55 lines
1.4 KiB
JavaScript
55 lines
1.4 KiB
JavaScript
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'use strict'
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const RE_PLUS = /\+/g
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const HEX = [
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
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0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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]
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function Decoder () {
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this.buffer = undefined
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}
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Decoder.prototype.write = function (str) {
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// Replace '+' with ' ' before decoding
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str = str.replace(RE_PLUS, ' ')
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let res = ''
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let i = 0; let p = 0; const len = str.length
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for (; i < len; ++i) {
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if (this.buffer !== undefined) {
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if (!HEX[str.charCodeAt(i)]) {
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res += '%' + this.buffer
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this.buffer = undefined
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--i // retry character
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} else {
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this.buffer += str[i]
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++p
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if (this.buffer.length === 2) {
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res += String.fromCharCode(parseInt(this.buffer, 16))
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this.buffer = undefined
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}
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}
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} else if (str[i] === '%') {
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if (i > p) {
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res += str.substring(p, i)
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p = i
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}
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this.buffer = ''
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++p
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}
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}
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if (p < len && this.buffer === undefined) { res += str.substring(p) }
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return res
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}
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Decoder.prototype.reset = function () {
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this.buffer = undefined
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}
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module.exports = Decoder
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