1 files changed, 96 insertions, 0 deletions
diff --git a/js/dojo/dojox/encoding/compression/lzw.js b/js/dojo/dojox/encoding/compression/lzw.js
new file mode 100644
index 0000000..ee771d4
--- /dev/null
+++ b/js/dojo/dojox/encoding/compression/lzw.js
@@ -0,0 +1,96 @@
+//>>built
+define("dojox/encoding/compression/lzw", [
+	"dojo/_base/lang",	// dojo.extend
+	"../bits"
+], function(lang, bits) {
+
+	var lzw = lang.getObject("dojox.encoding.compression.lzw", true);
+	/*=====
+		lzw = dojox.encoding.compression.lzw;
+	=====*/
+
+	var _bits = function(x){
+		var w = 1;
+		for(var v = 2; x >= v; v <<= 1, ++w);
+		return w;
+	};
+
+	lzw.Encoder = function(n){
+		this.size = n;
+		this.init();
+	};
+
+	lang.extend(lzw.Encoder, {
+		init: function(){
+			this.dict = {};
+			for(var i = 0; i < this.size; ++i){
+				this.dict[String.fromCharCode(i)] = i;
+			}
+			this.width = _bits(this.code = this.size);
+			this.p = "";
+		},
+		encode: function(value, stream){
+			var c = String.fromCharCode(value), p = this.p + c, r = 0;
+			// if already in the dictionary
+			if(p in this.dict){
+				this.p = p;
+				return r;
+			}
+			stream.putBits(this.dict[this.p], this.width);
+			// if we need to increase the code length
+			if((this.code & (this.code + 1)) == 0){
+				stream.putBits(this.code++, r = this.width++);
+			}
+			// add new string
+			this.dict[p] = this.code++;
+			this.p = c;
+			return r + this.width;
+		},
+		flush: function(stream){
+			if(this.p.length == 0){
+				return 0;
+			}
+			stream.putBits(this.dict[this.p], this.width);
+			this.p = "";
+			return this.width;
+		}
+	});
+
+	lzw.Decoder = function(n){
+		this.size = n;
+		this.init();
+	};
+
+	lang.extend(lzw.Decoder, {
+		init: function(){
+			this.codes = new Array(this.size);
+			for(var i = 0; i < this.size; ++i){
+				this.codes[i] = String.fromCharCode(i);
+			}
+			this.width = _bits(this.size);
+			this.p = -1;
+		},
+		decode: function(stream){
+			var c = stream.getBits(this.width), v;
+			if(c < this.codes.length){
+				v = this.codes[c];
+				if(this.p >= 0){
+					this.codes.push(this.codes[this.p] + v.substr(0, 1));
+				}
+			}else{
+				if((c & (c + 1)) == 0){
+					this.codes.push("");
+					++this.width;
+					return "";
+				}
+				var x = this.codes[this.p];
+				v = x + x.substr(0, 1);
+				this.codes.push(v);
+			}
+			this.p = c;
+			return v;
+		}
+	});
+
+	return lzw;
+});