SDL 3.0
|
#include <SDL3/SDL_stdinc.h>
#include <SDL3/SDL_error.h>
#include <SDL3/SDL_begin_code.h>
#include <SDL3/SDL_close_code.h>
Go to the source code of this file.
Data Structures | |
struct | SDL_RWops |
Macros | |
#define | SDL_RWOPS_UNKNOWN 0U |
#define | SDL_RWOPS_WINFILE 1U |
#define | SDL_RWOPS_STDFILE 2U |
#define | SDL_RWOPS_JNIFILE 3U |
#define | SDL_RWOPS_MEMORY 4U |
#define | SDL_RWOPS_MEMORY_RO 5U |
Functions | |
Read endian functions | |
Read an item of the specified endianness and return in native format. | |
Uint8 | SDL_ReadU8 (SDL_RWops *src) |
Uint16 | SDL_ReadLE16 (SDL_RWops *src) |
Uint16 | SDL_ReadBE16 (SDL_RWops *src) |
Uint32 | SDL_ReadLE32 (SDL_RWops *src) |
Uint32 | SDL_ReadBE32 (SDL_RWops *src) |
Uint64 | SDL_ReadLE64 (SDL_RWops *src) |
Uint64 | SDL_ReadBE64 (SDL_RWops *src) |
Write endian functions | |
Write an item of native format to the specified endianness. | |
size_t | SDL_WriteU8 (SDL_RWops *dst, Uint8 value) |
size_t | SDL_WriteLE16 (SDL_RWops *dst, Uint16 value) |
size_t | SDL_WriteBE16 (SDL_RWops *dst, Uint16 value) |
size_t | SDL_WriteLE32 (SDL_RWops *dst, Uint32 value) |
size_t | SDL_WriteBE32 (SDL_RWops *dst, Uint32 value) |
size_t | SDL_WriteLE64 (SDL_RWops *dst, Uint64 value) |
size_t | SDL_WriteBE64 (SDL_RWops *dst, Uint64 value) |
RWFrom functions | |
Functions to create SDL_RWops structures from various data streams. | |
#define | SDL_RW_SEEK_SET 0 |
#define | SDL_RW_SEEK_CUR 1 |
#define | SDL_RW_SEEK_END 2 |
SDL_RWops * | SDL_RWFromFile (const char *file, const char *mode) |
SDL_RWops * | SDL_RWFromMem (void *mem, size_t size) |
SDL_RWops * | SDL_RWFromConstMem (const void *mem, size_t size) |
SDL_RWops * | SDL_CreateRW (void) |
void | SDL_DestroyRW (SDL_RWops *area) |
Sint64 | SDL_RWsize (SDL_RWops *context) |
Sint64 | SDL_RWseek (SDL_RWops *context, Sint64 offset, int whence) |
Sint64 | SDL_RWtell (SDL_RWops *context) |
Sint64 | SDL_RWread (SDL_RWops *context, void *ptr, Sint64 size) |
Sint64 | SDL_RWwrite (SDL_RWops *context, const void *ptr, Sint64 size) |
int | SDL_RWclose (SDL_RWops *context) |
void * | SDL_LoadFile_RW (SDL_RWops *src, size_t *datasize, SDL_bool freesrc) |
void * | SDL_LoadFile (const char *file, size_t *datasize) |
This file provides a general interface for SDL to read and write data streams. It can easily be extended to files, memory, etc.
Definition in file SDL_rwops.h.
#define SDL_RW_SEEK_CUR 1 |
Seek relative to current read point
Definition at line 339 of file SDL_rwops.h.
#define SDL_RW_SEEK_END 2 |
Seek relative to the end of data
Definition at line 340 of file SDL_rwops.h.
#define SDL_RW_SEEK_SET 0 |
Seek from the beginning of data
Definition at line 338 of file SDL_rwops.h.
#define SDL_RWOPS_JNIFILE 3U |
Android asset
Definition at line 45 of file SDL_rwops.h.
#define SDL_RWOPS_MEMORY 4U |
Memory stream
Definition at line 46 of file SDL_rwops.h.
#define SDL_RWOPS_MEMORY_RO 5U |
Read-Only memory stream
Definition at line 47 of file SDL_rwops.h.
#define SDL_RWOPS_STDFILE 2U |
Stdio file
Definition at line 44 of file SDL_rwops.h.
#define SDL_RWOPS_UNKNOWN 0U |
Unknown stream type
Definition at line 42 of file SDL_rwops.h.
#define SDL_RWOPS_WINFILE 1U |
Win32 file
Definition at line 43 of file SDL_rwops.h.
SDL_RWops * SDL_CreateRW | ( | void | ) |
Use this function to allocate an empty, unpopulated SDL_RWops structure.
Applications do not need to use this function unless they are providing their own SDL_RWops implementation. If you just need a SDL_RWops to read/write a common data source, you should use the built-in implementations in SDL, like SDL_RWFromFile() or SDL_RWFromMem(), etc.
