tjc-sdk/dist/client/util/base64.js

TIANJI IM SDK

// 使用 Buffer 来处理 base64
import { Buffer } from 'buffer';

const c = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

export function btoa(e) {
    for (
        var t, r, o = String(e), n = 0, a = c, i = "";
        o.charAt(0 | n) || ((a = "="), n % 1);
        i += a.charAt(63 & (t >> (8 - (n % 1) * 8)))
    ) {
        if (255 < (r = o.charCodeAt((n += 0.75))))
            throw new Error(
                "'btoa' failed: The string to be encoded contains characters outside of the Latin1 range."
            );
        t = (t << 8) | r;
    }
    return i;
}

export function atob(e) {
    var t = String(e).replace(/[=]+$/, "");
    if (t.length % 4 == 1)
        throw new Error(
            "'atob' failed: The string to be decoded is not correctly encoded."
        );
    for (
        var r, o, n = 0, a = 0, i = "";
        (o = t.charAt(a++));
        ~o && ((r = n % 4 ? 64 * r + o : o), n++ % 4)
            ? (i += String.fromCharCode(255 & (r >> ((-2 * n) & 6))))
            : 0
    )
        o = c.indexOf(o);
    return i;
}

/**
 * UTF-8 字符串转 base64
 * @param {string} str UTF-8 字符串
 * @returns {string} base64 字符串
 */
export function utf8_to_b64(str) {
    return btoa(unescape(encodeURIComponent(str)));
}

/**
 * base64 转 UTF-8 字符串
 * @param {string} str base64 字符串
 * @returns {string} UTF-8 字符串
 */
export function b64_to_utf8(str) {
    return decodeURIComponent(escape(atob(str)));
}

/**
 * base64 转 ArrayBuffer
 * @param {string} str base64 字符串
 * @returns {ArrayBuffer} ArrayBuffer
 */
export function b64_to_arrayBuffer(str) {
    let binary_string = atob(str);
    let len = binary_string.length;
    let bytes = new Uint8Array(len);
    for (let i = 0; i < len; i++) {
        bytes[i] = binary_string.charCodeAt(i);
    }
    return bytes.buffer;
}

/**
 * ArrayBuffer 转 base64
 * @param {ArrayBuffer} data ArrayBuffer
 * @returns {string} base64 字符串
 */
export function arrayBuffer_to_b64(data) {
    return Buffer.from(data).toString('base64');
}

/**
 * URL 安全的 base64 解码
 * @param {string} str URL 安全的 base64 字符串
 * @returns {string} 标准 base64 字符串
 */
export function unescape(str) {
    return (str + '==='.slice((str.length + 3) % 4))
        .replace(/-/g, '+')
        .replace(/_/g, '/');
}

/**
 * URL 安全的 base64 编码
 * @param {string} str 标准 base64 字符串
 * @returns {string} URL 安全的 base64 字符串
 */
export function escape(str) {
    return str.replace(/\+/g, '-')
        .replace(/\//g, '_')
        .replace(/=/g, '');
}

export default {
    btoa,
    atob,
    utf8_to_b64,
    b64_to_utf8,
    b64_to_arrayBuffer,
    arrayBuffer_to_b64,
    unescape,
    escape
};