UnArchiving LHA Files Programmatically: Confused about XPK, XAD, XFD

[tygre]

Hi all!

I am trying to simply extract one (or all) files from a LHA archive programmatically and I am confused: should I use XPK, XAD, or XFD?

Reading the docs and Web sites, it sems that XAD is the way to go but then I look at the code examples and see that, for example, xadUnFile.c is a thousand lines of code! I was naively thinking that calling the xadmaster.library in few lines of code would be sufficient

Am I missing something or is there really no free lunch?
Thanks!

[BigFan]

xadunfile does more than just unpacking one file. it parses lots of arguments and options, has pattern matching, error handling, and code is prepared for use multiple files as input.

what should xadmaster do if your uncompressed file already exists? it is not part of the unpacking libs to handle these scenarios. that's the code you have to provide.

no, there is no free lunch

code block will be much smaller without that many options, see start() section

[tygre]

Hi BigFan!

Thanks a lot! You are right: the source code of the xadUnFile and its start() function is very helpful... I am stating from there and already got something compiling and working so-so...

Cheers!

[tygre]

@BigFan and all!

For the record, here is a minimal use of the xadmasterl.library to unarchive some archive, XAD is very neat!

int extract_archive(
	const char *archive_path,
	const char *destination_path)
{
	struct xadMasterBase  *xadmasterbase;
	struct xadArchiveInfo *ai;
	struct xadFileInfo    *fi;
	LONG                   e;
	UBYTE                  destination_name[NAMEBUFSIZE];

	if((xadmasterbase = (struct xadMasterBase *)OpenLibrary("xadmaster.library", 11)))
	{
		xadMasterBase = xadmasterbase;

		if((ai = (struct xadArchiveInfo *)xadAllocObjectA(XADOBJ_ARCHIVEINFO, 0)))
		{
			e = xadGetInfo(
				ai,
				XAD_INFILENAME, "RAM:Slurp10.lha",
				TAG_DONE);
			if(DEBUG)
			{
				printf("xc_ArchiverName = %s\n", ai->xai_Client->xc_ArchiverName);
			}
			if(!e)
			{
				fi = ai->xai_FileInfo;
				while(fi)
				{
					if(!(fi->xfi_Flags & XADFIF_LINK || fi->xfi_Flags & XADFIF_DIRECTORY))
					{
						CopyMem("RAM:", destination_name, strlen("RAM:") + 1);
						AddPart(destination_name, FilePart(fi->xfi_FileName), NAMEBUFSIZE);
						e = xadFileUnArc(
							ai,
							XAD_OUTFILENAME, destination_name,
							XAD_ENTRYNUMBER, fi->xfi_EntryNumber,
							TAG_DONE);
						if(DEBUG)
						{
							printf("e = %lu\n", e);
						}
					}
					else if(DEBUG)
					{
						printf("\tSkipped link or directory\n");
					}
					fi = fi->xfi_Next;
				}
				goto _RETURN_OK;
			}
			else
			{
				perror("Error in extract_archive(...), call to xadGetInfo(...) failed");
				goto _RETURN_ERROR;
			}
		}
		else
		{
			perror("Error in extract_archive(...), cannot allocate struct xadArchiveInfo");
			goto _RETURN_ERROR;
		}
	}
	else
	{
		perror("Error in  extract_archive(...), cannot open xadmaster.library");
		goto _RETURN_ERROR;
	}

	goto _RETURN_OK;
	_RETURN_OK:
		xadFreeInfo(ai);
		xadFreeObjectA(ai, 0);
		CloseLibrary((struct Library *)xadmasterbase);
		return OK;

	_RETURN_ERROR:
		if(ai)
		{
			xadFreeInfo(ai);
			xadFreeObjectA(ai, 0);
		}
		if(xadmasterbase)
		{
			CloseLibrary((struct Library *)xadmasterbase);
		}
		return ERROR;
}

Cheers!

PS. Being a newbie in Amiga programming, any advice is welcome to improve my code!

[Thorham]

Originally Posted by tygre

Being a newbie in Amiga programming, any advice is welcome to improve my code!

