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Groundwork for loading local disk images in PCjs

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This commit is contained in:
Jeff Parsons 2014-11-09 18:57:13 -08:00 • committed by jeffpar
commit 43860a588c
20 changed files with 1355 additions and 1157 deletions
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62
my_modules/diskdump/lib/diskdump.js
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@ -45,6 +45,7 @@ var net = require("../../shared/lib/netlib");
var proc = require("../../shared/lib/proclib");
var str = require("../../shared/lib/strlib");
var usr = require("../../shared/lib/usrlib");
var DiskAPI = require("../../shared/lib/diskapi");
var DumpAPI = require("../../shared/lib/dumpapi");
var X86 = require("../../pcjs-client/lib/x86");
@ -177,38 +178,6 @@ DiskDump.sCopyright = "© 2012-2014 by Jeff Parsons (@jeffpar)";
DiskDump.sNotice = DiskDump.sAPIURL + " " + DiskDump.sCopyright;
DiskDump.sUsage = "Usage: " + DiskDump.sAPIURL + "?" + DumpAPI.QUERY.PATH + "={url}&" + DumpAPI.QUERY.FORMAT + "=json|data|hex|bytes|img";
/*
* TODO: The following descriptions of common disk data structures should be moved to a common (shared) module,
* so that client code (eg, PCjs components) can access them, too (eg, something like /my_modules/shared/lib/bpbdefs.js)
*/
DiskDump.DisketteFormats = {
163840: [1,40,8], // media type 0xFE: 1 head (single-sided), 40 cylinders, 8 sectors/track, ( 320 total sectors x 512 bytes/sector == 163840)
184320: [1,40,9], // media type 0xFC: 1 head (single-sided), 40 cylinders, 9 sectors/track, ( 360 total sectors x 512 bytes/sector == 184320)
327680: [2,40,8], // media type 0xFF: 2 heads (double-sided), 40 cylinders, 8 sectors/track, ( 640 total sectors x 512 bytes/sector == 327680)
368640: [2,40,9], // media type 0xFD: 2 heads (double-sided), 40 cylinders, 9 sectors/track, ( 720 total sectors x 512 bytes/sector == 368640)
737280: [2,80,9], // media type 0xF9: 2 heads (double-sided), 80 cylinders, 9 sectors/track, (1440 total sectors x 512 bytes/sector == 737280)
1228800: [2,80,15], // media type 0xF9: 2 heads (double-sided), 80 cylinders, 15 sectors/track, (2400 total sectors x 512 bytes/sector == 1228800)
1474560: [2,80,18], // media type 0xF0: 2 heads (double-sided), 80 cylinders, 18 sectors/track, (2880 total sectors x 512 bytes/sector == 1474560)
2949120: [2,80,36] // media type 0xF0: 2 heads (double-sided), 80 cylinders, 36 sectors/track, (5760 total sectors x 512 bytes/sector == 2949120)
};
DiskDump.BPB = {
JMP_OPCODE: 0x00, // 1 byte for a JMP opcode, followed by a 1 or 2-byte offset
OEM_STRING: 0x03, // 8 bytes
SECTOR_BYTES: 0x0B, // 2 bytes: bytes per sector (eg, 0x200 or 512)
CLUSTER_SECS: 0x0D, // 1 byte: sectors per cluster (eg, 1)
RESERVED_SECS: 0x0E, // 2 bytes: reserved sectors; ie, # sectors preceding the first FAT--usually just the boot sector (eg, 1)
FAT_TOTAL: 0x10, // 1 byte: FAT copies (eg, 2)
ROOT_ENTRIES: 0x11, // 2 bytes: root directory entries (eg, 0x40 or 64) 0x40 * 0x20 = 0x800 (1 sector is 0x200 bytes, total of 4 sectors)
SECTOR_TOTAL: 0x13, // 2 bytes: number of sectors (eg, 0x140 or 320)
MEDIA_TYPE: 0x15, // 1 byte: media type (eg, 0xFF: 320Kb, 0xFE: 160Kb, 0xFD: 360Kb, 0xFC: 180Kb)
FAT_SECS: 0x16, // 2 bytes: sectors per FAT (eg, 1)
TRACK_SECS: 0x18, // 2 bytes: sectors per track (eg, 8)
HEAD_TOTAL: 0x1A, // 2 bytes: number of heads (eg, 1)
HIDDEN_SECS: 0x1C, // 4 bytes: number of hidden sectors (always 0 for non-partitioned media)
LARGE_SECS: 0x20 // 4 bytes: number of sectors if SECTOR_TOTAL is zero
};
/*
* MY_VOL_LABEL is our default label, used whenever a more suitable label (eg, based on the disk image's folder name)
* is not available or not supplied, and MY_OEM_STRING is inserted into any DiskDump-generated diskette images.
