TweetFollow Us on Twitter

Sector Dumps
Volume Number:5
Issue Number:7
Column Tag:HyperChat™

XCMD Corner: Sector Dumps

By Donald Koscheka, Arthur Young & Company, MacTutor Contributing Editor

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Reinventing the wheel often provides an opportunity to embellish on the original design. Recently, I needed a file dump utility. Several packages are available “over the counter”, but I needed a utility that dumps the entire file without having to manually move from sector to sector as is the case with most commercial solutions. Moreover, I use file dump tools frequently enough that I could afford to spend the effort writing one for Hypercard.

I dump the file in a fairly typical way. Each line in the dump contains the “sector address” of the first byte on the line followed by the hexadecimal dump of 16 bytes followed by the ASCII interpretation of the data. Not all ASCII characters are “printable” so we replace non-printing characters with the “.”, yielding a cleaner display.

This month’s XFCN, FilePeek.c (listing 1) accepts two parameters. The first parameter is the reference number of the opened file; the second parameter is the sector you want dumped. HFS sectors are 512 bytes so filepeek returns 32 lines of 16 bytes apiece.

Dumping the entire contents of a file becomes a matter of calling FilePeek repeatedly for all the logical sectors in the file.

The first line in the dump tells us how many bytes were read in. This number can be equal to or less than a full sector. If line 1 contains less than a sector full of data, then you know that logical end of file is after the last byte read in.

The Hypertalk afficianado will realize that this code can easily be written in Hypertalk. I chose to commit my scheme to an XFCN only after discovering that the Hypertalk version was too slow for my purposes.

The dumping scheme is amazingly simple. Position the file mark at the beginning of the sector that you want to dump. If the start of the sector extends beyond end of file, do nothing and return to hypercard with a result of zero (no bytes were read in), otherwise read the sector into the buffer we allocated (buf).

The sector is presented to Hypercard as a series of haxadecimal characters. Hypercard contains a call back “NumtoHex” which converts an arbitrary run of data to a hex string. We lose portability when using a callback so you’ll need to write your own hexdump algorithm or dig one up in the toolbox.

FilePeek dumps two bytes at a time (4 hex digits). This is analogous to dumping the contents of a short. We can use a pointer to short (rPtr). To dump the ascii data, we use a char pointer (cPtr) to the same data.

The current line in the dump is assembled by first displaying the “sector address” of that line. The sector address is 512 * blk (blk = sector number).

The sector address is delineated by the “:” character. Following the sector address, we display 16 bytes of data in hexadecimal format. The data is grouped into 8 words.

The hexadecimal data is followed by the ascii representation of the line. If the character falls in the range of printing characters, we display the character, otherwise print a “.”. Characters below the space (0x020) are not normally considered printing characters. Likewise, Inside Macintosh indicates that no characters above $D8 have a printable format. Using the period to represent non-printing characters results in a less-cluttered looking dump.

We need to cycle the character pointer, cPtr, twice for every cycle on rPtr (a character is half a word). We accumulate the ascii data into a separate string which we then concatenate onto the end of the hex data.

Once the current line is assembled, we stick a carriage return on the end, block move it to the output data handle and then go to the next 16 bytes in the input stream. When the outer loop completes, outdata will contain 32 lines of 16 bytes apiece, suitable for framing.

Figure 1.

How you open and close a file from Hypercard is a matter of taste. I prefer to keep my interface to the file manager as clean as possible. This requires passing a filename and working directory id to the file manager’s FSOpen call and subsequently referring to the file by the reference number returned by FSOpen. To close the file, pass the reference number to FSClose (last month I provided an XFCN that will return a file name and working directory id from the standard file package).

Listings 2 and 3 are two simple XFCNs that open and close a file respectively. FileOpen returns a reference number if the file opened ok (0 otherwise). Pass this reference number to FilePeek along with the number of the sector you wish to dump.

Figure 1. is a sample card that I use to dump the contents of the file. The dump is presented in a mono-spaced font to keep it “clean-looking”. The forward and back arrows allow the user to “browse” sectors by moving 1 sector forward or backward. The scripts for theses two buttons is fairly obvious so I’ve left them to the reader. The scripts for open, close are contained in listing 4.

