GRASS GIS 7 Programmer's Manual  7.5.svn(2018)-r73111
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rowio/put.c
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1 /*!
2  \file rowio/put.c
3 
4  \brief RowIO library - Write a row
5 
6  (C) 2001-2009 by the GRASS Development Team
7 
8  This program is free software under the GNU General Public License
9  (>=v2). Read the file COPYING that comes with GRASS for details.
10 
11  \author Original author CERL
12 */
13 
14 #include <stdio.h>
15 #include <string.h>
16 #include <grass/rowio.h>
17 
18 
19 /*!
20  * \brief Write a row
21  *
22  * Writes the buffer <i>buf</i>, which holds the data for row
23  * <i>n</i>, into the ROWIO structure <i>r</i>. If the row requested
24  * is currently in memory, the buffer is simply copied into the
25  * structure and marked as having been changed. It will be written out
26  * later. Otherwise it is written immediately. Note that when the row
27  * is finally written to disk, the putrow() routine specified in
28  * Rowio_setup() is called to write row <i>n</i> to the
29  * file. Rowio_flush() force pending updates to disk ROWIO *r;
30  * Rowio_flush() forces all rows modified by Rowio_put() to be
31  * written to the file. This routine must be called before closing the
32  * file or releasing the rowio structure if Rowio_put() has been
33  * called.
34  *
35  * \param R pointer to ROWIO structure
36  * \param buf pointer to data buffer
37  * \param row row number
38  *
39  * \return
40  */
41 
42 int Rowio_put(ROWIO * R, const void *buf, int row)
43 {
44  int i;
45 
46  if (row < 0)
47  return 0;
48 
49  for (i = 0; i < R->nrows; i++)
50  if (row == R->rcb[i].row) {
51  memcpy(R->rcb[i].buf, buf, R->len);
52  R->rcb[i].dirty = 1;
53  return 1;
54  }
55  return ((*R->putrow) (R->fd, buf, row, R->len));
56 }
void * buf
Definition: rowio.h:16
int Rowio_put(ROWIO *R, const void *buf, int row)
Write a row.
Definition: rowio/put.c:42
int(* putrow)(int, const void *, int, int)
Definition: rowio.h:12
int len
Definition: rowio.h:8
struct ROWIO::ROWIO_RCB * rcb
Definition: rowio.h:4
int fd
Definition: rowio.h:6
int nrows
Definition: rowio.h:7