147 lines
3.5 KiB
JavaScript
147 lines
3.5 KiB
JavaScript
'use strict';
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var util = require('util');
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var zlib = require('zlib');
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var ChunkStream = require('./chunkstream');
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var FilterAsync = require('./filter-parse-async');
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var Parser = require('./parser');
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var bitmapper = require('./bitmapper');
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var formatNormaliser = require('./format-normaliser');
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var ParserAsync = module.exports = function(options) {
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ChunkStream.call(this);
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this._parser = new Parser(options, {
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read: this.read.bind(this),
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error: this._handleError.bind(this),
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metadata: this._handleMetaData.bind(this),
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gamma: this.emit.bind(this, 'gamma'),
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palette: this._handlePalette.bind(this),
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transColor: this._handleTransColor.bind(this),
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finished: this._finished.bind(this),
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inflateData: this._inflateData.bind(this)
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});
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this._options = options;
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this.writable = true;
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this._parser.start();
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};
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util.inherits(ParserAsync, ChunkStream);
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ParserAsync.prototype._handleError = function(err) {
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this.emit('error', err);
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this.writable = false;
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this.destroy();
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if (this._inflate && this._inflate.destroy) {
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this._inflate.destroy();
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}
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this.errord = true;
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};
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ParserAsync.prototype._inflateData = function(data) {
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if (!this._inflate) {
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if (this._bitmapInfo.interlace) {
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this._inflate = zlib.createInflate();
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this._inflate.on('error', this.emit.bind(this, 'error'));
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this._filter.on('complete', this._complete.bind(this));
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this._inflate.pipe(this._filter);
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} else {
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var rowSize = ((this._bitmapInfo.width * this._bitmapInfo.bpp * this._bitmapInfo.depth + 7) >> 3) + 1;
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var imageSize = rowSize * this._bitmapInfo.height;
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var chunkSize = Math.max(imageSize, zlib.Z_MIN_CHUNK);
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this._inflate = zlib.createInflate({ chunkSize: chunkSize });
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var leftToInflate = imageSize;
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var emitError = this.emit.bind(this, 'error');
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this._inflate.on('error', function(err) {
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if (!leftToInflate) {
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return;
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}
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emitError(err);
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});
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this._filter.on('complete', this._complete.bind(this));
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var filterWrite = this._filter.write.bind(this._filter);
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this._inflate.on('data', function(chunk) {
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if (!leftToInflate) {
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return;
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}
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if (chunk.length > leftToInflate) {
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chunk = chunk.slice(0, leftToInflate);
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}
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leftToInflate -= chunk.length;
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filterWrite(chunk);
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});
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this._inflate.on('end', this._filter.end.bind(this._filter));
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}
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}
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this._inflate.write(data);
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};
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ParserAsync.prototype._handleMetaData = function(metaData) {
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this.emit('metadata', metaData);
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this._bitmapInfo = Object.create(metaData);
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this._filter = new FilterAsync(this._bitmapInfo);
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};
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ParserAsync.prototype._handleTransColor = function(transColor) {
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this._bitmapInfo.transColor = transColor;
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};
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ParserAsync.prototype._handlePalette = function(palette) {
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this._bitmapInfo.palette = palette;
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};
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ParserAsync.prototype._finished = function() {
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if (this.errord) {
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return;
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}
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if (!this._inflate) {
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this.emit('error', 'No Inflate block');
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}
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else {
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// no more data to inflate
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this._inflate.end();
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}
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this.destroySoon();
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};
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ParserAsync.prototype._complete = function(filteredData) {
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if (this.errord) {
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return;
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}
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try {
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var bitmapData = bitmapper.dataToBitMap(filteredData, this._bitmapInfo);
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var normalisedBitmapData = formatNormaliser(bitmapData, this._bitmapInfo);
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bitmapData = null;
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}
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catch (ex) {
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this._handleError(ex);
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return;
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}
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this.emit('parsed', normalisedBitmapData);
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};
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