You can avoid those indentation levels:

int bla(void)
{
    struct foo *a;
    struct bar *b;
    int c;
    
    a = function1("abcdef");
    if (a == NULL)
    {
        printError("Some error.");
        goto error1;
    }

    b = function2(12345);
    if (b == NULL)
    {
        printError("Some other error.");
        goto error2;
    }

    c = funtion3(a, b);
    
    cleanup2(b);
    cleanup1(a);
    return c;

error2:
    cleanup1(a);
error1:
    return -1;
}

Nothing wrong with goto, of course, and don't let anyone tell you any different.

[BigFan]

I disagree.

Goto is useless in this case. But first: Check your code for redundancy.
Doing so you'll notice, that goto is repeated and the code under both _RETURN_xx labels is identical.

My suggestion:
set an integer variable named rc (as returncode)
replace goto with rc=OK; or rc=ERROR; appropriatly.

delete labels

set cleanup code as if there is an error:

if(ai)
{
xadFreeInfo(ai);
xadFreeObjectA(ai, 0);
}
if(xadmasterbase)
{
CloseLibrary((struct Library *)xadmasterbase);
}
return rc;

this way your are always fine (on success and failure).

else {} conditions will be executed only when if() returns false, that is :
if inner loop succeeded , all if() succeeded before and none of the else{} will be executed.
if not then code will jump to the end of (un)conditioned {} , say it skips all else{} statements prior to the one that fails or can't be checked or do not need to be checked.

your goto doesn't do anything usefull. i think you used this to distuingish between success and failure.

be careful: any statement that is not part of else{} will be executed always as regular.

the exzessive use of goto is a sign of bad code. use goto wisely, e.g.
your code is recursive and the only way to exit on failure or infinite loop is a goto.

me too, i hate doctrines and religious talk about the use of goto, but in your case it leads to weird code quickly.

[tygre]

@Thorham and @BigFan

Thanks for reading and commenting my code! My use of gotos was my (poor) attempt to mimic throws/catches in C . I'll revise my code based on your suggestions...

Would you have any comment on my (mis)use/lack-of-use of AmigaOS functions?

Thanks!

[BigFan]

Path "RAM:" is hardcoded, CopyMem() is not necessary if you initialize with

ubyte destination_name[NAMEBUFFER]={'R','A','M',':',0};

Would be better to handle this with variables (values for testing can be macro), as it will ease the extension of the code with a file requester. Maybe in a later version or project.


What abuse of AOS functions? There aren't many.

[Thorham]

Originally Posted by BigFan

Goto is useless in this case.

No, it's not, because it can get rid of the deep indentation and the else blocks, making the code shorter and easier to follow. You can see this in my example.

Originally Posted by BigFan

Doing so you'll notice, that goto is repeated and the code under both

A few lines of identical code isn't a problem in this case, because having to set a return value variable really only adds more code back in.

Another point is that you may want to do a little more than just cleanup in the case of an error. Or just something different. My example shows the latter (only one cleanup function is called, because the first failed).

If you have to duplicate a large amount of code, then it's probably a good idea to use a return variable.

Here's an example of how I actually use goto:

static int monitor_readFile(lua_State *L)
{
   struct FileInfoBlock *finfo;
   BPTR fhandle;
   APTR fmem;
   char *fname = (char *)luaL_checkstring(L, 1);
   long ret;

   finfo = AllocDosObject(DOS_FIB, fibTags);
   if (finfo == NULL) goto error1;

   fhandle = Open(fname, MODE_OLDFILE);
   if (fhandle == NULL) goto error2;

   if (ExamineFH(fhandle, finfo) == 0) goto error3;

   fmem = malloc(finfo->fib_Size);
   if (fmem == NULL) goto error3;

   ret = Read(fhandle, fmem, finfo->fib_Size);
   Close(fhandle);
   FreeDosObject(DOS_FIB, finfo);

   lua_pushunsigned(L, (unsigned long)fmem);
   lua_pushinteger(L, finfo->fib_Size); // stupid bug here
   lua_pushinteger(L, ret);
   return 3;

error3:
   Close(fhandle);

error2:
   FreeDosObject(DOS_FIB, finfo);

error1:
   lua_pushnil(L);
   return 1;
}

[tygre]

Thanks BigFan and Thorham, I'm going to update my code to make it more lean and mean!

