date and time created 80/10/09 23:57:45 by bill

SCCS-vsn: old/sdb/old.c 4.1

diff --git a/usr/src/old/sdb/old.c b/usr/src/old/sdb/old.c
new file mode 100644 (file)
index 0000000..7458fa8
--- /dev/null
+++ b/usr/src/old/sdb/old.c
@@ -0,0 +1,78 @@
+static char sccsid[] = "@(#)old.c 4.1 %G%";
+/*
+ * sdb - a symbolic debugger for UNIX.
+ */
+
+/*
+ * This file contains support routines for older versions of the system.
+ */
+
+#ifndef VMUNIX
+/*
+ * These routines are used only if the system
+ * doesn't have virtual memory.  They
+ * are used only to read the symbol table, which
+ * is simply kept in VM on VMUNIX.
+ */
+#include <pagsiz.h>
+#include "bio.h"
+
+bread(brs, buff, nbytes)
+struct brbuf *brs; char *buff; {
+       register int k, nb;
+
+       if (nbytes > 0) {
+               for (nb=nbytes; nb>0; nb--) {
+                       if (brs->nr == 0) {
+                               brs->nr = read(brs->fd, brs->next=brs->b, BSIZE);
+                               brs->nl = 0;
+                               if (brs->nr < 0) return(-1);
+                               if (brs->nr == 0) return(nbytes-nb);
+                               }
+                       *buff++ = *brs->next++;
+                       brs->nr--;
+                       brs->nl++;
+                       }
+               }
+       else {
+               nbytes = -nbytes;
+               for (nb=nbytes; nb>0; nb--) {
+                       if (brs->nl == 0) {
+                               if ((k=tell(brs->fd)) >= BSIZE + brs->nr) {
+                                       lseek(brs->fd, (long) -(BSIZE + brs->nr), 1);
+                                       brs->nl = read(brs->fd, brs->b, BSIZE);
+                               } else {
+                                       lseek(brs->fd, 0L, 0);
+                                       k = k - brs->nr;
+                                       if (k < 0) k = 0;
+                                       brs->nl = read(brs->fd, brs->b, k);
+                               }
+                               if (brs->nl == 0) return(nbytes-nb);
+                               brs->next = brs->b + brs->nl;
+                               brs->nr = 0;
+                               }
+                       *--buff = *--brs->next;
+                       brs->nr++;
+                       brs->nl--;
+                       }
+               }
+       return(nbytes);
+       }
+
+blseek(brs, offset, flag) 
+struct brbuf *brs; long offset; {
+       brs->nl = 0;
+       brs->nr = 0;
+       return(lseek(brs->fd,offset,flag));
+       }
+
+binit(brs)
+struct brbuf *brs; {
+       brs->nl = brs->nr = 0;
+}
+
+long
+tell(fildes) {
+       return(lseek(fildes, 0L, 1));
+}
+#endif