b3024db677
When decoding a stream, the decode buffer is often grown multiple times, its byte size increasing like so: 512, 1024, 2048, etc. This patch estimates the minimum size in advance (using the length of the encoded stream), often allowing the smaller sizes to be skipped. It also renames numerous |length| variables as |maybeLength| to make it clear that they can be |null|. I measured this change on eight documents. This change reduces the cumulative size of decode buffer allocations by 0--32%, with 10--20% being typical. This reduces peak RSS by 10 or 20 MiB for several of them.
43 lines
1.3 KiB
JavaScript
43 lines
1.3 KiB
JavaScript
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
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/* globals expect, it, describe, beforeEach, Stream, PredictorStream, Dict */
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'use strict';
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describe('stream', function() {
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beforeEach(function() {
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this.addMatchers({
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toMatchTypedArray: function(expected) {
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var actual = this.actual;
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if (actual.length != expected.length)
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return false;
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for (var i = 0, ii = expected.length; i < ii; i++) {
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var a = actual[i], b = expected[i];
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if (a !== b)
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return false;
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}
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return true;
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}
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});
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});
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describe('PredictorStream', function() {
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it('should decode simple predictor data', function() {
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var dict = new Dict();
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dict.set('Predictor', 12);
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dict.set('Colors', 1);
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dict.set('BitsPerComponent', 8);
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dict.set('Columns', 2);
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var input = new Stream(new Uint8Array([2, 100, 3, 2, 1, 255, 2, 1, 255]),
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0, 9, dict);
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var predictor = new PredictorStream(input, /* length = */ 9, dict);
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var result = predictor.getBytes(6);
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expect(result).toMatchTypedArray(
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new Uint8Array([100, 3, 101, 2, 102, 1])
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);
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});
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});
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});
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