[Leffmann]

Originally Posted by Thorham

Here's an example of how I actually use goto:

That's spaghetti-code Four levels of indentation isn't really bad, but if you want to get rid of them, then initializing each pointer and structure on the condition that the previous one succeeded is a lot cleaner and easier to follow than a bunch of gotos.

You also have a bug in there: accessing the data in finfo after having called FreeDosObject on it.

[Thorham]

Originally Posted by Leffmann

That's spaghetti-code

I don't agree.

Originally Posted by Leffmann

Four levels of indentation isn't really bad

Originally Posted by Leffmann

but if you want to get rid of them, then initializing each pointer and structure on the condition that the previous one succeeded is a lot cleaner and easier to follow than a bunch of gotos.

That code is perfectly readable, and I'm certainly not restructuring it to get rid of those gotos.

Originally Posted by Leffmann

You also have a bug in there: accessing the data in finfo after having called FreeDosObject on it.

Missed that one, thanks

[Leffmann]

Originally Posted by Thorham

That code is perfectly readable, and I'm certainly not restructuring it to get rid of those gotos.

I think it's always a good idea to get rid of gotos if you can, and if you can make the program flow cleaner and getting rid of duplicate code at the same time, just the better. I would suggest this:

static int monitor_readFile(lua_State *L) {
  struct FileInfoBlock* finfo;
  char* fname;
  BPTR fhandle = 0;
  APTR fmem = NULL;
  BOOL exres = FALSE;
  int retval;

  fname = (char*)luaL_checkstring(L, 1);
  finfo = AllocDosObject(DOS_FIB, fibTags);

  if (finfo)    fhandle = Open(fname, MODE_OLDFILE);
  if (fhandle)  exres = ExamineFH(fhandle, finfo);
  if (exres)    fmem = malloc(finfo->fib_Size);

  if (fmem) {
    long ret = Read(fhandle, fmem, finfo->fib_Size);
    lua_pushunsigned(L, (unsigned long)fmem);
    lua_pushinteger(L, finfo->fib_Size);
    lua_pushinteger(L, ret);
    retval = 3;
  } else {
    lua_pushnil(L);
    retval = 1;
  }

  if (fhandle)  Close(fhandle);
  if (finfo)    FreeDosObject(DOS_FIB, finfo);

  return retval;
}

[BigFan]

@Thorham
My posting about 'goto' addresses Tygre, not you.
Mentioned '_Return_' code section is definitly not yours, so stop taking things personally.
And i'm not willing to use @ periodically and rewrite every posting to avoid users getting pissed when misinterpreting my posts.


And i agree with Leffmann, redundant code and usage of 'goto' is the path to the dark side of the force. Once you get used to it, you'll hardly find a way back into the 'light'.
It looks like someone has ported BASIC to C. Whenever a user is posting spaghetti code, he'll be confronted with harsh criticism in any advanded users forum.
No need to encourage the usage of 'goto', except you can fundamentally argue for it because of its advantage in a very special case.

[tygre]

@thread

Thank you all for your comments, I really appreciate your suggestions and will revise my code accordingly .

You all make good points pros and cons using gotos .

My using gotos was my (poor) attempt to simulate throws/catches but also to have "single exit points", actually two: one exit point for "normal returns" and one for "error returns". Please feel free to give more advices on my code!

Let's not argue whether this is spaghetti code or not... we are still far from Toyota's code and their 10,000 global variables .

Cheers!

[Thorham]

Originally Posted by Leffmann

I think it's always a good idea to get rid of gotos if you can, and if you can make the program flow cleaner and getting rid of duplicate code at the same time, just the better.

Nothing wrong with the code you posted, but the reason I'm using goto in my code is to get the program flow out of the main part of the the code block. The duplicate code is only there because it's just two short lines.

Originally Posted by BigFan

My posting about 'goto' addresses Tygre, not you.

That's what I was actually referring to. Goto isn't useless in that code if used properly.

Originally Posted by BigFan

Mentioned '_Return_' code section is definitly not yours, so stop taking things personally.

My comment was a general comment.

Originally Posted by tygre

Toyota's code and their 10,000 global variables

That's just totally insane

[tygre]

Hi all!

