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Move the RunLengthStream from src/core/stream.js and into its own file

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This commit is contained in:
Jonas Jenwald 2021-04-27 13:04:07 +02:00
parent 1f0685cee6
commit 342b0c1bbc
3 changed files with 68 additions and 50 deletions
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2
src/core/parser.js
View File

@ -19,7 +19,6 @@ import {
FlateStream,
NullStream,
PredictorStream,
RunLengthStream,
} from "./stream.js";
import {
assert,
@ -47,6 +46,7 @@ import { Jbig2Stream } from "./jbig2_stream.js";
import { JpegStream } from "./jpeg_stream.js";
import { JpxStream } from "./jpx_stream.js";
import { LZWStream } from "./lzw_stream.js";
import { RunLengthStream } from "./run_length_stream.js";
const MAX_LENGTH_TO_CACHE = 1000;
const MAX_ADLER32_LENGTH = 5552;

67
src/core/run_length_stream.js Normal file
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@ -0,0 +1,67 @@
/* Copyright 2012 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* eslint-disable no-var */
import { DecodeStream } from "./stream.js";
var RunLengthStream = (function RunLengthStreamClosure() {
// eslint-disable-next-line no-shadow
function RunLengthStream(str, maybeLength) {
this.str = str;
this.dict = str.dict;
DecodeStream.call(this, maybeLength);
}
RunLengthStream.prototype = Object.create(DecodeStream.prototype);
RunLengthStream.prototype.readBlock = function RunLengthStream_readBlock() {
// The repeatHeader has following format. The first byte defines type of run
// and amount of bytes to repeat/copy: n = 0 through 127 - copy next n bytes
// (in addition to the second byte from the header), n = 129 through 255 -
// duplicate the second byte from the header (257 - n) times, n = 128 - end.
var repeatHeader = this.str.getBytes(2);
if (!repeatHeader || repeatHeader.length < 2 || repeatHeader[0] === 128) {
this.eof = true;
return;
}
var buffer;
var bufferLength = this.bufferLength;
var n = repeatHeader[0];
if (n < 128) {
// copy n bytes
buffer = this.ensureBuffer(bufferLength + n + 1);
buffer[bufferLength++] = repeatHeader[1];
if (n > 0) {
var source = this.str.getBytes(n);
buffer.set(source, bufferLength);
bufferLength += n;
}
} else {
n = 257 - n;
var b = repeatHeader[1];
buffer = this.ensureBuffer(bufferLength + n + 1);
for (var i = 0; i < n; i++) {
buffer[bufferLength++] = b;
}
}
this.bufferLength = bufferLength;
};
return RunLengthStream;
})();
export { RunLengthStream };

49
src/core/stream.js
View File

@ -1148,54 +1148,6 @@ var AsciiHexStream = (function AsciiHexStreamClosure() {
return AsciiHexStream;
})();
var RunLengthStream = (function RunLengthStreamClosure() {
// eslint-disable-next-line no-shadow
function RunLengthStream(str, maybeLength) {
this.str = str;
this.dict = str.dict;
DecodeStream.call(this, maybeLength);
}
RunLengthStream.prototype = Object.create(DecodeStream.prototype);
RunLengthStream.prototype.readBlock = function RunLengthStream_readBlock() {
// The repeatHeader has following format. The first byte defines type of run
// and amount of bytes to repeat/copy: n = 0 through 127 - copy next n bytes
// (in addition to the second byte from the header), n = 129 through 255 -
// duplicate the second byte from the header (257 - n) times, n = 128 - end.
var repeatHeader = this.str.getBytes(2);
if (!repeatHeader || repeatHeader.length < 2 || repeatHeader[0] === 128) {
this.eof = true;
return;
}
var buffer;
var bufferLength = this.bufferLength;
var n = repeatHeader[0];
if (n < 128) {
// copy n bytes
buffer = this.ensureBuffer(bufferLength + n + 1);
buffer[bufferLength++] = repeatHeader[1];
if (n > 0) {
var source = this.str.getBytes(n);
buffer.set(source, bufferLength);
bufferLength += n;
}
} else {
n = 257 - n;
var b = repeatHeader[1];
buffer = this.ensureBuffer(bufferLength + n + 1);
for (var i = 0; i < n; i++) {
buffer[bufferLength++] = b;
}
}
this.bufferLength = bufferLength;
};
return RunLengthStream;
})();
var NullStream = (function NullStreamClosure() {
// eslint-disable-next-line no-shadow
function NullStream() {
@ -1215,7 +1167,6 @@ export {
FlateStream,
NullStream,
PredictorStream,
RunLengthStream,
Stream,
StreamsSequenceStream,
StringStream,