| 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); |
| } |