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Fix searching for end of inline (EI) images with ASCII85Decode filters (bug 1077808)

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This patch changes searching for the end of inline image streams to rely on the EOD marker for the filters: ASCII85Decode and ASCIIHexDecode.
This commit is contained in:
Jonas Jenwald 2014-10-05 00:12:47 +02:00
parent f5df30f967
commit 184880a751
3 changed files with 129 additions and 38 deletions
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157
src/core/parser.js
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@ -126,17 +126,117 @@ var Parser = (function ParserClosure() {
// simple object
return buf1;
},
/**
* Find the end of the stream by searching for the /EI\s/.
* @returns {number} The inline stream length.
*/
findDefaultInlineStreamEnd:
function Parser_findDefaultInlineStreamEnd(stream) {
var E = 0x45, I = 0x49, SPACE = 0x20, LF = 0xA, CR = 0xD;
var startPos = stream.pos, state = 0, ch, i, n, followingBytes;
while ((ch = stream.getByte()) !== -1) {
if (state === 0) {
state = (ch === E) ? 1 : 0;
} else if (state === 1) {
state = (ch === I) ? 2 : 0;
} else {
assert(state === 2);
if (ch === SPACE || ch === LF || ch === CR) {
// Let's check the next five bytes are ASCII... just be sure.
n = 5;
followingBytes = stream.peekBytes(n);
for (i = 0; i < n; i++) {
ch = followingBytes[i];
if (ch !== LF && ch !== CR && (ch < SPACE || ch > 0x7F)) {
// Not a LF, CR, SPACE or any visible ASCII character, i.e.
// it's binary stuff. Resetting the state.
state = 0;
break;
}
}
if (state === 2) {
break; // Finished!
}
} else {
state = 0;
}
}
}
return ((stream.pos - 4) - startPos);
},
/**
* Find the EOD (end-of-data) marker '~>' (i.e. TILDE + GT) of the stream.
* @returns {number} The inline stream length.
*/
findASCII85DecodeInlineStreamEnd:
function Parser_findASCII85DecodeInlineStreamEnd(stream) {
var TILDE = 0x7E, GT = 0x3E;
var startPos = stream.pos, ch, length;
while ((ch = stream.getByte()) !== -1) {
if (ch === TILDE && stream.peekByte() === GT) {
stream.skip();
break;
}
}
length = stream.pos - startPos;
if (ch === -1) {
warn('Inline ASCII85Decode image stream: ' +
'EOD marker not found, searching for /EI/ instead.');
stream.skip(-length); // Reset the stream position.
return this.findDefaultInlineStreamEnd(stream);
}
this.inlineStreamSkipEI(stream);
return length;
},
/**
* Find the EOD (end-of-data) marker '>' (i.e. GT) of the stream.
* @returns {number} The inline stream length.
*/
findASCIIHexDecodeInlineStreamEnd:
function Parser_findASCIIHexDecodeInlineStreamEnd(stream) {
var GT = 0x3E;
var startPos = stream.pos, ch, length;
while ((ch = stream.getByte()) !== -1) {
if (ch === GT) {
break;
}
}
length = stream.pos - startPos;
if (ch === -1) {
warn('Inline ASCIIHexDecode image stream: ' +
'EOD marker not found, searching for /EI/ instead.');
stream.skip(-length); // Reset the stream position.
return this.findDefaultInlineStreamEnd(stream);
}
this.inlineStreamSkipEI(stream);
return length;
},
/**
* Skip over the /EI/ for streams where we search for an EOD marker.
*/
inlineStreamSkipEI: function Parser_inlineStreamSkipEI(stream) {
var E = 0x45, I = 0x49;
var state = 0, ch;
while ((ch = stream.getByte()) !== -1) {
if (state === 0) {