--1

-- file open button
on mouseUp
  global fileName, DirectoryID
  global fileRefNum, theSector
  
  put getFileNameToOpen() into it
  put item 1 of it into fileName
  put item 2 of it into DirectoryID
  put filename into card field “file name”
  
  if filename is not empty then
    Put FileOpen( fileName, DirectoryID ) into fileRefNum
  end if
  
end mouseUp

-- Go to Sector
on mouseUp
  global fileRefNum, theSector
  
  if filerefnum is empty then
    answer “You have to open a file first, silly!”
  else
    
    ask “Read what sector?” with “0”
    
    if (it is not empty) then
      put it into theSector
      Peekat theSector
    end if
  end if
  
end mouseUp

-- file close
on mouseUp
  global fileRefNum
  
  put FileClose( fileRefNum ) into it
  -- ignore the result of a closed file
end mouseUp

Listing 4. Scripts for the buttons

An interesting variation on this theme would be to dump the files in reverse order so that it prints in ascending order on the LaserWriter. Several easy solutions exist for this problem, and I’ll leave it as this month’s exercise to the reader. As a hint, I can think of two ways to do this off hand, one easy but inefficient, the second a little more challenging: (1) create a card for every sector (make sure your file is small first!) or (2) Find out how many sectors the file contains before starting the dump ( a wonderful opportunity to try your hand at XFCN writing).

Note on a bug in last month’s article:

Last month’s XFCN, GetFileName, incorrectly returns the working directory id of the file selected from SFGetFile. Change the call to GetFileNameToOpen to Read:

/* 1 */

if( GetFileNameToOpen(typs,numTypes,FileName,&FileWDID ) ){
 temp = (long)FileWDID & 0xFFFF;
 NumToStr( paramPtr, temp, &WDIDString );
 PtoCstr( WDIDString );
Listing 1:  FilePeek.c

/********************************/
/* File: FilePeek.c*/
/* */
/* Given the sector index into*/
/* an existing file, read the */
/* sector in and “dump” it to */
/* the screen    */
/* */
/* Paramters:    */
/* param0 = file referencenum */
/* ( file is open) */
/* param1 = sector number */
/* (1 sector = 512 bytes) */
/* ----------------------------  */
/* To Build:*/
/* */
/* (1) Create a project using */
/* this file as well as the */
/* XCMD.Glue.c file. (Set */
/* project type to XCMD (or */
/* XFCN) from the Project menu.  */
/* */
/* (2) Bring the project up to*/
/* date.*/
/* */
/* (3) Build Code Resource. */
/* */
/* (4) Use ResEdit to copy the   */
/* resource to your stack.*/
/********************************/

#include<MacTypes.h>
#include<OSUtil.h>
#include<MemoryMgr.h>
#include<FileMgr.h>
#include<ResourceMgr.h>
#include<pascal.h>
#include<strings.h>
#include  “HyperXCmd.h”
#include“HyperUtils.h”

#define SECTOR   512 /***size of input buffer ***/
#define NUMROWS  8 /***across each line***/
#define NUMLINES 32/***lines of data ***/
#define NUMBYTES 16/***#bytes per row of data***/
#define SPACE    0x020  /***the space character***/

long  paramtoNum();
void  appendChar();
void  CopyStrToHandle();
char  *CopyAscii();

pascal void main( paramPtr )
 XCmdBlockPtr  paramPtr;
{
 short  err;
 short  fref;
 short  lc; /* line count */
 short  rc; /* row count  */
 long   cnt;
 long   blk;/* sector number  */
 Handle outData;
 short  *rPtr;   /* per row */
 char   *cPtr;   /* for ASCII */
 char   *aPtr;   /* points to asciival */
 char   *buf;
 char   asciiStr[32];
 char   curntLine[256]; 
 Str31  numString;
 
 outData = 0L;
 if( paramPtr->paramCount == 2 ){  
 /*** expect two parameters ***/
 /*** (1) Get our input parameters ***/
 fref = (short)paramtoNum( paramPtr, 0 );
 blk   = paramtoNum( paramPtr, 1 );

 /*** (2) Read a buffer of data    ***/
 blk = blk * SECTOR;
 err = SetFPos( fref, fsFromStart, blk );
 if ( !err ){
 cnt = SECTOR;
 
 /*** We need to keep this data locked ***/
 /*** Since we can;t trust callbacks not     ***/
 /*** to move stuff, we allocate the ***/
 /*** buffer as non-relocatable.   ***/
 buf = NewPtr( cnt );
 err = FSRead( fref, &cnt, buf );
 
 if ( err != noErr &&  err != eofErr ){
 paramPtr->returnValue = 0L;
 return;
 }
 }
 
 /*** result is returned to hypercard as     ***/
 /*** a null terminated string***/
 outData = NewHandle( 0L );

 /*** (3) Start filling the output buffer    ***/
 *curntLine = ‘\0’;
 
