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      1 /*
      2   Simple DirectMedia Layer
      3   Copyright (C) 1997-2014 Sam Lantinga <slouken (at) libsdl.org>
      4 
      5   This software is provided 'as-is', without any express or implied
      6   warranty.  In no event will the authors be held liable for any damages
      7   arising from the use of this software.
      8 
      9   Permission is granted to anyone to use this software for any purpose,
     10   including commercial applications, and to alter it and redistribute it
     11   freely, subject to the following restrictions:
     12 
     13   1. The origin of this software must not be misrepresented; you must not
     14      claim that you wrote the original software. If you use this software
     15      in a product, an acknowledgment in the product documentation would be
     16      appreciated but is not required.
     17   2. Altered source versions must be plainly marked as such, and must not be
     18      misrepresented as being the original software.
     19   3. This notice may not be removed or altered from any source distribution.
     20 */
     21 
     22 /**
     23  *  \file SDL_rwops.h
     24  *
     25  *  This file provides a general interface for SDL to read and write
     26  *  data streams.  It can easily be extended to files, memory, etc.
     27  */
     28 
     29 #ifndef _SDL_rwops_h
     30 #define _SDL_rwops_h
     31 
     32 #include "SDL_stdinc.h"
     33 #include "SDL_error.h"
     34 
     35 #include "begin_code.h"
     36 /* Set up for C function definitions, even when using C++ */
     37 #ifdef __cplusplus
     38 extern "C" {
     39 #endif
     40 
     41 /* RWops Types */
     42 #define SDL_RWOPS_UNKNOWN   0   /* Unknown stream type */
     43 #define SDL_RWOPS_WINFILE   1   /* Win32 file */
     44 #define SDL_RWOPS_STDFILE   2   /* Stdio file */
     45 #define SDL_RWOPS_JNIFILE   3   /* Android asset */
     46 #define SDL_RWOPS_MEMORY    4   /* Memory stream */
     47 #define SDL_RWOPS_MEMORY_RO 5   /* Read-Only memory stream */
     48 
     49 /**
     50  * This is the read/write operation structure -- very basic.
     51  */
     52 typedef struct SDL_RWops
     53 {
     54     /**
     55      *  Return the size of the file in this rwops, or -1 if unknown
     56      */
     57     Sint64 (SDLCALL * size) (struct SDL_RWops * context);
     58 
     59     /**
     60      *  Seek to \c offset relative to \c whence, one of stdio's whence values:
     61      *  RW_SEEK_SET, RW_SEEK_CUR, RW_SEEK_END
     62      *
     63      *  \return the final offset in the data stream, or -1 on error.
     64      */
     65     Sint64 (SDLCALL * seek) (struct SDL_RWops * context, Sint64 offset,
     66                              int whence);
     67 
     68     /**
     69      *  Read up to \c maxnum objects each of size \c size from the data
     70      *  stream to the area pointed at by \c ptr.
     71      *
     72      *  \return the number of objects read, or 0 at error or end of file.
     73      */
     74     size_t (SDLCALL * read) (struct SDL_RWops * context, void *ptr,
     75                              size_t size, size_t maxnum);
     76 
     77     /**
     78      *  Write exactly \c num objects each of size \c size from the area
     79      *  pointed at by \c ptr to data stream.
     80      *
     81      *  \return the number of objects written, or 0 at error or end of file.
     82      */
     83     size_t (SDLCALL * write) (struct SDL_RWops * context, const void *ptr,
     84                               size_t size, size_t num);
     85 
     86     /**
     87      *  Close and free an allocated SDL_RWops structure.
     88      *
     89      *  \return 0 if successful or -1 on write error when flushing data.
     90      */
     91     int (SDLCALL * close) (struct SDL_RWops * context);
     92 
     93     Uint32 type;
     94     union
     95     {
     96 #if defined(ANDROID)
     97         struct
     98         {
     99             void *fileNameRef;
    100             void *inputStreamRef;
    101             void *readableByteChannelRef;
    102             void *readMethod;
    103             void *assetFileDescriptorRef;
    104             long position;
    105             long size;
    106             long offset;
    107             int fd;
    108         } androidio;
    109 #elif defined(__WIN32__)
    110         struct
    111         {
    112             SDL_bool append;
    113             void *h;
    114             struct
    115             {
    116                 void *data;
    117                 size_t size;
    118                 size_t left;
    119             } buffer;
    120         } windowsio;
    121 #endif
    122 
    123 #ifdef HAVE_STDIO_H
    124         struct
    125         {
    126             SDL_bool autoclose;
    127             FILE *fp;
    128         } stdio;
    129 #endif
    130         struct
    131         {
    132             Uint8 *base;
    133             Uint8 *here;
    134             Uint8 *stop;
    135         } mem;
    136         struct
    137         {
    138             void *data1;
    139             void *data2;
    140         } unknown;
    141     } hidden;
    142 
    143 } SDL_RWops;
    144 
    145 
    146 /**
    147  *  \name RWFrom functions
    148  *
    149  *  Functions to create SDL_RWops structures from various data streams.
