107 lines
2.6 KiB
C
107 lines
2.6 KiB
C
/*
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lib/buffer.c
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functions for manipulating buffers
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COMEDILIB - Linux Control and Measurement Device Interface Library
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Copyright (C) 1997-2001 David A. Schleef <ds@schleef.org>
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation, version 2.1
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of the License.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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USA.
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*/
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#include <comedi.h>
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#include <libinternal.h>
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int comedi_set_buffer_size(comedi_t *it, unsigned int subdev, unsigned int size)
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{
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int ret;
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comedi_bufconfig bc;
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memset(&bc, 0, sizeof(bc));
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bc.subdevice = subdev;
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bc.size = size;
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ret = ioctl_bufconfig(it->fd, &bc);
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__comedi_errno = errno;
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if(ret < 0) return ret;
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return bc.size;
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}
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int comedi_set_max_buffer_size(comedi_t *it, unsigned int subdev, unsigned int max_size)
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{
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int ret;
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comedi_bufconfig bc;
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memset(&bc, 0, sizeof(bc));
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bc.subdevice = subdev;
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bc.maximum_size = max_size;
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ret = ioctl_bufconfig(it->fd, &bc);
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__comedi_errno = errno;
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if(ret < 0) return ret;
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return bc.maximum_size;
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}
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int comedi_get_max_buffer_size(comedi_t *it, unsigned int subdevice)
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{
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return comedi_set_max_buffer_size(it, subdevice, 0);
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}
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int comedi_get_buffer_size(comedi_t *it, unsigned int subdev)
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{
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return comedi_set_buffer_size(it, subdev, 0);
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}
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int comedi_get_buffer_contents(comedi_t *it, unsigned int subdev)
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{
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return comedi_mark_buffer_read(it, subdev, 0);
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}
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int comedi_mark_buffer_read(comedi_t *it, unsigned int subdev, unsigned int bytes)
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{
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int ret;
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comedi_bufinfo bi;
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memset(&bi, 0, sizeof(bi));
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bi.bytes_read = bytes;
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ret = ioctl_bufinfo(it->fd, &bi);
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__comedi_errno = errno;
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if(__comedi_errno == EINVAL)__comedi_errno = EBUF_OVR;
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return bi.buf_int_count - bi.buf_user_count;
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}
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int comedi_get_buffer_offset(comedi_t *it, unsigned int subdev)
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{
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int ret;
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comedi_bufinfo bi;
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memset(&bi, 0, sizeof(bi));
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ret = ioctl_bufinfo(it->fd, &bi);
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if(ret < 0) return ret;
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return bi.buf_user_ptr;
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}
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int comedi_get_front_count(comedi_t *it, unsigned int subdev)
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{
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int ret;
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comedi_bufinfo bi;
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memset(&bi, 0, sizeof(bi));
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ret = ioctl_bufinfo(it->fd, &bi);
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if(ret < 0) return ret;
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return bi.buf_int_count;
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}
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