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/**
* \file setup.c
*
* \brief Segment setup routines.
*
* This program is free software under the GNU General Public License
* (>=v2). Read the file COPYING that comes with GRASS for details.
*
* \author GRASS GIS Development Team
*
* \date 2005-2006
*/
#include <stdlib.h>
#include <stdio.h>
#include <grass/gis.h>
#include <grass/segment.h>
/**
* \fn int segment_setup (SEGMENT *SEG)
*
* \brief Setup segment.
*
* <b>SEG</b> must have the following parms set:
* fd (open for read and write), nrows, ncols, srows, scols, len, nseg
*
* \param[in,out] SEG segment
* \return 1 if successful
* \return -1 if illegal parameters are passed in <b>SEG</b>
* \return -2 if unable to allocate memory
*/
int segment_setup(SEGMENT * SEG)
{
int i;
SEG->open = 0;
if (SEG->nrows <= 0 || SEG->ncols <= 0
|| SEG->srows <= 0 || SEG->scols <= 0
|| SEG->len <= 0 || SEG->nseg <= 0) {
G_warning("segment_setup: illegal segment file parameters\n");
return -1;
}
/* This is close to the beginning of the file, so doesn't need to be an off_t */
SEG->offset = (int)lseek(SEG->fd, 0L, SEEK_CUR);
SEG->spr = SEG->ncols / SEG->scols;
SEG->spill = SEG->ncols % SEG->scols;
if (SEG->spill)
SEG->spr++;
if ((SEG->scb =
(struct SEGMENT_SCB *)G_malloc(SEG->nseg *
sizeof(struct SEGMENT_SCB))) == NULL)
return -2;
SEG->size = SEG->srows * SEG->scols * SEG->len;
for (i = 0; i < SEG->nseg; i++) {
if ((SEG->scb[i].buf = G_malloc(SEG->size)) == NULL)
return -2;
SEG->scb[i].n = -1; /* mark free */
SEG->scb[i].dirty = 0;
SEG->scb[i].age = 0;
}
SEG->cur = 0;
SEG->open = 1;
return 1;
}
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