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parse startxref

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This commit is contained in:
Andreas Gal 2011-05-06 01:16:09 -07:00
parent b860bc8d60
commit 16bc5f6fe3
1 changed files with 53 additions and 25 deletions
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78
pdf.js
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@ -27,6 +27,9 @@ var Stream = (function() {
} }
constructor.prototype = { constructor.prototype = {
get length() {
return this.bytes.length;
},
reset: function() { reset: function() {
this.pos = 0; this.pos = 0;
}, },
@ -39,7 +42,7 @@ var Stream = (function() {
getChar: function() { getChar: function() {
var ch = this.lookChar(); var ch = this.lookChar();
this.pos++; this.pos++;
return ch; return String.fromCharCode(ch);
}, },
putBack: function() { putBack: function() {
this.pos--; this.pos--;
@ -47,9 +50,26 @@ var Stream = (function() {
skipChar: function() { skipChar: function() {
this.pos++; this.pos++;
}, },
moveStart: function(delta) { skip: function(n) {
this.bytes = Uint8Array(arrayBuffer, delta); this.pos += n;
this.pos -= delta; },
moveStart: function() {
this.bytes = Uint8Array(bytes, pos);
this.pos = 0;
},
find: function(str, limit, backwards) {
var length = this.bytes.length;
var pos = this.pos;
var str = "";
if (pos + limit > length)
limit = length - pos;
for (var n = 0; n < limit; ++n)
str += this.getChar();
var index = backwards ? str.lastIndexOf(str) : str.indexOf(str);
if (index == -1)
return false; /* not found */
this.pos += index;
return true; /* found */
} }
}; };
@ -598,41 +618,49 @@ var PDFDoc = (function () {
if (linearization.length != length) if (linearization.length != length)
linearization = false; linearization = false;
} }
// shadow the prototype getter // shadow the prototype getter with a data property
return this.linearization = linearization; return this.linearization = linearization;
}, },
get startXRef() { get startXRef() {
var startXRef; var startXRef = 0;
var linearization = this.linearization; var linearization = this.linearization;
if (linearization) { if (linearization) {
// TODO // Find end of first obj.
stream.reset();
if (stream.find("endobj", 1024))
startXRef = stream.pos + 6;
} else { } else {
// TODO // Find startxref at the end of the file.
var start = stream.length - 1024;
if (start < 0)
start = 0;
stream.pos = start;
if (stream.find("startxref", 1024, true)) {
stream.skip(9);
var ch;
while ((ch = stream.getChar()) == " " || ch == "\t")
;
var str = "";
while ((ch - "0") <= 9) {
str += ch;
ch = stream.getChar();
}
startXRef = parseNumber(str);
if (isNaN(startXRef))
startXRef = 0;
}
} }
// shadow the prototype getter // shadow the prototype getter with a data property
return this.startXRef = startXRef; return this.startXRef = startXRef;
}, },
// Find the header, remove leading garbage and setup the stream // Find the header, remove leading garbage and setup the stream
// starting from the header. // starting from the header.
checkHeader: function(stream) { checkHeader: function(stream) {
const headerSearchSize = 1024;
stream.reset(); stream.reset();
if (stream.find("%PDF-", 1024)) {
var skip = 0;
var header = "%PDF-";
while (skip < headerSearchSize) {
stream.setPos(skip);
for (var i = 0; i < header.length; ++i) {
if (stream.getChar() != header.charCodeAt(i))
break;
}
// Found the header, trim off any garbage before it. // Found the header, trim off any garbage before it.
if (i == header.length) { stream.moveStart();
stream.moveStart(skip); return;
return;
}
} }
// May not be a PDF file, continue anyway. // May not be a PDF file, continue anyway.