mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
47 lines
1.0 KiB
JavaScript
47 lines
1.0 KiB
JavaScript
function base64DecToArr (sBase64) {
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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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var
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nInLen = sBase64.length,
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nOutLen = 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(sBase64.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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