 /*** first the number of bytes read in***/
 NumToHex( paramPtr, cnt, 4 , &numString );

 appendChar( PtoCstr( (char *)&numString), ‘\r’ );
 CopyStrToHandle( &numString, outData );

 /*** point to the input data ***/
 rPtr = (short *)buf;
 
 for( lc = 0;  lc < NUMLINES; ++lc ){
 *curntLine = ‘\0’;

 /*** blk is the sector address  ***/
 NumToHex( paramPtr, blk, 6, &numString );
 PtoCstr( (char *)&numString );
 strcat( curntLine, &numString );
 appendChar( curntLine, ‘:’ );
 appendChar( curntLine, SPACE );
 aPtr = asciiStr;
 blk += NUMBYTES;
 
 for( rc = 0; rc < NUMROWS; ++rc ){
 
 /*** convert eight shorts per row ***/
 /*** if we overrun the buffer, draw ***/
 /*** whatever data follows it...  ***/
 NumToHex( paramPtr, (long)*rPtr, 4 , &numString);
 strcat( curntLine, PtoCstr( (char *)&numString));
 appendChar( curntLine, ‘ ‘ );
 
 cPtr = (char *)rPtr;
 aPtr = CopyAscii( aPtr, *cPtr++ );
 aPtr = CopyAscii( aPtr, *cPtr++ );
 rPtr++;
 }
 
 *aPtr = ‘\0’; /*** terminate the ascii data ***/
 strcat( curntLine, asciiStr );
 appendChar( curntLine, ‘\r’ );
 
 /*** move  line into output buffer***/
 CopyStrToHandle( curntLine, outData );
 }
 
 DisposPtr( buf );
 }
 
 cnt = GetHandleSize( outData );
 *(*outData + cnt) = ‘\0’;
 paramPtr->returnValue = outData;
}

long  paramtoNum( paramPtr, i )
 XCmdBlockPtr  paramPtr;
 short  i;
/************************
* Given a handle to an input
* argument in the paramBlk
* return an integer representation
* of the data.
*
************************/
{
 Str31  theStr;
 
 HLock( paramPtr->params[ i ] );
 ZeroToPas( paramPtr, *(paramPtr->params[ i ]), &theStr );
 HUnlock( paramPtr->params[ i ] );
 return( StrToLong( paramPtr, &theStr ) );
}

void  appendChar( theStr, theChar )
 char *theStr;
 char theChar;
/************************
* append the character passed
* to the end of the string 
************************/
{
 long len = strlen( theStr );
 char *theEnd;

 theEnd = theStr + len;
 *theEnd++  = theChar;
 *theEnd  = ‘\0’;
}

char  *CopyAscii( outStr, theChar )
 char *outStr;
 char theChar;
/************************
* if the character passed  
* in the input stream is a 
* printing character, append
* it to the output string,
* otherwise, append the ‘.’
*
* return the update output 
* string.
************************/
{
 if ( theChar >= SPACE  &&  theChar <= 0x0D8  ) 
 *outStr++ = theChar;
 else
 *outStr++ = ‘.’;
 
 return( outStr );
}

void CopyStrToHandle( theStr, hand )
 char *theStr;
 Handle hand;
/************************
* Copy the input data to the
* output handle.
*
************************/
{
 long cnt = strlen( theStr );
 long oldSize  = GetHandleSize( hand );

 SetHandleSize( hand, oldSize + cnt );
 BlockMove( theStr, *hand + oldSize, cnt );
}
Listing 2: FileOpen.c

/********************************/
/* File: FIleOpen.c*/
/* */
/* open the file whose name and */
/* working directory id are */
/* passed as parameters.  This*/
/* information can be obtained*/
/* using GetFileNameToLoad... */
/* */
/* Paramters:    */
/* param0 = file namenum  */
/* param1 = directory id  */
/* */
/* Out: */
/* File RefNum if opened, 0 */
/* otherwise*/
/* ----------------------------  */
/********************************/

#include<MacTypes.h>
#include<OSUtil.h>
#include<MemoryMgr.h>
#include<FileMgr.h>
#include<ResourceMgr.h>
#include<pascal.h>
#include<strings.h>
#include  “HyperXCmd.h”
#include“HyperUtils.h”

pascal void main( paramPtr )
 XCmdBlockPtr  paramPtr;
{
 char   *filename;
 Str31  str, fName;
 short  wdid, refnum;

 HLock( paramPtr->params[0] );
 ZeroToPas( paramPtr, *(paramPtr->params[0]), &fName );
 HUnlock( paramPtr->params[0] );
 
