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LibrePilot/flight/Libraries/fifo_buffer.c
2012-05-05 09:40:44 -07:00

267 lines
6.5 KiB
C

/**
******************************************************************************
*
* @file fifo_buffer.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief GPIO input functions
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program 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 3 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include "fifo_buffer.h"
// *****************************************************************************
// circular buffer functions
uint16_t fifoBuf_getSize(t_fifo_buffer *buf)
{ // return the usable size of the buffer
uint16_t buf_size = buf->buf_size;
if (buf_size > 0)
return (buf_size - 1);
else
return 0;
}
uint16_t fifoBuf_getUsed(t_fifo_buffer *buf)
{ // return the number of bytes available in the rx buffer
uint16_t rd = buf->rd;
uint16_t wr = buf->wr;
uint16_t buf_size = buf->buf_size;
uint16_t num_bytes = wr - rd;
if (wr < rd)
num_bytes = (buf_size - rd) + wr;
return num_bytes;
}
uint16_t fifoBuf_getFree(t_fifo_buffer *buf)
{ // return the free space size in the buffer
uint16_t buf_size = buf->buf_size;
uint16_t num_bytes = fifoBuf_getUsed(buf);
return ((buf_size - num_bytes) - 1);
}
void fifoBuf_clearData(t_fifo_buffer *buf)
{ // remove all data from the buffer
buf->rd = buf->wr;
}
void fifoBuf_removeData(t_fifo_buffer *buf, uint16_t len)
{ // remove a number of bytes from the buffer
uint16_t rd = buf->rd;
uint16_t buf_size = buf->buf_size;
// get number of bytes available
uint16_t num_bytes = fifoBuf_getUsed(buf);
if (num_bytes > len)
num_bytes = len;
if (num_bytes < 1)
return; // nothing to remove
rd += num_bytes;
if (rd >= buf_size)
rd -= buf_size;
buf->rd = rd;
}
int16_t fifoBuf_getBytePeek(t_fifo_buffer *buf)
{ // get a data byte from the buffer without removing it
uint16_t rd = buf->rd;
// get number of bytes available
uint16_t num_bytes = fifoBuf_getUsed(buf);
if (num_bytes < 1)
return -1; // no byte retuened
return buf->buf_ptr[rd]; // return the byte
}
int16_t fifoBuf_getByte(t_fifo_buffer *buf)
{ // get a data byte from the buffer
uint16_t rd = buf->rd;
uint16_t buf_size = buf->buf_size;
uint8_t *buff = buf->buf_ptr;
// get number of bytes available
uint16_t num_bytes = fifoBuf_getUsed(buf);
if (num_bytes < 1)
return -1; // no byte returned
uint8_t b = buff[rd];
if (++rd >= buf_size)
rd = 0;
buf->rd = rd;
return b; // return the byte
}
uint16_t fifoBuf_getDataPeek(t_fifo_buffer *buf, void *data, uint16_t len)
{ // get data from the buffer without removing it
uint16_t rd = buf->rd;
uint16_t buf_size = buf->buf_size;
uint8_t *buff = buf->buf_ptr;
// get number of bytes available
uint16_t num_bytes = fifoBuf_getUsed(buf);
if (num_bytes > len)
num_bytes = len;
if (num_bytes < 1)
return 0; // return number of bytes copied
uint8_t *p = (uint8_t *)data;
uint16_t i = 0;
while (num_bytes > 0)
{
uint16_t j = buf_size - rd;
if (j > num_bytes)
j = num_bytes;
memcpy(p + i, buff + rd, j);
i += j;
num_bytes -= j;
rd += j;
if (rd >= buf_size)
rd = 0;
}
return i; // return number of bytes copied
}
uint16_t fifoBuf_getData(t_fifo_buffer *buf, void *data, uint16_t len)
{ // get data from our rx buffer
uint16_t rd = buf->rd;
uint16_t buf_size = buf->buf_size;
uint8_t *buff = buf->buf_ptr;
// get number of bytes available
uint16_t num_bytes = fifoBuf_getUsed(buf);
if (num_bytes > len)
num_bytes = len;
if (num_bytes < 1)
return 0; // return number of bytes copied
uint8_t *p = (uint8_t *)data;
uint16_t i = 0;
while (num_bytes > 0)
{
uint16_t j = buf_size - rd;
if (j > num_bytes)
j = num_bytes;
memcpy(p + i, buff + rd, j);
i += j;
num_bytes -= j;
rd += j;
if (rd >= buf_size)
rd = 0;
}
buf->rd = rd;
return i; // return number of bytes copied
}
uint16_t fifoBuf_putByte(t_fifo_buffer *buf, const uint8_t b)
{ // add a data byte to the buffer
uint16_t wr = buf->wr;
uint16_t buf_size = buf->buf_size;
uint8_t *buff = buf->buf_ptr;
uint16_t num_bytes = fifoBuf_getFree(buf);
if (num_bytes < 1)
return 0;
buff[wr] = b;
if (++wr >= buf_size)
wr = 0;
buf->wr = wr;
return 1; // return number of bytes copied
}
uint16_t fifoBuf_putData(t_fifo_buffer *buf, const void *data, uint16_t len)
{ // add data to the buffer
uint16_t wr = buf->wr;
uint16_t buf_size = buf->buf_size;
uint8_t *buff = buf->buf_ptr;
uint16_t num_bytes = fifoBuf_getFree(buf);
if (num_bytes > len)
num_bytes = len;
if (num_bytes < 1)
return 0; // return number of bytes copied
uint8_t *p = (uint8_t *)data;
uint16_t i = 0;
while (num_bytes > 0)
{
uint16_t j = buf_size - wr;
if (j > num_bytes)
j = num_bytes;
memcpy(buff + wr, p + i, j);
i += j;
num_bytes -= j;
wr += j;
if (wr >= buf_size)
wr = 0;
}
buf->wr = wr;
return i; // return number of bytes copied
}
void fifoBuf_init(t_fifo_buffer *buf, const void *buffer, const uint16_t buffer_size)
{
buf->buf_ptr = (uint8_t *)buffer;
buf->rd = 0;
buf->wr = 0;
buf->buf_size = buffer_size;
}
// *****************************************************************************