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#include <stdio.h>
#include <stdlib.h>
#include <grass/rowio.h>
/*!
* \brief configure rowio structure
*
* Rowio_setup()
* initializes the ROWIO structure <b>r</b> and allocates the required memory
* buffers. The file descriptor <b>fd</b> must be open for reading. The number
* of rows to be held in memory is <b>nrows.</b> The length in bytes of each
* row is <b>len.</b> The routine which will be called to read data from the
* file is <b>getrow()</b> and must be provided by the programmer. If the
* application requires that the rows be written back into the file if changed,
* the file descriptor <b>fd</b> must be open for write as well, and the
* programmer must provide a <b>putrow()</b> routine to write the data into
* the file. If no writing of the file is to occur, specify NULL for
* <b>putrow().</b>
* Return codes:
* 1 ok
* -1 there is not enough memory for buffer allocation
*
* \param
* \return int
*/
int rowio_setup(ROWIO * R,
int fd, int nrows, int len,
int (*getrow) (int, void *, int, int),
int (*putrow) (int, const void *, int, int))
{
int i;
R->getrow = getrow;
R->putrow = putrow;
R->nrows = nrows;
R->len = len;
R->cur = -1;
R->buf = NULL;
R->fd = fd;
R->rcb = (struct ROWIO_RCB *)malloc(nrows * sizeof(struct ROWIO_RCB));
if (R->rcb == NULL) {
fprintf(stderr, "rowio_setup: out of memory\n");
return -1;
}
for (i = 0; i < nrows; i++) {
R->rcb[i].buf = malloc(len);
if (R->rcb[i].buf == NULL) {
fprintf(stderr, "rowio_setup: out of memory\n");
return -1;
}
R->rcb[i].row = -1; /* mark not used */
}
return 1;
}
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