BitStream object. More...

Collaboration diagram for bitstream:

Typedefs
typedef struct __tag_bitstream	GF_BitStream

Enumerations
enum	{ GF_BITSTREAM_READ = 0, GF_BITSTREAM_WRITE }

Functions
GF_BitStream *	gf_bs_new (const char *buffer, u64 size, u32 mode)
	bitstream constructor More...

GF_BitStream *	gf_bs_from_file (FILE *f, u32 mode)
	bitstream constructor from file handle More...

void	gf_bs_del (GF_BitStream *bs)
	bitstream constructor from file handle More...

GF_Err	gf_bs_set_output_buffering (GF_BitStream *bs, u32 size)
	sets bitstream write cache size More...

u32	gf_bs_get_output_buffering (GF_BitStream *bs)
	gets bitstream write cache size More...

u32	gf_bs_read_int (GF_BitStream *bs, u32 nBits)
	integer reading More...

u64	gf_bs_read_long_int (GF_BitStream *bs, u32 nBits)
	large integer reading More...

Float	gf_bs_read_float (GF_BitStream *bs)
	float reading More...

Double	gf_bs_read_double (GF_BitStream *bs)
	double reading More...

u32	gf_bs_read_data (GF_BitStream bs, char data, u32 nbBytes)
	data reading More...

u32	gf_bs_read_u8 (GF_BitStream *bs)
	align char reading More...

u32	gf_bs_read_u8_until_delimiter (GF_BitStream bs, u8 delimiter, u8 out, u32 max_length)
	align char reading until reaching the given value More...

u32	gf_bs_read_u16 (GF_BitStream *bs)
	align short reading More...

u32	gf_bs_read_u24 (GF_BitStream *bs)
	align 24-bit integer reading More...

u32	gf_bs_read_u32 (GF_BitStream *bs)
	align integer reading More...

u64	gf_bs_read_u64 (GF_BitStream *bs)
	align large integer reading More...

u32	gf_bs_read_u32_le (GF_BitStream *bs)
	little endian integer reading More...

u16	gf_bs_read_u16_le (GF_BitStream *bs)
	little endian integer reading More...

u32	gf_bs_read_vluimsbf5 (GF_BitStream *bs)
	variable length integer reading More...

u32	gf_bs_get_bit_offset (GF_BitStream *bs)
	bit position More...

u32	gf_bs_get_bit_position (GF_BitStream *bs)
	current bit position More...

void	gf_bs_write_int (GF_BitStream *bs, s32 value, s32 nBits)
	integer writing More...

void	gf_bs_write_long_int (GF_BitStream *bs, s64 value, s32 nBits)
	large integer writing More...

void	gf_bs_write_float (GF_BitStream *bs, Float value)
	float writing More...

void	gf_bs_write_double (GF_BitStream *bs, Double value)
	double writing More...

u32	gf_bs_write_data (GF_BitStream bs, const char data, u32 nbBytes)
	data writing More...

void	gf_bs_write_u8 (GF_BitStream *bs, u32 value)
	align char writing More...

void	gf_bs_write_u16 (GF_BitStream *bs, u32 value)
	align short writing More...

void	gf_bs_write_u24 (GF_BitStream *bs, u32 value)
	align 24-bits integer writing More...

void	gf_bs_write_u32 (GF_BitStream *bs, u32 value)
	align integer writing More...

void	gf_bs_write_u64 (GF_BitStream *bs, u64 value)
	align large integer writing More...

void	gf_bs_write_u32_le (GF_BitStream *bs, u32 value)
	little endian integer writing More...

void	gf_bs_write_u16_le (GF_BitStream *bs, u32 value)
	little endian short writing More...

u32	gf_bs_write_byte (GF_BitStream *bs, u8 byte, u32 count)
	write byte multiple times More...

void	gf_bs_set_eos_callback (GF_BitStream bs, void(EndOfStream)(void par), void par)
	end of bitstream management More...

u8	gf_bs_align (GF_BitStream *bs)
	bitstream alignment More...

u64	gf_bs_available (GF_BitStream *bs)
	capacity query More...

void	gf_bs_get_content (GF_BitStream bs, char output, u32 outSize)
	buffer fetching More...

void	gf_bs_skip_bytes (GF_BitStream *bs, u64 nbBytes)
	byte skipping More...

