Sakurai/pdf.js
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Don't get bytes eagerly when creating FlateStream objects.

Browse Source
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
src/core/stream.js
View File

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