Sakurai/pdf.js
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Don't get bytes eagerly when creating FlateStream objects.

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This commit is contained in:
Nicholas Nethercote 2014-03-06 17:51:44 -08:00
parent d0253c8291
commit ea17749b93
1 changed files with 23 additions and 26 deletions
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49
src/core/stream.js
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@ -328,13 +328,12 @@ var FlateStream = (function FlateStreamClosure() {
0x50003, 0x50013, 0x5000b, 0x5001b, 0x50007, 0x50017, 0x5000f, 0x00000
]), 5];
function FlateStream(stream) {
var bytes = stream.getBytes();
var bytesPos = 0;
function FlateStream(str) {
this.str = str;
this.dict = str.dict;
this.dict = stream.dict;
var cmf = bytes[bytesPos++];
var flg = bytes[bytesPos++];
var cmf = str.getByte();
var flg = str.getByte();
if (cmf == -1 || flg == -1)
error('Invalid header in flate stream: ' + cmf + ', ' + flg);
if ((cmf & 0x0f) != 0x08)
@ -344,9 +343,6 @@ var FlateStream = (function FlateStreamClosure() {
if (flg & 0x20)
error('FDICT bit set in flate stream: ' + cmf + ', ' + flg);
this.bytes = bytes;
this.bytesPos = bytesPos;
this.codeSize = 0;
this.codeBuf = 0;
@ -356,37 +352,37 @@ var FlateStream = (function FlateStreamClosure() {
FlateStream.prototype = Object.create(DecodeStream.prototype);
FlateStream.prototype.getBits = function FlateStream_getBits(bits) {
var str = this.str;
var codeSize = this.codeSize;
var codeBuf = this.codeBuf;
var bytes = this.bytes;
var bytesPos = this.bytesPos;
var b;
while (codeSize < bits) {
if (typeof (b = bytes[bytesPos++]) == 'undefined')
if ((b = str.getByte()) === -1) {
error('Bad encoding in flate stream');
}
codeBuf |= b << codeSize;
codeSize += 8;
}
b = codeBuf & ((1 << bits) - 1);
this.codeBuf = codeBuf >> bits;
this.codeSize = codeSize -= bits;
this.bytesPos = bytesPos;
return b;
};
FlateStream.prototype.getCode = function FlateStream_getCode(table) {
var str = this.str;
var codes = table[0];
var maxLen = table[1];
var codeSize = this.codeSize;
var codeBuf = this.codeBuf;
var bytes = this.bytes;
var bytesPos = this.bytesPos;
while (codeSize < maxLen) {
var b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
if ((b = str.getByte()) === -1) {
error('Bad encoding in flate stream');
}
codeBuf |= (b << codeSize);
codeSize += 8;
}
@ -397,7 +393,6 @@ var FlateStream = (function FlateStreamClosure() {
error('Bad encoding in flate stream');
this.codeBuf = (codeBuf >> codeLen);
this.codeSize = (codeSize - codeLen);
this.bytesPos = bytesPos;
return codeVal;
};
@ -441,6 +436,7 @@ var FlateStream = (function FlateStreamClosure() {
};
FlateStream.prototype.readBlock = function FlateStream_readBlock() {
var str = this.str;
// read block header
var hdr = this.getBits(3);
if (hdr & 1)
@ -448,21 +444,23 @@ var FlateStream = (function FlateStreamClosure() {
hdr >>= 1;
if (hdr === 0) { // uncompressed block
var bytes = this.bytes;
var bytesPos = this.bytesPos;
var b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
if ((b = str.getByte()) === -1) {
error('Bad block header in flate stream');
}
var blockLen = b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
if ((b = str.getByte()) === -1) {
error('Bad block header in flate stream');
}
blockLen |= (b << 8);
if (typeof (b = bytes[bytesPos++]) == 'undefined')
if ((b = str.getByte()) === -1) {
error('Bad block header in flate stream');
}
var check = b;
if (typeof (b = bytes[bytesPos++]) == 'undefined')
if ((b = str.getByte()) === -1) {
error('Bad block header in flate stream');
}
check |= (b << 8);
if (check != (~blockLen & 0xffff) &&
(blockLen !== 0 || check !== 0)) {
@ -478,19 +476,18 @@ var FlateStream = (function FlateStreamClosure() {
var end = bufferLength + blockLen;
this.bufferLength = end;
if (blockLen === 0) {
if (typeof bytes[bytesPos] == 'undefined') {
if (str.peekBytes(1).length === 0) {
this.eof = true;
}
} else {
for (var n = bufferLength; n < end; ++n) {
if (typeof (b = bytes[bytesPos++]) == 'undefined') {
if ((b = str.getByte()) === -1) {
this.eof = true;
break;
}
buffer[n] = b;
}
}
this.bytesPos = bytesPos;
return;
}