SDL_rwops.h
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上传日期:2022-06-22
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- /*
- SDL - Simple DirectMedia Layer
- Copyright (C) 1997-2006 Sam Lantinga
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 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
- Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with this library; if not, write to the Free Software
- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- Sam Lantinga
- slouken@libsdl.org
- */
- /* This file provides a general interface for SDL to read and write
- data sources. It can easily be extended to files, memory, etc.
- */
- #ifndef _SDL_rwops_h
- #define _SDL_rwops_h
- #include "SDL_stdinc.h"
- #include "SDL_error.h"
- #include "begin_code.h"
- /* Set up for C function definitions, even when using C++ */
- #ifdef __cplusplus
- extern "C" {
- #endif
- /* This is the read/write operation structure -- very basic */
- typedef struct SDL_RWops {
- /* Seek to 'offset' relative to whence, one of stdio's whence values:
- SEEK_SET, SEEK_CUR, SEEK_END
- Returns the final offset in the data source.
- */
- int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
- /* Read up to 'num' objects each of size 'objsize' from the data
- source to the area pointed at by 'ptr'.
- Returns the number of objects read, or -1 if the read failed.
- */
- int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
- /* Write exactly 'num' objects each of size 'objsize' from the area
- pointed at by 'ptr' to data source.
- Returns 'num', or -1 if the write failed.
- */
- int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
- /* Close and free an allocated SDL_FSops structure */
- int (SDLCALL *close)(struct SDL_RWops *context);
- Uint32 type;
- union {
- #if defined(__WIN32__) && !defined(__SYMBIAN32__)
- struct {
- int append;
- void *h;
- struct {
- void *data;
- int size;
- int left;
- } buffer;
- } win32io;
- #endif
- #ifdef HAVE_STDIO_H
- struct {
- int autoclose;
- FILE *fp;
- } stdio;
- #endif
- struct {
- Uint8 *base;
- Uint8 *here;
- Uint8 *stop;
- } mem;
- struct {
- void *data1;
- } unknown;
- } hidden;
- } SDL_RWops;
- /* Functions to create SDL_RWops structures from various data sources */
- extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
- #ifdef HAVE_STDIO_H
- extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
- #endif
- extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
- extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
- extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
- extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
- #define RW_SEEK_SET 0 /* Seek from the beginning of data */
- #define RW_SEEK_CUR 1 /* Seek relative to current read point */
- #define RW_SEEK_END 2 /* Seek relative to the end of data */
- /* Macros to easily read and write from an SDL_RWops structure */
- #define SDL_RWseek(ctx, offset, whence) (ctx)->seek(ctx, offset, whence)
- #define SDL_RWtell(ctx) (ctx)->seek(ctx, 0, RW_SEEK_CUR)
- #define SDL_RWread(ctx, ptr, size, n) (ctx)->read(ctx, ptr, size, n)
- #define SDL_RWwrite(ctx, ptr, size, n) (ctx)->write(ctx, ptr, size, n)
- #define SDL_RWclose(ctx) (ctx)->close(ctx)
- /* Read an item of the specified endianness and return in native format */
- extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
- extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
- extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
- extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
- extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
- extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
- /* Write an item of native format to the specified endianness */
- extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
- extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
- extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
- extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
- extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
- extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
- /* Ends C function definitions when using C++ */
- #ifdef __cplusplus
- }
- #endif
- #include "close_code.h"
- #endif /* _SDL_rwops_h */