You must free the returned pointer with SDL_DestroyRW(). Depending on your operating system and compiler, there may be a difference between the malloc() and free() your program uses and the versions SDL calls internally. Trying to mix the two can cause crashing such as segmentation faults. Since all SDL_RWops must free themselves when their close method is called, all SDL_RWops must be allocated through this function, so they can all be freed correctly with SDL_DestroyRW().
void SDL_DestroyRW | ( | SDL_RWops * | area | ) |
Use this function to free an SDL_RWops structure allocated by SDL_CreateRW().
Applications do not need to use this function unless they are providing their own SDL_RWops implementation. If you just need a SDL_RWops to read/write a common data source, you should use the built-in implementations in SDL, like SDL_RWFromFile() or SDL_RWFromMem(), etc, and call the close method on those SDL_RWops pointers when you are done with them.
Only use SDL_DestroyRW() on pointers returned by SDL_CreateRW(). The pointer is invalid as soon as this function returns. Any extra memory allocated during creation of the SDL_RWops is not freed by SDL_DestroyRW(); the programmer must be responsible for managing that memory in their close method.
area | the SDL_RWops structure to be freed |
void * SDL_LoadFile | ( | const char * | file, |
size_t * | datasize | ||
) |
Load all the data from a file path.
The data is allocated with a zero byte at the end (null terminated) for convenience. This extra byte is not included in the value reported via datasize
.
The data should be freed with SDL_free().
Prior to SDL 2.0.10, this function was a macro wrapping around SDL_LoadFile_RW.
file | the path to read all available data from |
datasize | if not NULL, will store the number of bytes read |
Load all the data from an SDL data stream.
The data is allocated with a zero byte at the end (null terminated) for convenience. This extra byte is not included in the value reported via datasize
.
The data should be freed with SDL_free().
src | the SDL_RWops to read all available data from |
datasize | if not NULL, will store the number of bytes read |
freesrc | if SDL_TRUE, calls SDL_RWclose() on src before returning, even in the case of an error |
Use this function to read 16 bits of big-endian data from an SDL_RWops and return in native format.
SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.
src | the stream from which to read data |
Use this function to read 32 bits of big-endian data from an SDL_RWops and return in native format.
SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.
src | the stream from which to read data |
Use this function to read 64 bits of big-endian data from an SDL_RWops and return in native format.
SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.
src | the stream from which to read data |
Use this function to read 16 bits of little-endian data from an SDL_RWops and return in native format.
SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.
src | the stream from which to read data |
Use this function to read 32 bits of little-endian data from an SDL_RWops and return in native format.
SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.
src | the stream from which to read data |
Use this function to read 64 bits of little-endian data from an SDL_RWops and return in native format.
SDL byteswaps the data only if necessary, so the data returned will be in the native byte order.
src | the stream from which to read data |
Use this function to read a byte from an SDL_RWops.
src | the SDL_RWops to read from |
int SDL_RWclose | ( | SDL_RWops * | context | ) |
Close and free an allocated SDL_RWops structure.
SDL_RWclose() closes and cleans up the SDL_RWops stream. It releases any resources used by the stream and frees the SDL_RWops itself with SDL_DestroyRW(). This returns 0 on success, or -1 if the stream failed to flush to its output (e.g. to disk).
Note that if this fails to flush the stream to disk, this function reports an error, but the SDL_RWops is still invalid once this function returns.
Prior to SDL 2.0.10, this function was a macro.
context | SDL_RWops structure to close |
SDL_RWops * SDL_RWFromConstMem | ( | const void * | mem, |
size_t | size | ||
) |
Use this function to prepare a read-only memory buffer for use with RWops.
This function sets up an SDL_RWops struct based on a memory area of a certain size. It assumes the memory area is not writable.
Attempting to write to this RWops stream will report an error without writing to the memory buffer.
This memory buffer is not copied by the RWops; the pointer you provide must remain valid until you close the stream. Closing the stream will not free the original buffer.
If you need to write to a memory buffer, you should use SDL_RWFromMem() with a writable buffer of memory instead.
mem | a pointer to a read-only buffer to feed an SDL_RWops stream |
size | the buffer size, in bytes |
SDL_RWops * SDL_RWFromFile | ( | const char * | file, |
const char * | mode | ||
) |
Use this function to create a new SDL_RWops structure for reading from and/or writing to a named file.
The mode
string is treated roughly the same as in a call to the C library's fopen(), even if SDL doesn't happen to use fopen() behind the scenes.
Available mode
strings:
NOTE: In order to open a file as a binary file, a "b" character has to be included in the mode
string. This additional "b" character can either be appended at the end of the string (thus making the following compound modes: "rb", "wb", "ab", "r+b", "w+b", "a+b") or be inserted between the letter and the "+" sign for the mixed modes ("rb+", "wb+", "ab+"). Additional characters may follow the sequence, although they should have no effect. For example, "t" is sometimes appended to make explicit the file is a text file.
This function supports Unicode filenames, but they must be encoded in UTF-8 format, regardless of the underlying operating system.