state = (ch === E) ? 1 : 0;
} else if (state === 1) {
state = (ch === I) ? 2 : 0;
} else if (state === 2) {
break;
}
}
},
makeInlineImage: function Parser_makeInlineImage(cipherTransform) {
var lexer = this.lexer;
var stream = lexer.stream;
// parse dictionary
// Parse dictionary.
var dict = new Dict(null);
while (!isCmd(this.buf1, 'ID') && !isEOF(this.buf1)) {
if (!isName(this.buf1)) {
error('Dictionary key must be a name object');
}
var key = this.buf1.name;
this.shift();
if (isEOF(this.buf1)) {
@ -145,45 +245,26 @@ var Parser = (function ParserClosure() {
dict.set(key, this.getObj(cipherTransform));
}
// parse image stream
var startPos = stream.pos;
// searching for the /EI\s/
var state = 0, ch, i, ii;
var E = 0x45, I = 0x49, SPACE = 0x20, NL = 0xA, CR = 0xD;
while ((ch = stream.getByte()) !== -1) {
if (state === 0) {
state = (ch === E) ? 1 : 0;
} else if (state === 1) {
state = (ch === I) ? 2 : 0;
} else {
assert(state === 2);
if (ch === SPACE || ch === NL || ch === CR) {
// Let's check the next five bytes are ASCII... just be sure.
var n = 5;
var followingBytes = stream.peekBytes(n);
for (i = 0; i < n; i++) {
ch = followingBytes[i];
if (ch !== NL && ch !== CR && (ch < SPACE || ch > 0x7F)) {
// Not a LF, CR, SPACE or any visible ASCII character, i.e.
// it's binary stuff. Resetting the state.
state = 0;
break;
}
}
if (state === 2) {
break; // finished!
}
} else {
state = 0;
}
}
// Extract the name of the first (i.e. the current) image filter.
var filter = this.fetchIfRef(dict.get('Filter', 'F')), filterName;
if (isName(filter)) {
filterName = filter.name;
} else if (isArray(filter) && isName(filter[0])) {
filterName = filter[0].name;
}
var length = (stream.pos - 4) - startPos;
// Parse image stream.
var startPos = stream.pos, length, i, ii;
if (filterName === 'ASCII85Decide' || filterName === 'A85') {
length = this.findASCII85DecodeInlineStreamEnd(stream);
} else if (filterName === 'ASCIIHexDecode' || filterName === 'AHx') {
length = this.findASCIIHexDecodeInlineStreamEnd(stream);
} else {
length = this.findDefaultInlineStreamEnd(stream);
}
var imageStream = stream.makeSubStream(startPos, length, dict);
// cache all images below the MAX_LENGTH_TO_CACHE threshold by their
// Cache all images below the MAX_LENGTH_TO_CACHE threshold by their
// adler32 checksum.
var adler32;
if (length < MAX_LENGTH_TO_CACHE) {
@ -193,7 +274,7 @@ var Parser = (function ParserClosure() {
var a = 1;
var b = 0;
for (i = 0, ii = imageBytes.length; i < ii; ++i) {
// no modulo required in the loop if imageBytes.length < 5552
// No modulo required in the loop if imageBytes.length < 5552.
a += imageBytes[i] & 0xff;
b += a;
}

1
test/pdfs/bug1077808.pdf.link Normal file
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@ -0,0 +1 @@
https://bug1077808.bugzilla.mozilla.org/attachment.cgi?id=8499998

9
test/test_manifest.json
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@ -1524,6 +1524,15 @@
"type": "eq",
"about": "Type3 font with negative HScale and font size"
},
{ "id": "bug1077808",
"file": "pdfs/bug1077808.pdf",
"md5": "4a4bfc27e3fafe2f74e7a4a4cd04b8dc",
"rounds": 1,
"lastPage": 1,
"link": true,
"type": "eq",
"about": "Inline image with ASCII85Decode filter."
},
{ "id": "bug1108753",
"file": "pdfs/bug1108753.pdf",
"md5": "a7aaf92d55b4602afb0ca3d75198b56b",