Input Interface

Typedefs
typedef struct _snd_input	snd_input_t
	Internal structure for an input object.
Enumerations
enum	snd_input_type_t { SND_INPUT_STDIO, SND_INPUT_BUFFER }
Functions
int	snd_input_stdio_open (snd_input_t **inputp, const char *file, const char *mode)
	Creates a new input object reading from a file.
int	snd_input_stdio_attach (snd_input_t **inputp, FILE *fp, int _close)
	Creates a new input object using an existing stdio FILE pointer.
int	snd_input_buffer_open (snd_input_t **inputp, const char *buffer, ssize_t size)
	Creates a new input object from a memory buffer.
int	snd_input_close (snd_input_t *input)
	Closes an input handle.
int	snd_input_scanf (snd_input_t *input, const char *format,...)
	Reads formatted input (like fscanf(3)) from an input handle.
char *	snd_input_gets (snd_input_t *input, char *str, size_t size)
	Reads a line from an input handle (like fgets(3)).
int	snd_input_getc (snd_input_t *input)
	Reads a character from an input handle (like fgetc(3)).
int	snd_input_ungetc (snd_input_t *input, int c)
	Puts the last character read back to an input handle (like ungetc(3)).

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Detailed Description

The input functions present an interface similar to the stdio functions on top of different underlying input sources.

The snd_config_load function uses such an input handle to be able to load configurations not only from standard files but also from other sources, e.g. from memory buffers.

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Typedef Documentation

typedef struct _snd_input snd_input_t

Internal structure for an input object.

The ALSA library uses a pointer to this structure as a handle to an input object. Applications don't access its contents directly.

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Enumeration Type Documentation

enum snd_input_type_t

Input type.

Enumerator:

SND_INPUT_STDIO	Input from a stdio stream.
SND_INPUT_BUFFER	Input from a memory buffer.

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Function Documentation

int snd_input_buffer_open	(	snd_input_t **	inputp,
		const char *	buf,
		ssize_t	size
	)

Creates a new input object from a memory buffer.

Parameters:

	inputp	The function puts the pointer to the new input object at the address specified by inputp.
	buf	Address of the input buffer.
	size	Size of the input buffer.

Returns:

Zero if successful, otherwise a negative error code.

This functions creates a copy of the input buffer, so the application is not required to preserve the buffer after this function has been called.

int snd_input_close

(

snd_input_t *

input

)

Closes an input handle.

Parameters:

input

The input handle to be closed.

Returns:

Zero if successful, otherwise a negative error code.

int snd_input_getc

(

snd_input_t *

input

)

Reads a character from an input handle (like fgetc(3)).

Parameters:

input

The input handle.

Returns:

The character read, or EOF on end of file or error.

char* snd_input_gets	(	snd_input_t *	input,
		char *	str,
		size_t	size
	)

Reads a line from an input handle (like fgets(3)).

Parameters:

	input	The input handle.
	str	Address of the destination buffer.
	size	The size of the destination buffer.

Returns:

Pointer to the buffer if successful, otherwise NULL.

Like fgets, the returned string is zero-terminated, and contains the new-line character '\n' if the line fits into the buffer.

int snd_input_scanf	(	snd_input_t *	input,
		const char *	format,
			...
	)

Reads formatted input (like fscanf(3)) from an input handle.

Parameters:

	input	The input handle.
	format	Format string in fscanf format.
	...	Other fscanf arguments.

Returns:

The number of input items assigned, or EOF.

Bug:

Reading from a memory buffer doesn't work.

int snd_input_stdio_attach	(	snd_input_t **	inputp,
		FILE *	fp,
		int	_close
	)

Creates a new input object using an existing stdio FILE pointer.

Parameters:

	inputp	The function puts the pointer to the new input object at the address specified by inputp.
	fp	The FILE pointer to read from. Reading begins at the current file position.
	_close	Close flag. Set this to 1 if snd_input_close should close fp by calling fclose.

Returns:

Zero if successful, otherwise a negative error code.

int snd_input_stdio_open	(	snd_input_t **	inputp,
		const char *	file,
		const char *	mode
	)

Creates a new input object reading from a file.

Parameters:

	inputp	The functions puts the pointer to the new input object at the address specified by inputp.
	file	The name of the file to read from.
	mode	The open mode, like fopen(3).

Returns:

Zero if successful, otherwise a negative error code.

int snd_input_ungetc	(	snd_input_t *	input,
		int	c
	)

Puts the last character read back to an input handle (like ungetc(3)).

Parameters:

	input	The input handle.
	c	The character to push back.

Returns:

The character pushed back, or EOF on error.