AudioFile Class Reference

A class used to manipulate audio data.audio file access. More...

#include <audio.h>

Inheritance diagram for AudioFile:

List of all members.

Public Member Functions
	AudioFile (const char *fname, unsigned long samples=0)
	AudioFile (const char *fname, Info *info, unsigned long min=0)
	AudioFile ()
virtual	~AudioFile ()
void	open (const char *fname)
	Open an audio file and associate it with this object.
void	create (const char *fname, Info *info)
	Create a new audio file and associate it with this object.
void	close (void)
	Close an object associated with an open file.
void	clear (void)
	Clear the AudioFile structure.
int	getBuffer (void *addr, unsigned len)
	Retrieve bytes from the file into a memory buffer.
unsigned	getLinear (Linear buffer, unsigned request)
	Retrieve and convert content to linear encoded audio data from it's original form.
int	putBuffer (void *attr, unsigned len)
	Insert bytes into the file from a memory buffer.
unsigned	putLinear (Linear buffer, unsigned request)
	Convert and store content from linear encoded audio data to the format of the audio file.
Error	getSamples (void *addr, unsigned samples)
	Retrieve samples from the file into a memory buffer.
Error	putSamples (void *addr, unsigned samples)
	Insert samples into the file from a memory buffer.
Error	skip (long samples)
Error	setPosition (unsigned long samples=~0l)
Error	setLimit (unsigned long samples=0l)
Error	getInfo (Info *info)
Error	setMinimum (unsigned long samples)
unsigned long	getAbsolutePosition (void)
	Get the current file pointer in bytes relative to the start of the file.
unsigned long	getPosition (void)
	Get the current file pointer in samples relative to the start of the sample buffer.
virtual bool	isOpen (void)
virtual bool	hasPositioning (void)
Encoding	getEncoding (void)
Format	getFormat (void)
unsigned	getSampleRate (void)
char *	getAnnotation (void)
Error	getError (void)
bool	operator! (void)
bool	isSigned (void)
	Return if the current content is signed or unsigned samples.
Protected Member Functions
virtual bool	afCreate (const char *path)
virtual bool	afOpen (const char *path)
virtual bool	afPeek (unsigned char *data, unsigned size)
AudioCodec *	getCodec (void)
virtual int	afRead (unsigned char *data, unsigned size)
	Read a given number of bytes from the file, starting from the current file pointer.
virtual int	afWrite (unsigned char *data, unsigned size)
	Write a number of bytes into the file at the current file pointer.
virtual bool	afSeek (unsigned long pos)
	Seek to the given position relative to the start of the file and set the file pointer.
virtual void	afClose (void)
virtual char *	getContinuation (void)
const char *	getErrorStr (Error err)
	Return a human-readable error message given a numeric error code of type Audio::Error.
Error	setError (Error err)
unsigned long	getHeader (void)
unsigned short	getShort (unsigned char *data)
void	setShort (unsigned char *data, unsigned short value)
unsigned long	getLong (unsigned char *data)
void	setLong (unsigned char *data, unsigned long value)
Protected Attributes
union {
int   fd
void *   handle
}	file
unsigned long	limit

---

Detailed Description

A class used to manipulate audio data.audio file access.

This class provides file level access to audio data stored in different formats. This class also provides the ability to write audio data into a disk file.

Author:

David Sugar <dyfet@ostel.com>

---

Constructor & Destructor Documentation

AudioFile::AudioFile	(	const char *	fname,
		unsigned long	samples = 0
	)

AudioFile::AudioFile	(	const char *	fname,
		Info *	info,
		unsigned long	min = 0
	)

AudioFile::AudioFile

(

)

[inline]

virtual AudioFile::~AudioFile

(

)

[inline, virtual]

---

Member Function Documentation

virtual bool AudioFile::afCreate

(

const char *

path

)

[protected, virtual]

virtual bool AudioFile::afOpen

(

const char *

path

)

[protected, virtual]

virtual bool AudioFile::afPeek	(	unsigned char *	data,
		unsigned	size
	)			[protected, virtual]

AudioCodec* AudioFile::getCodec

(

void

)

[protected]

virtual int AudioFile::afRead	(	unsigned char *	data,
		unsigned	size
	)			[protected, virtual]

Read a given number of bytes from the file, starting from the current file pointer.

