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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-10-21 15:52:04 +1100
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-10-21 15:52:04 +1100
commita02efb906d12c9d4eb2ab7c59049ba9545e5412d (patch)
treebf1f6467978ec63a22f42299ecac2ee7f7e73336 /scripts/basic/hash.c
parent84dfcb4b318463cd4883b6a19937824f49aee564 (diff)
parent2515ddc6db8eb49a79f0fe5e67ff09ac7c81eab4 (diff)
Merge commit 'origin' into master
Manual merge of: arch/powerpc/Kconfig arch/powerpc/include/asm/page.h
Diffstat (limited to 'scripts/basic/hash.c')
-rw-r--r--scripts/basic/hash.c64
1 files changed, 64 insertions, 0 deletions
diff --git a/scripts/basic/hash.c b/scripts/basic/hash.c
new file mode 100644
index 000000000000..3299ad7fc8c0
--- /dev/null
+++ b/scripts/basic/hash.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define DYNAMIC_DEBUG_HASH_BITS 6
+
+static const char *program;
+
+static void usage(void)
+{
+ printf("Usage: %s <djb2|r5> <modname>\n", program);
+ exit(1);
+}
+
+/* djb2 hashing algorithm by Dan Bernstein. From:
+ * http://www.cse.yorku.ca/~oz/hash.html
+ */
+
+unsigned int djb2_hash(char *str)
+{
+ unsigned long hash = 5381;
+ int c;
+
+ c = *str;
+ while (c) {
+ hash = ((hash << 5) + hash) + c;
+ c = *++str;
+ }
+ return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
+}
+
+unsigned int r5_hash(char *str)
+{
+ unsigned long hash = 0;
+ int c;
+
+ c = *str;
+ while (c) {
+ hash = (hash + (c << 4) + (c >> 4)) * 11;
+ c = *++str;
+ }
+ return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
+}
+
+int main(int argc, char *argv[])
+{
+ program = argv[0];
+
+ if (argc != 3)
+ usage();
+ if (!strcmp(argv[1], "djb2"))
+ printf("%d\n", djb2_hash(argv[2]));
+ else if (!strcmp(argv[1], "r5"))
+ printf("%d\n", r5_hash(argv[2]));
+ else
+ usage();
+ exit(0);
+}
+