@creit.tech/stellar-wallets-kit/script/deps/jsr.io/@std/encoding/1.0.10/ascii85.js

A kit to handle all Stellar Wallets at once

"use strict";
// Copyright 2018-2025 the Deno authors. MIT license.
// This module is browser compatible.
Object.defineProperty(exports, "__esModule", { value: true });
exports.encodeAscii85 = encodeAscii85;
exports.decodeAscii85 = decodeAscii85;
/**
 * Utilities for working with {@link https://en.wikipedia.org/wiki/Ascii85 | ascii85} encoding.
 *
 * ## Specifying a standard and delimiter
 *
 * By default, all functions are using the most popular Adobe version of ascii85
 * and not adding any delimiter. However, there are three more standards
 * supported - btoa (different delimiter and additional compression of 4 bytes
 * equal to 32), {@link https://rfc.zeromq.org/spec/32/ | Z85} and
 * {@link https://www.rfc-editor.org/rfc/rfc1924.html | RFC 1924}. It's possible to use a
 * different encoding by specifying it in `options` object as a second parameter.
 *
 * Similarly, it's possible to make `encode` add a delimiter (`<~` and `~>` for
 * Adobe, `xbtoa Begin` and `xbtoa End` with newlines between the delimiters and
 * encoded data for btoa. Checksums for btoa are not supported. Delimiters are not
 * supported by other encodings.)
 *
 * @module
 */
const _validate_binary_like_js_1 = require("./_validate_binary_like.js");
const rfc1924 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
const Z85 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#";
/**
 * Converts data into an ascii85-encoded string.
 *
 * @param data The data to encode.
 * @param options Options for encoding.
 *
 * @returns The ascii85-encoded string.
 *
 * @example Usage
 * ```ts
 * import { encodeAscii85 } from "@std/encoding/ascii85";
 * import { assertEquals } from "@std/assert";
 *
 * assertEquals(encodeAscii85("Hello world!"), "87cURD]j7BEbo80");
 * ```
 */
function encodeAscii85(data, options = {}) {
    let uint8 = (0, _validate_binary_like_js_1.validateBinaryLike)(data);
    const { standard = "Adobe" } = options;
    let output = [];
    let v;
    let n = 0;
    let difference = 0;
    if (uint8.length % 4 !== 0) {
        const tmp = uint8;
        difference = 4 - (tmp.length % 4);
        uint8 = new Uint8Array(tmp.length + difference);
        uint8.set(tmp);
    }
    const view = new DataView(uint8.buffer, uint8.byteOffset, uint8.byteLength);
    for (let i = 0; i < uint8.length; i += 4) {
        v = view.getUint32(i);
        // Adobe and btoa standards compress 4 zeroes to single "z" character
        if ((standard === "Adobe" || standard === "btoa") &&
            v === 0 &&
            i < uint8.length - difference - 3) {
            output[n++] = "z";
            continue;
        }
        // btoa compresses 4 spaces - that is, bytes equal to 32 - into single "y" character
        if (standard === "btoa" && v === 538976288) {
            output[n++] = "y";
            continue;
        }
        for (let j = 4; j >= 0; j--) {
            output[n + j] = String.fromCharCode((v % 85) + 33);
            v = Math.trunc(v / 85);
        }
        n += 5;
    }
    switch (standard) {
        case "Adobe":
            if (options?.delimiter) {
                return `<~${output.slice(0, output.length - difference).join("")}~>`;
            }
            break;
        case "btoa":
            if (options?.delimiter) {
                return `xbtoa Begin\n${output
                    .slice(0, output.length - difference)
                    .join("")}\nxbtoa End`;
            }
            break;
        case "RFC 1924":
            output = output.map((val) => rfc1924[val.charCodeAt(0) - 33]);
            break;
        case "Z85":
            output = output.map((val) => Z85[val.charCodeAt(0) - 33]);
            break;
    }
    return output.slice(0, output.length - difference).join("");
}
/**
 * Decodes a ascii85-encoded string.
 *
 * @param ascii85 The ascii85-encoded string to decode.
 * @param options Options for decoding.
 * @returns The decoded data.
 *
 * @example Usage
 * ```ts
 * import { decodeAscii85 } from "@std/encoding/ascii85";
 * import { assertEquals } from "@std/assert";
 *
 * assertEquals(
 *   decodeAscii85("87cURD]j7BEbo80"),
 *   new TextEncoder().encode("Hello world!"),
 * );
 * ```
 */
function decodeAscii85(ascii85, options = {}) {
    const { standard = "Adobe" } = options;
    // translate all encodings to most basic adobe/btoa one and decompress some special characters ("z" and "y")
    switch (standard) {
        case "Adobe":
            ascii85 = ascii85.replaceAll(/(<~|~>)/g, "").replaceAll("z", "!!!!!");
            break;
        case "btoa":
            ascii85 = ascii85
                .replaceAll(/(xbtoa Begin|xbtoa End|\n)/g, "")
                .replaceAll("z", "!!!!!")
                .replaceAll("y", "+<VdL");
            break;
        case "RFC 1924":
            ascii85 = ascii85.replaceAll(/./g, (match) => String.fromCharCode(rfc1924.indexOf(match) + 33));
            break;
        case "Z85":
            ascii85 = ascii85.replaceAll(/./g, (match) => String.fromCharCode(Z85.indexOf(match) + 33));
            break;
    }
    // remove all invalid characters
    ascii85 = ascii85.replaceAll(/[^!-u]/g, "");
    const len = ascii85.length;
    const output = new Uint8Array(len + 4 - (len % 4));
    const view = new DataView(output.buffer);
    let v = 0;
    let n = 0;
    let max = 0;
    for (let i = 0; i < len;) {
        for (max += 5; i < max; i++) {
            v = v * 85 + (i < len ? ascii85.charCodeAt(i) : 117) - 33;
        }
        view.setUint32(n, v);
        v = 0;
        n += 4;
    }
    return output.slice(0, Math.trunc(len * 0.8));
}