TweetFollow Us on Twitter

CopyFile XCMD
Volume Number:5
Issue Number:10
Column Tag:HyperChat™

Related Info: File Manager

XCMD Corner: CopyFile

By Donald Koscheka, Arthur Young & Co., MacTutor Contributing Editor

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

CopyFile XCMD

From time to time I monitor the developer forums on AppleLink and MacNet to see what the rest of the Macintosh development community is up to. Recently, Richard Greenawalt of Foremost Computer Systems issued a request for some help. It seems he needed a routine that copies Macintosh files, data fork, resource fork and finder information.

Not one to miss an opportunity to write an interesting XCMD, I 'linked Rick back and told him that I would be happy to write the routine for him.

The moral of the story is: ask and you might receive. If you need some help with an XCMD or if this column just doesn’t do it for you, let me know; I will be more than happy to help you out. Although I am up on AppleLink, I prefer to use MacNet (KOSCHEKA). If you don’t have access to a modem, write me care of MacTutor.

Copying a Macintosh file is not difficult as long as you keep in mind that Mac files are really two files in one. Each file on the Macintosh has a split personality - the data fork and the resource fork. Although the two forks act as one entity, the file manager treats them as separate files.

CopyFile is a handy little XCMD that lets you copy files from Hypercard. Actually the routine is written to work from any programming milieu which is why I’ve split it into two listings. The first consists of the Hypercard interface. Note that you need to pass both the file name and the working directory id. The second listing contains the actual code, void of any references to Hypercard. This approach lets me build libraries of usable routines that I can use with or without Hypercard, and I intend to use it for all future listings.

The CopyFile function expects to see the name of the input file, the name of the output file and the working directory id’s of both. This gives you some flexibility in naming the copy as well as deciding what folder to put it in. For example, you can concatenate the name of the input file to “copy of “ so that the duplicated file is called “copy of file”. Put this concept in a loop and you get the finder like capability of creating files and naming them “copy of ... “ , “copy of copy of ...” and so on. I chose not to implement this approach because I think the user should have the opportunity to specify the name of the copied file.

Although there are several ways to go about copying a file, I chose a path that goes something like this: First, get the collective size of the data and resource fork along with the finder information about the input file. Using this information, attempt to create a file that is as large as the input file (ie as large as the data and resource fork combined). If the space can be allocated, then copy each fork in turn. If not, delete the newly created file and quit.

Space for each fork is allocated before we do the copy so that we can determine a priori whether the file will fit. To be safe, we reposition the file mark at the beginning of the file before we start copying. If, for any reason, the file copy fails, delete what remains of the file and return the error message to the caller.

The real work is done by the function, CopyFork. This routine will attempt to read the entire fork into a single buffer. Failing that, it divides the size in half until enough memory can be allocated to read some of the fork. Note that copyfork attempts to allocate a buffer large enough to read the entire fork into memory. If that much memory is not available, it keeps dividing the original size by two until a large enough buffer can be allocated.

That’s file copying in a nutshell. It’s not particularly difficult once you realize that you’re really copying two files - the data fork and the resource fork. I’ve tried it with files up to 4 megabytes in size and it works fine.

/**********************************/
/* File: FileCopy.c*/
/* param0 = file reference num*/
/* ( file is open) IN:    */
/* params[0]= name of input */
/* params[1]= wdid of input */
/* params[2]   = name of output  */
/* params[3]   = wdid of output  */
/**********************************/
#include<MacTypes.h>
#include<OSUtil.h>
#include<MemoryMgr.h>
#include<FileMgr.h>
#include<ResourceMgr.h>
#include<pascal.h>
#include<string.h>
#include  “HyperXCMD.h”
#include“HyperUtils.h”

