add code from MDN
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AJ ONeal
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README.md
35
README.md
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@ -4,10 +4,41 @@ utf8-typed
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Base64, TypedArrays, and UTF-8 / Unicode conversions in Browser (and Node) JavaScript
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This is based wholly on the work by good folks at the MDN.
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See <https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding>
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See https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
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Examples
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========
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```javascript
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// Base64
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var myArray = base64DecToArr("QmFzZSA2NCDigJQgTW96aWxsYSBEZXZlbG9wZXIgTmV0d29yaw=="); // "Base 64 \u2014 Mozilla Developer Network"
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var myBuffer = base64DecToArr("QmFzZSA2NCDigJQgTW96aWxsYSBEZXZlbG9wZXIgTmV0d29yaw==").buffer; // "Base 64 \u2014 Mozilla Developer Network"
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console.log(myBuffer.byteLength);
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// Crazy Unicode
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var sMyInput = "I'm a ☢ ☃ that plays 𝄢 guitar and spea̧͈͖ks Ar̽̾̈́͒͑ ̶̧̨̱̹̭̯ͧ̾ͬC̷̙̲̝͖ͭ̏ͥͮ͟Oͮ͏̮̪̝͍M̲̖͊̒ͪͩͬ̚̚͜!";
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var aMyUTF8Input = strToUTF8Arr(sMyInput);
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var sMyBase64 = base64EncArr(aMyUTF8Input);
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alert(sMyBase64);
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var aMyUTF8Output = base64DecToArr(sMyBase64);
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var sMyOutput = UTF8ArrToStr(aMyUTF8Output);
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alert(sMyOutput);
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```
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License
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=======
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Mozilla has licensed this code in the Public Domain, which means that I am at liberty to re-license my copy under the Apache 2, which is something that, general speaking, your legal department will feel more comfortable with.
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Mozilla has licensed this code in the Public Domain, which means that I am at liberty to re-license my copy
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under the Apache 2, which is something that, general speaking, your legal department will feel more comfortable with.
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See <https://developer.mozilla.org/en-US/docs/MDN/About#Copyrights_and_licenses>
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@ -0,0 +1,172 @@
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"use strict";
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/*\
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|*|
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|*| Base64 / binary data / UTF-8 strings utilities
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|*|
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|*| https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding
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|*|
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\*/
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/* Array of bytes to base64 string decoding */
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function b64ToUint6 (nChr) {
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return nChr > 64 && nChr < 91 ?
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nChr - 65
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: nChr > 96 && nChr < 123 ?
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nChr - 71
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: nChr > 47 && nChr < 58 ?
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nChr + 4
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: nChr === 43 ?
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62
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: nChr === 47 ?
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63
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:
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0;
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}
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function base64DecToArr (sBase64, nBlocksSize) {
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var
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sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,
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nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize : nInLen * 3 + 1 >> 2, taBytes = new Uint8Array(nOutLen);
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for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
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nMod4 = nInIdx & 3;
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nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 6 * (3 - nMod4);
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if (nMod4 === 3 || nInLen - nInIdx === 1) {
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for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
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taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
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}
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nUint24 = 0;
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}
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}
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return taBytes;
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}
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/* Base64 string to array encoding */
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function uint6ToB64 (nUint6) {
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return nUint6 < 26 ?
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nUint6 + 65
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: nUint6 < 52 ?
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nUint6 + 71
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: nUint6 < 62 ?
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nUint6 - 4
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: nUint6 === 62 ?
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43
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: nUint6 === 63 ?