GF_Err	gf_bs_seek (GF_BitStream *bs, u64 offset)
	bitstream seeking More...

void	gf_bs_truncate (GF_BitStream *bs)
	bitstream truncation More...

u32	gf_bs_peek_bits (GF_BitStream *bs, u32 numBits, u64 byte_offset)
	bit peeking More...

u8	gf_bs_bits_available (GF_BitStream *bs)
	bit reservoir query More...

u64	gf_bs_get_position (GF_BitStream *bs)
	position query More...

u64	gf_bs_get_size (GF_BitStream *bs)
	size query More...

u64	gf_bs_get_refreshed_size (GF_BitStream *bs)
	file-based size query More...

GF_Err	gf_bs_transfer (GF_BitStream dst, GF_BitStream src)
	transfer content from source bitstream to destination bitstream More...

void	gf_bs_flush (GF_BitStream *bs)
	Flushes bitstream contet to disk. More...

void	gf_bs_reassign (GF_BitStream bs, FILE stream)
	Reassigns FILE object for stream-based bitstreams. More...

Detailed Description

This section documents the bitstream object of the GPAC framework.

Note: Unless specified, all functions assume Big-Endian ordering of data in the bitstream.

Typedef Documentation

typedef struct __tag_bitstream GF_BitStream

Enumeration Type Documentation

anonymous enum

Enumerator
GF_BITSTREAM_READ
GF_BITSTREAM_WRITE

Function Documentation

GF_BitStream* gf_bs_new	(	const char *	buffer,
		u64	size,
		u32	mode
	)

Constructs a bitstream from a buffer (read or write mode)

Parameters

buffer	buffer to read or write. In WRITE mode, this can be NULL to let the bitstream object dynamically allocate memory, in which case the size param is ignored.
size	size of the buffer given.
mode	operation mode for this bitstream: GF_BITSTREAM_READ for read, GF_BITSTREAM_WRITE for write.

Returns: new bitstream object

Note: In write mode on an existing data buffer, data overflow is never signaled but simply ignored, it is the caller responsability to ensure it does not write more than possible.

GF_BitStream* gf_bs_from_file	(	FILE *	f,
		u32	mode
	)

Creates a bitstream from a file handle.

Parameters

f	handle of the file to use. This handle must be created with binary mode.
mode	operation mode for this bitstream: GF_BITSTREAM_READ for read, GF_BITSTREAM_WRITE for write.

Returns: new bitstream object

Note

- You have to open your file in the appropriated mode:

GF_BITSTREAM_READ: bitstream is constructed for reading
GF_BITSTREAM_WRITE: bitstream is constructed for writing

- you may use any of these modes for a file with read/write access.

Warning: RESULTS ARE UNEXPECTED IF YOU TOUCH THE FILE WHILE USING THE BITSTREAM.

void gf_bs_del ( GF_BitStream * bs )

Deletes the bitstream object. If the buffer was created by the bitstream, it is deleted if still present.

GF_Err gf_bs_set_output_buffering	(	GF_BitStream *	bs,
		u32	size
	)

Sets the write cache size for file-based bitstreams.

Parameters

bs	the target bitstream
size	size of the write cache in bytes

Returns: error if any.

u32 gf_bs_get_output_buffering ( GF_BitStream * bs )

Gets the write cache size for file-based bitstreams.

Parameters

bs	the target bitstream

Returns: size of the write cache in bytes, 0 if no cache

u32 gf_bs_read_int	(	GF_BitStream *	bs,
		u32	nBits
	)

Reads an integer coded on a number of bit.

Parameters

bs	the target bitstream
nBits	the number of bits to read

Returns: the integer value read.

u64 gf_bs_read_long_int	(	GF_BitStream *	bs,
		u32	nBits
	)

Reads a large integer coded on a number of bit bigger than 32.

Parameters

bs	the target bitstream
nBits	the number of bits to read

Returns: the large integer value read.

Float gf_bs_read_float ( GF_BitStream * bs )

Reads a float coded as IEEE 32 bit format.

Parameters

bs	the target bitstream

Returns: the float value read.

Double gf_bs_read_double ( GF_BitStream * bs )

Reads a double coded as IEEE 64 bit format.

Parameters

bs	the target bitstream

Returns: the double value read.

u32 gf_bs_read_data	(	GF_BitStream *	bs,
		char *	data,
		u32	nbBytes
	)

Reads a data buffer

Parameters

bs	the target bitstream
data	the data buffer to be filled
nbBytes	the amount of bytes to read

Returns: the number of bytes actually read.

