413 lines
13 KiB
C
Executable File
413 lines
13 KiB
C
Executable File
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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/**
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* \file SDL_rwops.h
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*
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* This file provides a general interface for SDL to read and write
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* data streams. It can easily be extended to files, memory, etc.
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*/
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#ifndef SDL_rwops_h_
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#define SDL_rwops_h_
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#include "SDL_stdinc.h"
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#include "SDL_error.h"
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#include "begin_code.h"
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* RWops Types */
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#define SDL_RWOPS_UNKNOWN 0U /**< Unknown stream type */
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#define SDL_RWOPS_WINFILE 1U /**< Win32 file */
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#define SDL_RWOPS_STDFILE 2U /**< Stdio file */
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#define SDL_RWOPS_JNIFILE 3U /**< Android asset */
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#define SDL_RWOPS_MEMORY 4U /**< Memory stream */
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#define SDL_RWOPS_MEMORY_RO 5U /**< Read-Only memory stream */
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#if defined(__VITA__)
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#define SDL_RWOPS_VITAFILE 6U /**< Vita file */
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#endif
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/**
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* This is the read/write operation structure -- very basic.
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*/
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typedef struct SDL_RWops
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{
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/**
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* Return the size of the file in this rwops, or -1 if unknown
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*/
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Sint64 (SDLCALL * size) (struct SDL_RWops * context);
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/**
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* Seek to \c offset relative to \c whence, one of stdio's whence values:
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* RW_SEEK_SET, RW_SEEK_CUR, RW_SEEK_END
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*
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* \return the final offset in the data stream, or -1 on error.
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*/
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Sint64 (SDLCALL * seek) (struct SDL_RWops * context, Sint64 offset,
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int whence);
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/**
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* Read up to \c maxnum objects each of size \c size from the data
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* stream to the area pointed at by \c ptr.
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*
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* \return the number of objects read, or 0 at error or end of file.
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*/
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size_t (SDLCALL * read) (struct SDL_RWops * context, void *ptr,
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size_t size, size_t maxnum);
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/**
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* Write exactly \c num objects each of size \c size from the area
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* pointed at by \c ptr to data stream.
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*
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* \return the number of objects written, or 0 at error or end of file.
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*/
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size_t (SDLCALL * write) (struct SDL_RWops * context, const void *ptr,
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size_t size, size_t num);
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/**
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* Close and free an allocated SDL_RWops structure.
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*
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* \return 0 if successful or -1 on write error when flushing data.
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*/
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int (SDLCALL * close) (struct SDL_RWops * context);
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Uint32 type;
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union
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{
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#if defined(__ANDROID__)
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struct
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{
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void *asset;
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} androidio;
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#elif defined(__WIN32__)
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struct
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{
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SDL_bool append;
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void *h;
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struct
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{
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void *data;
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size_t size;
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size_t left;
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} buffer;
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} windowsio;
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#elif defined(__VITA__)
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struct
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{
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int h;
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struct
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{
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void *data;
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size_t size;
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size_t left;
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} buffer;
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} vitaio;
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#endif
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#ifdef HAVE_STDIO_H
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struct
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{
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SDL_bool autoclose;
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FILE *fp;
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} stdio;
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#endif
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struct
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{
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Uint8 *base;
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Uint8 *here;
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Uint8 *stop;
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} mem;
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struct
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{
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void *data1;
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void *data2;
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} unknown;
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} hidden;
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} SDL_RWops;
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/**
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* \name RWFrom functions
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*
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* Functions to create SDL_RWops structures from various data streams.
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*/
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/* @{ */
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extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFile(const char *file,
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const char *mode);
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#ifdef HAVE_STDIO_H
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extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(FILE * fp,
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SDL_bool autoclose);
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#else
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extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(void * fp,
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SDL_bool autoclose);
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#endif
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extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromMem(void *mem, int size);
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extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromConstMem(const void *mem,
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int size);
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/* @} *//* RWFrom functions */
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extern DECLSPEC SDL_RWops *SDLCALL SDL_AllocRW(void);
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extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops * area);
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#define RW_SEEK_SET 0 /**< Seek from the beginning of data */
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#define RW_SEEK_CUR 1 /**< Seek relative to current read point */
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#define RW_SEEK_END 2 /**< Seek relative to the end of data */
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/**
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* Use this macro to get the size of the data stream in an SDL_RWops.
