0,0 → 1,207 |
/* |
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 |
*/ |
|
/* 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 <stdio.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 ) |
{ |
fclose(context->hidden.stdio.fp); |
} |
free(context); |
} |
return(0); |
} |
|
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); |
} |
|
SDL_RWops *SDL_RWFromFile(const char *file, const char *mode) |
{ |
FILE *fp; |
SDL_RWops *rwops; |
rwops = NULL; |
fp = fopen(file, mode); |
if ( fp == NULL ) |
{ |
SDL_SetError("Couldn't open %s", file); |
} else { |
rwops = SDL_RWFromFP(fp, 1); |
} |
return(rwops); |
} |
|
SDL_RWops *SDL_RWFromFP(FILE *fp, int autoclose) |
{ |
SDL_RWops *rwops; |
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); |
} |