    150  */
    151 /* @{ */
    152 
    153 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFile(const char *file,
    154                                                   const char *mode);
    155 
    156 #ifdef HAVE_STDIO_H
    157 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(FILE * fp,
    158                                                 SDL_bool autoclose);
    159 #else
    160 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(void * fp,
    161                                                 SDL_bool autoclose);
    162 #endif
    163 
    164 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromMem(void *mem, int size);
    165 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromConstMem(const void *mem,
    166                                                       int size);
    167 
    168 /* @} *//* RWFrom functions */
    169 
    170 
    171 extern DECLSPEC SDL_RWops *SDLCALL SDL_AllocRW(void);
    172 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops * area);
    173 
    174 #define RW_SEEK_SET 0       /**< Seek from the beginning of data */
    175 #define RW_SEEK_CUR 1       /**< Seek relative to current read point */
    176 #define RW_SEEK_END 2       /**< Seek relative to the end of data */
    177 
    178 /**
    179  *  \name Read/write macros
    180  *
    181  *  Macros to easily read and write from an SDL_RWops structure.
    182  */
    183 /* @{ */
    184 #define SDL_RWsize(ctx)         (ctx)->size(ctx)
    185 #define SDL_RWseek(ctx, offset, whence) (ctx)->seek(ctx, offset, whence)
    186 #define SDL_RWtell(ctx)         (ctx)->seek(ctx, 0, RW_SEEK_CUR)
    187 #define SDL_RWread(ctx, ptr, size, n)   (ctx)->read(ctx, ptr, size, n)
    188 #define SDL_RWwrite(ctx, ptr, size, n)  (ctx)->write(ctx, ptr, size, n)
    189 #define SDL_RWclose(ctx)        (ctx)->close(ctx)
    190 /* @} *//* Read/write macros */
    191 
    192 
    193 /**
    194  *  \name Read endian functions
    195  *
    196  *  Read an item of the specified endianness and return in native format.
    197  */
    198 /* @{ */
    199 extern DECLSPEC Uint8 SDLCALL SDL_ReadU8(SDL_RWops * src);
    200 extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops * src);
    201 extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops * src);
    202 extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops * src);
    203 extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops * src);
    204 extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops * src);
    205 extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops * src);
    206 /* @} *//* Read endian functions */
    207 
    208 /**
    209  *  \name Write endian functions
    210  *
    211  *  Write an item of native format to the specified endianness.
    212  */
    213 /* @{ */
    214 extern DECLSPEC size_t SDLCALL SDL_WriteU8(SDL_RWops * dst, Uint8 value);
    215 extern DECLSPEC size_t SDLCALL SDL_WriteLE16(SDL_RWops * dst, Uint16 value);
    216 extern DECLSPEC size_t SDLCALL SDL_WriteBE16(SDL_RWops * dst, Uint16 value);
    217 extern DECLSPEC size_t SDLCALL SDL_WriteLE32(SDL_RWops * dst, Uint32 value);
    218 extern DECLSPEC size_t SDLCALL SDL_WriteBE32(SDL_RWops * dst, Uint32 value);
    219 extern DECLSPEC size_t SDLCALL SDL_WriteLE64(SDL_RWops * dst, Uint64 value);
    220 extern DECLSPEC size_t SDLCALL SDL_WriteBE64(SDL_RWops * dst, Uint64 value);
    221 /* @} *//* Write endian functions */
    222 
    223 
    224 /* Ends C function definitions when using C++ */
    225 #ifdef __cplusplus
    226 }
    227 #endif
    228 #include "close_code.h"
    229 
    230 #endif /* _SDL_rwops_h */
    231 
    232 /* vi: set ts=4 sw=4 expandtab: */
    233