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/*-------------------------------------------------------------------------
*
* beard.c
* sample routines to use large objects
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/tutorial/Attic/beard.c,v 1.2 1999/02/13 23:22:47 momjian Exp $
*
*-------------------------------------------------------------------------
*/
typedef struct ImageHdr
{
int size;
} ImageHdr;
#define BUFSIZE 10
/*
* beard -
* clips lower 1/3 of picture and return as large object
*/
Oid
beard(Oid picture)
{
Oid beard;
int pic_fd,
beard_fd;
ImageHdr ihdr;
char buf[BUFSIZE];
int cc;
if ((pic_fd = lo_open(picture, INV_READ)) == -1)
elog(ERROR, "Cannot access picture large object");
if (lo_read(pic_fd, (char *) &ihdr, sizeof(ihdr)) != sizeof(ihdr))
elog(ERROR, "Picture large object corrupted");
beardOffset = (ihdr.size / 3) * 2;
/*
* new large object
*/
if ((beard = lo_creat(INV_MD)) == 0) /* ?? is this right? */
elog(ERROR, "Cannot create new large object");
if ((beard_fd = lo_open(beard, INV_WRITE)) == -1)
elog(ERROR, "Cannot access beard large object");
lo_lseek(pic_fd, beardOffset, SET_CUR);
while ((cc = lo_read(pic_fd, buf, BUFSIZE)) > 0)
{
if (lo_write(beard_fd, buf, cc) != cc)
elog(ERROR, "error while writing large object");
}
lo_close(pic_fd);
lo_close(beard_fd);
return beard;
}
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