work.suroh.tk/node_modules/mdurl/decode.js

123 lines
2.8 KiB
JavaScript

'use strict';
/* eslint-disable no-bitwise */
var decodeCache = {};
function getDecodeCache(exclude) {
var i, ch, cache = decodeCache[exclude];
if (cache) { return cache; }
cache = decodeCache[exclude] = [];
for (i = 0; i < 128; i++) {
ch = String.fromCharCode(i);
cache.push(ch);
}
for (i = 0; i < exclude.length; i++) {
ch = exclude.charCodeAt(i);
cache[ch] = '%' + ('0' + ch.toString(16).toUpperCase()).slice(-2);
}
return cache;
}
// Decode percent-encoded string.
//
function decode(string, exclude) {
var cache;
if (typeof exclude !== 'string') {
exclude = decode.defaultChars;
}
cache = getDecodeCache(exclude);
return string.replace(/(%[a-f0-9]{2})+/gi, function(seq) {
var i, l, b1, b2, b3, b4, chr,
result = '';
for (i = 0, l = seq.length; i < l; i += 3) {
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
b2 = parseInt(seq.slice(i + 4, i + 6), 16);
if ((b2 & 0xC0) === 0x80) {
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
b2 = parseInt(seq.slice(i + 4, i + 6), 16);
b3 = parseInt(seq.slice(i + 7, i + 9), 16);
if ((b2 & 0xC0) === 0x80 && (b3 & 0xC0) === 0x80) {
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
b2 = parseInt(seq.slice(i + 4, i + 6), 16);
b3 = parseInt(seq.slice(i + 7, i + 9), 16);
b4 = parseInt(seq.slice(i + 10, i + 12), 16);
if ((b2 & 0xC0) === 0x80 && (b3 & 0xC0) === 0x80 && (b4 & 0xC0) === 0x80) {
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 = '';
module.exports = decode;