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October 9, 2016 13:18
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| // A bitfield represents a binary number of arbitrary length | |
| // This implementation requires the JavaScript Uint32Array data type | |
| function BitField(length,data) { | |
| if (length instanceof BitField) { | |
| // Copy-Constructor from a given BitField | |
| this.length = length.length | |
| this.maxIndex = length.maxIndex | |
| this.maxMask = length.maxMask | |
| this.maxPlaces = length.maxPlaces | |
| this.data = Uint32Array.from(length.data) | |
| } | |
| else { | |
| this.length = length | |
| this.maxIndex = ( ~~(length/32) + (length % 32 && 1) ) - 1 | |
| this.maxMask = length % 32 ? (1 << length % 32) - 1 : 0xffffffff | |
| this.maxPlaces = length % 32 || 32 | |
| if (data) { | |
| if (data instanceof Uint32Array) | |
| this.data = data | |
| else if (data instanceof Array) { | |
| this.data = Uint32Array.from(data) | |
| } | |
| else if (typeof data == "number") { | |
| this.data = new Uint32Array( this.maxIndex + 1 ) | |
| this.data[0] = data | |
| } | |
| } | |
| else | |
| this.data = new Uint32Array( this.maxIndex + 1 ) | |
| } | |
| } | |
| BitField.prototype.get = function(pos) { | |
| return ( this.data[~~(pos/32)] & (1 << (pos % 32) ) ) && 1 | |
| } | |
| BitField.prototype.set = function(pos) { | |
| this.data[~~(pos/32)] |= ( 1 << (pos % 32)) | |
| } | |
| BitField.prototype.unset = function(pos) { | |
| this.data[~~(pos/32)] &= ~( 1 << (pos % 32)) | |
| } | |
| BitField.prototype.clear = function() { | |
| this.data.fill(0) | |
| } | |
| BitField.prototype.increment = function() { | |
| for (var i=0;i<this.maxIndex;i++) { | |
| if (this.data[i] != 0xffffffff) { | |
| this.data[i]++ | |
| return true | |
| } | |
| else { | |
| this.data[i] = 0 | |
| } | |
| } | |
| if (this.data[this.maxIndex] != this.maxMask) { | |
| this.data[this.maxIndex]++ | |
| return true | |
| } | |
| else { | |
| return false // Maximum reached | |
| } | |
| } | |
| BitField.prototype.equals = function(bf) { | |
| if (this.length != bf.length) return false | |
| for (var i=0;i<this.maxIndex;i++) { | |
| if (this.data[i] != bf.data[i]) return false; | |
| } | |
| return (((this.data[this.maxIndex]^bf.data[this.maxIndex])&this.maxMask)==0) | |
| } | |
| BitField.prototype.toString = function() { | |
| return pad((this.data[this.maxIndex]&this.maxMask).toString(2),this.maxPlaces) + | |
| this.data.slice(0,this.data.length-1).reverse().map(function(i){ | |
| return pad(i.toString(2),32) | |
| }).join("") | |
| function pad(s,k) { | |
| return ("00000000000000000000000000000000"+s).slice(-k) | |
| } | |
| } | |
| /* Some additions for retarded browsers | |
| The implementations do not pretend to be fully-featured | |
| They are just enough to make the class BitField usable in older browsers */ | |
| if (!Uint32Array.from) { | |
| Uint32Array.from = function(array) { | |
| var result = new Uint32Array(array.length) | |
| for (var i=0;i<array.length;i++) result[i] = array[i] | |
| return result | |
| } | |
| } | |
| if (!Array.prototype.fill) { | |
| Array.prototype.fill = function(value) { | |
| for (var i=0;i<this.length;i++) this[i] = value | |
| return this | |
| } | |
| } | |
| if (!Uint32Array.prototype.slice) { | |
| Uint32Array.prototype.slice = function(i1,i2) { | |
| var result = new Uint32Array(i2-i1) | |
| for (var i=i1;i<i2;i++) result[i-i1] = this[i] | |
| return result | |
| } | |
| } | |
| if (!Uint32Array.prototype.reverse) { | |
| Uint32Array.prototype.reverse = function() { | |
| var len = this.length | |
| var result = new Uint32Array(len) | |
| for (var i=0;i<len;i++) result[i]=this[len-i-1] | |
| return result | |
| } | |
| } | |
| if (!Uint32Array.prototype.map) { | |
| Uint32Array.prototype.map = function(f) { | |
| var len = this.length | |
| var result = new Uint32Array(len) | |
| for (var i=0;i<len;i++) result[i] = f(this[i]) | |
| return result | |
| } | |
| } | |
| if (!Uint32Array.prototype.join) { | |
| Uint32Array.prototype.join = function(s) { | |
| var len = this.length | |
| var result = "" | |
| for (var i=0;i<len;i++) { | |
| if (i>0 && i<len-1) result += s | |
| result += this[i] | |
| } | |
| return result | |
| } | |
| } |
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