Loading files from a compressed archive with C++ and SDL

[Nuticulus]

Hi,

I am writing a SDL game at the moment and I'm looking for a way to load images and sounds from a compressed archive and display / play them using SDL_RWops.
I don't really mind what format the compressed archive is in, just as long as it's easy to edit the contents of the archive.

Does anyone know how to do this?

[TheBuzzSaw]

I think zlib might have what you're looking for... unless I'm way off on what zlib actually does.

[JordyD]

Is this what you're looking for: http://www.kekkai.org/roger/sdl/rwops/rwops.html?

[Nuticulus]

I'm pretty sure zlib can't do this sort of thing, but I'm not absolutely certain.
I had a look at http://www.kekkai.org/roger/sdl/rwops/rwops.html, but unfortunately it only covers .gz archives, which as far as I know can only hold one file...

Edit: I'm an idiot. The solution was on http://www.kekkai.org/roger/sdl/rwops/rwops.html, and I didn't see it! :p Grrr...

Anyway, I got it working! Thanks JordyD! ):P

[Nuticulus]

Ok, Now I have a new problem. Here is my code for loading an image from a zip file:


#ifndef loadImage
#define loadImage

#include "SDL/SDL.h"
#include "SDL_rwops_zzip.h"
#include "zzip.h"
#include "iostream"
#include "string"

SDL_Surface *loadImage(char* zipFileName, char* imageName, int fileSize);

SDL_Surface *loadImage(char* zipFileName, char* imageName, int fileSize)
{
SDL_Surface *NewImage;
SDL_RWops *rw;
ZZIP_FILE *file;
Uint8 *buffer;
buffer = (Uint8*)malloc(fileSize);
int filesize;

std::string strZipFile = zipFileName;
std::string strImgName = imageName;
std::string strArg = strZipFile + '/' + strImgName;

file = zzip_open(strArg.c_str(), 0);
if(file==NULL)
{
std::cout << "Unable to load image \'" << imageName << "\' from archive \'" << zipFileName << "\'.\n";
return NULL;
}
filesize = zzip_read(file, buffer, fileSize);
rw = SDL_RWFromMem(buffer, filesize);
NewImage = IMG_Load_RW(rw, 0);

free(buffer);
SDL_FreeRW(rw);
zzip_close(file);

return NewImage;
}

#endif

Right now, you have to pass the size of the uncompressed image in order to allocate memory for a buffer.
Is there any way to load the size of the image from the zip file using zZipLib?

[JordyD]

Ok, Now I have a new problem. Here is my code for loading an image from a zip file:


#ifndef loadImage
#define loadImage

#include "SDL/SDL.h"
#include "SDL_rwops_zzip.h"
#include "zzip.h"
#include "iostream"
#include "string"

SDL_Surface *loadImage(char* zipFileName, char* imageName, int fileSize);

SDL_Surface *loadImage(char* zipFileName, char* imageName, int fileSize)
{
SDL_Surface *NewImage;
SDL_RWops *rw;
ZZIP_FILE *file;
Uint8 *buffer;
buffer = (Uint8*)malloc(fileSize);
int filesize;

std::string strZipFile = zipFileName;
std::string strImgName = imageName;
std::string strArg = strZipFile + '/' + strImgName;

file = zzip_open(strArg.c_str(), 0);
if(file==NULL)
{
std::cout << "Unable to load image \'" << imageName << "\' from archive \'" << zipFileName << "\'.\n";
return NULL;
}
filesize = zzip_read(file, buffer, fileSize);
rw = SDL_RWFromMem(buffer, filesize);
NewImage = IMG_Load_RW(rw, 0);

free(buffer);
SDL_FreeRW(rw);
zzip_close(file);

return NewImage;
}

#endif

Right now, you have to pass the size of the uncompressed image in order to allocate memory for a buffer.
Is there any way to load the size of the image from the zip file using zZipLib?
I do not use zZipLib, but these functions may be what you're looking for: zZipLib Library Functions (http://zziplib.sourceforge.net/zziplib.html#zzip_dir_stat). The zzip_file_stat or zzip_fstat functions look like what you may be talking about.

[Nuticulus]

Ok, I seem to have messed up my build options. It now comes out with this error:

SDL_rwops_zzip.c|63|error: lvalue required as left operand of assignment
Does anyone know what the necessary build options are? I'm using the Code::Blocks IDE.

Here is the code for SDL_rwops_zzip.c:

/*
* Copyright (c) 2001 Guido Draheim <guidod@gmx.de>
* Use freely under the restrictions of the ZLIB License
*/

#include "SDL_rwops_zzip.h"
#include <zziplib.h>

#define SDL_RWOPS_ZZIP_FILE(_context) \
((ZZIP_FILE*) (_context)->hidden.unknown.data1)

static int _zzip_seek(SDL_RWops *context, int offset, int whence)
{
return zzip_seek(SDL_RWOPS_ZZIP_FILE(context), offset, whence);
}

static int _zzip_read(SDL_RWops *context, void *ptr, int size, int maxnum)
{
return zzip_read(SDL_RWOPS_ZZIP_FILE(context), ptr, size*maxnum);
}

static int _zzip_write(SDL_RWops *context, const void *ptr, int size, int num)
{
return 0; /* ignored */
}

static int _zzip_close(SDL_RWops *context)
{
zzip_close (SDL_RWOPS_ZZIP_FILE(context));

if ( context )
SDL_FreeRW (context);

return 0;
}

#ifndef O_BINARY
#define O_BINARY 0
#endif

SDL_RWops *SDL_RWFromZZIP(const char* file, const char* mode)
{
register int mo = 0;
register SDL_RWops* rwops;
register ZZIP_FILE* zzip_file;

for (; *mode; ++mode)
switch (*mode)
{
case 'r': mo |= O_RDONLY; break;
case '+': mo |= ZZIP_CASEINSENSITIVE; break; /* == O_APPEND */
case 'b': mo |= O_BINARY; break;
case 'w': /* ouch! */ return 0;
/* default, 't', 'a', etc, just ignore */
}

zzip_file = zzip_open (file, mo);
if (! zzip_file) return 0;

rwops = SDL_AllocRW ();
if (! rwops) { zzip_close (zzip_file); return 0; }

SDL_RWOPS_ZZIP_FILE(rwops) = zzip_file;
rwops->read = _zzip_read;
rwops->write = _zzip_write;
rwops->seek = _zzip_seek;
rwops->close = _zzip_close;
return rwops;
}