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- /*
- * vim: ts=4:sw=4:expandtab
- */
- ;(function() {
- "use strict";
- window.StringView = {
- /*
- * These functions from the Mozilla Developer Network
- * and have been placed in the public domain.
- * https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
- * https://developer.mozilla.org/en-US/docs/MDN/About#Copyrights_and_licenses
- */
- b64ToUint6: function(nChr) {
- return nChr > 64 && nChr < 91 ?
- nChr - 65
- : nChr > 96 && nChr < 123 ?
- nChr - 71
- : nChr > 47 && nChr < 58 ?
- nChr + 4
- : nChr === 43 ?
- 62
- : nChr === 47 ?
- 63
- :
- 0;
- },
- base64ToBytes: function(sBase64, nBlocksSize) {
- var
- sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,
- nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize : nInLen * 3 + 1 >> 2;
- var aBBytes = new ArrayBuffer(nOutLen);
- var taBytes = new Uint8Array(aBBytes);
- for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
- nMod4 = nInIdx & 3;
- nUint24 |= StringView.b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;
- if (nMod4 === 3 || nInLen - nInIdx === 1) {
- for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
- taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
- }
- nUint24 = 0;
- }
- }
- return aBBytes;
- },
- uint6ToB64: function(nUint6) {
- return nUint6 < 26 ?
- nUint6 + 65
- : nUint6 < 52 ?
- nUint6 + 71
- : nUint6 < 62 ?
- nUint6 - 4
- : nUint6 === 62 ?
- 43
- : nUint6 === 63 ?
- 47
- :
- 65;
- },
- bytesToBase64: function(aBytes) {
- var nMod3, sB64Enc = "";
- for (var nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
- nMod3 = nIdx % 3;
- if (nIdx > 0 && (nIdx * 4 / 3) % 76 === 0) { sB64Enc += "\r\n"; }
- nUint24 |= aBytes[nIdx] << (16 >>> nMod3 & 24);
- if (nMod3 === 2 || aBytes.length - nIdx === 1) {
- sB64Enc += String.fromCharCode(
- StringView.uint6ToB64(nUint24 >>> 18 & 63),
- StringView.uint6ToB64(nUint24 >>> 12 & 63),
- StringView.uint6ToB64(nUint24 >>> 6 & 63),
- StringView.uint6ToB64(nUint24 & 63)
- );
- nUint24 = 0;
- }
- }
- return sB64Enc.replace(/A(?=A$|$)/g, "=");
- }
- };
- }());
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