GRASS GIS 8 Programmer's Manual 8.2.1RC1(2022)-exported
segment/put.c
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1
2/**
3 * \file lib/segment/put.c
4 *
5 * \brief Segment write routines.
6 *
7 * This program is free software under the GNU General Public License
8 * (>=v2). Read the file COPYING that comes with GRASS for details.
9 *
10 * \author GRASS GIS Development Team
11 *
12 * \date 2005-2018
13 */
14
15#include <string.h>
16#include <grass/gis.h>
17#include "local_proto.h"
18
19
20/*bugfix: buf: char* vs int* -> wrong pointer arithmetics!!!. Pierre de Mouveaux - 09 april 2000 */
21/* int Segment_put (SEGMENT *SEG,int *buf,int row,int col) */
22
23
24/**
25 * \fn int Segment_put (SEGMENT *SEG, void *buf, int row, int col)
26 *
27 * \brief Write value to segment file.
28 *
29 * Provides random write access to the segmented data. It
30 * copies <i>len</i> bytes of data from <b>buf</b> into the segment
31 * structure <b>seg</b> for the corresponding <b>row</b> and <b>col</b> in
32 * the original data matrix.
33 *
34 * The data is not written to disk immediately. It is stored in a memory segment
35 * until the segment routines decide to page the segment to disk.
36 *
37 * \param[in,out] seg segment
38 * \param[in] buf value to write to segment
39 * \param[in] row
40 * \param[in] col
41 * \return 1 if successful
42 * \return -1 if unable to seek or write segment file
43 */
44
45int Segment_put(SEGMENT * SEG, const void *buf, off_t row, off_t col)
46{
47 int index, n, i;
48
49 if (SEG->cache) {
50 memcpy(SEG->cache + ((size_t)row * SEG->ncols + col) * SEG->len, buf, SEG->len);
51
52 return 1;
53 }
54
55 SEG->address(SEG, row, col, &n, &index);
56 if ((i = seg_pagein(SEG, n)) < 0) {
57 G_warning("segment lib: put: pagein failed");
58 return -1;
59 }
60
61 SEG->scb[i].dirty = 1;
62
63 memcpy(&SEG->scb[i].buf[index], buf, SEG->len);
64
65 return 1;
66}
void G_warning(const char *msg,...)
Print a warning message to stderr.
Definition: gis/error.c:204
int seg_pagein(SEGMENT *SEG, int n)
Internal use only.
Definition: pagein.c:37
int Segment_put(SEGMENT *SEG, const void *buf, off_t row, off_t col)
Definition: segment/put.c:45