Warning: the data buffer passed must be large enough to hold the desired amount of bytes.

u32 gf_bs_read_u8 ( GF_BitStream * bs )

Reads an integer coded on 8 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream

Returns: the char value read.

u32 gf_bs_read_u8_until_delimiter	(	GF_BitStream *	bs,
		u8	delimiter,
		u8 *	out,
		u32	max_length
	)

Reads an integer coded on 8 bits starting at a byte boundary in the bitstream until

the given appears on the bitstream.

Note: the bytes read in the bitstream will only be update if the delimiter is found

Parameters

bs	the target bitstream
delimiter	the stop condition
out	the resulting value
max_length	the maximum length of the output

Returns: the number of value read.

u32 gf_bs_read_u16 ( GF_BitStream * bs )

Reads an integer coded on 16 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream

Returns: the short value read.

u32 gf_bs_read_u24 ( GF_BitStream * bs )

Reads an integer coded on 24 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream

Returns: the integer value read.

u32 gf_bs_read_u32 ( GF_BitStream * bs )

Reads an integer coded on 32 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream

Returns: the integer value read.

u64 gf_bs_read_u64 ( GF_BitStream * bs )

Reads an integer coded on 64 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream

Returns: the large integer value read.

u32 gf_bs_read_u32_le ( GF_BitStream * bs )

Reads an integer coded on 32 bits in little-endian order.

Parameters

bs	the target bitstream

Returns: the integer value read.

u16 gf_bs_read_u16_le ( GF_BitStream * bs )

Reads an integer coded on 16 bits in little-endian order.

Parameters

bs	the target bitstream

Returns: the integer value read.

u32 gf_bs_read_vluimsbf5 ( GF_BitStream * bs )

Reads an integer coded on a variable number of 4-bits chunks. The number of chunks is given by the number of non-0 bits at the beginning.

Parameters

bs	the target bitstream

Returns: the integer value read.

u32 gf_bs_get_bit_offset ( GF_BitStream * bs )

Returns current bit position in the bitstream - only works in memory mode.

Parameters

bs	the target bitstream

Returns: the integer value read.

u32 gf_bs_get_bit_position ( GF_BitStream * bs )

Returns bit position in the current byte of the bitstream - only works in memory mode.

Parameters

bs	the target bitstream

Returns: the integer value read.

void gf_bs_write_int	(	GF_BitStream *	bs,
		s32	value,
		s32	nBits
	)

Writes an integer on a given number of bits.

Parameters

bs	the target bitstream
value	the integer to write
nBits	number of bits used to code the integer

void gf_bs_write_long_int	(	GF_BitStream *	bs,
		s64	value,
		s32	nBits
	)

Writes an integer on a given number of bits greater than 32.

Parameters

bs	the target bitstream
value	the large integer to write
nBits	number of bits used to code the integer

void gf_bs_write_float	(	GF_BitStream *	bs,
		Float	value
	)

Writes a float in IEEE 32 bits format.

Parameters

bs	the target bitstream
value	the float to write

void gf_bs_write_double	(	GF_BitStream *	bs,
		Double	value
	)

Writes a double in IEEE 64 bits format.

Parameters

bs	the target bitstream
value	the double to write

u32 gf_bs_write_data	(	GF_BitStream *	bs,
		const char *	data,
		u32	nbBytes
	)

Writes a data buffer.

Parameters

bs	the target bitstream
data	the data to write
nbBytes	number of data bytes to write

void gf_bs_write_u8	(	GF_BitStream *	bs,
		u32	value
	)

Writes an integer on 8 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream
value	the char value to write

void gf_bs_write_u16	(	GF_BitStream *	bs,
		u32	value
	)

Writes an integer on 16 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream
value	the short value to write

void gf_bs_write_u24	(	GF_BitStream *	bs,
		u32	value
	)

Writes an integer on 24 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream
value	the integer value to write

void gf_bs_write_u32	(	GF_BitStream *	bs,
		u32	value
	)

Writes an integer on 32 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream
value	the integer value to write

void gf_bs_write_u64	(	GF_BitStream *	bs,
		u64	value
	)

Writes an integer on 64 bits starting at a byte boundary in the bitstream.

Warning: you must not use this function if the bitstream is not aligned

Parameters

bs	the target bitstream
value	the large integer value to write

void gf_bs_write_u32_le	(	GF_BitStream *	bs,
		u32	value
	)

Writes an integer on 32 bits in little-endian order.

Parameters

bs	the target bitstream
value	the integer value to write

void gf_bs_write_u16_le	(	GF_BitStream *	bs,
		u32	value
	)

Writes an integer on 16 bits in little-endian order.