pascal void main( paramPtr )
 XCmdBlockPtr  paramPtr;
/*****************************
*params[0]= name of input 
*params[1]= wdid of input 
*params[2]  = name of output
*params[3]  = wdid of output
*****************************/
{ OSErr err;
 short  inWD;
 short  outWD;
 long   temp;
 Str31  errCode;
 char   inFile[256];
 char   outFile[256];
 paramPtr->returnValue = 0L;
 /*** (1) Get input parameters     ***/
 HLock( paramPtr->params[0] );
 ZeroToPas( paramPtr, *(paramPtr->params[0]), &inFile );
 HUnlock( paramPtr->params[0] );
 inWD = (short)paramtoNum( paramPtr, 1 );
 HLock( paramPtr->params[2] );
 ZeroToPas( paramPtr, *(paramPtr->params[2]), &outFile );
 HUnlock( paramPtr->params[2] );
 outWD = (short)paramtoNum( paramPtr, 3 );
 temp = (long)CopyFile( inFile, inWD, outFile, outWD );
 /*** Flush the output volume ***/
 err = FlushVol( 0L, 0 );
 NumToStr( paramPtr, temp, &errCode );
 paramPtr->returnValue = PasToZero( paramPtr, &errCode );
}

LISTING 1: CopyFile XCMD.


OSErr CopyFork( inref, outref, siz )
 short  inref;   short  outref;  longsiz;
/*****************************
* Given that the caller has opened
* a fork and passed you the names of 
* the input, copy the number of bytes
* from the input fork to the output 
* fork.
* The input mark should be set to 
* start of fork.
* We use a “semi-smart” algorithm
* to do the copy.  If the entire
* fork can be copied, we try doing 
* that, otherwise, we keep dividing
* the size by two until we get enough
* room to read some data in.
******************************/
{
 OSErr  rd_err   = noErr;
 OSErr  wrt_err  = noErr;
 long   rd_len;  /*** actual bytes read ***/
 Ptr    inbuf;
 /*** make sure that the size is even ***/
 if( siz % 2 )
 ++siz;
 if( siz > 0 ){
 do{
 inbuf = NewPtr( siz );
 if( !inbuf )
 siz = ( siz >> 1 );
 }while( !inbuf );
 /*** inbuf is the buffer that we  ***/
 /*** read the data into. If not   ***/
 /*** allocated, don’t attempt to do ***/
 /*** the read   ***/
 if( inbuf ){
 do{
 rd_len = siz;
 rd_err = FSRead( inref, &rd_len, inbuf );
 wrt_err= FSWrite( outref, &rd_len, inbuf );
 }while( !rd_err && !wrt_err );
 
