Make hash_value() accept an optional seed

diff --git a/ext/Hash-Util/Util.xs b/ext/Hash-Util/Util.xs
index 3210200..0687f7f 100644 (file)
--- a/ext/Hash-Util/Util.xs
+++ b/ext/Hash-Util/Util.xs
@@ -70,17 +70,28 @@ hash_seed()
 
 
 void
-hash_value(string)
+hash_value(string,...)
         SV* string
-    PROTOTYPE: $
+    PROTOTYPE: $;$
     PPCODE:
-    STRLEN len;
-    char *pv;
+{
     UV uv;
+    STRLEN len;
+    char *pv= SvPV(string,len);
+    if (items<2) {
+        PERL_HASH(uv, pv, len);
+    } else {
+        STRLEN seedlen;
+        char *seedbuf= SvPV(ST(1),seedlen);
+        if ( seedlen < PERL_HASH_SEED_BYTES ) {
+            sv_dump(ST(1));
+            Perl_croak(aTHX_ "seed len must be at least %d long only got %d bytes", PERL_HASH_SEED_BYTES, seedlen);
+        }
 
-    pv= SvPV(string,len);
-    PERL_HASH(uv,pv,len);
+        PERL_HASH_WITH_SEED(seedbuf, uv, pv, len);
+    }
     XSRETURN_UV(uv);
+}
 
 void
 hash_traversal_mask(rhv, ...)

diff --git a/hv_func.h b/hv_func.h
index 473ec46..1923f3e 100644 (file)
--- a/hv_func.h
+++ b/hv_func.h
@@ -28,38 +28,38 @@
 #if defined(PERL_HASH_FUNC_SIPHASH)
 #   define PERL_HASH_FUNC "SIPHASH_2_4"
 #   define PERL_HASH_SEED_BYTES 16
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_siphash_2_4(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_siphash_2_4((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_SUPERFAST)
 #   define PERL_HASH_FUNC "SUPERFAST"
 #   define PERL_HASH_SEED_BYTES 4
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_superfast(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_superfast((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_MURMUR3)
 #   define PERL_HASH_FUNC "MURMUR3"
 #   define PERL_HASH_SEED_BYTES 4
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_murmur3(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_murmur3((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_DJB2)
 #   define PERL_HASH_FUNC "DJB2"
 #   define PERL_HASH_SEED_BYTES 4
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_djb2(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_djb2((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_SDBM)
 #   define PERL_HASH_FUNC "SDBM"
 #   define PERL_HASH_SEED_BYTES 4
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_sdbm(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_sdbm((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD)
 #   define PERL_HASH_FUNC "ONE_AT_A_TIME_HARD"
 #   define PERL_HASH_SEED_BYTES 8
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_one_at_a_time_hard(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_one_at_a_time_hard((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME)
 #   define PERL_HASH_FUNC "ONE_AT_A_TIME"
 #   define PERL_HASH_SEED_BYTES 4
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_one_at_a_time(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_one_at_a_time((seed),(U8*)(str),(len))
 #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD)
 #   define PERL_HASH_FUNC "ONE_AT_A_TIME_OLD"
 #   define PERL_HASH_SEED_BYTES 4
-#   define PERL_HASH(hash,str,len) (hash)= S_perl_hash_old_one_at_a_time(PERL_HASH_SEED,(U8*)(str),(len))
+#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_old_one_at_a_time((seed),(U8*)(str),(len))
 #endif
 
-#ifndef PERL_HASH
+#ifndef PERL_HASH_WITH_SEED
 #error "No hash function defined!"
 #endif
 #ifndef PERL_HASH_SEED_BYTES
@@ -81,6 +81,8 @@
 #   endif
 #endif
 
+#define PERL_HASH(hash,str,len) PERL_HASH_WITH_SEED(PERL_HASH_SEED,hash,str,len)
+
 /*-----------------------------------------------------------------------------
  * Endianess, misalignment capabilities and util macros
  *