X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/0db7b0a391241c3195ec5518c3b16bd3abba20ae..20801428bec07ed58c348d25ad39878f2c208389:/include/xbt/str.h

diff --git a/include/xbt/str.h b/include/xbt/str.h
index 50be43f5b8..865ea28b4b 100644
--- a/include/xbt/str.h
+++ b/include/xbt/str.h
@@ -49,7 +49,90 @@ XBT_PUBLIC(char *) xbt_str_diff(const char *a, const char *b);
 
 XBT_PUBLIC(char *) xbt_str_from_file(FILE * file);
 
-/** @brief Classical alias to (char*)
+#define DJB2_HASH_FUNCTION
+//#define FNV_HASH_FUNCTION
+
+/**
+ * @brief Returns the hash code of a string.
+ */
+static XBT_INLINE unsigned int xbt_str_hash_ext(const char *str, int str_len)
+{
+
+#ifdef DJB2_HASH_FUNCTION
+  /* fast implementation of djb2 algorithm */
+  int c;
+  register unsigned int hash = 5381;
+
+  while (str_len--) {
+    c = *str++;
+    hash = ((hash << 5) + hash) + c;    /* hash * 33 + c */
+  }
+# elif defined(FNV_HASH_FUNCTION)
+  register unsigned int hash = 0x811c9dc5;
+  unsigned char *bp = (unsigned char *) str;    /* start of buffer */
+  unsigned char *be = bp + str_len;     /* beyond end of buffer */
+
+  while (bp < be) {
+    /* multiply by the 32 bit FNV magic prime mod 2^32 */
+    hash +=
+        (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) +
+        (hash << 24);
+
+    /* xor the bottom with the current octet */
+    hash ^= (unsigned int) *bp++;
+  }
+
+# else
+  register unsigned int hash = 0;
+
+  while (str_len--) {
+    hash += (*str) * (*str);
+    str++;
+  }
+#endif
+
+  return hash;
+}
+
+/**
+ * @brief Returns the hash code of a string.
+ */
+static XBT_INLINE unsigned int xbt_str_hash(const char *str)
+{
+#ifdef DJB2_HASH_FUNCTION
+  /* fast implementation of djb2 algorithm */
+  int c;
+  register unsigned int hash = 5381;
+
+  while ((c = *str++)) {
+    hash = ((hash << 5) + hash) + c;    /* hash * 33 + c */
+  }
+
+# elif defined(FNV_HASH_FUNCTION)
+  register unsigned int hash = 0x811c9dc5;
+
+  while (*str) {
+    /* multiply by the 32 bit FNV magic prime mod 2^32 */
+    hash +=
+        (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) +
+        (hash << 24);
+
+    /* xor the bottom with the current byte */
+    hash ^= (unsigned int) *str++;
+  }
+
+# else
+  register unsigned int hash = 0;
+
+  while (*str) {
+    hash += (*str) * (*str);
+    str++;
+  }
+#endif
+  return hash;
+}
+                                                      
+/** @brief Classical alias to (char*)
  *
  * This of almost no use, beside cosmetics and the XBT datadesc parsing macro (see \ref XBT_dd_auto).
  */