/*------------------------------------------------------------------------- * * lotest.c *	  test using large objects with libpq * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION *	  $Header: /usr/local/cvsroot/pgsql/src/test/examples/testlo2.c,v 1.12 1999/05/25 16:15:22 momjian Exp $ * *------------------------------------------------------------------------- */#include <stdlib.h>#include <stdio.h>#include <fcntl.h>#include <unistd.h>#include "libpq-fe.h"#include "libpq/libpq-fs.h"#define BUFSIZE			1024/* * importFile - *	  import file "in_filename" into database as large object "lobjOid" * */static OidimportFile(PGconn *conn, char *filename){	Oid			lobjId;	int			lobj_fd;	char		buf[BUFSIZE];	int			nbytes,				tmp;	int			fd;	/*	 * open the file to be read in	 */	fd = open(filename, O_RDONLY, 0666);	if (fd < 0)	{							/* error */		fprintf(stderr, "can't open unix file\"%s\"\n", filename);	}	/*	 * create the large object	 */	lobjId = lo_creat(conn, INV_READ | INV_WRITE);	if (lobjId == 0)		fprintf(stderr, "can't create large object");	lobj_fd = lo_open(conn, lobjId, INV_WRITE);	/*	 * read in from the Unix file and write to the inversion file	 */	while ((nbytes = read(fd, buf, BUFSIZE)) > 0)	{		tmp = lo_write(conn, lobj_fd, buf, nbytes);		if (tmp < nbytes)			fprintf(stderr, "error while reading \"%s\"", filename);	}	close(fd);	lo_close(conn, lobj_fd);	return lobjId;}static voidpickout(PGconn *conn, Oid lobjId, int start, int len){	int			lobj_fd;	char	   *buf;	int			nbytes;	int			nread;	lobj_fd = lo_open(conn, lobjId, INV_READ);	if (lobj_fd < 0)		fprintf(stderr, "can't open large object %u", lobjId);	lo_lseek(conn, lobj_fd, start, SEEK_SET);	buf = malloc(len + 1);	nread = 0;	while (len - nread > 0)	{		nbytes = lo_read(conn, lobj_fd, buf, len - nread);		buf[nbytes] = '\0';		fprintf(stderr, ">>> %s", buf);		nread += nbytes;	}	fprintf(stderr, "\n");	lo_close(conn, lobj_fd);}static voidoverwrite(PGconn *conn, Oid lobjId, int start, int len){	int			lobj_fd;	char	   *buf;	int			nbytes;	int			nwritten;	int			i;	lobj_fd = lo_open(conn, lobjId, INV_READ);	if (lobj_fd < 0)		fprintf(stderr, "can't open large object %u", lobjId);	lo_lseek(conn, lobj_fd, start, SEEK_SET);	buf = malloc(len + 1);	for (i = 0; i < len; i++)		buf[i] = 'X';	buf[i] = '\0';	nwritten = 0;	while (len - nwritten > 0)	{		nbytes = lo_write(conn, lobj_fd, buf + nwritten, len - nwritten);		nwritten += nbytes;	}	fprintf(stderr, "\n");	lo_close(conn, lobj_fd);}/* * exportFile - *	  export large object "lobjOid" to file "out_filename" * */static voidexportFile(PGconn *conn, Oid lobjId, char *filename){	int			lobj_fd;	char		buf[BUFSIZE];	int			nbytes,				tmp;	int			fd;	/*	 * create an inversion "object"	 */	lobj_fd = lo_open(conn, lobjId, INV_READ);	if (lobj_fd < 0)		fprintf(stderr, "can't open large object %u", lobjId);	/*	 * open the file to be written to	 */	fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);	if (fd < 0)	{							/* error */		fprintf(stderr, "can't open unix file\"%s\"",				filename);	}	/*	 * read in from the Unix file and write to the inversion file	 */	while ((nbytes = lo_read(conn, lobj_fd, buf, BUFSIZE)) > 0)	{		tmp = write(fd, buf, nbytes);		if (tmp < nbytes)		{			fprintf(stderr, "error while writing \"%s\"",					filename);		}	}	lo_close(conn, lobj_fd);	close(fd);	return;}static voidexit_nicely(PGconn *conn){	PQfinish(conn);	exit(1);}intmain(int argc, char **argv){	char	   *in_filename,			   *out_filename;	char	   *database;	Oid			lobjOid;	PGconn	   *conn;	PGresult   *res;	if (argc != 4)	{		fprintf(stderr, "Usage: %s database_name in_filename out_filename\n",				argv[0]);		exit(1);	}	database = argv[1];	in_filename = argv[2];	out_filename = argv[3];	/*	 * set up the connection	 */	conn = PQsetdb(NULL, NULL, NULL, NULL, database);	/* check to see that the backend connection was successfully made */	if (PQstatus(conn) == CONNECTION_BAD)	{		fprintf(stderr, "Connection to database '%s' failed.\n", database);		fprintf(stderr, "%s", PQerrorMessage(conn));		exit_nicely(conn);	}	res = PQexec(conn, "begin");	PQclear(res);	printf("importing file \"%s\" ...\n", in_filename);/*	  lobjOid = importFile(conn, in_filename); */	lobjOid = lo_import(conn, in_filename);	printf("\tas large object %u.\n", lobjOid);	printf("picking out bytes 1000-2000 of the large object\n");	pickout(conn, lobjOid, 1000, 1000);	printf("overwriting bytes 1000-2000 of the large object with X's\n");	overwrite(conn, lobjOid, 1000, 1000);	printf("exporting large object to file \"%s\" ...\n", out_filename);/*	  exportFile(conn, lobjOid, out_filename); */	lo_export(conn, lobjOid, out_filename);	res = PQexec(conn, "end");	PQclear(res);	PQfinish(conn);	exit(0);}