GT2/GT2-iOS/node_modules/base64-js/index.js

115 lines
3.4 KiB
JavaScript

'use strict'
exports.byteLength = byteLength
exports.toByteArray = toByteArray
exports.fromByteArray = fromByteArray
var lookup = []
var revLookup = []
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array
var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
for (var i = 0, len = code.length; i < len; ++i) {
lookup[i] = code[i]
revLookup[code.charCodeAt(i)] = i
}
revLookup['-'.charCodeAt(0)] = 62
revLookup['_'.charCodeAt(0)] = 63
function placeHoldersCount (b64) {
var len = b64.length
if (len % 4 > 0) {
throw new Error('Invalid string. Length must be a multiple of 4')
}
// the number of equal signs (place holders)
// if there are two placeholders, than the two characters before it
// represent one byte
// if there is only one, then the three characters before it represent 2 bytes
// this is just a cheap hack to not do indexOf twice
return b64[len - 2] === '=' ? 2 : b64[len - 1] === '=' ? 1 : 0
}
function byteLength (b64) {
// base64 is 4/3 + up to two characters of the original data
return b64.length * 3 / 4 - placeHoldersCount(b64)
}
function toByteArray (b64) {
var i, j, l, tmp, placeHolders, arr
var len = b64.length
placeHolders = placeHoldersCount(b64)
arr = new Arr(len * 3 / 4 - placeHolders)
// if there are placeholders, only get up to the last complete 4 chars
l = placeHolders > 0 ? len - 4 : len
var L = 0
for (i = 0, j = 0; i < l; i += 4, j += 3) {
tmp = (revLookup[b64.charCodeAt(i)] << 18) | (revLookup[b64.charCodeAt(i + 1)] << 12) | (revLookup[b64.charCodeAt(i + 2)] << 6) | revLookup[b64.charCodeAt(i + 3)]
arr[L++] = (tmp >> 16) & 0xFF
arr[L++] = (tmp >> 8) & 0xFF
arr[L++] = tmp & 0xFF
}
if (placeHolders === 2) {
tmp = (revLookup[b64.charCodeAt(i)] << 2) | (revLookup[b64.charCodeAt(i + 1)] >> 4)
arr[L++] = tmp & 0xFF
} else if (placeHolders === 1) {
tmp = (revLookup[b64.charCodeAt(i)] << 10) | (revLookup[b64.charCodeAt(i + 1)] << 4) | (revLookup[b64.charCodeAt(i + 2)] >> 2)
arr[L++] = (tmp >> 8) & 0xFF
arr[L++] = tmp & 0xFF
}
return arr
}
function tripletToBase64 (num) {
return lookup[num >> 18 & 0x3F] + lookup[num >> 12 & 0x3F] + lookup[num >> 6 & 0x3F] + lookup[num & 0x3F]
}
function encodeChunk (uint8, start, end) {
var tmp
var output = []
for (var i = start; i < end; i += 3) {
tmp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2])
output.push(tripletToBase64(tmp))
}
return output.join('')
}
function fromByteArray (uint8) {
var tmp
var len = uint8.length
var extraBytes = len % 3 // if we have 1 byte left, pad 2 bytes
var output = ''
var parts = []
var maxChunkLength = 16383 // must be multiple of 3
// go through the array every three bytes, we'll deal with trailing stuff later
for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)))
}
// pad the end with zeros, but make sure to not forget the extra bytes
if (extraBytes === 1) {
tmp = uint8[len - 1]
output += lookup[tmp >> 2]
output += lookup[(tmp << 4) & 0x3F]
output += '=='
} else if (extraBytes === 2) {
tmp = (uint8[len - 2] << 8) + (uint8[len - 1])
output += lookup[tmp >> 10]
output += lookup[(tmp >> 4) & 0x3F]
output += lookup[(tmp << 2) & 0x3F]
output += '='
}
parts.push(output)
return parts.join('')
}