Initial commit

1 files changed, 190 insertions, 0 deletions

diff --git a/unix/boot/mkpkg/fdcache.c b/unix/boot/mkpkg/fdcache.c
new file mode 100644
index 00000000..7dfca1a3
--- /dev/null
+++ b/unix/boot/mkpkg/fdcache.c
@@ -0,0 +1,190 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+/*
+ * FDCACHE -- Maintain a cache of filenames and their associated modification
+ * dates.  This can greatly reduce the amount of time required to determine
+ * which, if any, of the modules in a library need updating because an include
+ * file they depend upon has been modified.
+ *
+ * External entry points:
+ *
+ *   l = m_fdate (fname)		# return file (modification) date
+ *	m_fdinit (debug)		# initialize cache
+ */
+
+#define	MAX_FILES	20		/* size of the cache		*/
+#define	SZ_NAME		32		/* size of filename slot	*/
+#define	EOS		'\0'
+
+struct _fdate {				/* cache list element structure	*/
+	struct	_fdate *uplnk;
+	struct	_fdate *dnlnk;
+	int	nrefs;			/* number of references		*/
+	int	chksum;			/* speeds searches		*/
+	long	fdate;			/* file modification date	*/
+	char	fname[SZ_NAME+1];	/* file name			*/
+};
+
+struct	_fdate fdcache[MAX_FILES];	/* the cache			*/
+struct	_fdate *fd_head;		/* doubly linked list		*/
+struct	_fdate *fd_tail;
+int	fd_hits, fd_misses;
+
+struct	_fdate *fd_unlink();
+struct	_fdate *fd_tohead();
+struct	_fdate *fd_totail();
+
+long  m_fdate (char *fname);
+void  m_fdinit (int debug);
+int   fd_chksum (char *s);
+
+extern  long         os_fdate (char *fname);
+
+
+/* M_FDATE -- Get file modification date.  This is functionally equivalent to
+ * os_fdate().
+ */
+long
+m_fdate (char *fname)
+{
+	register struct _fdate *fd;
+	register int	chksum;
+
+	/* Look in the cache first.
+	 */
+	chksum = fd_chksum (fname);
+	for (fd=fd_head;  fd != NULL;  fd=fd->dnlnk)
+	    if (fd->chksum == chksum && strcmp (fname, fd->fname) == 0) {
+		fd_tohead (fd_unlink (fd));
+		fd->nrefs++;
+		fd_hits++;
+		return (fd->fdate);
+	    }
+
+	/* Cache miss.  Don't put in cache it name is too long.
+	 */
+	fd_misses++;
+	if (strlen (fname) > SZ_NAME)
+	    return (os_fdate (fname));
+
+	/* Put fname in the cache.  Reuse slot at tail of list.
+	 */
+	fd = fd_tohead (fd_unlink (fd_tail));
+	strncpy (fd->fname, fname, SZ_NAME);
+	fd->chksum = fd_chksum (fname);
+	fd->fdate  = os_fdate (fname);
+	fd->nrefs  = 1;
+
+	return (fd->fdate);
+}
+
+
+/* M_FDINIT -- Initialize (clear) the fdate cache.
+ */
+void
+m_fdinit (int debug)
+{
+	register struct _fdate *fd;
+	register int	i;
+	int	total;
+
+	if (debug) {
+	    total = fd_hits + fd_misses;
+	    printf ("file date cache: %d hits, %d misses, %d%% of %d\n",
+		fd_hits, fd_misses, (total ? fd_hits * 100 / total : 0), total);
+
+	    for (fd=fd_head;  fd != NULL;  fd=fd->dnlnk)
+		if (fd->fname[0])
+		    printf ("%3d %10ld (%05d) %s\n",
+			fd->nrefs, fd->fdate, fd->chksum, fd->fname);
+
+	    fd_hits   = 0;
+	    fd_misses = 0;
+
+	    fflush (stdout);
+	}
+
+	fd = fd_head = fd_tail = &fdcache[0];
+	fd->uplnk   = NULL;
+	fd->dnlnk   = NULL;
+	fd->nrefs   = 0;
+	fd->chksum  = -1;
+	fd->fname[0] = EOS;
+
+	for (i=1;  i < MAX_FILES;  i++) {
+	    fd = fd_tohead (&fdcache[i]);
+	    fd->fname[0] = EOS;
+	    fd->chksum   = -1;
+	    fd->nrefs    = 0;
+	}
+}
+
+
+/* FD_TOHEAD -- Link a fdate struct at the head of the list.
+ */
+struct _fdate *
+fd_tohead (register struct _fdate *fd)
+{
+	if (fd != fd_head) {
+	    fd->uplnk = NULL;
+	    fd->dnlnk = fd_head;
+	    fd_head->uplnk = fd;
+	    fd_head = fd;
+	}
+
+	return (fd);
+}
+
+
+/* FD_TOTAIL -- Link a fdate struct at the tail of the list.
+ */
+struct _fdate *
+fd_totail (register struct _fdate *fd)
+{
+	if (fd != fd_tail) {
+	    fd->uplnk = fd_tail;
+	    fd->dnlnk = NULL;
+	    fd_tail->dnlnk = fd;
+	    fd_tail = fd;
+	}
+
+	return (fd);
+}
+
+
+/* FD_UNLINK -- Unlink an fdate struct.
+ */
+struct _fdate *
+fd_unlink (register struct _fdate *fd)
+{
+	if (fd == fd_head)
+	    fd_head = fd->dnlnk;
+	if (fd == fd_tail)
+	    fd_tail = fd->uplnk;
+
+	if (fd->uplnk)
+	    fd->uplnk->dnlnk = fd->dnlnk;
+	if (fd->dnlnk)
+	    fd->dnlnk->uplnk = fd->uplnk;
+	
+	return (fd);
+}
+
+
+/* FD_CHKSUM -- Compute the checksum of a character string.
+ */
+int
+fd_chksum (char *s)
+{
+	register int sum=0;
+
+	while (*s)
+	    sum += *s++;
+
+	return (sum);
+}