May be overridden by derived classes.

Parameters:

	data	A pointer to the buffer to copy the bytes to.
	size	The number of bytes to read.

Returns:

The number of bytes read, or -1 if an error occurs. On UNIX platforms, use strerror(errno) to get the human-readable error string or FormatMessage(GetLastError()) on Windows platforms.

virtual int AudioFile::afWrite	(	unsigned char *	data,
		unsigned	size
	)			[protected, virtual]

Write a number of bytes into the file at the current file pointer.

May be overridden by derived classes.

Parameters:

	data	A pointer to the buffer with the bytes to write.
	size	The number of bytes to write from the buffer.

Returns:

The number of bytes written, or -1 if an error occurs. On UNIX platforms, use strerror(errno) to get the human-readable error string or FormatMessage(GetLastError()) on Windows platforms.

virtual bool AudioFile::afSeek

(

unsigned long

pos

)

[protected, virtual]

Seek to the given position relative to the start of the file and set the file pointer.

This does not use 64-bit clean seek functions, so seeking to positions greater than (2^32)-1 will result in undefined behavior.

Parameters:

pos

The position to seek to.

Returns:

true if successful, false otherwise.

virtual void AudioFile::afClose

(

void

)

[protected, virtual]

virtual char* AudioFile::getContinuation

(

void

)

[inline, protected, virtual]

const char* AudioFile::getErrorStr

(

Error

err

)

[protected]

Return a human-readable error message given a numeric error code of type Audio::Error.

Parameters:

err

The numeric error code to translate.

Returns:

A pointer to a character string containing the human-readable error message.

Error AudioFile::setError

(

Error

err

)

[protected]

unsigned long AudioFile::getHeader

(

void

)

[inline, protected]

unsigned short AudioFile::getShort

(

unsigned char *

data

)

[protected]

void AudioFile::setShort	(	unsigned char *	data,
		unsigned short	value
	)			[protected]

unsigned long AudioFile::getLong

(

unsigned char *

data

)

[protected]

void AudioFile::setLong	(	unsigned char *	data,
		unsigned long	value
	)			[protected]

void AudioFile::open

(

const char *

fname

)

Open an audio file and associate it with this object.

Called implicitly by the two-argument version of the constructor.

Parameters:

fname

The name of the file to open. Don't forget to double your backslashes for DOS-style pathnames.

void AudioFile::create	(	const char *	fname,
		Info *	info
	)

Create a new audio file and associate it with this object.

Called implicitly by the three-argument version of the constructor.

Parameters:

	fname	The name of the file to open.
	info	The type of the audio file to be created.

void AudioFile::close

(

void

)

Close an object associated with an open file.

This updates the header metadata with the file length if the file length has changed.

void AudioFile::clear

(

void

)

Clear the AudioFile structure.

Called by AudioFile::close(). Sets all fields to zero and deletes the dynamically allocated memory pointed to by the pathname and info.annotation members. See AudioFile::initialize() for the dynamic allocation code.

int AudioFile::getBuffer	(	void *	addr,
		unsigned	len
	)

Retrieve bytes from the file into a memory buffer.

This increments the file pointer so subsequent calls read further bytes. If you want to read a number of samples rather than bytes, use getSamples().

Parameters:

	addr	A pointer to the memory area to copy the samples to.
	len	The number of bytes (not samples) to copy.

Returns:

The number of bytes (not samples) read. Returns -1 if no bytes are read and an error occurs.

unsigned AudioFile::getLinear	(	Linear	buffer,
		unsigned	request
	)

Retrieve and convert content to linear encoded audio data from it's original form.