 DisposPtr( inbuf );
 }
 }
 return( wrt_err );
}

OSErr CopyFile( inFile, inWD, outFile, outWD )
 char   *inFile;
 short  inWD; char *outFile;
 short  outWD;
/*****************************
* (1) Determine the size of the input 
* file. 
* (2) Attempt to allocate that 
* much space for the output file.
* (3) If allocation successful,
* create the output file.
* (4) Once the file is created,
* copy the data fork, the resource
* fork and the finder information
* from the input file.
* The file will be called “copy of...”
* Each time we create the file, first
* see if that name exists, if so, keep
* sticking “copy of” onto the name.
******************************/
{
 OSErr  err;
 OSErr  err2;
 short  inref;
 short  outref;
 long   data_eof = 0L;
 long   rsrc_eof = 0L;
 FInfo  fndrinfo;
 /*** (2) Determine how big the input file is ***/
 if( (err = FSOpen( inFile, inWD, &inref )) == noErr){
 err = GetEOF( inref, &data_eof );
 err = FSClose( inref );
 } 
 if( (err = OpenRF( inFile, inWD, &inref )) == noErr ){
 err = GetEOF( inref, &rsrc_eof );
 err = FSClose( inref );  
 }
 /*** (2) Create  output file and allocate space***/
 if( ( err = GetFInfo( inFile, inWD, &fndrinfo ) ) != noErr )
 return( err );
 if( ( err = Create( outFile, inWD, fndrinfo.fdCreator, fndrinfo.fdType 
)) != noErr )
 return( err );
 /*** (3) Try to allocate enough space for both***/
 /*** forks. Note that if we get enough space. ***/
 if( (err = FSOpen( outFile, outWD, &outref )) != noErr)
 return( err );
 if( (err = SetEOF( outref, data_eof  )) != noErr ){
 err2 = FSClose( outref );
 err2 = FSDelete( outFile, outWD );
 return( err );
 }
 err2   = FSClose( outref );
 err  = OpenRF( outFile, outWD, &outref );
 if( (err = SetEOF( outref, rsrc_eof  )) != noErr ){
 err2 = FSClose( outref );
 err2 = FSDelete( outFile, outWD );
 return( err );
 }
 err2 = FSClose( outref );
 /*** (4) Copy the Data fork***/
 err  = FSOpen( inFile, inWD, &inref );
 if( !err ){
 err2   = SetFPos( inref, fsFromStart, 0L );
 err    = CopyFork( inref, outref, data_eof );
 err2   = FSClose( inref );
 err2   = FSClose( outref );
 }
 if( err ){
 err2 = FSDelete( outFile, outWD );
 return( err );
 }
 /*** (5) Now copy the resource fork ***/
 err  = OpenRF( inFile, inWD, &inref );
 if( !err ){
 err2   = SetFPos( inref, fsFromStart, 0L );
 err  = OpenRF( outFile, outWD, &outref );
 err    = CopyFork( inref, outref, rsrc_eof );
 err2   = FSClose( inref );
 err2   = FSClose( outref );
 }
 if( err ){
 err2 = FSDelete( outFile, outWD );
 return( err );
 }
 return( noErr );
}

LISTING 2: CopyFile and CopyFork Functions.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Tokkun Studio unveils alpha trailer for...
We are back on the MMORPG news train, and this time it comes from the sort of international developers Tokkun Studio. They are based in France and Japan, so it counts. Anyway, semantics aside, they have released an alpha trailer for the upcoming... | Read more »
Win a host of exclusive in-game Honor of...
To celebrate its latest Jujutsu Kaisen crossover event, Honor of Kings is offering a bounty of login and achievement rewards kicking off the holiday season early. [Read more] | Read more »
Miraibo GO comes out swinging hard as it...
Having just launched what feels like yesterday, Dreamcube Studio is wasting no time adding events to their open-world survival Miraibo GO. Abyssal Souls arrives relatively in time for the spooky season and brings with it horrifying new partners to... | Read more »
Ditch the heavy binders and high price t...
As fun as the real-world equivalent and the very old Game Boy version are, the Pokemon Trading Card games have historically been received poorly on mobile. It is a very strange and confusing trend, but one that The Pokemon Company is determined to... | Read more »
Peace amongst mobile gamers is now shatt...
Some of the crazy folk tales from gaming have undoubtedly come from the EVE universe. Stories of spying, betrayal, and epic battles have entered history, and now the franchise expands as CCP Games launches EVE Galaxy Conquest, a free-to-play 4x... | Read more »
Lord of Nazarick, the turn-based RPG bas...
Crunchyroll and A PLUS JAPAN have just confirmed that Lord of Nazarick, their turn-based RPG based on the popular OVERLORD anime, is now available for iOS and Android. Starting today at 2PM CET, fans can download the game from Google Play and the... | Read more »
Digital Extremes' recent Devstream...
If you are anything like me you are impatiently waiting for Warframe: 1999 whilst simultaneously cursing the fact Excalibur Prime is permanently Vault locked. To keep us fed during our wait, Digital Extremes hosted a Double Devstream to dish out a... | Read more »
The Frozen Canvas adds a splash of colou...
It is time to grab your gloves and layer up, as Torchlight: Infinite is diving into the frozen tundra in its sixth season. The Frozen Canvas is a colourful new update that brings a stylish flair to the Netherrealm and puts creativity in the... | Read more »
Back When AOL WAS the Internet – The Tou...
In Episode 606 of The TouchArcade Show we kick things off talking about my plans for this weekend, which has resulted in this week’s show being a bit shorter than normal. We also go over some more updates on our Patreon situation, which has been... | Read more »
Creative Assembly's latest mobile p...
The Total War series has been slowly trickling onto mobile, which is a fantastic thing because most, if not all, of them are incredibly great fun. Creative Assembly's latest to get the Feral Interactive treatment into portable form is Total War:... | Read more »