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47
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:
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65;
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}
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function base64EncArr (aBytes) {
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var nMod3 = 2, sB64Enc = "";
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for (var nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
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nMod3 = nIdx % 3;
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if (nIdx > 0 && (nIdx * 4 / 3) % 76 === 0) { sB64Enc += "\r\n"; }
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nUint24 |= aBytes[nIdx] << (16 >>> nMod3 & 24);
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if (nMod3 === 2 || aBytes.length - nIdx === 1) {
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sB64Enc += String.fromCharCode(uint6ToB64(nUint24 >>> 18 & 63), uint6ToB64(nUint24 >>> 12 & 63), uint6ToB64(nUint24 >>> 6 & 63), uint6ToB64(nUint24 & 63));
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nUint24 = 0;
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}
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}
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return sB64Enc.substr(0, sB64Enc.length - 2 + nMod3) + (nMod3 === 2 ? '' : nMod3 === 1 ? '=' : '==');
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}
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/* UTF-8 array to DOMString and vice versa */
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function UTF8ArrToStr (aBytes) {
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var sView = "";
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for (var nPart, nLen = aBytes.length, nIdx = 0; nIdx < nLen; nIdx++) {
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nPart = aBytes[nIdx];
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sView += String.fromCharCode(
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nPart > 251 && nPart < 254 && nIdx + 5 < nLen ? /* six bytes */
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/* (nPart - 252 << 30) may be not so safe in ECMAScript! So...: */
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(nPart - 252) * 1073741824 + (aBytes[++nIdx] - 128 << 24) + (aBytes[++nIdx] - 128 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
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: nPart > 247 && nPart < 252 && nIdx + 4 < nLen ? /* five bytes */
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(nPart - 248 << 24) + (aBytes[++nIdx] - 128 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
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: nPart > 239 && nPart < 248 && nIdx + 3 < nLen ? /* four bytes */
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(nPart - 240 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
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: nPart > 223 && nPart < 240 && nIdx + 2 < nLen ? /* three bytes */
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(nPart - 224 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
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: nPart > 191 && nPart < 224 && nIdx + 1 < nLen ? /* two bytes */
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(nPart - 192 << 6) + aBytes[++nIdx] - 128
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: /* nPart < 127 ? */ /* one byte */
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nPart
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);
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}
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return sView;
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}
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function strToUTF8Arr (sDOMStr) {
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var aBytes, nChr, nStrLen = sDOMStr.length, nArrLen = 0;
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/* mapping... */
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for (var nMapIdx = 0; nMapIdx < nStrLen; nMapIdx++) {
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nChr = sDOMStr.charCodeAt(nMapIdx);
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nArrLen += nChr < 0x80 ? 1 : nChr < 0x800 ? 2 : nChr < 0x10000 ? 3 : nChr < 0x200000 ? 4 : nChr < 0x4000000 ? 5 : 6;
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}
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aBytes = new Uint8Array(nArrLen);
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/* transcription... */
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for (var nIdx = 0, nChrIdx = 0; nIdx < nArrLen; nChrIdx++) {
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nChr = sDOMStr.charCodeAt(nChrIdx);
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if (nChr < 128) {
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/* one byte */
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aBytes[nIdx++] = nChr;
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} else if (nChr < 0x800) {
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/* two bytes */
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aBytes[nIdx++] = 192 + (nChr >>> 6);
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aBytes[nIdx++] = 128 + (nChr & 63);
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} else if (nChr < 0x10000) {
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/* three bytes */
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aBytes[nIdx++] = 224 + (nChr >>> 12);
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aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
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aBytes[nIdx++] = 128 + (nChr & 63);
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} else if (nChr < 0x200000) {
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/* four bytes */
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aBytes[nIdx++] = 240 + (nChr >>> 18);
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aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
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aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
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aBytes[nIdx++] = 128 + (nChr & 63);
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} else if (nChr < 0x4000000) {
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/* five bytes */
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aBytes[nIdx++] = 248 + (nChr >>> 24);
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aBytes[nIdx++] = 128 + (nChr >>> 18 & 63);
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aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
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aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
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aBytes[nIdx++] = 128 + (nChr & 63);
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} else /* if (nChr <= 0x7fffffff) */ {
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/* six bytes */
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aBytes[nIdx++] = 252 + (nChr >>> 30);
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aBytes[nIdx++] = 128 + (nChr >>> 24 & 63);
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aBytes[nIdx++] = 128 + (nChr >>> 18 & 63);
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aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
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aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
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aBytes[nIdx++] = 128 + (nChr & 63);
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}
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}
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return aBytes;
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}
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