105 lines
2.4 KiB
JavaScript
105 lines
2.4 KiB
JavaScript
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'use strict';
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function ArrayBufferSer(arrayBuffer) {
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this.buffer = arrayBuffer;
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this.offset = 0;
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this.sections = this.readArray();
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this.headers = this.sections[0];
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this._headersIndex = {};
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for(var i = 0; i < this.headers.length; ++i) {
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this._headersIndex[this.headers[i]] = i;
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}
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if(this.sections.length > 1) {
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this.length = this.sections[1].length;
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}
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}
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ArrayBufferSer.INT8 = 1;
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ArrayBufferSer.UINT8 = 2;
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ArrayBufferSer.UINT8_CLAMP = 3;
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ArrayBufferSer.INT16 = 4;
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ArrayBufferSer.UINT16 = 5;
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ArrayBufferSer.INT32 = 6;
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ArrayBufferSer.UINT32 = 7;
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ArrayBufferSer.FLOAT32 = 8;
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//ArrayBufferSer.FLOAT64 = 9; not supported
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ArrayBufferSer.STRING = 10;
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ArrayBufferSer.BUFFER = 11;
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ArrayBufferSer.prototype = {
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sizes: [NaN, 1, 1, 1, 2, 2, 4, 4, 4, 8],
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types: [
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null,
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Int8Array,
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Uint8Array,
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Uint8ClampedArray,
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Int16Array,
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Uint16Array,
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Int32Array,
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Uint32Array,
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Float32Array,
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Float64Array
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],
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get: function(columnName) {
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var i = this._headersIndex[columnName]
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if(i != undefined) {
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return this.sections[i + 1]
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}
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return;
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},
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_paddingFor: function(offset, type) {
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var s = this.sizes[type]
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if(s) {
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var r = offset % s;
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return r == 0 ? 0 : s - r;
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}
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return 0;
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},
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readUInt32: function() {
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var i = new DataView(this.buffer).getUint32(this.offset);
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this.offset += 4;
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return i
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},
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readArray: function() {
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var type = this.readUInt32();
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var size = this.readUInt32();
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if(type < ArrayBufferSer.STRING) {
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var a = new this.types[type](this.buffer, this.offset, size/this.sizes[type]);
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this.offset += size;
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return a;
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} else if(type == ArrayBufferSer.STRING) {
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var target = this.offset + size;
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var b = [];
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while(this.offset < target) {
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this.offset += this._paddingFor(this.offset, ArrayBufferSer.INT32);
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var arr = this.readArray();
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if(arr) {
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var str = '';
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for(var i = 0; i < arr.length; ++i) {
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str += String.fromCharCode(arr[i]);
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}
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b.push(str);
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}
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// parse sttring
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}
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return b;
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} else if(type == ArrayBufferSer.BUFFER) {
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var b = [];
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var target = this.offset + size;
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while(this.offset < target) {
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this.offset += this._paddingFor(this.offset, ArrayBufferSer.INT32);
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b.push(this.readArray());
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}
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return b;
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}
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}
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};
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