From: CSRG <csrg@ucbvax.Berkeley.EDU>
Date: Mon, 7 Jun 1993 23:42:07 +0000 (-0800)
Subject: BSD 4_4_Lite2 development
X-Git-Tag: BSD-4_4_Lite2~640
X-Git-Url: https://git.subgeniuskitty.com/unix-history/.git/commitdiff_plain/eefc9db17b78ee71123f19906557f3d228b94070

BSD 4_4_Lite2 development
Work on file usr/src/contrib/news/trn3/backpage.c

Synthesized-from: CSRG/cd3/4.4BSD-Lite2
---

diff --git a/usr/src/contrib/news/trn3/backpage.c b/usr/src/contrib/news/trn3/backpage.c
new file mode 100644
index 0000000000..3b54779029
--- /dev/null
+++ b/usr/src/contrib/news/trn3/backpage.c
@@ -0,0 +1,114 @@
+/* $Id: backpage.c,v 3.0 1991/09/09 20:18:23 davison Trn $
+ */
+/* This software is Copyright 1991 by Stan Barber. 
+ *
+ * Permission is hereby granted to copy, reproduce, redistribute or otherwise
+ * use this software as long as: there is no monetary profit gained
+ * specifically from the use or reproduction of this software, it is not
+ * sold, rented, traded or otherwise marketed, and this copyright notice is
+ * included prominently in any copy made. 
+ *
+ * The author make no claims as to the fitness or correctness of this software
+ * for any use whatsoever, and it is provided as is. Any use of this software
+ * is at the user's own risk. 
+ */
+
+#include "EXTERN.h"
+#include "common.h"
+#include "intrp.h"
+#include "final.h"
+#include "INTERN.h"
+#include "backpage.h"
+
+ART_LINE maxindx = -1;
+
+void
+backpage_init()
+{
+    char *varyname;
+    
+    varyname = filexp(VARYNAME);
+    close(creat(varyname,0600));
+    varyfd = open(varyname,2);
+    UNLINK(varyname);
+    if (varyfd < 0) {
+	printf(cantopen,varyname) FLUSH;
+	sig_catcher(0);
+    }
+    
+}
+
+/* virtual array read */
+
+ART_POS
+vrdary(indx)
+ART_LINE indx;
+{
+    int subindx;
+    long offset;
+
+#ifdef DEBUG
+    if (indx > maxindx) {
+	printf("vrdary(%ld) > %ld\n",(long)indx, (long)maxindx) FLUSH;
+	return 0;
+    }
+#endif
+    if (indx < 0)
+	return 0;
+    subindx = indx % VARYSIZE;
+    offset = (indx - subindx) * sizeof(varybuf[0]);
+    if (offset != oldoffset) {
+	if (oldoffset >= 0) {
+#ifndef lint
+	    (void)lseek(varyfd,oldoffset,0);
+	    write(varyfd, (char *)varybuf,sizeof(varybuf));
+#endif /* lint */
+	}
+#ifndef lint
+	(void)lseek(varyfd,offset,0);
+	read(varyfd,(char *)varybuf,sizeof(varybuf));
+#endif /* lint */
+	oldoffset = offset;
+    }
+    return varybuf[subindx];
+}
+
+/* write to virtual array */
+
+void
+vwtary(indx,newvalue)
+ART_LINE indx;
+ART_POS newvalue;
+{
+    int subindx;
+    long offset;
+
+#ifdef DEBUG
+    if (indx < 0)
+	printf("vwtary(%ld)\n",(long)indx) FLUSH;
+    if (!indx)
+	maxindx = 0;
+    if (indx > maxindx) {
+	if (indx != maxindx + 1)
+	    printf("indx skipped %d-%d\n",maxindx+1,indx-1) FLUSH;
+	maxindx = indx;
+    }
+#endif
+    subindx = indx % VARYSIZE;
+    offset = (indx - subindx) * sizeof(varybuf[0]);
+    if (offset != oldoffset) {
+	if (oldoffset >= 0) {
+#ifndef lint
+	    (void)lseek(varyfd,oldoffset,0);
+	    write(varyfd,(char *)varybuf,sizeof(varybuf));
+#endif /* lint */
+	}
+#ifndef lint
+	(void)lseek(varyfd,offset,0);
+	read(varyfd,(char *)varybuf,sizeof(varybuf));
+#endif /* lint */
+	oldoffset = offset;
+    }
+    varybuf[subindx] = newvalue;
+}
+