/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2006 Sam Lantinga

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

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 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

Lesser General Public License for more details.

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

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

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Sam Lantinga

slouken@libsdl.org

*/

#include "SDL_config.h"

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

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

*/

#include "SDL_endian.h"

#include "SDL_rwops.h"

#ifdef HAVE_STDIO_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);

}

SDL_FreeRW(context);

}

return(0);

}

#endif /* HAVE_STDIO_H */

/* Functions to read/write memory pointers */

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

{

Uint8 *newpos;

switch (whence) {

case RW_SEEK_SET:

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

break;

case RW_SEEK_CUR:

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

break;

case RW_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 total_bytes;

int mem_available;

total_bytes = (maxnum * size);

if ( (maxnum <= 0) || (size <= 0) || ((total_bytes / maxnum) != size) ) {

return 0;

}

mem_available = (context->hidden.mem.stop - context->hidden.mem.here);

if (total_bytes > mem_available) {

total_bytes = mem_available;

}

SDL_memcpy(ptr, context->hidden.mem.here, total_bytes);

context->hidden.mem.here += total_bytes;

return (total_bytes / size);

}

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;

}

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

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

return(num);

}

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

{

SDL_SetError("Can't write to read-only memory");

return(-1);

}

static int mem_close(SDL_RWops *context)

{

if ( context ) {

SDL_FreeRW(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 __MACOS__

/*

* 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 = SDL_strlen(file);

char *path = SDL_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 = SDL_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 {

SDL_memcpy(dst, src, len);

dst += len;

}

if(end < file + flen)

*dst++ = ':';

}

src = end + 1;

}

*dst++ = '\0';

return path;

}

#endif /* __MACOS__ */

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

{

SDL_RWops *rwops = NULL;

#ifdef HAVE_STDIO_H

FILE *fp;

#ifdef __MACOS__

{

char *mpath = unix_to_mac(file);

fp = fopen(mpath, mode);

SDL_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

}

#endif /* HAVE_STDIO_H */

return(rwops);

}

#ifdef HAVE_STDIO_H

SDL_RWops *SDL_RWFromFP(FILE *fp, int autoclose)

{

SDL_RWops *rwops = NULL;

#ifdef __WIN32__

if ( ! in_sdl ) {

/* It's when SDL and the app are compiled with different C runtimes */

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);

}

#endif /* HAVE_STDIO_H */

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_RWFromConstMem(const void *mem, int size)

{

SDL_RWops *rwops;

rwops = SDL_AllocRW();

if ( rwops != NULL ) {

rwops->seek = mem_seek;

rwops->read = mem_read;

rwops->write = mem_writeconst;

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 *)SDL_malloc(sizeof *area);

if ( area == NULL ) {

SDL_OutOfMemory();

}

return(area);

}

void SDL_FreeRW(SDL_RWops *area)

{

SDL_free(area);

}

/* Functions for dynamically reading and writing endian-specific values */

Uint16 SDL_ReadLE16 (SDL_RWops *src)

{

Uint16 value;

SDL_RWread(src, &value, (sizeof value), 1);

return(SDL_SwapLE16(value));

}

Uint16 SDL_ReadBE16 (SDL_RWops *src)

{

Uint16 value;

SDL_RWread(src, &value, (sizeof value), 1);

return(SDL_SwapBE16(value));

}

Uint32 SDL_ReadLE32 (SDL_RWops *src)

{

Uint32 value;

SDL_RWread(src, &value, (sizeof value), 1);

return(SDL_SwapLE32(value));

}

Uint32 SDL_ReadBE32 (SDL_RWops *src)

{

Uint32 value;

SDL_RWread(src, &value, (sizeof value), 1);

return(SDL_SwapBE32(value));

}

Uint64 SDL_ReadLE64 (SDL_RWops *src)

{

Uint64 value;

SDL_RWread(src, &value, (sizeof value), 1);

return(SDL_SwapLE64(value));

}

Uint64 SDL_ReadBE64 (SDL_RWops *src)

{

Uint64 value;

SDL_RWread(src, &value, (sizeof value), 1);

return(SDL_SwapBE64(value));

}

int SDL_WriteLE16 (SDL_RWops *dst, Uint16 value)

{

value = SDL_SwapLE16(value);

return(SDL_RWwrite(dst, &value, (sizeof value), 1));

}

int SDL_WriteBE16 (SDL_RWops *dst, Uint16 value)

{

value = SDL_SwapBE16(value);

return(SDL_RWwrite(dst, &value, (sizeof value), 1));

}

int SDL_WriteLE32 (SDL_RWops *dst, Uint32 value)

{

value = SDL_SwapLE32(value);

return(SDL_RWwrite(dst, &value, (sizeof value), 1));

}

int SDL_WriteBE32 (SDL_RWops *dst, Uint32 value)

{

value = SDL_SwapBE32(value);

return(SDL_RWwrite(dst, &value, (sizeof value), 1));

}

int SDL_WriteLE64 (SDL_RWops *dst, Uint64 value)

{

value = SDL_SwapLE64(value);

return(SDL_RWwrite(dst, &value, (sizeof value), 1));

}

int SDL_WriteBE64 (SDL_RWops *dst, Uint64 value)

{

value = SDL_SwapBE64(value);

return(SDL_RWwrite(dst, &value, (sizeof value), 1));

}