Parameters

bs	the target bitstream
value	the short value to write

u32 gf_bs_write_byte	(	GF_BitStream *	bs,
		u8	byte,
		u32	count
	)

Writes a give byte multiple times.

Parameters

bs	the target bitstream
byte	the byte value to write
count	the number of times the byte should be written

Returns: the number of bytes written

void gf_bs_set_eos_callback	(	GF_BitStream *	bs,
		void()(void par)	EndOfStream,
		void *	par
	)

Assigns a notification callback function for end of stream signaling in read mode

Parameters

bs	the target bitstream
EndOfStream	the notification function to use
par	opaque user data passed to the bitstream

u8 gf_bs_align ( GF_BitStream * bs )

Aligns bitstream to next byte boundary. In write mode, this will write 0 bit values until alignment.

Parameters

bs	the target bitstream

Returns: the number of bits read/written until alignment

u64 gf_bs_available ( GF_BitStream * bs )

Returns the number of bytes still available in the bitstream in read mode.

Parameters

bs	the target bitstream

Returns: the number of bytes still available in read mode, -1 in write modes.

void gf_bs_get_content	(	GF_BitStream *	bs,
		char **	output,
		u32 *	outSize
	)

Fetches the internal bitstream buffer in write mode. If a buffer was given at the bitstream construction, or if the bitstream is in read mode, this does nothing.

Parameters

bs	the target bitstream
output	address of a memory block to be allocated for bitstream data.
outSize	set to the size of the allocated memory block.

Note: It is the user responsability to destroy the allocated buffer Once this function has been called, the internal bitstream buffer is reseted.

void gf_bs_skip_bytes	(	GF_BitStream *	bs,
		u64	nbBytes
	)

    Skips bytes in the bitstream. In Write mode, this will write the 0 integer value for memory-based bitstreams or seek the stream

for file-based bitstream.

Parameters

bs	the target bitstream
nbBytes	the number of bytes to skip

GF_Err gf_bs_seek	(	GF_BitStream *	bs,
		u64	offset
	)

Seeks the bitstream to a given offset after the beginning of the stream. This will perform alignment of the bitstream in all modes.

Warning: Results are unpredictable if seeking beyond the bitstream end is performed.

Parameters

bs	the target bitstream
offset	buffer/file offset to seek to

void gf_bs_truncate ( GF_BitStream * bs )

Truncates the bitstream at the current position

Parameters

bs	the target bitstream

u32 gf_bs_peek_bits	(	GF_BitStream *	bs,
		u32	numBits,
		u64	byte_offset
	)

Peeks a given number of bits (read without moving the position indicator) for read modes only.

Parameters

bs	the target bitstream
numBits	the number of bits to peek
byte_offset	if set, bitstream is aligned and moved from byte_offset before peeking (byte-aligned picking) otherwise, bitstream is not aligned and bits are peeked from current state

Returns: the integer value read

u8 gf_bs_bits_available ( GF_BitStream * bs )

Queries the number of bits available in read mode.

Parameters

bs	the target bitstream

Returns: number of available bits if position is in the last byte of the buffer/stream, 8 otherwise

u64 gf_bs_get_position ( GF_BitStream * bs )

Returns the reading/writting position in the buffer/file.

Parameters

bs	the target bitstream

Returns: the read/write position of the bitstream

u64 gf_bs_get_size ( GF_BitStream * bs )

Returns the size of the associated buffer/file.

Parameters

bs	the target bitstream

Returns: the size of the bitstream

u64 gf_bs_get_refreshed_size ( GF_BitStream * bs )

Returns the size of a file-based bitstream and force a seek to end of file. This is used in case the file handle describes a file being constructed on disk while being read?

Parameters

bs	the target bitstream

Returns: the disk size of the associated file

GF_Err gf_bs_transfer	(	GF_BitStream *	dst,
		GF_BitStream *	src
	)

Returns the size of the associated buffer/file.

Parameters

dst	the target bitstream
src	the source bitstream. This bitstream is empty after calling teh function

Returns: error if any

void gf_bs_flush ( GF_BitStream * bs )

Flushes bitstream contet to disk

Parameters

bs	the target bitstream

void gf_bs_reassign	(	GF_BitStream *	bs,
		FILE *	stream
	)

Reassigns FILE object for stream-based bitstreams. Automatically sets the stream position to the bitstream position

Parameters

bs	the target bitstream
stream	the new stream to assign

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

Enumeration Type Documentation

Function Documentation