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

OmniOutliner Pro 4.2 - Pro version of th...
OmniOutliner Pro is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more
VLC Media Player 2.2.1 - Popular multime...
VLC Media Player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, MP3, OGG, ...) as well as DVDs, VCDs, and various streaming protocols. It... Read more
Nisus Writer Pro 2.1.1 - Multilingual wo...
Nisus Writer Pro is a powerful multilingual word processor, similar to its entry level products, but brings new features such as table of contents, indexing, bookmarks, widow and orphan control,... Read more
Tinderbox 6.2.0 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
OmniOutliner 4.2 - Organize your ideas,...
OmniOutliner is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more
Things 2.5.4 - Elegant personal task man...
Things is a task management solution that helps to organize your tasks in an elegant and intuitive way. Things combines powerful features with simplicity through the use of tags and its intelligent... Read more
NeoOffice 2014.10 - Mac-tailored, OpenOf...
NeoOffice is a complete office suite for OS X. With NeoOffice, users can view, edit, and save OpenOffice documents, PDF files, and most Microsoft Word, Excel, and PowerPoint documents. NeoOffice 3.x... Read more
iPhoto Library Manager 4.2 - Manage mult...
iPhoto Library Manager allows you to organize your photos among multiple iPhoto libraries, rather than having to store all of your photos in one giant library. You can browse the photos in all your... Read more
Web Snapper 3.3.8 - Capture entire Web p...
Web Snapper lets you capture Web pages exactly as they appear in your browser. You can send them to a file as images or vector-based, multi-page PDFs. It captures the whole Web page - eliminating the... Read more
TeamViewer 10.0.41404 - Establish remote...
TeamViewer gives you remote control of any computer or Mac over the Internet within seconds, or can be used for online meetings. Find out why more than 200 million users trust TeamViewer! Free for... Read more

Chainsaw Warrior: Lords of the Night has...
It's time to put the Darkness back in its place now that Chainsaw Warrior: Lords of the Night has officially made it to iOS. | Read more »
A World of Ice and Fire Lets You Stalk 2...
George R. R. Martin’s A World of Ice and Fire, by Random House, is a mobile guide to the epic series. The new update gives you the Journeys map feture that will let you track the movements of 25 different characters. But don't worry, you can protect... | Read more »
Gameloft Announces Battle Odyssey, a New...
Battle Odyssey, Gameloft's newest puzzle RPG, is coming to the App Store next week. Set in the world of Pondera, you will need to control the power of the elements to defend the world from evil. You'll be able to entlist over 500 allies to aid you... | Read more »
Fusion - HDR Camera (Photography)
Fusion - HDR Camera 1.0.0 Device: iOS Universal Category: Photography Price: $1.99, Version: 1.0.0 (iTunes) Description: Fusion creates HDR (high dynamic range) photos by capturing different exposures and then combining them into one... | Read more »
Sago Mini Toolbox (Education)
Sago Mini Toolbox 1.1 Device: iOS Universal Category: Education Price: $2.99, Version: 1.1 (iTunes) Description: Come build with the Sago Mini friends! Use a wrench, try a saw, or hammer some nails. From sewing hand puppets to... | Read more »
You Should Probably Grab Hitman GO While...
Hitman GO is a surprisingly cool (yet also incredibly drastic) departure from the Hitman series. It's well worth playing for any puzzle game fans out there, and at the moment you can get your hands - or garrotte if you will - on it for a mere $0.99... | Read more »
IFTTT is Bringing Do Button and Do Note...
IFTTT has announced Do Button and Do Note for the Apple Watch. Do Button lets you make your own personalized button that can connect to things like your Google Drive, control the temperature in your home with Nest Thermostat, or turn the lights on... | Read more »
How Many Days, Hours, and Minutes Are Le...
Countdown, by Yves Tscherry, is now available on the App Store. The app keeps track of countdowns to your favorite things such as someones birthday or days till the New Year. You can display the time in seconds, minutes, hours, days, weeks, months,... | Read more »
The All-New Misfit 2.0 App is Available...
Misfit has just given their app a complete overhaul. Misfit 2.0 now has a brand new interface with a sleek design and is easier to navigate. You'll be able to sync your Misfit device and look up health and fitness information faster than ever before... | Read more »
Halo: Spartan Strike (Games)
Halo: Spartan Strike 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: Delve into 30 challenging missions through cities and jungles using a devastating arsenal of weapons, abilities and... | Read more »

Price Scanner via MacPrices.net

TigerText Introduces First Secure Enterprise...
TigerText, a provider of secure, real-time messaging for the enterprise, has announced the launch of TigerText for the Apple Watch. TigerText for the Apple Watch enables users to securely send and... Read more
The Conservation Fund Partners with Apple To...
The Conservation Fund has announced that it will partner with Apple to help protect working forests in the United States. The Apple initiative will conserve more than 36,000 acres of working... Read more
Clearance 13-inch 2.6GHz Retina MacBook Pro a...
B&H Photo has clearance 2014 13″ 2.6GHz/128GB Retina MacBook Pros now available for $1099, or $200 off original MSRP. Shipping is free, and B&H charges NY sales tax only. Read more
Apple refurbished 2014 13-inch Retina MacBook...
The Apple Store has Apple Certified Refurbished 2014 13″ Retina MacBook Pros available for up to $400 off original MSRP, starting at $979. An Apple one-year warranty is included with each model, and... Read more
iMacs on sale for up to $205 off MSRP, NY tax...
B&H Photo has 21″ and 27″ iMacs on sale for up to $205 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1019 $80 off - 21″ 2.7GHz iMac: $1189 $110 off - 21″ 2.9GHz... Read more
Sale! 16GB iPhone 5S for $1 with service
Best Buy is offering 16GB iPhone 5Ss for $1.00 with 2-year activation at a participating cellular provider. Choose free home shipping and activation, or buy online and activate during in-store pickup... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store has Apple Certified Refurbished 2014 MacBook Airs available starting at $679. An Apple one-year warranty is included with each MacBook, and shipping is free. These are currently the... Read more
27-inch 3.5GHz 5K iMac on sale for $2349, sav...
 Adorama has the 27″ 3.5GHz 5K iMac in stock today and on sale for $2349 including free shipping plus NY & NJ sales tax only. Their price is $150 off MSRP. For a limited time, Adorama will... Read more
Save up to $380 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $380 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $2119 $... Read more
iFixIt Teardown Awards 12-IInch Retina MacBoo...
iFixIt has posted its illustrated teardown of the new 12-inch MacBook Retina. They note that this new MacBook is less than half the thickness of the last Apple notebook called just “MacBook” back in... Read more

Jobs Board

*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Technical Project Manager - *Apple* Pay - A...
**Job Summary** Apple Pay is seeking an experienced technical PM to…manage the on boarding of new merchants for the Apple Pay platform in the US Within this role you Read more
Senior Identity Architect - *Apple* Pay - A...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior identity architect to join the Apple Pay Engineering team. You will Read more
Program Manager, *Apple* Retail Global Tale...
…for the worldwide creation and implementation of the key talent development initiatives within Apple Retail. He or she will work closely with our Retail Corporate team, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.