyphs[i]);
}
cff.charStrings = charStringsIndex;
var privateDict = new CFFPrivateDict();
privateDict.setByName('Subrs', null); // placeholder
var fields = [
'BlueValues',
'OtherBlues',
'FamilyBlues',
'FamilyOtherBlues',
'StemSnapH',
'StemSnapV',
'BlueShift',
'BlueFuzz',
'BlueScale',
'LanguageGroup',
'ExpansionFactor',
'ForceBold',
'StdHW',
'StdVW'
];
for (i = 0, ii = fields.length; i < ii; i++) {
var field = fields[i];
if (!(field in properties.privateData)) {
continue;
}
var value = properties.privateData[field];
if (isArray(value)) {
// All of the private dictionary array data in CFF must be stored as
// "delta-encoded" numbers.
for (var j = value.length - 1; j > 0; j--) {
value[j] -= value[j - 1]; // ... difference from previous value
getSeacs: function Type1Font_getSeacs(charstrings) {
var i, ii;
var seacMap = [];
for (i = 0, ii = charstrings.length; i < ii; i++) {
var charstring = charstrings[i];
if (charstring.seac) {
// Offset by 1 for .notdef
seacMap[i + 1] = charstring.seac;
}
}
privateDict.setByName(field, value);
}
cff.topDict.privateDict = privateDict;
return seacMap;
},
var subrIndex = new CFFIndex();
for (i = 0, ii = subrs.length; i < ii; i++) {
subrIndex.add(subrs[i]);
}
privateDict.subrsIndex = subrIndex;
getType2Charstrings: function Type1Font_getType2Charstrings(
type1Charstrings) {
var type2Charstrings = [];
for (var i = 0, ii = type1Charstrings.length; i < ii; i++) {
type2Charstrings.push(type1Charstrings[i].charstring);
}
return type2Charstrings;
},
var compiler = new CFFCompiler(cff);
return compiler.compile();
}
};
getType2Subrs: function Type1Font_getType2Subrs(type1Subrs) {
var bias = 0;
var count = type1Subrs.length;
if (count < 1133) {
bias = 107;
} else if (count < 33769) {
bias = 1131;
} else {
bias = 32768;
}
// Add a bunch of empty subrs to deal with the Type2 bias
var type2Subrs = [];
var i;
for (i = 0; i < bias; i++) {
type2Subrs.push([0x0B]);
}
for (i = 0; i < count; i++) {
type2Subrs.push(type1Subrs[i]);
}
return type2Subrs;
},
wrap: function Type1Font_wrap(name, glyphs, charstrings, subrs,
properties) {
var cff = new CFF();
cff.header = new CFFHeader(1, 0, 4, 4);
cff.names = [name];
var topDict = new CFFTopDict();
// CFF strings IDs 0...390 are predefined names, so refering
// to entries in our own String INDEX starts at SID 391.
topDict.setByName('version', 391);
topDict.setByName('Notice', 392);
topDict.setByName('FullName', 393);
topDict.setByName('FamilyName', 394);
topDict.setByName('Weight', 395);
topDict.setByName('Encoding', null); // placeholder
topDict.setByName('FontMatrix', properties.fontMatrix);
topDict.setByName('FontBBox', properties.bbox);
topDict.setByName('charset', null); // placeholder
topDict.setByName('CharStrings', null); // placeholder
topDict.setByName('Private', null); // placeholder
cff.topDict = topDict;
var strings = new CFFStrings();
strings.add('Version 0.11'); // Version
strings.add('See original notice'); // Notice
strings.add(name); // FullName
strings.add(name); // FamilyName
strings.add('Medium'); // Weight
cff.strings = strings;
cff.globalSubrIndex = new CFFIndex();
var count = glyphs.length;
var charsetArray = [0];
var i, ii;
for (i = 0; i < count; i++) {
var index = CFFStandardStrings.indexOf(charstrings[i].glyphName);
// TODO: Insert the string and correctly map it. Previously it was
// thought mapping names that aren't in the standard strings to .notdef
// was fine, however in issue818 when mapping them all to .notdef the
// adieresis glyph no longer worked.
if (index === -1) {
index = 0;
}
charsetArray.push((index >> 8) & 0xff, index & 0xff);
}
cff.charset = new CFFCharset(false, 0, [], charsetArray);
var charStringsIndex = new CFFIndex();
charStringsIndex.add([0x8B, 0x0E]); // .notdef
for (i = 0; i < count; i++) {
charStringsIndex.add(glyphs[i]);
}
cff.charStrings = charStringsIndex;
var privateDict = new CFFPrivateDict();
privateDict.setByName('Subrs', null); // placeholder
var fields = [
'BlueValues',
'OtherBlues',
'FamilyBlues',
'FamilyOtherBlues',
'StemSnapH',
'StemSnapV',
'BlueShift',
'BlueFuzz',
'BlueScale',
'LanguageGroup',
'ExpansionFactor',
'ForceBold',
'StdHW',
'StdVW'
];
for (i = 0, ii = fields.length; i < ii; i++) {
var field = fields[i];
if (!(field in properties.privateData)) {
continue;
}
var value = properties.privateData[field];
if (isArray(value)) {
// All of the private dictionary array data in CFF must be stored as
// "delta-encoded" numbers.
for (var j = value.length - 1; j > 0; j--) {
value[j] -= value[j - 1]; // ... difference from previous value
}
}
privateDict.setByName(field, value);
}
cff.topDict.privateDict = privateDict;
var subrIndex = new CFFIndex();
for (i = 0, ii = subrs.length; i < ii; i++) {
subrIndex.add(subrs[i]);
}
privateDict.subrsIndex = subrIndex;
var compiler = new CFFCompiler(cff);
return compiler.compile();
}
};
return Type1Font;
})();
var CFFFont = (function CFFFontClosure() {
function CFFFont(file, properties) {

2
test/pdfs/.gitignore vendored
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@ -49,6 +49,8 @@
!issue3207r.pdf
!issue3263r.pdf
!issue3879r.pdf
!issue5686.pdf
!issue3928.pdf
!close-path-bug.pdf
!issue6019.pdf
!issue6621.pdf

BIN
test/pdfs/issue3928.pdf Normal file
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BIN
test/pdfs/issue5686.pdf Normal file
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16
test/test_manifest.json
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@ -1443,6 +1443,22 @@
"link": false,
"type": "eq"
},
{ "id": "issue5686",
"file": "pdfs/issue5686.pdf",
"md5": "78d16b9df07a355ad00d70504a9194f8",
"rounds": 1,
"link": false,
"type": "eq",
"about": "Type1 font where Length1/Length2 are slightly incorrect."
},
{ "id": "issue3928",
"file": "pdfs/issue3928.pdf",
"md5": "1963493f843e981cbe768b707ef7f08a",
"rounds": 1,
"link": false,
"type": "eq",
"about": "Type1 font where Length1/Length2 are several orders of magnitude too large."
},
{ "id": "html5checker",
"file": "pdfs/html5checker.pdf",
"md5": "74bbd80d1e7eb5f2951582233ef9ebab",