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*
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* \param context the SDL_RWops to get the size of the data stream from
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* \returns the size of the data stream in the SDL_RWops on success, -1 if
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* unknown or a negative error code on failure; call SDL_GetError()
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* for more information.
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*
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* \since This function is available since SDL 2.0.0.
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*/
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extern DECLSPEC Sint64 SDLCALL SDL_RWsize(SDL_RWops *context);
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/**
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* Seek within an SDL_RWops data stream.
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*
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* This function seeks to byte `offset`, relative to `whence`.
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*
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* `whence` may be any of the following values:
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*
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* - `RW_SEEK_SET`: seek from the beginning of data
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* - `RW_SEEK_CUR`: seek relative to current read point
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* - `RW_SEEK_END`: seek relative to the end of data
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*
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* If this stream can not seek, it will return -1.
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*
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* SDL_RWseek() is actually a wrapper function that calls the SDL_RWops's
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* `seek` method appropriately, to simplify application development.
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*
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* \param context a pointer to an SDL_RWops structure
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* \param offset an offset in bytes, relative to **whence** location; can be
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* negative
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* \param whence any of `RW_SEEK_SET`, `RW_SEEK_CUR`, `RW_SEEK_END`
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* \returns the final offset in the data stream after the seek or -1 on error.
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*
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* \sa SDL_RWclose
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* \sa SDL_RWFromConstMem
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* \sa SDL_RWFromFile
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* \sa SDL_RWFromFP
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* \sa SDL_RWFromMem
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* \sa SDL_RWread
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* \sa SDL_RWtell
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* \sa SDL_RWwrite
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*/
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extern DECLSPEC Sint64 SDLCALL SDL_RWseek(SDL_RWops *context,
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Sint64 offset, int whence);
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/**
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* Determine the current read/write offset in an SDL_RWops data stream.
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*
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* SDL_RWtell is actually a wrapper function that calls the SDL_RWops's `seek`
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* method, with an offset of 0 bytes from `RW_SEEK_CUR`, to simplify
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* application development.
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*
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* \param context a SDL_RWops data stream object from which to get the current
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* offset
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* \returns the current offset in the stream, or -1 if the information can not
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* be determined.
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*
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* \sa SDL_RWclose
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* \sa SDL_RWFromConstMem
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* \sa SDL_RWFromFile
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* \sa SDL_RWFromFP
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* \sa SDL_RWFromMem
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* \sa SDL_RWread
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* \sa SDL_RWseek
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* \sa SDL_RWwrite
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*/
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extern DECLSPEC Sint64 SDLCALL SDL_RWtell(SDL_RWops *context);
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/**
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* Read from a data source.
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*
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* This function reads up to `maxnum` objects each of size `size` from the
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* data source to the area pointed at by `ptr`. This function may read less
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* objects than requested. It will return zero when there has been an error or
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* the data stream is completely read.
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*
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* SDL_RWread() is actually a function wrapper that calls the SDL_RWops's
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* `read` method appropriately, to simplify application development.
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*
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* \param context a pointer to an SDL_RWops structure
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* \param ptr a pointer to a buffer to read data into
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* \param size the size of each object to read, in bytes
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* \param maxnum the maximum number of objects to be read
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* \returns the number of objects read, or 0 at error or end of file; call
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* SDL_GetError() for more information.
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*
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* \sa SDL_RWclose
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* \sa SDL_RWFromConstMem
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* \sa SDL_RWFromFile
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* \sa SDL_RWFromFP
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* \sa SDL_RWFromMem
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* \sa SDL_RWseek
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* \sa SDL_RWwrite
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*/
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extern DECLSPEC size_t SDLCALL SDL_RWread(SDL_RWops *context,
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void *ptr, size_t size,
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size_t maxnum);
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/**
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* Write to an SDL_RWops data stream.
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*
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* This function writes exactly `num` objects each of size `size` from the
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* area pointed at by `ptr` to the stream. If this fails for any reason, it'll
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* return less than `num` to demonstrate how far the write progressed. On
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* success, it returns `num`.
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*
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* SDL_RWwrite is actually a function wrapper that calls the SDL_RWops's
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* `write` method appropriately, to simplify application development.
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*
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* \param context a pointer to an SDL_RWops structure
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* \param ptr a pointer to a buffer containing data to write
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* \param size the size of an object to write, in bytes
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* \param num the number of objects to write
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* \returns the number of objects written, which will be less than **num** on
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* error; call SDL_GetError() for more information.