Price Scanner via MacPrices.net

Early Black Friday Deal: Apple’s newly upgrad...
Amazon has Apple 13″ MacBook Airs with M2 CPUs and 16GB of RAM on early Black Friday sale for $200 off MSRP, only $799. Their prices are the lowest currently available for these newly upgraded 13″ M2... Read more
13-inch 8GB M2 MacBook Airs for $749, $250 of...
Best Buy has Apple 13″ MacBook Airs with M2 CPUs and 8GB of RAM in stock and on sale on their online store for $250 off MSRP. Prices start at $749. Their prices are the lowest currently available for... Read more
Amazon is offering an early Black Friday $100...
Amazon is offering early Black Friday discounts on Apple’s new 2024 WiFi iPad minis ranging up to $100 off MSRP, each with free shipping. These are the lowest prices available for new minis anywhere... Read more
Price Drop! Clearance 14-inch M3 MacBook Pros...
Best Buy is offering a $500 discount on clearance 14″ M3 MacBook Pros on their online store this week with prices available starting at only $1099. Prices valid for online orders only, in-store... Read more
Apple AirPods Pro with USB-C on early Black F...
A couple of Apple retailers are offering $70 (28%) discounts on Apple’s AirPods Pro with USB-C (and hearing aid capabilities) this weekend. These are early AirPods Black Friday discounts if you’re... Read more
Price drop! 13-inch M3 MacBook Airs now avail...
With yesterday’s across-the-board MacBook Air upgrade to 16GB of RAM standard, Apple has dropped prices on clearance 13″ 8GB M3 MacBook Airs, Certified Refurbished, to a new low starting at only $829... Read more
Price drop! Apple 15-inch M3 MacBook Airs now...
With yesterday’s release of 15-inch M3 MacBook Airs with 16GB of RAM standard, Apple has dropped prices on clearance Certified Refurbished 15″ 8GB M3 MacBook Airs to a new low starting at only $999.... Read more
Apple has clearance 15-inch M2 MacBook Airs a...
Apple has clearance, Certified Refurbished, 15″ M2 MacBook Airs now available starting at $929 and ranging up to $410 off original MSRP. These are the cheapest 15″ MacBook Airs for sale today at... Read more
Apple drops prices on 13-inch M2 MacBook Airs...
Apple has dropped prices on 13″ M2 MacBook Airs to a new low of only $749 in their Certified Refurbished store. These are the cheapest M2-powered MacBooks for sale at Apple. Apple’s one-year warranty... Read more
Clearance 13-inch M1 MacBook Airs available a...
Apple has clearance 13″ M1 MacBook Airs, Certified Refurbished, now available for $679 for 8-Core CPU/7-Core GPU/256GB models. Apple’s one-year warranty is included, shipping is free, and each... Read more

Jobs Board

Seasonal Cashier - *Apple* Blossom Mall - J...
Seasonal Cashier - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Read more
Seasonal Fine Jewelry Commission Associate -...
…Fine Jewelry Commission Associate - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) Read more
Seasonal Operations Associate - *Apple* Blo...
Seasonal Operations Associate - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Read more
Hair Stylist - *Apple* Blossom Mall - JCPen...
Hair Stylist - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Blossom Read more
Cashier - *Apple* Blossom Mall - JCPenney (...
Cashier - Apple Blossom Mall Location:Winchester, VA, United States (https://jobs.jcp.com/jobs/location/191170/winchester-va-united-states) - Apple Blossom Mall Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.