/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

This library 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Sam Lantinga

slouken@devolution.com

*/

#ifdef SAVE_RCSID

static char rcsid =

"@(#) $Id$";

#endif

/* This file provides a general interface for SDL to read and write

data sources. It can easily be extended to files, memory, etc.

*/

#include <stdlib.h>

#include <string.h>

#include "SDL_error.h"

#include "SDL_rwops.h"

/* Functions to read/write stdio file pointers */

static int stdio_seek(SDL_RWops *context, int offset, int whence)

{

if ( fseek(context->hidden.stdio.fp, offset, whence) == 0 ) {

return(ftell(context->hidden.stdio.fp));

} else {

SDL_Error(SDL_EFSEEK);

return(-1);

}

}

static int stdio_read(SDL_RWops *context, void *ptr, int size, int maxnum)

{

size_t nread;

nread = fread(ptr, size, maxnum, context->hidden.stdio.fp);

if ( nread == 0 && ferror(context->hidden.stdio.fp) ) {

SDL_Error(SDL_EFREAD);

}

return(nread);

}

static int stdio_write(SDL_RWops *context, const void *ptr, int size, int num)

{

size_t nwrote;

nwrote = fwrite(ptr, size, num, context->hidden.stdio.fp);

if ( nwrote == 0 && ferror(context->hidden.stdio.fp) ) {

SDL_Error(SDL_EFWRITE);

}

return(nwrote);

}

static int stdio_close(SDL_RWops *context)

{

if ( context ) {

if ( context->hidden.stdio.autoclose ) {

/* WARNING: Check the return value here! */

fclose(context->hidden.stdio.fp);

}

free(context);

}

return(0);

}

/* Functions to read/write memory pointers */

static int mem_seek(SDL_RWops *context, int offset, int whence)

{

Uint8 *newpos;

switch (whence) {

case SEEK_SET:

newpos = context->hidden.mem.base+offset;

break;

case SEEK_CUR:

newpos = context->hidden.mem.here+offset;

break;

case SEEK_END:

newpos = context->hidden.mem.stop+offset;

break;

default:

SDL_SetError("Unknown value for 'whence'");

return(-1);

}

if ( newpos < context->hidden.mem.base ) {

newpos = context->hidden.mem.base;

}

if ( newpos > context->hidden.mem.stop ) {

newpos = context->hidden.mem.stop;

}

context->hidden.mem.here = newpos;

return(context->hidden.mem.here-context->hidden.mem.base);

}

static int mem_read(SDL_RWops *context, void *ptr, int size, int maxnum)

{

int num;

num = maxnum;

if ( (context->hidden.mem.here + (num*size)) > context->hidden.mem.stop ) {

num = (context->hidden.mem.stop-context->hidden.mem.here)/size;

}

memcpy(ptr, context->hidden.mem.here, num*size);

context->hidden.mem.here += num*size;

return(num);

}

static int mem_write(SDL_RWops *context, const void *ptr, int size, int num)

{

if ( (context->hidden.mem.here + (num*size)) > context->hidden.mem.stop ) {

num = (context->hidden.mem.stop-context->hidden.mem.here)/size;

}

memcpy(context->hidden.mem.here, ptr, num*size);

context->hidden.mem.here += num*size;

return(num);

}

static int mem_close(SDL_RWops *context)

{

if ( context ) {

free(context);

}

return(0);

}

/* Functions to create SDL_RWops structures from various data sources */

#ifdef WIN32

/* Aggh. You can't (apparently) open a file in an application and

read from it in a DLL.

*/

static int in_sdl = 0;

#endif

#ifdef macintosh

/*

* translate unix-style slash-separated filename to mac-style colon-separated

* name; return malloced string

*/

static char *unix_to_mac(const char *file)

{

int flen = strlen(file);

char *path = malloc(flen + 2);

const char *src = file;

char *dst = path;

if(*src == '/') {

/* really depends on filesystem layout, hope for the best */

src++;

} else {

/* Check if this is a MacOS path to begin with */

if(*src != ':')

*dst++ = ':'; /* relative paths begin with ':' */

}

while(src < file + flen) {

const char *end = strchr(src, '/');

int len;

if(!end)

end = file + flen; /* last component */

len = end - src;

if(len == 0 || (len == 1 && src[0] == '.')) {

/* remove repeated slashes and . */

} else {

if(len == 2 && src[0] == '.' && src[1] == '.') {

/* replace .. with the empty string */

} else {

memcpy(dst, src, len);

dst += len;

}

if(end < file + flen)

*dst++ = ':';

}

src = end + 1;

}

*dst++ = '\0';

return path;

}

#endif /* macintosh */

SDL_RWops *SDL_RWFromFile(const char *file, const char *mode)

{

FILE *fp;

SDL_RWops *rwops;

rwops = NULL;

#ifdef macintosh

{

char *mpath = unix_to_mac(file);

fp = fopen(mpath, mode);

free(mpath);

}

#else

fp = fopen(file, mode);

#endif

if ( fp == NULL ) {

SDL_SetError("Couldn't open %s", file);

} else {

#ifdef WIN32

in_sdl = 1;

rwops = SDL_RWFromFP(fp, 1);

in_sdl = 0;

#else

rwops = SDL_RWFromFP(fp, 1);

#endif

}

return(rwops);

}

SDL_RWops *SDL_RWFromFP(FILE *fp, int autoclose)

{

SDL_RWops *rwops;

#ifdef WIN32

if ( ! in_sdl ) {

SDL_SetError("You can't pass a FILE pointer to a DLL (??)");

/*return(NULL);*/

}

#endif

rwops = SDL_AllocRW();

if ( rwops != NULL ) {

rwops->seek = stdio_seek;

rwops->read = stdio_read;

rwops->write = stdio_write;

rwops->close = stdio_close;

rwops->hidden.stdio.fp = fp;

rwops->hidden.stdio.autoclose = autoclose;

}

return(rwops);

}

SDL_RWops *SDL_RWFromMem(void *mem, int size)

{

SDL_RWops *rwops;

rwops = SDL_AllocRW();

if ( rwops != NULL ) {

rwops->seek = mem_seek;

rwops->read = mem_read;

rwops->write = mem_write;

rwops->close = mem_close;

rwops->hidden.mem.base = (Uint8 *)mem;

rwops->hidden.mem.here = rwops->hidden.mem.base;

rwops->hidden.mem.stop = rwops->hidden.mem.base+size;

}

return(rwops);

}

SDL_RWops *SDL_AllocRW(void)

{

SDL_RWops *area;

area = (SDL_RWops *)malloc(sizeof *area);

if ( area == NULL ) {

SDL_OutOfMemory();

}

return(area);

}

void SDL_FreeRW(SDL_RWops *area)

{

free(area);

}