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| Rev | Author | Line No. | Line |
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| 5131 | clevermous | 1 | /* |
| 2 | SDL - Simple DirectMedia Layer |
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| 3 | Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga |
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| 4 | |||
| 5 | This library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Library General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2 of the License, or (at your option) any later version. |
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| 9 | |||
| 10 | This library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Library General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU Library General Public |
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| 16 | License along with this library; if not, write to the Free |
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| 17 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 18 | |||
| 19 | Sam Lantinga |
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| 20 | slouken@devolution.com |
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| 21 | */ |
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| 22 | |||
| 23 | /* This file provides a general interface for SDL to read and write |
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| 24 | data sources. It can easily be extended to files, memory, etc. |
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| 25 | */ |
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| 26 | |||
| 27 | #include |
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| 28 | #include |
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| 29 | #include |
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| 30 | |||
| 31 | #include "SDL_error.h" |
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| 32 | #include "SDL_rwops.h" |
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| 33 | |||
| 34 | /* Functions to read/write stdio file pointers */ |
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| 35 | |||
| 36 | static int stdio_seek(SDL_RWops *context, int offset, int whence) |
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| 37 | { |
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| 38 | if ( fseek(context->hidden.stdio.fp, offset, whence) == 0 ) |
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| 39 | { |
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| 40 | return(ftell(context->hidden.stdio.fp)); |
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| 41 | } else { |
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| 42 | SDL_Error(SDL_EFSEEK); |
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| 43 | return(-1); |
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| 44 | } |
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| 45 | } |
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| 46 | |||
| 47 | static int stdio_read(SDL_RWops *context, void *ptr, int size, int maxnum) |
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| 48 | { |
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| 49 | size_t nread; |
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| 50 | nread = fread(ptr, size, maxnum, context->hidden.stdio.fp); |
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| 51 | if ( nread == 0 && ferror(context->hidden.stdio.fp) ) |
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| 52 | { |
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| 53 | SDL_Error(SDL_EFREAD); |
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| 54 | } |
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| 55 | return(nread); |
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| 56 | } |
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| 57 | |||
| 58 | static int stdio_write(SDL_RWops *context, const void *ptr, int size, int num) |
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| 59 | { |
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| 60 | size_t nwrote; |
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| 61 | nwrote = fwrite(ptr, size, num, context->hidden.stdio.fp); |
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| 62 | if ( nwrote == 0 && ferror(context->hidden.stdio.fp) ) |
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| 63 | { |
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| 64 | SDL_Error(SDL_EFWRITE); |
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| 65 | } |
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| 66 | return(nwrote); |
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| 67 | } |
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| 68 | |||
| 69 | static int stdio_close(SDL_RWops *context) |
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| 70 | { |
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| 71 | if ( context ) |
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| 72 | { |
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| 73 | if ( context->hidden.stdio.autoclose ) |
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| 74 | { |
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| 75 | fclose(context->hidden.stdio.fp); |
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| 76 | } |
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| 77 | free(context); |
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| 78 | } |
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| 79 | return(0); |
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| 80 | } |
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| 81 | |||
| 82 | static int mem_seek(SDL_RWops *context, int offset, int whence) |
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| 83 | { |
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| 84 | Uint8 *newpos; |
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| 85 | switch (whence) |
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| 86 | { |
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| 87 | case SEEK_SET: |
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| 88 | newpos = context->hidden.mem.base+offset; |
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| 89 | break; |
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| 90 | case SEEK_CUR: |
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| 91 | newpos = context->hidden.mem.here+offset; |
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| 92 | break; |
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| 93 | case SEEK_END: |
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| 94 | newpos = context->hidden.mem.stop+offset; |
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| 95 | break; |
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| 96 | default: |
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| 97 | SDL_SetError("Unknown value for 'whence'"); |
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| 98 | return(-1); |
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| 99 | } |
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| 100 | if ( newpos < context->hidden.mem.base ) |
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| 101 | { |
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| 102 | newpos = context->hidden.mem.base; |
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| 103 | } |
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| 104 | if ( newpos > context->hidden.mem.stop ) |
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| 105 | { |
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| 106 | newpos = context->hidden.mem.stop; |
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| 107 | } |
