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00df61d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 | /**
* @license
* Copyright 2020 The Emscripten Authors
* SPDX-License-Identifier: MIT
*/
addToLibrary({
// Decodes a _known valid_ base64 string (without validation) and returns it as a new Uint8Array.
// Benchmarked to be around 5x faster compared to a simple
// "Uint8Array.from(atob(b64), c => c.charCodeAt(0))" (TODO: perhaps use this form in -Oz builds?)
#if !JS_BASE64_API
$base64Decode__postset: `
// Precreate a reverse lookup table from chars
// "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" back to
// bytes to make decoding fast.
for (var base64ReverseLookup = new Uint8Array(123/*'z'+1*/), __b64i = 25; __b64i >= 0; --__b64i) {
base64ReverseLookup[48+__b64i] = 52+__b64i; // '0-9'
base64ReverseLookup[65+__b64i] = __b64i; // 'A-Z'
base64ReverseLookup[97+__b64i] = 26+__b64i; // 'a-z'
}
base64ReverseLookup[43] = 62; // '+'
base64ReverseLookup[47] = 63; // '/'
`,
#endif
$base64Decode__docs: '/** @noinline */',
$base64Decode: (b64) => {
#if JS_BASE64_API
return Uint8Array.fromBase64(b64);
#else
#if ENVIRONMENT_MAY_BE_NODE
if (ENVIRONMENT_IS_NODE) {
var buf = Buffer.from(b64, 'base64');
return new Uint8Array(buf.buffer, buf.byteOffset, buf.length);
}
#endif
#if ASSERTIONS
assert(b64.length % 4 == 0);
#endif
var b1, b2, i = 0, j = 0, bLength = b64.length;
var output = new Uint8Array((bLength*3>>2) - (b64[bLength-2] == '=') - (b64[bLength-1] == '='));
for (; i < bLength; i += 4, j += 3) {
b1 = base64ReverseLookup[b64.charCodeAt(i+1)];
b2 = base64ReverseLookup[b64.charCodeAt(i+2)];
output[j] = base64ReverseLookup[b64.charCodeAt(i)] << 2 | b1 >> 4;
output[j+1] = b1 << 4 | b2 >> 2;
output[j+2] = b2 << 6 | base64ReverseLookup[b64.charCodeAt(i+3)];
}
return output;
#endif
},
});
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