@polkadot/wasm-util/cjs/base64.js

Utilities used exclusively inside Wasm decoding

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.base64Decode = base64Decode;
const CHR = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
const map = new Array(256);
for (let i = 0, count = CHR.length; i < count; i++) {
    map[CHR.charCodeAt(i)] = i;
}
/**
 * @name base64Decode
 * @description
 * A base64 decoding function that operates in all environments. Unlike decoding
 * from Buffer (Node.js only) or atob (browser-only) this implementation is
 * slightly slower, but it is platform independent.
 *
 * For our usage, since we have access to the static final size, so we decode
 * to a specified output buffer. This also means we have applied a number of
 * optimizations based on this - checking output position instead of chars.
 */
function base64Decode(data, out) {
    let byte = 0;
    let bits = 0;
    let pos = -1;
    for (let i = 0, last = out.length - 1; pos !== last; i++) {
        // each character represents 6 bits
        byte = (byte << 6) | map[data.charCodeAt(i)];
        // each byte needs to contain 8 bits
        if ((bits += 6) >= 8) {
            out[++pos] = (byte >>> (bits -= 8)) & 0xff;
        }
    }
    return out;
}