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Base64 Function for JS
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/* | |
Copyright Vassilis Petroulias [DRDigit] | |
Licensed under the Apache License, Version 2.0 (the "License"); | |
you may not use this file except in compliance with the License. | |
You may obtain a copy of the License at | |
http://www.apache.org/licenses/LICENSE-2.0 | |
Unless required by applicable law or agreed to in writing, software | |
distributed under the License is distributed on an "AS IS" BASIS, | |
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
See the License for the specific language governing permissions and | |
limitations under the License. | |
*/ | |
var B64 = { | |
alphabet: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=', | |
lookup: null, | |
ie: /MSIE /.test(navigator.userAgent), | |
ieo: /MSIE [67]/.test(navigator.userAgent), | |
encode: function (s) { | |
var buffer = B64.toUtf8(s), | |
position = -1, | |
len = buffer.length, | |
nan1, nan2, enc = [, , , ]; | |
if (B64.ie) { | |
var result = []; | |
while (++position < len) { | |
nan1 = buffer[position + 1], nan2 = buffer[position + 2]; | |
enc[0] = buffer[position] >> 2; | |
enc[1] = ((buffer[position] & 3) << 4) | (buffer[++position] >> 4); | |
if (isNaN(nan1)) enc[2] = enc[3] = 64; | |
else { | |
enc[2] = ((buffer[position] & 15) << 2) | (buffer[++position] >> 6); | |
enc[3] = (isNaN(nan2)) ? 64 : buffer[position] & 63; | |
} | |
result.push(B64.alphabet[enc[0]], B64.alphabet[enc[1]], B64.alphabet[enc[2]], B64.alphabet[enc[3]]); | |
} | |
return result.join(''); | |
} else { | |
result = ''; | |
while (++position < len) { | |
nan1 = buffer[position + 1], nan2 = buffer[position + 2]; | |
enc[0] = buffer[position] >> 2; | |
enc[1] = ((buffer[position] & 3) << 4) | (buffer[++position] >> 4); | |
if (isNaN(nan1)) enc[2] = enc[3] = 64; | |
else { | |
enc[2] = ((buffer[position] & 15) << 2) | (buffer[++position] >> 6); | |
enc[3] = (isNaN(nan2)) ? 64 : buffer[position] & 63; | |
} | |
result += B64.alphabet[enc[0]] + B64.alphabet[enc[1]] + B64.alphabet[enc[2]] + B64.alphabet[enc[3]]; | |
} | |
return result; | |
} | |
}, | |
decode: function (s) { | |
var buffer = B64.fromUtf8(s), | |
position = 0, | |
len = buffer.length; | |
if (B64.ieo) { | |
result = []; | |
while (position < len) { | |
if (buffer[position] < 128) result.push(String.fromCharCode(buffer[position++])); | |
else if (buffer[position] > 191 && buffer[position] < 224) result.push(String.fromCharCode(((buffer[position++] & 31) << 6) | (buffer[position++] & 63))); | |
else result.push(String.fromCharCode(((buffer[position++] & 15) << 12) | ((buffer[position++] & 63) << 6) | (buffer[position++] & 63))); | |
} | |
return result.join(''); | |
} else { | |
result = ''; | |
while (position < len) { | |
if (buffer[position] < 128) result += String.fromCharCode(buffer[position++]); | |
else if (buffer[position] > 191 && buffer[position] < 224) result += String.fromCharCode(((buffer[position++] & 31) << 6) | (buffer[position++] & 63)); | |
else result += String.fromCharCode(((buffer[position++] & 15) << 12) | ((buffer[position++] & 63) << 6) | (buffer[position++] & 63)); | |
} | |
return result; | |
} | |
}, | |
toUtf8: function (s) { | |
var position = -1, | |
len = s.length, | |
chr, buffer = []; | |
if (/^[\x00-\x7f]*$/.test(s)) while (++position < len) | |
buffer.push(s.charCodeAt(position)); | |
else while (++position < len) { | |
chr = s.charCodeAt(position); | |
if (chr < 128) buffer.push(chr); | |
else if (chr < 2048) buffer.push((chr >> 6) | 192, (chr & 63) | 128); | |
else buffer.push((chr >> 12) | 224, ((chr >> 6) & 63) | 128, (chr & 63) | 128); | |
} | |
return buffer; | |
}, | |
fromUtf8: function (s) { | |
var position = -1, | |
len, buffer = [], | |
enc = [, , , ]; | |
if (!B64.lookup) { | |
len = B64.alphabet.length; | |
B64.lookup = {}; | |
while (++position < len) | |
B64.lookup[B64.alphabet[position]] = position; | |
position = -1; | |
} | |
len = s.length; | |
while (position < len) { | |
enc[0] = B64.lookup[s.charAt(++position)]; | |
enc[1] = B64.lookup[s.charAt(++position)]; | |
buffer.push((enc[0] << 2) | (enc[1] >> 4)); | |
enc[2] = B64.lookup[s.charAt(++position)]; | |
if (enc[2] == 64) break; | |
buffer.push(((enc[1] & 15) << 4) | (enc[2] >> 2)); | |
enc[3] = B64.lookup[s.charAt(++position)]; | |
if (enc[3] == 64) break; | |
buffer.push(((enc[2] & 3) << 6) | enc[3]); | |
} | |
return buffer; | |
} | |
}; |
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