65 lines
1.4 KiB
JavaScript
65 lines
1.4 KiB
JavaScript
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dojo.provide("dojox.encoding.bits");
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dojox.encoding.bits.OutputStream = function(){
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this.reset();
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};
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dojo.extend(dojox.encoding.bits.OutputStream, {
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reset: function(){
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this.buffer = [];
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this.accumulator = 0;
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this.available = 8;
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},
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putBits: function(value, width){
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while(width){
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var w = Math.min(width, this.available);
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var v = (w <= width ? value >>> (width - w) : value) << (this.available - w);
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this.accumulator |= v & (255 >>> (8 - this.available));
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this.available -= w;
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if(!this.available){
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this.buffer.push(this.accumulator);
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this.accumulator = 0;
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this.available = 8;
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}
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width -= w;
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}
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},
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getWidth: function(){
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return this.buffer.length * 8 + (8 - this.available);
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},
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getBuffer: function(){
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var b = this.buffer;
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if(this.available < 8){ b.push(this.accumulator & (255 << this.available)); }
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this.reset();
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return b;
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}
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});
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dojox.encoding.bits.InputStream = function(buffer, width){
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this.buffer = buffer;
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this.width = width;
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this.bbyte = this.bit = 0;
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};
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dojo.extend(dojox.encoding.bits.InputStream, {
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getBits: function(width){
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var r = 0;
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while(width){
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var w = Math.min(width, 8 - this.bit);
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var v = this.buffer[this.bbyte] >>> (8 - this.bit - w);
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r <<= w;
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r |= v & ~(~0 << w);
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this.bit += w;
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if(this.bit == 8){
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++this.bbyte;
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this.bit = 0;
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}
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width -= w;
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}
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return r;
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},
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getWidth: function(){
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return this.width - this.bbyte * 8 - this.bit;
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}
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});
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