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/** @file bitbuffer.h
*
* A circular buffer of bits.
*
* @author Daniel Silverstone
*/
#ifndef RANDOMSOUND_BITBUFFER_H
#define RANDOMSOUND_BITBUFFER_H
/** A bit buffer.
*
* A circular buffer of a given number of bits.
*/
typedef struct bitbuffer_s *BitBuffer;
/** A bit field, cunningly disguised as an unsigned char. */
typedef unsigned char BitField;
/** Allocate a new bitbuffer.
*
* Given the \a size requested, create a new bit buffer which can store
* that number of bits and return it having initialised it properly.
*
* @param size The number of bits to store in this buffer.
* @return The new ::BitBuffer
*/
BitBuffer bitbuffer_new(const int size);
/** Free a bit buffer.
*
* Free a bitbuffer and all associated storage.
*
* @param buf The ::BitBuffer to free.
*/
void bitbuffer_free(BitBuffer buf);
/** Get free space in bit buffer.
*
* Return the number of free bits in \a buf.
*
* @param buf The ::BitBuffer in question.
* @return The number of free bits in the buffer.
*/
int bitbuffer_free_space(const BitBuffer buf);
/** Get the number of bits available for extraction.
*
* Return the number of bits stored in the buffer and which are thus
* available for extraction.
*
* @param buf The ::BitBuffer in question
* @return The number of bits available for extraction.
*/
int bitbuffer_available_bits(const BitBuffer buf);
/** Store some bits into a buffer.
*
* Store \a count of bits out of \a bits into \s buf.
*
* This routine works least-significant-bit first so if you are only
* storing one bit, make sure it's in bit zero of the ::BitField.
*
* @param buf The ::BitBuffer to add to.
* @param bits The ::BitField to find the bits in.
* @param count The number of bits to add to \a buf.
* @return The number of bits actually added.
*/
int bitbuffer_add_bits(BitBuffer buf, const BitField bits, int count);
/** Extract some bits from a buffer.
*
* Extract \a count of bits out of \a buf into \s bits.
*
* This routine works least-significant-bit first so if you are only
* extracting one bit, it will be in bit zero of the ::BitField.
*
* @param buf The ::BitBuffer to extract from.
* @param bits A pointer to a ::BitField to put the bits in.
* @param count The number of bits to add to \a bits.
* @return The number of bits actually added.
*/
int bitbuffer_extract_bits(BitBuffer buf, BitField *bits, int count);
#endif
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