For the record, here is the (minimum?) code needed to use the xadmaster.library to unarchive an archive file (no subfolders or links, no checking whether the destination exists... really the bare minimum), thanks a lot for your help and suggestions!

The rest of the code is available here and I welcome all your comments/suggestions to improve it!

Cheers!
Tygre

/*
	AmiModRadio
	All of Aminet modules at your fingertips



	Copyright 2015 Tygre <tygre@chingu.asia>

	This file is part of AmiModRadio.

	AmiModRadio is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	AmiModRadio is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with AmiModRadio. If not, see <http://www.gnu.org/licenses/>.



	Entirely developed on an Amiga!
	(Except for source code versioning...)
	tygre@chingu.asia
*/



#include "xad.h"
#include "fortify.h"
#include "utils.h"

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <proto/xadmaster.h>
#include <proto/exec.h>
#include <proto/dos.h>



#define DEBUG         0
#define DEBUG_VERBOSE 0

#define MAX_SIZE_LIST 512
#define MAX_SIZE_NAME 512



struct xadMasterBase *xadMasterBase = NULL;



int extract_archive(
	IN  char  *archive_path,
	IN  char  *destination_path,
	OUT char **list)
{
	struct xadMasterBase  *xadmasterbase           = NULL;
	struct xadArchiveInfo *ai                      = NULL;
	struct xadFileInfo    *fi                      = NULL;
	LONG                   e                       = 0;
	char                  *list_temp               = NULL;
	char                  *list_temp_for_realloc   = NULL;
	int                    number_of_chars         = 0;
	int                    maximum_number_of_chars = 0;
	UBYTE                  destination_name[MAX_SIZE_NAME];

	maximum_number_of_chars = MAX_SIZE_LIST;
	list_temp = calloc(maximum_number_of_chars, sizeof(char));
	if(list_temp == NULL)
	{
		perror("Error in  extract_archive(...), cannot allocate memory");
		goto _RETURN_ERROR;
	}

	if(!(xadmasterbase = (struct xadMasterBase *)OpenLibrary("xadmaster.library", 11)))
	{
		perror("Error in  extract_archive(...), cannot open xadmaster.library");
		goto _RETURN_ERROR;
	}
	xadMasterBase = xadmasterbase;

	if(!(ai = (struct xadArchiveInfo *)xadAllocObjectA(XADOBJ_ARCHIVEINFO, 0)))
	{
		perror("Error in extract_archive(...), cannot allocate struct xadArchiveInfo");
		goto _RETURN_ERROR;
	}

	e = xadGetInfo(
		ai,
		XAD_INFILENAME, archive_path,
		TAG_DONE);
	if(e)
	{
		perror("Error in extract_archive(...), call to xadGetInfo(...) failed");
		goto _RETURN_ERROR;
	}

	if(DEBUG)
	{
		printf("xc_ArchiverName = %s\n", ai->xai_Client->xc_ArchiverName);
	}

	// Everything is set, let's extract the content of the archive :-)
	// This loop ignores links and directories. It only extracts files in the archive root.
	fi = ai->xai_FileInfo;
	while(fi)
	{
		if(!(fi->xfi_Flags & XADFIF_LINK || fi->xfi_Flags & XADFIF_DIRECTORY))
		{
			CopyMem(destination_path, destination_name, strlen(destination_path) + 1);
			AddPart(destination_name, FilePart(fi->xfi_FileName), MAX_SIZE_NAME);
			e = xadFileUnArc(
				ai,
				XAD_OUTFILENAME, destination_name,
				XAD_ENTRYNUMBER, fi->xfi_EntryNumber,
				TAG_DONE);
			if(e)
			{
				printf("Error in extract_archive(...), call to xadFileUnArc(...) failed\n");
				printf("\te = %ld for file = %s\n", e, destination_name);
			}
			else
			{
				number_of_chars += strlen(destination_name) + 2;
				if(number_of_chars >= maximum_number_of_chars)
				{
					maximum_number_of_chars += MAX_SIZE_LIST;
					list_temp_for_realloc = realloc(list_temp, maximum_number_of_chars);
					if(list_temp_for_realloc == NULL)
					{
						perror("Error in  extract_archive(...), cannot reallocate memory");
						goto _RETURN_ERROR;
					}
					list_temp = list_temp_for_realloc;
				}
				strcat(list_temp, destination_name);
				strcat(list_temp, "\n");
			}
		}
		else if(DEBUG)
		{
			printf("\tSkipped link or directory\n");
		}
		fi = fi->xfi_Next;
	}

