apple2js/js/base64.ts

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import { memory } from './types';
const B64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
/** Encode an array of bytes in base64. */
export function base64_encode(data: null | undefined): undefined;
export function base64_encode(data: memory): string;
export function base64_encode(data: memory | null | undefined): string | undefined {
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// Twacked by Will Scullin to handle arrays of 'bytes'
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// http://kevin.vanzonneveld.net
// + original by: Tyler Akins (http://rumkin.com)
// + improved by: Bayron Guevara
// + improved by: Thunder.m
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// + bugfixed by: Pellentesque Malesuada
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// - depends on: utf8_encode
// * example 1: base64_encode('Kevin van Zonneveld');
// * returns 1: 'S2V2aW4gdmFuIFpvbm5ldmVsZA=='
// mozilla has this native
// - but breaks in 2.0.0.12!
//if (typeof this.window['atob'] == 'function') {
// return atob(data);
//}
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let o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0, enc='';
const tmp_arr = [];
if (!data) {
return undefined;
}
do { // pack three octets into four hexets
o1 = data[i++];
o2 = data[i++];
o3 = data[i++];
bits = o1<<16 | o2<<8 | o3;
h1 = bits>>18 & 0x3f;
h2 = bits>>12 & 0x3f;
h3 = bits>>6 & 0x3f;
h4 = bits & 0x3f;
// use hexets to index into b64, and append result to encoded string
tmp_arr[ac++] = B64.charAt(h1) + B64.charAt(h2) + B64.charAt(h3) + B64.charAt(h4);
} while (i < data.length);
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enc = tmp_arr.join('');
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switch (data.length % 3) {
case 1:
enc = enc.slice(0, -2) + '==';
break;
case 2:
enc = enc.slice(0, -1) + '=';
break;
}
return enc;
}
/** Returns undefined if the input is null or undefined. */
export function base64_decode(data: null | undefined): undefined;
/** Returns an array of bytes from the given base64-encoded string. */
export function base64_decode(data: string): memory;
/** Returns an array of bytes from the given base64-encoded string. */
export function base64_decode(data: string | null | undefined): memory | undefined {
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// Twacked by Will Scullin to handle arrays of 'bytes'
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// http://kevin.vanzonneveld.net
// + original by: Tyler Akins (http://rumkin.com)
// + improved by: Thunder.m
// + input by: Aman Gupta
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// + bugfixed by: Onno Marsman
// + bugfixed by: Pellentesque Malesuada
// + improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// + input by: Brett Zamir (http://brett-zamir.me)
// + bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
// - depends on: utf8_decode
// * example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==');
// * returns 1: 'Kevin van Zonneveld'
// mozilla has this native
// - but breaks in 2.0.0.12!
//if (typeof this.window['btoa'] == 'function') {
// return btoa(data);
//}
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let o1, o2, o3, h1, h2, h3, h4, bits, i = 0, ac = 0;
const tmp_arr = [];
if (!data) {
return undefined;
}
do { // unpack four hexets into three octets using index points in B64
h1 = B64.indexOf(data.charAt(i++));
h2 = B64.indexOf(data.charAt(i++));
h3 = B64.indexOf(data.charAt(i++));
h4 = B64.indexOf(data.charAt(i++));
bits = h1<<18 | h2<<12 | h3<<6 | h4;
o1 = bits>>16 & 0xff;
o2 = bits>>8 & 0xff;
o3 = bits & 0xff;
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tmp_arr[ac++] = o1;
if (h3 != 64) {
tmp_arr[ac++] = o2;
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}
if (h4 != 64) {
tmp_arr[ac++] = o3;
}
} while (i < data.length);
Convert `cards/disk2.js` to Typescript (#54) * Convert `cards/disk2.js` to Typescript This is mostly a straightforward conversion of `cards/disk2.js` to Typescript, with the following exceptions: * `setState()` did not restore the drive light state correctly because the callback was called with the old `on` value. * `setPhase()` did not work for WOZ images. * `getBinary()` did not work for `nib` files. * `getBase64()` did not work for `nib` files and maybe didn't work right at all. Even with these fixes, local storage still doesn't work correctly. I have also added several TODOs where methods don't support WOZ disks. * Convert most uses of `memory` to `Uint8Array` There are many places in the existing code where we use `Uint8Array` directly. This change merely makes the `memory` type equivalent to `Uint8Array`. This change also changes most ROM data to be read-only in Typescript to ensure that it is not modified by mistake. This can't be done just by applying `as const` to the declaration because `Uint8Array`s are can not be expressed as literals. Instead, we create a new type, `ReadonlyUint8Array` that drops the mutation methods and makes indexed access read-only. See https://www.growingwiththeweb.com/2020/10/typescript-readonly-typed-arrays.html for details. * Tighten types and document `disk2.ts` While trying to understand the Disk ][ emulation, I tighted the types and documented the parts that I could, including references to other sources, like _Understanding the Apple //e_ by Jim Sather. The one functional change is the addition of the P6 ROM of DOS 3.2 and earlier. This is automatically selected if the card is initialized for 13 sector disks.
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return new Uint8Array(tmp_arr);
}
const DATA_URL_PREFIX = 'data:application/octet-stream;base64,';
export function base64_json_parse(json: string) {
const reviver = (_key: string, value: any) => {
if (typeof value ==='string' && value.startsWith(DATA_URL_PREFIX)) {
return base64_decode(value.slice(DATA_URL_PREFIX.length));
}
return value;
};
return JSON.parse(json, reviver);
}
export function base64_json_stringify(json: any) {
const replacer = (_key: string, value: any) => {
if (value instanceof Uint8Array) {
return DATA_URL_PREFIX + base64_encode(value);
}
return value;
};
return JSON.stringify(json, replacer);
}