dragonfs.h File Reference

DragonFS. More...

Go to the source code of this file.

Macros
#define	DFS_DEFAULT_LOCATION   0
	Default filesystem location.
#define	MAX_FILENAME_LEN   243
	Maximum filename length.
#define	MAX_DIRECTORY_DEPTH   100
	Maximum depth of directories supported.
#define	FILETYPE(x)   ((x) & 3)
	Macro to extract the file type from a DragonFS file flag.
DragonFS Return values
#define	DFS_ESUCCESS   0
	Success.
#define	DFS_EBADINPUT   -1
	Input parameters invalid.
#define	DFS_ENOFILE   -2
	File does not exist.
#define	DFS_EBADFS   -3
	Bad filesystem.
#define	DFS_ENFILE   -4
	Too many open files.
#define	DFS_EBADHANDLE   -5
	Invalid file handle.
DragonFS file type flags
#define	FLAGS_FILE   0x0
	This is a file entry.
#define	FLAGS_DIR   0x1
	This is a directory entry.
#define	FLAGS_EOF   0x2
	This is the end of a directory list.

Functions
int	dfs_init (uint32_t base_fs_loc)
	Initialize the filesystem.
int	dfs_chdir (const char *const path)
	Change directories to the specified path.
int	dfs_dir_findfirst (const char *const path, char *buf)
	Find the first file or directory in a directory listing.
int	dfs_dir_findnext (char *buf)
	Find the next file or directory in a directory listing.
int	dfs_open (const char *const path)
	Open a file given a path.
int	dfs_read (void *const buf, int size, int count, uint32_t handle)
	Read data from a file.
int	dfs_seek (uint32_t handle, int offset, int origin)
	Seek to an offset in the file.
int	dfs_tell (uint32_t handle)
	Return the current offset into a file.
int	dfs_close (uint32_t handle)
	Close an already open file handle.
int	dfs_eof (uint32_t handle)
	Return whether the end of file has been reached.
int	dfs_size (uint32_t handle)
	Return the file size of an open file.
uint32_t	dfs_rom_addr (const char *path)
	Return the physical address of a file (in ROM space)
const char *	dfs_strerror (int error)
	Convert DFS error code into an error string.

Detailed Description

DragonFS.

Function Documentation

dfs_init()

int dfs_init

(

uint32_t

base_fs_loc

)

Initialize the filesystem.

Given a base offset where the filesystem should be found, this function will initialize the filesystem to read from cartridge space. This function will also register DragonFS with newlib so that standard POSIX/C file operations work with DragonFS, using the "rom:/" prefix".

The function needs to know where the DFS image is located within the cartridge space. To simplify this, you can pass DFS_DEFAULT_LOCATION which tells dfs_init to search for the DFS image by itself, using the rompak TOC (see rompak_internal.h). Most users should use this option.

Otherwise, if the ROM cannot be built with a rompak TOC for some reason, a virtual address should be passed. This is normally 0xB0000000 + the offset used when building your ROM + the size of the header file used (typically 0x1000).

Parameters

[in]

base_fs_loc

Virtual address in cartridge space at which to find the filesystem, or DFS_DEFAULT_LOCATION to automatically search for the filesystem in the cartridge (using the rompak).

Returns

DFS_ESUCCESS on success or a negative error otherwise.

dfs_chdir()

int dfs_chdir

(

const char *const

path

)

Change directories to the specified path.

Supports absolute and relative

Parameters

[in]

path

Relative or absolute path to change directories to

Returns

DFS_ESUCCESS on success or a negative value on error.

dfs_dir_findfirst()

int dfs_dir_findfirst	(	const char *const	path,
		char *	buf
	)

Find the first file or directory in a directory listing.

Supports absolute and relative. If the path is invalid, returns a negative DFS_errno. If a file or directory is found, returns the flags of the entry and copies the name into buf.

Parameters

[in]	path	The path to look for files in
[out]	buf	Buffer to place the name of the file or directory found

Returns

The flags (FLAGS_FILE, FLAGS_DIR, FLAGS_EOF) or a negative value on error.

dfs_dir_findnext()

int dfs_dir_findnext

(

char *

buf

)

Find the next file or directory in a directory listing.

Note

Should be called after doing a dfs_dir_findfirst.

Parameters

[out]

buf

Buffer to place the name of the next file or directory found

Returns

The flags (FLAGS_FILE, FLAGS_DIR, FLAGS_EOF) or a negative value on error.

dfs_open()

int dfs_open

(

const char *const

path

)

Open a file given a path.

Check if we have any free file handles, and if we do, try to open the file specified. Supports absolute and relative paths

Parameters

[in]

path

Path of the file to open

Returns

A valid file handle to reference the file by or a negative error on failure.

dfs_read()

int dfs_read	(	void *const	buf,
		int	size,
		int	count,
		uint32_t	handle
	)

Read data from a file.

Note that no caching is performed: if you need to read small amounts (eg: one byte at a time), consider using standard C API instead (fopen()) which performs internal buffering to avoid too much overhead.

Parameters

[out]	buf	Buffer to read into
[in]	size	Size of each element to read
[in]	count	Number of elements to read
[in]	handle	A valid file handle as returned from dfs_open.

Returns

The actual number of bytes read or a negative value on failure.

dfs_seek()

int dfs_seek	(	uint32_t	handle,
		int	offset,
		int	origin
	)

Seek to an offset in the file.

Parameters

[in]	handle	A valid file handle as returned from dfs_open.
[in]	offset	A byte offset from the origin to seek from.
[in]	origin	An offset to seek from. Either SEEK_SET, SEEK_CUR or SEEK_END.

Returns

DFS_ESUCCESS on success or a negative value on error.

dfs_tell()

int dfs_tell

(

uint32_t

handle

)

Return the current offset into a file.

Parameters

[in]

handle

A valid file handle as returned from dfs_open.

Returns

The current byte offset into a file or a negative error on failure.

dfs_close()

int dfs_close

(

uint32_t

handle

)

Close an already open file handle.

Parameters

[in]

handle

A valid file handle as returned from dfs_open.

Returns

DFS_ESUCCESS on success or a negative value on error.

dfs_eof()

int dfs_eof

(

uint32_t

handle

)

Return whether the end of file has been reached.

Parameters

[in]

handle

A valid file handle as returned from dfs_open.

Returns

1 if the end of file is reached, 0 if not, and a negative value on error.

dfs_size()

int dfs_size

(

uint32_t

handle

)

Return the file size of an open file.

Parameters

[in]

handle

A valid file handle as returned from dfs_open.

Returns

The file size in bytes or a negative value on failure.

dfs_rom_addr()

uint32_t dfs_rom_addr

(

const char *

path

)

Return the physical address of a file (in ROM space)

This function should be used for highly-specialized, high-performance use cases. Using dfs_open / dfs_read is generally acceptable performance-wise, and is easier to use rather than managing direct access to PI space.

Direct access to ROM data must go through io_read or dma_read. Do not dereference directly as the console might hang if the PI is busy.

Parameters

[in]

path

Name of the file

Returns

A pointer to the physical address of the file body, or 0 if the file was not found.