ringbuffer.h

/*
   Copyright (C) 2009 - 2010

   Artem Makhutov <artem@makhutov.org>
   http://www.makhutov.org

   Dmitry Vagin <dmitry2004@yandex.ru>
*/

#ifndef ____RINGBUFFER_H__
#define ____RINGBUFFER_H__

#include <sys/uio.h>			/* struct iovec */
#include "export.h"			/* EXPORT_DECL EXPORT_DEF */

typedef void * (*rb_write_f)(void* s1, const void* s2, size_t n);

struct ringbuffer
{
	void*	buffer;			/*!< pointer to data buffer */
	size_t	size;			/*!< size of buffer */
	size_t	used;			/*!< number of bytes used */
	size_t	read;			/*!< read position */
	size_t	write;			/*!< write position */
};


INLINE_DECL void rb_init (struct ringbuffer* rb, void* buf, size_t size)
{
	rb->buffer = buf;
	rb->size   = size;
	rb->used   = 0;
	rb->read   = 0;
	rb->write  = 0;
}

INLINE_DECL size_t rb_used (const struct ringbuffer* rb)
{
	return rb->used;
}

INLINE_DECL size_t rb_free (const struct ringbuffer* rb)
{
	return rb->size - rb->used;
}

EXPORT_DECL int rb_memcmp (const struct ringbuffer*, const char*, size_t);

/*!< fill io vectors array with read data (situable for writev()) and return number of io vectors updated  */
EXPORT_DECL int rb_read_all_iov (const struct ringbuffer* rb, struct iovec iov[2]);

/*!< fill io vectors array and return number of io vectors updated for reading len bytes */
EXPORT_DECL int rb_read_n_iov (const struct ringbuffer* rb, struct iovec* iov, size_t len);

EXPORT_DECL int rb_read_until_char_iov (const struct ringbuffer*, struct iovec iov[2], char);
EXPORT_DECL int rb_read_until_mem_iov (const struct ringbuffer*, struct iovec iov[2], const void*, size_t);

/*!< advice read position to len bytes */
EXPORT_DECL size_t rb_read_upd (struct ringbuffer* rb, size_t len);

/*!< fill io vectors array with free data (situable for readv()) and return number of io vectors updated  */
EXPORT_DECL int rb_write_iov (const struct ringbuffer*, struct iovec iov[2]);

/*!< advice write position to len bytes */
EXPORT_DECL size_t rb_write_upd (struct ringbuffer*, size_t);

EXPORT_DEF size_t rb_write_core (struct ringbuffer* rb, const char* buf, size_t len, rb_write_f method);

INLINE_DECL size_t rb_write (struct ringbuffer* rb, const char* buf, size_t len)
{
	return rb_write_core(rb, buf, len, memmove);
}

#endif /* ____RINGBUFFER_H__ */