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| 108 | context->hidden.mem.here = newpos; |
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| 109 | return(context->hidden.mem.here-context->hidden.mem.base); |
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| 110 | } |
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| 111 | |||
| 112 | static int mem_read(SDL_RWops *context, void *ptr, int size, int maxnum) |
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| 113 | { |
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| 114 | int num; |
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| 115 | num = maxnum; |
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| 116 | if ( (context->hidden.mem.here + (num*size)) > context->hidden.mem.stop ) |
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| 117 | { |
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| 118 | num = (context->hidden.mem.stop-context->hidden.mem.here)/size; |
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| 119 | } |
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| 120 | memcpy(ptr, context->hidden.mem.here, num*size); |
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| 121 | context->hidden.mem.here += num*size; |
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| 122 | return(num); |
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| 123 | } |
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| 124 | |||
| 125 | static int mem_write(SDL_RWops *context, const void *ptr, int size, int num) |
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| 126 | { |
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| 127 | if ( (context->hidden.mem.here + (num*size)) > context->hidden.mem.stop ) |
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| 128 | { |
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| 129 | num = (context->hidden.mem.stop-context->hidden.mem.here)/size; |
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| 130 | } |
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| 131 | memcpy(context->hidden.mem.here, ptr, num*size); |
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| 132 | context->hidden.mem.here += num*size; |
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| 133 | return(num); |
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| 134 | } |
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| 135 | |||
| 136 | static int mem_close(SDL_RWops *context) |
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| 137 | { |
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| 138 | if ( context ) |
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| 139 | { |
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| 140 | free(context); |
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| 141 | } |
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| 142 | return(0); |
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| 143 | } |
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| 144 | |||
| 145 | SDL_RWops *SDL_RWFromFile(const char *file, const char *mode) |
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| 146 | { |
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| 147 | FILE *fp; |
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| 148 | SDL_RWops *rwops; |
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| 149 | rwops = NULL; |
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| 150 | fp = fopen(file, mode); |
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| 151 | if ( fp == NULL ) |
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| 152 | { |
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| 153 | SDL_SetError("Couldn't open %s", file); |
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| 154 | } else { |
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| 155 | rwops = SDL_RWFromFP(fp, 1); |
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| 156 | } |
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| 157 | return(rwops); |
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| 158 | } |
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| 159 | |||
| 160 | SDL_RWops *SDL_RWFromFP(FILE *fp, int autoclose) |
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| 161 | { |
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| 162 | SDL_RWops *rwops; |
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| 163 | rwops = SDL_AllocRW(); |
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| 164 | if ( rwops != NULL ) |
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| 165 | { |
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| 166 | rwops->seek = stdio_seek; |
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| 167 | rwops->read = stdio_read; |
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| 168 | rwops->write = stdio_write; |
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| 169 | rwops->close = stdio_close; |
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| 170 | rwops->hidden.stdio.fp = fp; |
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| 171 | rwops->hidden.stdio.autoclose = autoclose; |
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| 172 | } |
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| 173 | return(rwops); |
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| 174 | } |
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| 175 | |||
| 176 | SDL_RWops *SDL_RWFromMem(void *mem, int size) |
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| 177 | { |
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| 178 | SDL_RWops *rwops; |
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| 179 | rwops = SDL_AllocRW(); |
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| 180 | if ( rwops != NULL ) |
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| 181 | { |
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| 182 | rwops->seek = mem_seek; |
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| 183 | rwops->read = mem_read; |
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| 184 | rwops->write = mem_write; |
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| 185 | rwops->close = mem_close; |
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| 186 | rwops->hidden.mem.base = (Uint8 *)mem; |
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| 187 | rwops->hidden.mem.here = rwops->hidden.mem.base; |
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| 188 | rwops->hidden.mem.stop = rwops->hidden.mem.base+size; |
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| 189 | } |
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| 190 | return(rwops); |
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| 191 | } |
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| 192 | |||
| 193 | SDL_RWops *SDL_AllocRW(void) |
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| 194 | { |
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| 195 | SDL_RWops *area; |
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| 196 | area = (SDL_RWops *)malloc(sizeof *area); |
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| 197 | if ( area == NULL ) |
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| 198 | { |
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| 199 | SDL_OutOfMemory(); |
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| 200 | } |
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| 201 | return(area); |
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| 202 | } |
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| 203 | |||
| 204 | void SDL_FreeRW(SDL_RWops *area) |
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| 205 | { |
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| 206 | free(area); |
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| 207 | } |