As a fallback, SDL_RWFromFile() will transparently open a matching filename in an Android app's assets
.
Closing the SDL_RWops will close the file handle SDL is holding internally.
file | a UTF-8 string representing the filename to open |
mode | an ASCII string representing the mode to be used for opening the file. |
SDL_RWops * SDL_RWFromMem | ( | void * | mem, |
size_t | size | ||
) |
Use this function to prepare a read-write memory buffer for use with SDL_RWops.
This function sets up an SDL_RWops struct based on a memory area of a certain size, for both read and write access.
This memory buffer is not copied by the RWops; the pointer you provide must remain valid until you close the stream. Closing the stream will not free the original buffer.
If you need to make sure the RWops never writes to the memory buffer, you should use SDL_RWFromConstMem() with a read-only buffer of memory instead.
mem | a pointer to a buffer to feed an SDL_RWops stream |
size | the buffer size, in bytes |
Read from a data source.
This function reads up size
bytes from the data source to the area pointed at by ptr
. This function may read less bytes than requested. It will return zero when the data stream is completely read, or -1 on error. For streams that support non-blocking operation, if nothing was read because it would require blocking, this function returns -2 to distinguish that this is not an error or end-of-file, and the caller can try again later.
SDL_RWread() is actually a function wrapper that calls the SDL_RWops's read
method appropriately, to simplify application development.
It is an error to specify a negative size
, but this parameter is signed so you definitely cannot overflow the return value on a successful run with enormous amounts of data.
context | a pointer to an SDL_RWops structure |
ptr | a pointer to a buffer to read data into |
size | the number of bytes to read from the data source. |
Seek within an SDL_RWops data stream.
This function seeks to byte offset
, relative to whence
.
whence
may be any of the following values:
SDL_RW_SEEK_SET
: seek from the beginning of dataSDL_RW_SEEK_CUR
: seek relative to current read pointSDL_RW_SEEK_END
: seek relative to the end of dataIf this stream can not seek, it will return -1.
SDL_RWseek() is actually a wrapper function that calls the SDL_RWops's seek
method appropriately, to simplify application development.
Prior to SDL 2.0.10, this function was a macro.
context | a pointer to an SDL_RWops structure |
offset | an offset in bytes, relative to whence location; can be negative |
whence | any of SDL_RW_SEEK_SET , SDL_RW_SEEK_CUR , SDL_RW_SEEK_END |
Use this function to get the size of the data stream in an SDL_RWops.
Prior to SDL 2.0.10, this function was a macro.
context | the SDL_RWops to get the size of the data stream from |
Determine the current read/write offset in an SDL_RWops data stream.
SDL_RWtell is actually a wrapper function that calls the SDL_RWops's seek
method, with an offset of 0 bytes from SDL_RW_SEEK_CUR
, to simplify application development.
Prior to SDL 2.0.10, this function was a macro.
context | a SDL_RWops data stream object from which to get the current offset |
Write to an SDL_RWops data stream.
This function writes exactly size
bytes from the area pointed at by ptr
to the stream. If this fails for any reason, it'll return less than size
to demonstrate how far the write progressed. On success, it returns num
.
On error, this function still attempts to write as much as possible, so it might return a positive value less than the requested write size. If the function failed to write anything and there was an actual error, it will return -1. For streams that support non-blocking operation, if nothing was written because it would require blocking, this function returns -2 to distinguish that this is not an error and the caller can try again later.
SDL_RWwrite is actually a function wrapper that calls the SDL_RWops's write
method appropriately, to simplify application development.
It is an error to specify a negative size
, but this parameter is signed so you definitely cannot overflow the return value on a successful run with enormous amounts of data.
context | a pointer to an SDL_RWops structure |
ptr | a pointer to a buffer containing data to write |
size | the number of bytes to write |
num
on error; call SDL_GetError() for more information.Use this function to write 16 bits in native format to a SDL_RWops as big-endian data.
SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.
dst | the stream to which data will be written |
value | the data to be written, in native format |
Use this function to write 32 bits in native format to a SDL_RWops as big-endian data.
SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.
dst | the stream to which data will be written |
value | the data to be written, in native format |
Use this function to write 64 bits in native format to a SDL_RWops as big-endian data.
SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in big-endian format.
dst | the stream to which data will be written |
value | the data to be written, in native format |
Use this function to write 16 bits in native format to a SDL_RWops as little-endian data.
SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.
dst | the stream to which data will be written |
value | the data to be written, in native format |
Use this function to write 32 bits in native format to a SDL_RWops as little-endian data.
SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.
dst | the stream to which data will be written |
value | the data to be written, in native format |
Use this function to write 64 bits in native format to a SDL_RWops as little-endian data.
SDL byteswaps the data only if necessary, so the application always specifies native format, and the data written will be in little-endian format.
dst | the stream to which data will be written |
value | the data to be written, in native format |
Use this function to write a byte to an SDL_RWops.
dst | the SDL_RWops to write to |
value | the byte value to write |