Parameters:

	addr	A pointer to copy linear data into.
	len	Number of linear samples to extract.

Returns:

number of samples retrieved, 0 if no codec or eof.

int AudioFile::putBuffer	(	void *	attr,
		unsigned	len
	)

Insert bytes into the file from a memory buffer.

This increments the file pointer so subsequent calls append further samples. If you want to write a number of samples rather than bytes, use putSamples().

Parameters:

	attr	A pointer to the memory area to append the samples from.
	len	The number of bytes (not samples) to append.

Returns:

The number of bytes (not samples) read. Returns -1 if an error occurs and no bytes are written.

unsigned AudioFile::putLinear	(	Linear	buffer,
		unsigned	request
	)

Convert and store content from linear encoded audio data to the format of the audio file.

Parameters:

	addr	A pointer to copy linear data from.
	len	Number of linear samples to save.

Returns:

number of samples saved, 0 if no codec or eof.

Error AudioFile::getSamples	(	void *	addr,
		unsigned	samples
	)

Retrieve samples from the file into a memory buffer.

This increments the file pointer so subsequent calls read further samples. If a limit has been set using setLimit(), the number of samples read will be truncated to the limit position. If you want to read a certain number of bytes rather than a certain number of samples, use getBuffer().

Parameters:

	addr	A pointer to the memory area to copy the samples to.
	samples	The number of samples to read.

Returns:

errSuccess if successful, !errSuccess if error. Use getErrorStr() to retrieve the human-readable error string.

Error AudioFile::putSamples	(	void *	addr,
		unsigned	samples
	)

Insert samples into the file from a memory buffer.

This increments the file pointer so subsequent calls append further samples. If you want to write a certain number of bytes rather than a certain number of samples, use putBuffer().

Parameters:

	addr	A pointer to the memory area to append the samples from.
	samples	The number of samples (not bytes) to append.

Returns:

errSuccess if successful, !errSuccess if error. Use getErrorStr() to retrieve the human-readable error string.

Error AudioFile::skip

(

long

samples

)

Error AudioFile::setPosition

(

unsigned long

samples = ~0l

)

Error AudioFile::setLimit

(

unsigned long

samples = 0l

)

Error AudioFile::getInfo

(

Info *

info

)

Error AudioFile::setMinimum

(

unsigned long

samples

)

unsigned long AudioFile::getAbsolutePosition

(

void

)

Get the current file pointer in bytes relative to the start of the file.

See getPosition() to determine the position relative to the start of the sample buffer.

Returns:

The current file pointer in bytes relative to the start of the file. Returns 0 if the file is not open, is empty, or an error has occured.

unsigned long AudioFile::getPosition

(

void

)

Get the current file pointer in samples relative to the start of the sample buffer.

Note that you must multiply this result by the result of a call to toBytes(info.encoding, 1) in order to determine the offset in bytes.

Returns:

the current file pointer in samples relative to the start of the sample buffer. Returns 0 if the file is not open, is empty, or an error has occured.

virtual bool AudioFile::isOpen

(

void

)

[virtual]

virtual bool AudioFile::hasPositioning

(

void

)

[inline, virtual]

Encoding AudioFile::getEncoding

(

void

)

[inline]

Format AudioFile::getFormat

(

void

)

[inline]

unsigned AudioFile::getSampleRate

(

void

)

[inline]

char* AudioFile::getAnnotation

(

void

)

[inline]

Error AudioFile::getError

(

void

)

[inline]

bool AudioFile::operator!

(

void

)

[inline]

bool AudioFile::isSigned

(

void

)

Return if the current content is signed or unsigned samples.

Returns:

true if signed.

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Member Data Documentation

int AudioFile::fd [protected]

void* AudioFile::handle [protected]

union { ... } AudioFile::file [protected]

unsigned long AudioFile::limit [protected]

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The documentation for this class was generated from the following file:

• audio.h

---