	goto _RETURN_OK;
	_RETURN_OK:
		xadFreeInfo(ai);
		xadFreeObjectA(ai, 0);
		CloseLibrary((struct Library *)xadmasterbase);
		if(string_fit(&*list, list_temp) == ERROR)
		{
			perror("Error in  extract_archive(...), cannot trim list");
			goto _RETURN_ERROR;
		}
		free(list_temp);
		return OK;

	goto _RETURN_ERROR;
	_RETURN_ERROR:
		if(ai)
		{
			xadFreeInfo(ai);
			xadFreeObjectA(ai, 0);
		}
		if(xadmasterbase)
		{
			CloseLibrary((struct Library *)xadmasterbase);
		}
		if(list_temp != NULL)
		{
			free(list_temp);
		}
		return ERROR;
}

[BigFan]

My suggestions:

Use either c or aos functions. this code is not portable and i suggest you to replace c functions, especially when it comes to memory allocation.

Sometimes perror and printf is used. Why?

Do not use goto like you did in the past. Your code is f*cking weird spaghetti
code. Your code gets unreadible, instead use modular and structured code.

Split functions. Keep them small and simple.

If **list is for viewing/printing only, then write dest_names to file open in T:
This saves you from reallocation and the possible failure of it. Thats another reason to split up your functions. AddtoList can be file open/write instead of realloc() without interefering with existing code blocks.
I hope you get the point

I have not compiled this. Take it with a grain of salt.

#include "xad.h"
#include "fortify.h"
#include "utils.h"

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <proto/xadmaster.h>
#include <proto/exec.h>
#include <proto/dos.h>



#define DEBUG         0
#define DEBUG_VERBOSE 0

#define MAX_SIZE_LIST 512
#define MAX_SIZE_NAME 512

// Error messages used in extract_archive()
// message text takes less memory now

#define ERRMSG_100 "Error in  extract_archive(), "
#define ERRMSG_101 "cannot allocate memory!"
#define ERRMSG_102 "cannot open xadmaster.library!"
#define ERRMSG_103 "call to xadFileUnArc(...) failed!"
#define ERRMSG_104 "cannot reallocate memory!"
#define ERRMSG_104 "cannot trim list!"
//char * errmsg_105 = ;
//char * errmsg_106 = ;

struct xadMasterBase * xadMasterBase = NULL;
// list entry management is new function
// keep function bodies lean and clean, do not overload with different purposes
// do not overload with features
int AddtoList(char *, char *);

int extract_archive(
	IN  char  *archive_path,
	IN  char  *destination_path,
	OUT char **list)
{
	struct xadMasterBase  *xadmasterbase           = NULL;
	struct xadArchiveInfo *ai                      = NULL;
	struct xadFileInfo    *fi                      = NULL;
	char                  *list_temp               = NULL;
	char                  *list_temp_for_realloc   = NULL;
	long                   e                       ;
	int 				   rc 					   = OK;
	UBYTE                  destination_name[MAX_SIZE_NAME];

	if ((list_temp = calloc(MAX_SIZE_LIST, sizeof(char))) == NULL);
	{
		// compiler concatenates subsequent strings automatically
		perror(ERRMSG_100 ERRMSG_101);
		// there is not much to clean up at this point, so just quit this funtion block
		return ERROR;
	}

	if((xadmasterbase = (struct xadMasterBase *)OpenLibrary("xadmaster.library", 11)) == NULL)
	{
		perror(ERRMSG_100 ERRMSG_102);
		return ERROR;
	}
	
	xadMasterBase = xadmasterbase;

	if(ai = (struct xadArchiveInfo *)xadAllocObjectA(XADOBJ_ARCHIVEINFO, 0))
	{
		if(e = xadGetInfo(ai, XAD_INFILENAME, archive_path,	TAG_DONE))
		{
			// Everything is set, let's extract the content of the archive :-)
			// This loop ignores links and directories. It only extracts files in the archive root.
			fi = ai->xai_FileInfo;
			while(fi)
			{
				if(!(fi->xfi_Flags & XADFIF_LINK || fi->xfi_Flags & XADFIF_DIRECTORY))
				{
					CopyMem(destination_path, destination_name, strlen(destination_path) + 1);
					
