57 lines
1.6 KiB
JavaScript
57 lines
1.6 KiB
JavaScript
const {toByteArray} = require('base64-js');
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function base64ToBinary(input) {
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var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
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const lookup = new Uint8Array(130);
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for (var i = 0; i < chars.length; i++) {
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lookup[chars.charCodeAt(i)] = i;
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}
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// Ignore
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var len = input.length;
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if (input.charAt(len - 1) === '=') {
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len--;
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}
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if (input.charAt(len - 1) === '=') {
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len--;
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}
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var uarray = new Uint8Array((len / 4) * 3);
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for (var i = 0, j = 0; i < uarray.length;) {
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var c1 = lookup[input.charCodeAt(j++)];
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var c2 = lookup[input.charCodeAt(j++)];
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var c3 = lookup[input.charCodeAt(j++)];
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var c4 = lookup[input.charCodeAt(j++)];
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uarray[i++] = (c1 << 2) | (c2 >> 4);
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uarray[i++] = ((c2 & 15) << 4) | (c3 >> 2);
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uarray[i++] = ((c3 & 3) << 6) | c4;
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}
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return uarray.buffer;
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}
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var data = new Float32Array(11565);
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for (let i = 0; i < data.length; i++) {
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data[i] = Math.random();
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}
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const str = new Buffer(data.buffer).toString('base64');
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// console.log(str);
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console.time('native');
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console.log(new Buffer(str, 'base64'));
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console.timeEnd('native');
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console.time('js');
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console.log(base64ToBinary(str).byteLength);
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console.timeEnd('js');
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console.time('base64-js');
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console.log(toByteArray(str).buffer.byteLength);
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console.timeEnd('base64-js');
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var result = new Float32Array(base64ToBinary(str));
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for (var i = 0; i < result.length; i++) {
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if (result[i] !== data[i]) {
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console.error('wrong result');
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break;
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}
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} |