From cb5f37d93b0f40468f141d87714060511a265288 Mon Sep 17 00:00:00 2001
From: Michael Graff <mgraff@isc.org>
Date: Wed, 15 Dec 1999 01:49:07 +0000
Subject: [PATCH] add lfsr.h

---
 lib/isc/include/isc/Makefile.in |  2 +-
 lib/isc/include/isc/lfsr.h      | 49 +++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 lib/isc/include/isc/lfsr.h

diff --git a/lib/isc/include/isc/Makefile.in b/lib/isc/include/isc/Makefile.in
index c654adf01a..383aaec70b 100644
--- a/lib/isc/include/isc/Makefile.in
+++ b/lib/isc/include/isc/Makefile.in
@@ -21,7 +21,7 @@ top_srcdir =	@top_srcdir@
 
 HEADERS =	assertions.h base64.h boolean.h buffer.h bufferlist.h \
 		commandline.h error.h event.h eventclass.h \
-		heap.h int.h interfaceiter.h lang.h lex.h lib.h \
+		heap.h int.h interfaceiter.h lang.h lex.h lfsr.h lib.h \
 		list.h magic.h mem.h msgcat.h mutexblock.h netaddr.h \
 		print.h random.h rbtgen.h region.h result.h \
 		resultclass.h rwlock.h serial.h sockaddr.h socket.h str.h \
diff --git a/lib/isc/include/isc/lfsr.h b/lib/isc/include/isc/lfsr.h
new file mode 100644
index 0000000000..0068ce84ea
--- /dev/null
+++ b/lib/isc/include/isc/lfsr.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 1999  Internet Software Consortium.
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
+ * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
+ * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+ * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+ * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+ * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ */
+
+#ifndef ISC_LFSR_H
+#define ISC_LFSR_H 1
+
+#include <isc/types.h>
+
+/*
+ * The members of this structure can be used by the application, but care
+ * needs to be taken to not change state once the lfsr is in operation.
+ */
+typedef struct {
+	isc_uint32_t	state;	/* previous state */
+	isc_uint32_t	bits;	/* length */
+	isc_uint32_t	tap;	/* bit taps */
+} isc_lfsr_t;
+
+/*
+ * This structure contains some standard LFSR values that can be used.
+ * One can use the isc_lfsr_findlfsr() to search for one with at least
+ * a certain number of bits.
+ */
+extern isc_lfsr_t isc_lfsr_standard[];
+
+ISC_LANG_BEGINDECLS
+
+isc_uint32_t isc_lfsr_generate(isc_lfsr_t *lfsr);
+isc_uint32_t isc_lfsr_skipgenerate(isc_lfsr_t *lfsr, unsigned int skip);
+isc_uint32_t isc_lfsr_lfsrskipgenerate(isc_lfsr_t *lfsr1, isc_lfsr_t *lfsr2,
+				       unsigned int skipbits);
+
+ISC_LANG_ENDDECLS
+
+#endif /* ISC_LFSR_H */