					AddPart(destination_name, FilePart(fi->xfi_FileName), MAX_SIZE_NAME);
					
					if (e = xadFileUnArc(ai, XAD_OUTFILENAME, destination_name,
									 XAD_ENTRYNUMBER, fi->xfi_EntryNumber, TAG_DONE))
					{
						printf(ERRMSG_100 ERRMSG_103);
						printf("\te = %ld for file = %s\n", e, destination_name);
					}
					else
					{
						//quit while-loop on error (realloc failed)
						if(AddtoList(list_temp, destination_name)) 
                                                {
                                                      rc = ERROR;             
                                                      break;
                                                 }
					}
				}
				fi = fi->xfi_Next;
			}
		}
		else
		{
			rc = ERROR;
		}
	}
	else
	{
		rc = ERROR;
	}
// clean up section

		if(ai)
		{
			xadFreeInfo(ai);
			xadFreeObjectA(ai, 0);
		}
		if(xadmasterbase)
		{
			CloseLibrary((struct Library *)xadmasterbase);
		}
		if(string_fit(&*list, list_temp) == ERROR)
		{
			perror("Error in  extract_archive(...), cannot trim list");
		}
		if(list_temp)
		{
			free(list_temp);
		}
		return rc;
}

int AddtoList(char * list_temp, char * destination_name)
{
	static int num_chars = 0;
	static int listsize = MAX_SIZE_LIST;

	num_chars += strlen(destination_name) + 2;
	
	if(number_of_chars >= MAX_SIZE_LIST)
	{
		int * list_temp_for_realloc = realloc(list_temp, (listsize += MAX_SIZE_LIST));
		if(list_temp_for_realloc != NULL)
		{
			list_temp = list_temp_for_realloc;
		}
		else 
		{
			perror(ERRMSG_100 ERRMSG_104);
			return 20; // or set return code to ERROR
		}
	}
	strcat(list_temp, destination_name);
	strcat(list_temp, "\n");
	return 0;
}

[tygre]

Hi BigFan!

Originally Posted by BigFan

Use either c or aos functions. this code is not portable and i suggest you to replace c functions, especially when it comes to memory allocation.

I agree but as a newbie, I am confused about C vs. AmigaOS functions: is there anyway to have a tool warn me about using C functions instead of the proper AmigaOS functions? I am using Cubic IDE and vbcc.

Originally Posted by BigFan

Sometimes perror and printf is used. Why?

No good reason, my bad Actually, could you suggest me the related AmigaOS function? I saw PrintFault but it seems to require always at least one parameter?

Originally Posted by BigFan

Do not use goto like you did in the past. Your code is f*cking weird spaghetti
code. Your code gets unreadible, instead use modular and structured code.
Split functions. Keep them small and simple.

Okay!

Originally Posted by BigFan

If **list is for viewing/printing only, then write dest_names to file open in T:. This saves you from reallocation and the possible failure of it. Thats another reason to split up your functions. AddtoList can be file open/write instead of realloc() without interefering with existing code blocks. I hope you get the point

Hum, not quite but I am going to think about it

Originally Posted by BigFan

I have not compiled this. Take it with a grain of salt.

#include "xad.h"
#include "fortify.h"
#include "utils.h"

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <proto/xadmaster.h>
#include <proto/exec.h>
#include <proto/dos.h>



#define DEBUG         0
#define DEBUG_VERBOSE 0

#define MAX_SIZE_LIST 512
#define MAX_SIZE_NAME 512

// Error messages used in extract_archive()
// message text takes less memory now