 /* convert the wdid to a usable form */
 HLock( paramPtr->params[1] );
 ZeroToPas( paramPtr, *(paramPtr->params[1]), &str );
 HUnlock( paramPtr->params[1] );
 wdid = (short)StrToNum( paramPtr, &str );
 
 if( FSOpen( &fName, wdid, &refnum) == noErr )
 NumToStr( paramPtr, (long)refnum, &str );
 else
 NumToStr( paramPtr, 0L, &str );

 paramPtr->returnValue = PasToZero( paramPtr, &str );
}
Listing 3:  FileClose.c

/********************************/
/* File: FileClose.c */
/* */
/* XCMD to access the file mgr*/
/* call FSClose  */
/* Paramters:    */
/* param0 = file reference from  */
/* the fileopen xcmd */
/* ----------------------------  */
/********************************/

#include<MacTypes.h>
#include<OSUtil.h>
#include<MemoryMgr.h>
#include<FileMgr.h>
#include<ResourceMgr.h>
#include<pascal.h>
#include<strings.h>
#include  “HyperXCmd.h”
#include“HyperUtils.h”

pascal void main( paramPtr )
 XCmdBlockPtr  paramPtr;
{
 short  refnum;
 char   str[256];
 
 /* convert the refnum to a usable form */
 HLock( paramPtr->params[0] );
 ZeroToPas( paramPtr, *(paramPtr->params[0]), &str );
 HUnlock( paramPtr->params[0] );
 refnum = (short)StrToNum( paramPtr, &str );
 
 /* Normally we should check the result      */
 /* code but it won’t kill us to ignore*/
 /* the reslt of a close file call */
 if ( FSClose(refnum) )
 ;
 paramPtr->returnValue = 0L;
}

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Sketch 45 - Design app for UX/UI for iOS...
Sketch is an innovative and fresh look at vector drawing. Its intentionally minimalist design is based upon a drawing space of unlimited size and layers, free of palettes, panels, menus, windows, and... Read more
NeoFinder 7.1 - Catalog your external me...
NeoFinder (formerly CDFinder) rapidly organizes your data, either on external or internal disks, or any other volumes. It catalogs all your data, so you stay in control of your data archive or disk... Read more
TunnelBear 3.0.15 - Subscription-based p...
TunnelBear is a subscription-based virtual private network (VPN) service and companion app, enabling you to browse the internet privately and securely. Features Browse privately - Secure your data... Read more
Hopper Disassembler 4.2.5- - Binary disa...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32-bit and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about... Read more
BetterTouchTool 2.261 - Customize Multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
Sketch 44.1 - Design app for UX/UI for i...
Sketch is an innovative and fresh look at vector drawing. Its intentionally minimalist design is based upon a drawing space of unlimited size and layers, free of palettes, panels, menus, windows, and... Read more
BetterTouchTool 2.260 - Customize Multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
Chromium 59.0.3071.115 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 59.0.3071.115: This update has no Flash plug... Read more
SyncTwoFolders 2.2.3 - Syncs two user-sp...
SyncTwoFolders simply synchronizes two folders. It supports synchronization across mounted network drives and it is a possibility to run a simulation showing in a log what will be done. Please visit... Read more
Myriad 4.1 - $79.00
Myriad is, simply put, one of the best audio batch processors. Totally redesigned, it looks beautiful and delivers incredible performance. Let Myriad do the heavy lifting while you get back to doing... Read more

