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/**
* @file mecirc_buf.h
*
* @brief Meilhaus circular buffer implementation.
* @note Copyright (C) 2007 Meilhaus Electronic GmbH (support@meilhaus.de)
* @author Guenter Gebhardt
* @author Krzysztof Gantzke (k.gantzke@meilhaus.de)
*/
/*
* Copyright (C) 2007 Meilhaus Electronic GmbH (support@meilhaus.de)
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _MECIRC_BUF_H_
#define _MECIRC_BUF_H_
# ifdef __KERNEL__
# ifdef BOSCH
typedef struct me_circ_buf {
unsigned int mask;
// unsigned int count;
uint32_t *buf;
int volatile head;
int volatile tail;
} me_circ_buf_t;
static inline int me_circ_buf_values(me_circ_buf_t * buf)
{
// return ((buf->head - buf->tail) & (buf->count - 1));
return ((buf->head - buf->tail) & (buf->mask));
}
static inline int me_circ_buf_space(me_circ_buf_t * buf)
{
// return ((buf->tail - (buf->head + 1)) & (buf->count - 1));
return ((buf->tail - (buf->head + 1)) & (buf->mask));
}
static inline int me_circ_buf_values_to_end(me_circ_buf_t * buf)
{
int end;
int n;
// end = buf->count - buf->tail;
// n = (buf->head + end) & (buf->count - 1);
end = buf->mask + 1 - buf->tail;
n = (buf->head + end) & (buf->mask);
return (n < end) ? n : end;
}
static inline int me_circ_buf_space_to_end(me_circ_buf_t * buf)
{
int end;
int n;
// end = buf->count - 1 - buf->head;
// n = (end + buf->tail) & (buf->count - 1);
end = buf->mask - buf->head;
n = (end + buf->tail) & (buf->mask);
return (n <= end) ? n : (end + 1);
}
#define _CBUFF_32b_t
# else //~BOSCH
/// @note buf->mask = buf->count-1 = ME4600_AI_CIRC_BUF_COUNT-1
# ifdef _CBUFF_32b_t
//32 bit
typedef struct me_circ_buf_32b {
int volatile head;
int volatile tail;
unsigned int mask; //buffor size-1 must be 2^n-1 to work
uint32_t *buf;
} me_circ_buf_t;
# else
//16 bit
typedef struct me_circ_buf_16b {
int volatile head;
int volatile tail;
unsigned int mask; //buffor size-1 must be 2^n-1 to work
uint16_t *buf;
} me_circ_buf_t;
# endif //_CBUFF_32b_t
/** How many values is in buffer */
static inline int me_circ_buf_values(me_circ_buf_t * buf)
{
return ((buf->head - buf->tail) & (buf->mask));
}
/** How many space left */
static inline int me_circ_buf_space(me_circ_buf_t * buf)
{
return ((buf->tail - (buf->head + 1)) & (buf->mask));
}
/** How many values can be read from buffor in one chunck. */
static inline int me_circ_buf_values_to_end(me_circ_buf_t * buf)
{
return (buf->tail <=
buf->head) ? (buf->head - buf->tail) : (buf->mask - buf->tail +
1);
}
/** How many values can be write to buffer in one chunck. */
static inline int me_circ_buf_space_to_end(me_circ_buf_t * buf)
{
return (buf->tail <=
buf->head) ? (buf->mask - buf->head + 1) : (buf->tail -
buf->head - 1);
}
# endif //BOSCH
# endif //__KERNEL__
#endif //_MECIRC_BUF_H_
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