#define ERRMSG_100 "Error in  extract_archive(), "
#define ERRMSG_101 "cannot allocate memory!"
#define ERRMSG_102 "cannot open xadmaster.library!"
#define ERRMSG_103 "call to xadFileUnArc(...) failed!"
#define ERRMSG_104 "cannot reallocate memory!"
#define ERRMSG_104 "cannot trim list!"
//char * errmsg_105 = ;
//char * errmsg_106 = ;

struct xadMasterBase * xadMasterBase = NULL;
// list entry management is new function
// keep function bodies lean and clean, do not overload with different purposes
// do not overload with features
int AddtoList(char *, char *);

int extract_archive(
    IN  char  *archive_path,
    IN  char  *destination_path,
    OUT char **list)
{
    struct xadMasterBase  *xadmasterbase           = NULL;
    struct xadArchiveInfo *ai                      = NULL;
    struct xadFileInfo    *fi                      = NULL;
    char                  *list_temp               = NULL;
    char                  *list_temp_for_realloc   = NULL;
    long                   e                       ;
    int                    rc                        = OK;
    UBYTE                  destination_name[MAX_SIZE_NAME];

    if ((list_temp = calloc(MAX_SIZE_LIST, sizeof(char))) == NULL);
    {
        // compiler concatenates subsequent strings automatically
        perror(ERRMSG_100 ERRMSG_101);
        // there is not much to clean up at this point, so just quit this funtion block
        return ERROR;
    }

    if((xadmasterbase = (struct xadMasterBase *)OpenLibrary("xadmaster.library", 11)) == NULL)
    {
        perror(ERRMSG_100 ERRMSG_102);
        return ERROR;
    }
    
    xadMasterBase = xadmasterbase;

    if(ai = (struct xadArchiveInfo *)xadAllocObjectA(XADOBJ_ARCHIVEINFO, 0))
    {
        if(e = xadGetInfo(ai, XAD_INFILENAME, archive_path,    TAG_DONE))
        {
            // Everything is set, let's extract the content of the archive :-)
            // This loop ignores links and directories. It only extracts files in the archive root.
            fi = ai->xai_FileInfo;
            while(fi)
            {
                if(!(fi->xfi_Flags & XADFIF_LINK || fi->xfi_Flags & XADFIF_DIRECTORY))
                {
                    CopyMem(destination_path, destination_name, strlen(destination_path) + 1);
                    
                    AddPart(destination_name, FilePart(fi->xfi_FileName), MAX_SIZE_NAME);
                    
                    if (e = xadFileUnArc(ai, XAD_OUTFILENAME, destination_name,
                                     XAD_ENTRYNUMBER, fi->xfi_EntryNumber, TAG_DONE))
                    {
                        printf(ERRMSG_100 ERRMSG_103);
                        printf("\te = %ld for file = %s\n", e, destination_name);
                    }
                    else
                    {
                        //quit while-loop on error (realloc failed)
                        if(AddtoList(list_temp, destination_name)) 
                                                {
                                                      rc = ERROR;             
                                                      break;
                                                 }
                    }
                }
                fi = fi->xfi_Next;
            }
        }
        else
        {
            rc = ERROR;
        }
    }
    else
    {
        rc = ERROR;
    }
// clean up section

        if(ai)
        {
            xadFreeInfo(ai);
            xadFreeObjectA(ai, 0);
        }
        if(xadmasterbase)
        {
            CloseLibrary((struct Library *)xadmasterbase);
        }
        if(string_fit(&*list, list_temp) == ERROR)
        {
            perror("Error in  extract_archive(...), cannot trim list");
        }
        if(list_temp)
        {
            free(list_temp);
        }
        return rc;
}

int AddtoList(char * list_temp, char * destination_name)
{
    static int num_chars = 0;
    static int listsize = MAX_SIZE_LIST;

    num_chars += strlen(destination_name) + 2;
    
    if(number_of_chars >= MAX_SIZE_LIST)
    {
        int * list_temp_for_realloc = realloc(list_temp, (listsize += MAX_SIZE_LIST));
        if(list_temp_for_realloc != NULL)
        {
            list_temp = list_temp_for_realloc;
        }
        else 
        {
            perror(ERRMSG_100 ERRMSG_104);
            return 20; // or set return code to ERROR
        }
    }
    strcat(list_temp, destination_name);
    strcat(list_temp, "\n");
    return 0;
}

Thanks a lot! Excellent ideas

Cheers!