2024-11-03 17:16:20 +01:00

113 lines
2.8 KiB
JavaScript

/* eslint-disable no-bitwise */
const decodeCache = {}
function getDecodeCache (exclude) {
let cache = decodeCache[exclude]
if (cache) { return cache }
cache = decodeCache[exclude] = []
for (let i = 0; i < 128; i++) {
const ch = String.fromCharCode(i)
cache.push(ch)
}
for (let i = 0; i < exclude.length; i++) {
const ch = exclude.charCodeAt(i)
cache[ch] = '%' + ('0' + ch.toString(16).toUpperCase()).slice(-2)
}
return cache
}
// Decode percent-encoded string.
//
function decode (string, exclude) {
if (typeof exclude !== 'string') {
exclude = decode.defaultChars
}
const cache = getDecodeCache(exclude)
return string.replace(/(%[a-f0-9]{2})+/gi, function (seq) {
let result = ''
for (let i = 0, l = seq.length; i < l; i += 3) {
const b1 = parseInt(seq.slice(i + 1, i + 3), 16)
if (b1 < 0x80) {
result += cache[b1]
continue
}
if ((b1 & 0xE0) === 0xC0 && (i + 3 < l)) {
// 110xxxxx 10xxxxxx
const b2 = parseInt(seq.slice(i + 4, i + 6), 16)
if ((b2 & 0xC0) === 0x80) {
const chr = ((b1 << 6) & 0x7C0) | (b2 & 0x3F)
if (chr < 0x80) {
result += '\ufffd\ufffd'
} else {
result += String.fromCharCode(chr)
}
i += 3
continue
}
}
if ((b1 & 0xF0) === 0xE0 && (i + 6 < l)) {
// 1110xxxx 10xxxxxx 10xxxxxx
const b2 = parseInt(seq.slice(i + 4, i + 6), 16)
const b3 = parseInt(seq.slice(i + 7, i + 9), 16)
if ((b2 & 0xC0) === 0x80 && (b3 & 0xC0) === 0x80) {
const chr = ((b1 << 12) & 0xF000) | ((b2 << 6) & 0xFC0) | (b3 & 0x3F)
if (chr < 0x800 || (chr >= 0xD800 && chr <= 0xDFFF)) {
result += '\ufffd\ufffd\ufffd'
} else {
result += String.fromCharCode(chr)
}
i += 6
continue
}
}
if ((b1 & 0xF8) === 0xF0 && (i + 9 < l)) {
// 111110xx 10xxxxxx 10xxxxxx 10xxxxxx
const b2 = parseInt(seq.slice(i + 4, i + 6), 16)
const b3 = parseInt(seq.slice(i + 7, i + 9), 16)
const b4 = parseInt(seq.slice(i + 10, i + 12), 16)
if ((b2 & 0xC0) === 0x80 && (b3 & 0xC0) === 0x80 && (b4 & 0xC0) === 0x80) {
let chr = ((b1 << 18) & 0x1C0000) | ((b2 << 12) & 0x3F000) | ((b3 << 6) & 0xFC0) | (b4 & 0x3F)
if (chr < 0x10000 || chr > 0x10FFFF) {
result += '\ufffd\ufffd\ufffd\ufffd'
} else {
chr -= 0x10000
result += String.fromCharCode(0xD800 + (chr >> 10), 0xDC00 + (chr & 0x3FF))
}
i += 9
continue
}
}
result += '\ufffd'
}
return result
})
}
decode.defaultChars = ';/?:@&=+$,#'
decode.componentChars = ''
export default decode