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*
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* \sa SDL_RWclose
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* \sa SDL_RWFromConstMem
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* \sa SDL_RWFromFile
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* \sa SDL_RWFromFP
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* \sa SDL_RWFromMem
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* \sa SDL_RWread
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* \sa SDL_RWseek
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*/
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extern DECLSPEC size_t SDLCALL SDL_RWwrite(SDL_RWops *context,
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const void *ptr, size_t size,
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size_t num);
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/**
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* Close and free an allocated SDL_RWops structure.
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*
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* SDL_RWclose() closes and cleans up the SDL_RWops stream. It releases any
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* resources used by the stream and frees the SDL_RWops itself with
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* SDL_FreeRW(). This returns 0 on success, or -1 if the stream failed to
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* flush to its output (e.g. to disk).
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*
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* Note that if this fails to flush the stream to disk, this function reports
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* an error, but the SDL_RWops is still invalid once this function returns.
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*
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* SDL_RWclose() is actually a macro that calls the SDL_RWops's `close` method
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* appropriately, to simplify application development.
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*
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* \param context SDL_RWops structure to close
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* \returns 0 on success or a negative error code on failure; call
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* SDL_GetError() for more information.
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*
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* \sa SDL_RWFromConstMem
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* \sa SDL_RWFromFile
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* \sa SDL_RWFromFP
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* \sa SDL_RWFromMem
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* \sa SDL_RWread
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* \sa SDL_RWseek
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* \sa SDL_RWwrite
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*/
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extern DECLSPEC int SDLCALL SDL_RWclose(SDL_RWops *context);
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/**
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* Load all the data from an SDL data stream.
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*
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* The data is allocated with a zero byte at the end (null terminated) for
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* convenience. This extra byte is not included in the value reported via
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* `datasize`.
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*
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* The data should be freed with SDL_free().
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*
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* \param src the SDL_RWops to read all available data from
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* \param datasize if not NULL, will store the number of bytes read
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* \param freesrc if non-zero, calls SDL_RWclose() on `src` before returning
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* \returns the data, or NULL if there was an error.
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*/
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extern DECLSPEC void *SDLCALL SDL_LoadFile_RW(SDL_RWops *src,
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size_t *datasize,
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int freesrc);
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/**
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* Load all the data from a file path.
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*
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* The data is allocated with a zero byte at the end (null terminated) for
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* convenience. This extra byte is not included in the value reported via
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* `datasize`.
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*
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* The data should be freed with SDL_free().
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*
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* \param file the path to read all available data from
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* \param datasize if not NULL, will store the number of bytes read
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* \returns the data, or NULL if there was an error.
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*/
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extern DECLSPEC void *SDLCALL SDL_LoadFile(const char *file, size_t *datasize);
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/**
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* \name Read endian functions
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*
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* Read an item of the specified endianness and return in native format.
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*/
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/* @{ */
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extern DECLSPEC Uint8 SDLCALL SDL_ReadU8(SDL_RWops * src);
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extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops * src);
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extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops * src);
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extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops * src);
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extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops * src);
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extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops * src);
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extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops * src);
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/* @} *//* Read endian functions */
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/**
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* \name Write endian functions
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*
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* Write an item of native format to the specified endianness.
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*/
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/* @{ */
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extern DECLSPEC size_t SDLCALL SDL_WriteU8(SDL_RWops * dst, Uint8 value);
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extern DECLSPEC size_t SDLCALL SDL_WriteLE16(SDL_RWops * dst, Uint16 value);
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extern DECLSPEC size_t SDLCALL SDL_WriteBE16(SDL_RWops * dst, Uint16 value);
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extern DECLSPEC size_t SDLCALL SDL_WriteLE32(SDL_RWops * dst, Uint32 value);
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extern DECLSPEC size_t SDLCALL SDL_WriteBE32(SDL_RWops * dst, Uint32 value);
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extern DECLSPEC size_t SDLCALL SDL_WriteLE64(SDL_RWops * dst, Uint64 value);
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extern DECLSPEC size_t SDLCALL SDL_WriteBE64(SDL_RWops * dst, Uint64 value);
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/* @} *//* Write endian functions */
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#include "close_code.h"
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#endif /* SDL_rwops_h_ */
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/* vi: set ts=4 sw=4 expandtab: */
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