@ -2129,8 +2098,8 @@ DiskDump.prototype.convertToJSON = function()
*/
}
var bByte0 = this.bufDisk.readUInt8(offBootSector + DiskDump.BPB.JMP_OPCODE);
var cbSectorBPB = this.bufDisk.readUInt16LE(offBootSector + DiskDump.BPB.SECTOR_BYTES);
var bByte0 = this.bufDisk.readUInt8(offBootSector + DiskAPI.BPB.JMP_OPCODE);
var cbSectorBPB = this.bufDisk.readUInt16LE(offBootSector + DiskAPI.BPB.SECTOR_BYTES);
/*
* These checks are not only necessary for DOS 1.x diskette images (and other pre-BPB images),
@ -2145,11 +2114,11 @@ DiskDump.prototype.convertToJSON = function()
* image whose logical format doesn't agree with its physical structure.
*/
var fXDFOutput = false;
var oDisketteFormat = DiskDump.DisketteFormats[cbDiskData];
if (oDisketteFormat) {
nHeads = oDisketteFormat[0];
nCylinders = oDisketteFormat[1];
nSectorsPerTrack = oDisketteFormat[2];
var disketteFormat = DiskAPI.DISKETTE_FORMATS[cbDiskData];
if (disketteFormat) {
nCylinders = disketteFormat[0];
nHeads = disketteFormat[1];
nSectorsPerTrack = disketteFormat[2];
}
else {
/*
@ -2159,10 +2128,13 @@ DiskDump.prototype.convertToJSON = function()
* 0xE9 is JMP with a 2-byte displacement). What else?
*/
if ((bByte0 == X86.OPCODE.JMP || bByte0 == X86.OPCODE.JMPS) && cbSectorBPB == cbSector) {
var nHeadsBPB = this.bufDisk.readUInt16LE(offBootSector + DiskDump.BPB.HEAD_TOTAL);
var nSectorsTotalBPB = this.bufDisk.readUInt16LE(offBootSector + DiskDump.BPB.SECTOR_TOTAL);
var nSectorsPerTrackBPB = this.bufDisk.readUInt16LE(offBootSector + DiskDump.BPB.TRACK_SECS);
var nHeadsBPB = this.bufDisk.readUInt16LE(offBootSector + DiskAPI.BPB.HEAD_TOTAL);
var nSectorsTotalBPB = this.bufDisk.readUInt16LE(offBootSector + DiskAPI.BPB.SECTOR_TOTAL);
var nSectorsPerTrackBPB = this.bufDisk.readUInt16LE(offBootSector + DiskAPI.BPB.TRACK_SECS);
if (nSectorsPerTrackBPB && nHeadsBPB) {
var nSectorsPerCylinderBPB = nSectorsPerTrackBPB * nHeadsBPB;
nHeads = nHeadsBPB;
nCylinders = Math.floor(nSectorsTotalBPB / nSectorsPerCylinderBPB);
@ -2727,13 +2699,13 @@ DiskDump.prototype.convertToIMG = function()
/*
* Mimic the BPB test in convertToJSON(), because we don't want to blast an OEM string into non-DOS diskette images
*/
var bByte0 = buf.readUInt8(DiskDump.BPB.JMP_OPCODE);
var cbSectorBPB = buf.readUInt16LE(DiskDump.BPB.SECTOR_BYTES);
var bByte0 = buf.readUInt8(DiskAPI.BPB.JMP_OPCODE);
var cbSectorBPB = buf.readUInt16LE(DiskAPI.BPB.SECTOR_BYTES);
if ((bByte0 == X86.OPCODE.JMP || bByte0 == X86.OPCODE.JMPS) && cbSectorBPB == 512) {
/*
* Overwrite the OEM string with our own, so that people know how the image originated
*/
buf.write(DiskDump.MY_OEM_STRING, DiskDump.BPB.OEM_STRING, DiskDump.MY_OEM_STRING.length);
buf.write(DiskDump.MY_OEM_STRING, DiskAPI.BPB.OEM_STRING, DiskDump.MY_OEM_STRING.length);
}
}
} catch(err) {