locutus/esm/php/url/base64_decode.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

import { getPhpGlobalCallable, getPhpGlobalEntry, getPhpObjectEntry } from "../_helpers/_phpRuntimeState.js";
import { isObjectLike, isPhpCallable } from "../_helpers/_phpTypes.js";
export function base64_decode(encodedData) {
    //  discuss at: https://locutus.io/php/base64_decode/
    // original by: Tyler Akins (https://rumkin.com)
    // improved by: Thunder.m
    // improved by: Kevin van Zonneveld (https://kvz.io)
    // improved by: Kevin van Zonneveld (https://kvz.io)
    //    input by: Aman Gupta
    //    input by: Brett Zamir (https://brett-zamir.me)
    // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
    // bugfixed by: Pellentesque Malesuada
    // bugfixed by: Kevin van Zonneveld (https://kvz.io)
    // improved by: Indigo744
    //   example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==')
    //   returns 1: 'Kevin van Zonneveld'
    //   example 2: base64_decode('YQ==')
    //   returns 2: 'a'
    //   example 3: base64_decode('4pyTIMOgIGxhIG1vZGU=')
    //   returns 3: '✓ à la mode'
    // decodeUTF8string()
    // Internal function to decode properly UTF8 string
    // Adapted from Solution #1 at https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
    const decodeUTF8string = function (str) {
        // Going backwards: from bytestream, to percent-encoding, to original string.
        return decodeURIComponent(str
            .split('')
            .map(function (c) {
            return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
        })
            .join(''));
    };
    const bufferValue = getPhpGlobalEntry('Buffer');
    if (isObjectLike(bufferValue)) {
        const bufferFrom = getPhpObjectEntry(bufferValue, 'from');
        if (isPhpCallable(bufferFrom)) {
            const decoded = bufferFrom.call(bufferValue, String(encodedData), 'base64');
            if (typeof decoded === 'object' && decoded !== null) {
                const decodedToString = getPhpObjectEntry(decoded, 'toString');
                if (isPhpCallable(decodedToString)) {
                    const utf8Value = decodedToString.call(decoded, 'utf-8');
                    if (typeof utf8Value === 'string') {
                        return utf8Value;
                    }
                }
            }
        }
    }
    const atobValue = getPhpGlobalCallable('atob');
    if (atobValue) {
        const decoded = atobValue(String(encodedData));
        if (typeof decoded === 'string') {
            return decodeUTF8string(decoded);
        }
    }
    const b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
    let o1;
    let o2;
    let o3;
    let h1;
    let h2;
    let h3;
    let h4;
    let bits;
    let i = 0;
    let ac = 0;
    let dec = '';
    const tmpArr = [];
    if (!encodedData) {
        return encodedData;
    }
    encodedData += '';
    do {
        // unpack four hexets into three octets using index points in b64
        h1 = b64.indexOf(encodedData.charAt(i++));
        h2 = b64.indexOf(encodedData.charAt(i++));
        h3 = b64.indexOf(encodedData.charAt(i++));
        h4 = b64.indexOf(encodedData.charAt(i++));
        bits = (h1 << 18) | (h2 << 12) | (h3 << 6) | h4;
        o1 = (bits >> 16) & 0xff;
        o2 = (bits >> 8) & 0xff;
        o3 = bits & 0xff;
        if (h3 === 64) {
            tmpArr[ac++] = String.fromCharCode(o1);
        }
        else if (h4 === 64) {
            tmpArr[ac++] = String.fromCharCode(o1, o2);
        }
        else {
            tmpArr[ac++] = String.fromCharCode(o1, o2, o3);
        }
    } while (i < encodedData.length);
    dec = tmpArr.join('');
    return decodeUTF8string(dec.replace(/\0+$/, ''));
}