base91-prebuilt
Version:
base91 implementation in javascript for node.js and browsers
199 lines (187 loc) • 6.45 kB
JavaScript
(function() {
var hasNode = (typeof process !== 'undefined' && process.versions && process.versions.node),
hasTypedArray = (typeof Uint8Array !== 'undefined');
if (hasNode) {
var platform = require('os').platform();
var modulePath = __dirname + '/../built/' + platform + '-base91encdec.node';
if (require('fs').existsSync(modulePath)) {
module.exports = require(modulePath);
return;
}
}
var AVERAGE_ENCODING_RATIO = 1.2297,
ENCODING_TABLE = [
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'!', '#', '$', '%', '&', '(', ')', '*', '+', ',', '.', '/', ':', ';',
'<', '=', '>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~',
'"'
],
DECODING_TABLE = [
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 62, 90, 63, 64, 65, 66, 91, 67, 68, 69, 70, 71, 91, 72, 73,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 74, 75, 76, 77, 78, 79,
80, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 81, 91, 82, 83, 84,
85, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 86, 87, 88, 89, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91
];
var i = 0;
var base91 = {
encode: function(data) {
var len = data.length,
output = '', ebq = 0, en = 0, ev = 0, j = 0, byte = 0;
if (typeof data === 'string') {
for (i = 0; i < len; ++i) {
byte = data.charCodeAt(i);
j = 0;
var lenj = (byte < 128
? 1
: (byte > 127 && byte < 2048
? 2
: 3));
for (; j < lenj; ++j) {
if (lenj === 1)
ebq |= byte << en;
else if (lenj === 2) {
if (j === 0)
ebq |= ((byte >> 6) | 192) << en;
else
ebq |= ((byte & 63) | 128) << en;
} else {
if (j === 0)
ebq |= ((byte >> 12) | 224) << en;
else if (j === 1)
ebq |= (((byte >> 6) & 63) | 128) << en;
else
ebq |= ((byte & 63) | 128) << en;
}
en += 8;
if (en > 13) {
ev = ebq & 8191;
if (ev > 88) {
ebq >>= 13;
en -= 13;
} else {
ev = ebq & 16383;
ebq >>= 14;
en -= 14;
}
output += ENCODING_TABLE[ev % 91];
output += ENCODING_TABLE[(ev / 91) | 0];
}
}
}
} else {
for (i = 0; i < len; ++i) {
ebq |= (data[i] & 255) << en;
en += 8;
if (en > 13) {
ev = ebq & 8191;
if (ev > 88) {
ebq >>= 13;
en -= 13;
} else {
ev = ebq & 16383;
ebq >>= 14;
en -= 14;
}
output += ENCODING_TABLE[ev % 91];
output += ENCODING_TABLE[(ev / 91) | 0];
}
}
}
if (en > 0) {
output += ENCODING_TABLE[ebq % 91];
if (en > 7 || ebq > 90)
output += ENCODING_TABLE[(ebq / 91) | 0];
}
return output;
},
decode: function(data) {
var len = data.length,
estimatedSize = ((len / AVERAGE_ENCODING_RATIO) | 0),
dbq = 0, dn = 0, dv = -1, i = 0, o = -1, byte = 0,
output = new Array(estimatedSize);
if (typeof data === 'string') {
for (i = 0; i < len; ++i) {
byte = data.charCodeAt(i);
if (DECODING_TABLE[byte] === 91)
continue;
if (dv === -1)
dv = DECODING_TABLE[byte];
else {
dv += DECODING_TABLE[byte] * 91;
dbq |= dv << dn;
dn += ((dv & 8191) > 88 ? 13 : 14);
do {
if (++o >= estimatedSize)
output.push(dbq & 0xFF);
else
output[o] = dbq & 0xFF;
dbq >>= 8;
dn -= 8;
} while (dn > 7);
dv = -1;
}
}
} else {
for (i = 0; i < len; ++i) {
byte = data[i];
if (DECODING_TABLE[byte] === 91)
continue;
if (dv === -1)
dv = DECODING_TABLE[byte];
else {
dv += DECODING_TABLE[byte] * 91;
dbq |= dv << dn;
dn += ((dv & 8191) > 88 ? 13 : 14);
do {
if (++o >= estimatedSize)
output.push(dbq & 0xFF);
else
output[o] = dbq & 0xFF;
dbq >>= 8;
dn -= 8;
} while (dn > 7);
dv = -1;
}
}
}
if (dv !== -1) {
if (++o >= estimatedSize)
output.push(dbq | dv << dn);
else
output[o] = (dbq | dv << dn);
}
if (o > -1 && o < estimatedSize - 1)
output = output.slice(0, o + 1);
var ret;
if (hasNode)
ret = new Buffer(output);
else if (hasTypedArray) {
ret = new Uint8Array(output.length);
for (i = 0, len = output.length; i < len; ++i)
ret[i] = output[i];
} else
ret = output;
return ret;
}
};
if (hasNode)
module.exports = base91;
else
window.base91 = base91;
})();