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Merge pull request #4405 from nnethercote/avoid-re-reading-streams

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Avoid unnecessary re-reading of streams
This commit is contained in:
Brendan Dahl 2014-03-12 14:45:56 -07:00
commit c3ed71c9c5
3 changed files with 60 additions and 40 deletions
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2
src/core/chunked_stream.js
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@ -187,6 +187,8 @@ var ChunkedStream = (function ChunkedStreamClosure() {
},
makeSubStream: function ChunkedStream_makeSubStream(start, length, dict) {
this.ensureRange(start, start + length);
function ChunkedStreamSubstream() {}
ChunkedStreamSubstream.prototype = Object.create(this);
ChunkedStreamSubstream.prototype.getMissingChunks = function() {

9
src/core/parser.js
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@ -300,12 +300,10 @@ var Parser = (function ParserClosure() {
return new LZWStream(stream, earlyChange);
}
if (name == 'DCTDecode' || name == 'DCT') {
var bytes = stream.getBytes(length);
return new JpegStream(bytes, stream.dict, this.xref);
return new JpegStream(stream, length, stream.dict, this.xref);
}
if (name == 'JPXDecode' || name == 'JPX') {
var bytes = stream.getBytes(length);
return new JpxStream(bytes, stream.dict);
return new JpxStream(stream, length, stream.dict);
}
if (name == 'ASCII85Decode' || name == 'A85') {
return new Ascii85Stream(stream);
@ -320,8 +318,7 @@ var Parser = (function ParserClosure() {
return new RunLengthStream(stream);
}
if (name == 'JBIG2Decode') {
var bytes = stream.getBytes(length);
return new Jbig2Stream(bytes, stream.dict);
return new Jbig2Stream(stream, length, stream.dict);
}
warn('filter "' + name + '" not supported yet');
return stream;

89
src/core/stream.js
View File

@ -14,8 +14,8 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* globals bytesToString, ColorSpace, Dict, EOF, error, info, Jbig2Image,
JpegImage, JpxImage, Lexer, Util, PDFJS, isArray, warn */
/* globals bytesToString, ColorSpace, Dict, EOF, error, info, isArray,
Jbig2Image, JpegImage, JpxImage, Lexer, PDFJS, shadow, Util, warn */
'use strict';
@ -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;
}
@ -777,17 +774,25 @@ var PredictorStream = (function PredictorStreamClosure() {
* DecodeStreams.
*/
var JpegStream = (function JpegStreamClosure() {
function JpegStream(bytes, dict, xref) {
function JpegStream(stream, length, dict, xref) {
// TODO: per poppler, some images may have 'junk' before that
// need to be removed
this.stream = stream;
this.length = length;
this.dict = dict;
this.bytes = bytes;
DecodeStream.call(this);
}
JpegStream.prototype = Object.create(DecodeStream.prototype);
Object.defineProperty(JpegStream.prototype, 'bytes', {
get: function JpegStream_bytes() {
return shadow(this, 'bytes', this.stream.getBytes(this.length));
},
configurable: true
});
JpegStream.prototype.ensureBuffer = function JpegStream_ensureBuffer(req) {
if (this.bufferLength)
return;
@ -836,15 +841,23 @@ var JpegStream = (function JpegStreamClosure() {
* the stream behaves like all the other DecodeStreams.
*/
var JpxStream = (function JpxStreamClosure() {
function JpxStream(bytes, dict) {
function JpxStream(stream, length, dict) {
this.stream = stream;
this.length = length;
this.dict = dict;
this.bytes = bytes;
DecodeStream.call(this);
}
JpxStream.prototype = Object.create(DecodeStream.prototype);
Object.defineProperty(JpxStream.prototype, 'bytes', {
get: function JpxStream_bytes() {
return shadow(this, 'bytes', this.stream.getBytes(this.length));
},
configurable: true
});
JpxStream.prototype.ensureBuffer = function JpxStream_ensureBuffer(req) {
if (this.bufferLength)
return;
@ -935,15 +948,23 @@ var JpxStream = (function JpxStreamClosure() {
* the stream behaves like all the other DecodeStreams.
*/
var Jbig2Stream = (function Jbig2StreamClosure() {
function Jbig2Stream(bytes, dict) {
function Jbig2Stream(stream, length, dict) {
this.stream = stream;
this.length = length;
this.dict = dict;
this.bytes = bytes;
DecodeStream.call(this);
}
Jbig2Stream.prototype = Object.create(DecodeStream.prototype);
Object.defineProperty(Jbig2Stream.prototype, 'bytes', {
get: function Jbig2Stream_bytes() {
return shadow(this, 'bytes', this.stream.getBytes(this.length));
},
configurable: true
});
Jbig2Stream.prototype.ensureBuffer = function Jbig2Stream_ensureBuffer(req) {
if (this.bufferLength)
return;