Postgres95 1.01 Distribution - Virgin Sources

src/test/examples/testlo.c

@@ -0,0 +1,232 @@
+/*-------------------------------------------------------------------------
+ *
+ * testlo.c--
+ *    test using large objects with libpq
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/test/examples/testlo.c,v 1.1.1.1 1996/07/09 06:22:23 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include <stdio.h>
+#include "libpq-fe.h"
+#include "libpq/libpq-fs.h"
+
+#define BUFSIZE		1024
+
+/*
+ * importFile -
+ *    import file "in_filename" into database as large object "lobjOid"
+ *
+ */
+Oid importFile(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);
+	}
+    }
+    
+    (void) close(fd);
+    (void) lo_close(conn, lobj_fd);
+
+    return lobjId;
+}
+
+void pickout(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 %d",
+		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);
+}
+
+void overwrite(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 %d",
+		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"
+ *
+ */
+void exportFile(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 %d",
+		lobjId);
+    }
+
+    /*
+     * open the file to be written to
+     */
+    fd = open(filename, O_CREAT|O_WRONLY, 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);
+	}
+    }
+
+    (void) lo_close(conn, lobj_fd);
+    (void) close(fd);
+
+    return;
+}
+
+void 
+exit_nicely(PGconn* conn)
+{
+  PQfinish(conn);
+  exit(1);
+}
+
+int
+main(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 %d.\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);
+}