buf.h: Spurious `\' prevents declaration of `buf_putstr*'.

[mLib] / unihash.c

diff --git a/unihash.c b/unihash.c
index 39e2f06803d4cfe9c341dd19e1fc7306e01bc86f..9f9719bffbd0dbf7243f2627a75f302a4fedc97e 100644 (file)
--- a/unihash.c
+++ b/unihash.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: unihash.c,v 1.1 2003/10/12 14:43:24 mdw Exp $
+ * $Id: unihash.c,v 1.3 2004/04/08 01:36:13 mdw Exp $
  *
  * Simple and efficient universal hashing for hashtables
  *
  * (c) 2003 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of the mLib utilities library.
  *
@@ -15,26 +15,18 @@
  * it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
- * 
+ *
  * mLib is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Library General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Library General Public
  * License along with mLib; if not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: unihash.c,v $
- * Revision 1.1  2003/10/12 14:43:24  mdw
- * Universal hashing.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <assert.h>
@@ -92,9 +84,9 @@ void unihash_setkey(unihash_info *i, uint32 k)
  *             @const void *p@ = pointer to data to hash
  *             @size_t sz@ = size of the data
  *
- * Returns:    ---
+ * Returns:    Hash of data so far.
  *
- * Use:                Hashes data.  Call this as many times as needed.  
+ * Use:                Hashes data.  Call this as many times as needed.
  */
 
 uint32 unihash_hash(const unihash_info *i, uint32 a,
@@ -105,7 +97,7 @@ uint32 unihash_hash(const unihash_info *i, uint32 a,
   assert(UNIHASH_NBATCH == 4);
 
 #define FULLMULT(u, x)                                                 \
-  (i->s[u][0][U8((x) >>  0)] ^ i->s[u][1][U8((x) >>  8)] ^             \
+  (i->s[u][0][U8((x) >>         0)] ^ i->s[u][1][U8((x) >>  8)] ^              \
    i->s[u][2][U8((x) >> 16)] ^ i->s[u][3][U8((x) >> 24)]);
 
 #define BYTEMULT(u, x) i->s[u][0][x]
@@ -123,6 +115,7 @@ uint32 unihash_hash(const unihash_info *i, uint32 a,
     a ^= BYTEMULT(2, *pp++);
     a ^= BYTEMULT(1, *pp++);
     a ^= BYTEMULT(0, *pp++);
+    sz -= UNIHASH_NBATCH;
   }
 
   /* --- The tail end is a smaller batch --- */
@@ -148,7 +141,7 @@ uint32 unihash_hash(const unihash_info *i, uint32 a,
  * Returns:    The hash value computed.
  *
  * Use:                All-in-one hashing function.  No faster than using the
- *             separate calls, but more convenient.
+ *             separate calls, but more convenient.
  */
 
 uint32 unihash(const unihash_info *i, const void *p, size_t sz)
@@ -156,4 +149,71 @@ uint32 unihash(const unihash_info *i, const void *p, size_t sz)
   return (UNIHASH(i, p, sz));
 }
 
+/*----- Test rig ----------------------------------------------------------*/
+
+#ifdef TEST_RIG
+
+#include "testrig.h"
+
+static int verify(dstr *v)
+{
+  unihash_info ui;
+  uint32 k;
+  uint32 h, hh;
+  size_t n;
+  int i, c;
+  const char *p;
+  int ok = 1;
+
+  static const int step[] = { 0, 1, 5, 6, 7, 8, 23, -1 };
+
+  /* --- Set up for using this key --- */
+
+  k = *(uint32 *)v[0].buf;
+  h = *(uint32 *)v[2].buf;
+  unihash_setkey(&ui, k);
+
+  /* --- Hash the data a lot --- */
+
+  for (i = 0; step[i] >= 0; i++) {
+    c = step[i];
+    if (!c)
+      hh = unihash(&ui, v[1].buf, v[1].len);
+    else {
+      hh = UNIHASH_INIT(&ui);
+      p = v[1].buf;
+      n = v[1].len;
+      while (n) {
+       if (c > n) c = n;
+       hh = unihash_hash(&ui, hh, p, c);
+       p += c;
+       n -= c;
+      }
+    }
+    if (h != hh) {
+      ok = 0;
+      fprintf(stderr, "\nunihash failed\n");
+      fprintf(stderr, "         key = %08lx\n", (unsigned long)k);
+      fprintf(stderr, "         data = %s\n", v[1].buf);
+      fprintf(stderr, "         step = %d\n", step[i]);
+      fprintf(stderr, "         expected = %08lx\n", (unsigned long)h);
+      fprintf(stderr, "         computed = %08lx\n", (unsigned long)hh);
+    }
+  }
+  return (ok);
+}
+
+static const test_chunk tests[] = {
+  { "hash", verify, { &type_uint32, &type_string, &type_uint32 } },
+  { 0, 0, { 0 } }
+};
+
+int main(int argc, char *argv[])
+{
+  test_run(argc, argv, tests, "unihash.in");
+  return (0);
+}
+
+#endif
+
 /*----- That's all, folks -------------------------------------------------*/