apple2js/js/ui/tape.ts
Ian Flanigan 04ae0327c2
Add the recommended eslint plugins for TypeScript (#121)
This adds both the recommended TypeScript checks, plus the recommended
TypeScript checks that require type checking.  This latter addition
means that eslint essentially has to compile all of the TypeScript in
the project, causing it to be slower. This isn't much of a problem in
VS Code because there's a lot of caching being done, but it's clearly
slower when run on the commandline.

All of the errors are either fixed or suppressed.  Some errors are
suppressed because fixing them would be too laborious for the little
value gained.

The eslint config is also slightly refactored to separate the strictly
TypeScript checks from the JavaScript checks.
2022-05-31 08:38:40 -07:00

75 lines
2.9 KiB
TypeScript

import { TapeData } from '../types';
import Apple2IO from '../apple2io';
import { debug } from '../util';
export const TAPE_TYPES = ['wav', 'aiff', 'aif', 'mp3', 'm4a'] as const;
export default class Tape {
constructor(private readonly io: Apple2IO) {}
public doLoadLocalTape(file: File, done?: () => void) {
const kHz = this.io.getKHz();
// Audio Buffer Source
let context: AudioContext;
if (AudioContext) {
context = new AudioContext();
} else {
window.alert('Not supported by your browser');
done && done();
return;
}
const fileReader = new FileReader();
fileReader.onload = (ev: ProgressEvent) => {
const target: FileReader = ev.target as FileReader;
const result: ArrayBuffer = target.result as ArrayBuffer;
context.decodeAudioData(result).then((buffer) => {
const buf: TapeData = [];
const data = buffer.getChannelData(0);
let datum = data[0];
let old = (datum > 0.0), current;
let last = 0;
let delta: number;
debug(`Sample Count: ${data.length}`);
debug(`Sample rate: ${buffer.sampleRate}`);
for (let idx = 1; idx < data.length; idx++) {
datum = data[idx];
if ((datum > 0.1) || (datum < -0.1)) {
current = (datum > 0.0);
if (current !== old) {
delta = idx - last;
if (delta > 2000000) {
delta = 2000000;
}
let ival = delta / buffer.sampleRate * 1000;
if (ival >= 0.550 && ival < 0.750) {
ival = 0.650; // Header
} else if (ival >= 0.175 && ival < 0.225) {
ival = 0.200; // sync 1
} else if (ival >= 0.225 && ival < 0.275) {
ival = 0.250; // 0 / sync 2
} else if (ival >= 0.450 && ival < 0.550) {
ival = 0.500; // 1
} else {
// debug(idx + ' ' + buf.length + ' ' + ival);
}
buf.push([ival * kHz, current]);
old = current;
last = idx;
}
}
}
this.io.setTape(buf);
if (done) {
done();
}
}, (error: Error) => {
window.alert(error.message);
});
};
fileReader.readAsArrayBuffer(file);
}
}