52 lines
946 B
JavaScript
52 lines
946 B
JavaScript
'use strict';
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function History()
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{
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this.index = 0;
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this.a = [];
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this.clear = function()
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{
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this.a = [];
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this.index = 0;
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}
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this.push = function(data)
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{
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if(this.index < this.a.length-1){
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this.fork();
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}
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this.index = this.a.length;
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this.a = this.a.slice(0,this.index);
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this.a.push(copy(data));
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if(this.a.length > 20){
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this.a.shift();
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}
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}
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this.fork = function()
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{
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this.a = this.a.slice(0,this.index+1);
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}
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this.pop = function()
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{
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return this.a.pop();
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}
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this.prev = function()
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{
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this.index = clamp(this.index-1,0,this.a.length-1);
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return copy(this.a[this.index]);
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}
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this.next = function()
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{
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this.index = clamp(this.index+1,0,this.a.length-1);
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return copy(this.a[this.index]);
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}
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function copy(data){ return data ? JSON.parse(JSON.stringify(data)) : []; }
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function clamp(v, min, max) { return v < min ? min : v > max ? max : v; }
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} |