Latest Forum Discussions

See All

Missile Cards (Games)
Missile Cards 1.0.9 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.9 (iTunes) Description: "Missile Command meets Solitaire...only with more doomlasers, death, and explosions." | Read more »
Collect mini assassins in 'Assassin...
Assassin's Creed is traveling back in time to the Spanish Inquisition for its latest mobile entry, Assassin's Creed Rebellion. The game is giving the series a look that's a huge departure from its past design, recreating classic characters in a... | Read more »
Animal Crossing is still coming to mobil...
Animal Crossing is still coming to mobile in 2017, according to aWaypointinterview with Nintendo. Announced in 2016, the game was delayed without a defined release window. However, fans of Nintendo's fantasy slice of life game won't have to wait... | Read more »
Ravenscroft 275 Piano (Music)
Ravenscroft 275 Piano 1.0.0 Device: iOS Universal Category: Music Price: $35.99, Version: 1.0.0 (iTunes) Description: Experience the splendor of a Ravenscroft Grand with the most realistic sounding piano ever created for iOS. Launch... | Read more »
This War of Mine gets a new ending and m...
This War of Mine just got a big new update, featuring free DLC that adds a new ending to the game, among other exciting changes. The update is celebrating the game's two-year release anniversary. Apart from the new ending, which will be quite... | Read more »
Summon eight new heroes in Fire Emblem H...
Nintendo keeps coming at us with Fire Emblem Heroes updates, and it doesn't look like that trend is stopping anytime soon. The folks behind the game have just announced the new War of the Clerics Voting Gauntlet, expected to start next Tuesday. [... | Read more »
The best deals on the App Store this wee...
iOS publishers are pulling out all the stops this week -- there's a huge number of seriously great games at discounted prices this week. Let's not waste any time and get right down to business. [Read more] | Read more »
The House of da Vinci (Games)
The House of da Vinci 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: Enter The House of Da Vinci, a new must-try 3D puzzle adventure game. Solve mechanical puzzles, discover hidden... | Read more »
Solve the disappearance of history’s gre...
Blue Brain Games invites you to indulge in an immersive hands-on 3D puzzle adventure in similar vein to The Room series, with its debut release The House of Da Vinci. Set during the historic period of the Italian Renaissance (when Leonardo himself... | Read more »
Age of Rivals (Games)
Age of Rivals 3.3 Device: iOS Universal Category: Games Price: $.99, Version: 3.3 (iTunes) Description: Deep civilization-building strategy in a fast-paced card game! | Read more »

Price Scanner via MacPrices.net

Clearance 2016 13-inch MacBook Pros available...
B&H Photo has clearance 2016 13″ MacBook Pros in stock today for up to $210 off original MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: - 13″ 2.9GHz/512GB Touch Bar... Read more
Apple Releases iOS 11 Public Beta; How To Get...
The official release of Apple’s latest mobile operating system iOS 11 is vaguely slated for the fall, but as of June 26, ordinary users can download an iOS 11 public beta. To download the iOS 11... Read more
Extend Life of MacBook Pro Retina 2.0TB With...
MacSales.com/Other World Computing has announced availability of the new OWC 2.0TB Aura Pro Solid State Drive for mid-2012 to early 2013 Apple MacBook Pro with Retina display. One of the fastest... Read more
BBEdit SummerFest 2017 Discount Ends Friday,...
You can get 20% off BBEdit for a limited time in Bare Bones Software’s http://www.eastgate.com/Tinderbox/Specials/SummerFest.html?mc_cid=f2101ca260&mc_eid=[UNIQID]SummerFest 2017 sale and... Read more
Use Apple’s Education discount to save up to...
Purchase a new Mac using Apple’s Education discount, and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free: - 15″ 2... Read more
Clearance 27-inch 3.3GHz 5K iMac available fo...
Amazon clearance 27″ 3.3GHz 5K iMacs (MK482LL/A) available for $1799.90 including free shipping. Their price is $500 off original MSRP, and it’s the lowest price available for this model from any... Read more
13-inch 1.8GHz/256GB MacBook Air on sale for...
B&H Photo has the updated 2017 13″ 1.8GHz/256GB MacBook Air (MQD42LL/A) in stock and on sale for $1129 including free shipping plus NY & NJ tax only. Their price is $70 off MSRP. Read more
27-inch 3.4GHz iMac on sale for $1699, save $...
B&H Photo has the new 2017 27″ 3.4GHz iMac (MNE92LL/A) in stock and on sale for $1699 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
21-inch 2.3GHz iMac on sale for $1049, save $...
B&H Photo has the new 2017 21″ 2.3GHz iMac (MMQA2LL/A) in stock and on sale for $1049 including free shipping plus NY & NJ tax only. Their price is $50 off MSRP. Read more
ABBYY TextGrabber 6 for iOS Implements Instan...
ABBYY has announced the release of TextGrabber 6.0.0, an important feature update to the company’s productivity app developed for iOS and Android devices. TextGrabber 6.0 now offers Real-Time... Read more

Jobs Board

*Apple* News Product Marketing Mgr., Publish...
…organizational consensus on strategy and vision for publisher tools, authoring, and Apple News Format.Carries this strategy and vision across the organization to Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Security Data Analyst - *Apple* Information...
…data sources need to be collected to allow Information Security to better protect Apple employees and customers from a wide range of threats.Act as the subject matter Read more
Lead *Apple* Solutions Consultant - Apple I...
…integrity, and trust.Success Metrics/Key Performance Indicators:Quantitative* Year over Year growth in Apple Product and Beyond the Box sales in the assigned Point of Read more
*Apple* Solutions Consultant till v%u00E5r...
…ethics, integrity, and trust.Success Metrics/Key Performance Indicators:QuantitativeYear over Year growth in Apple Product and Beyond the Box sales in the assigned Point Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.