57 lines
1.8 KiB
TypeScript
57 lines
1.8 KiB
TypeScript
import { explodeSector13, D13O } from './format_utils';
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import { NibbleDisk, DiskOptions, ENCODING_NIBBLE } from './types';
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/**
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* Returns a `Disk` object from DOS 3.2-ordered image data.
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* @param options the disk image and options
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* @returns A nibblized disk
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*/
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export default function createDiskFromDOS13(options: DiskOptions) {
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const { data, name, side, rawData, volume, readOnly } = options;
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const disk: NibbleDisk = {
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format: 'd13',
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encoding: ENCODING_NIBBLE,
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name,
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side,
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volume,
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readOnly,
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tracks: []
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};
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if (!data && !rawData) {
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throw new Error('data or rawData required');
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}
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/*
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* DOS 13-sector disks have the physical sectors skewed on the track. The skew
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* between physical sectors is 10 (A), resulting in the following physical order:
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*
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* 0 A 7 4 1 B 8 5 2 C 9 6 3
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*
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* Note that because physical sector == logical sector, this works slightly
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* differently from the DOS and ProDOS nibblizers.
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*/
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for (let t = 0; t < 35; t++) {
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let track: number[] = [];
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for (let disk_sector = 0; disk_sector < 13; disk_sector++) {
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const physical_sector = D13O[disk_sector];
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let sector: Uint8Array;
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if (rawData) {
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const off = (13 * t + physical_sector) * 256;
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sector = new Uint8Array(rawData.slice(off, off + 256));
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} else if (data) {
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sector = data[t][physical_sector];
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} else {
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throw new Error('Requires data or rawData');
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}
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track = track.concat(
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explodeSector13(volume, t, physical_sector, sector)
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);
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}
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disk.tracks.push(new Uint8Array(track));
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}
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return disk;
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}
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