X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/3deca554c91ecb8309424e4f088fdde80e21248b..7f4a9bc72716574716b99e45c11129541a8fbeb7:/zaphod32_hash.h?ds=sidebyside

diff --git a/zaphod32_hash.h b/zaphod32_hash.h
index ec091f7..c9b60cc 100644
--- a/zaphod32_hash.h
+++ b/zaphod32_hash.h
@@ -25,29 +25,35 @@
 #define ZAPHOD32_WARN2(pat,v0,v1)
 #endif
 
+/* Find best way to ROTL32/ROTL64 */
 #ifndef ROTL32
-#define _ROTL_SIZED(x,r,s) ( ((x) << (r)) | ((x) >> ((s) - (r))) )
-#define _ROTR_SIZED(x,r,s) ( ((x) << ((s) - (r))) | ((x) >> (r)) )
-#define ROTL32(x,r) _ROTL_SIZED(x,r,32)
-#define ROTR32(x,r) _ROTR_SIZED(x,r,32)
+#if defined(_MSC_VER)
+#include <stdlib.h>  /* Microsoft put _rotl declaration in here */
+#define ROTL32(x,r)  _rotl(x,r)
+#define ROTR32(x,r)  _rotr(x,r)
+#else
+/* gcc recognises this code and generates a rotate instruction for CPUs with one */
+#define ROTL32(x,r)  (((U32)(x) << (r)) | ((U32)(x) >> (32 - (r))))
+#define ROTR32(x,r)  (((U32)(x) << (32 - (r))) | ((U32)(x) >> (r)))
+#endif
 #endif
 
 #ifndef PERL_SEEN_HV_FUNC_H
 #if !defined(U64)
-    #include <stdint.h>
-    #define U64 uint64_t
+#include <stdint.h>
+#define U64 uint64_t
 #endif
 
 #if !defined(U32)
-  #define U32 uint32_t
+#define U32 uint32_t
 #endif
 
 #if !defined(U8)
-    #define U8 unsigned char
+#define U8 unsigned char
 #endif
 
 #if !defined(U16)
-    #define U16 uint16_t
+#define U16 uint16_t
 #endif
 
 #ifndef STRLEN
@@ -68,14 +74,39 @@
 #define STMT_END while(0)
 #endif
 
-#ifndef U8TO64_LE
-#define U8TO64_LE(ptr)  (*((const U64 *)(ptr)))
+#ifndef ZAPHOD32_ALLOW_UNALIGNED_AND_LITTLE_ENDIAN
+/* ZAPHOD32_ALLOW_UNALIGNED_AND_LITTLE_ENDIAN only matters if nothing has defined U8TO64_LE etc,
+ * and when built with Perl these should be defined before this file is loaded.
+ */
+#ifdef U32_ALIGNMENT_REQUIRED
+#define ZAPHOD32_ALLOW_UNALIGNED_AND_LITTLE_ENDIAN 0
+#else
+#define ZAPHOD32_ALLOW_UNALIGNED_AND_LITTLE_ENDIAN 1
 #endif
+#endif
+
 #ifndef U8TO32_LE
+#if ZAPHOD32_ALLOW_UNALIGNED_AND_LITTLE_ENDIAN
 #define U8TO32_LE(ptr)  (*((const U32 *)(ptr)))
+#else
+#define U8TO32_LE(ptr)  (\
+    (U32)(ptr)[3] << 24 | \
+    (U32)(ptr)[2] << 16 | \
+    (U32)(ptr)[1] << 8  | \
+    (U32)(ptr)[0]         \
+)
 #endif
+#endif
+
 #ifndef U8TO16_LE
+#if ZAPHOD32_ALLOW_UNALIGNED_AND_LITTLE_ENDIAN
 #define U8TO16_LE(ptr)  (*((const U16 *)(ptr)))
+#else
+#define U8TO16_LE(ptr)  (\
+    (U16)(ptr)[1] << 8  | \
+    (U16)(ptr)[0]         \
+)
+#endif
 #endif
 
 /* This is two marsaglia xor-shift permutes, with a prime-multiple
@@ -134,7 +165,7 @@ void zaphod32_seed_state (
     const U8 *seed_ch,
     U8 *state_ch
 ) {
-    U32 *seed= (U32 *)seed_ch;
+    const U32 *seed= (const U32 *)seed_ch;
     U32 *state= (U32 *)state_ch;
   
     /* hex expansion of pi, skipping first two digits. pi= 3.2[43f6...]*/
@@ -184,10 +215,10 @@ U32 zaphod32_hash_with_state(
 ) {
     U32 *state= (U32 *)state_ch;
     const U8 *end;
-    U32 len = key_len; 
+    STRLEN len = key_len;
     U32 v0= state[0];
     U32 v1= state[1];
-    U32 v2= state[2] ^ (0xC41A7AB1 * (key_len + 1));
+    U32 v2= state[2] ^ (0xC41A7AB1 * ((U32)key_len + 1));
 
     ZAPHOD32_WARN4("v0=%08x v1=%08x v2=%08x ln=%08x HASH START\n",
             (unsigned int)state[0], (unsigned int)state[1],
@@ -195,24 +226,24 @@ U32 zaphod32_hash_with_state(
     {
         switch (len) {
             default: goto zaphod32_read8;
-            case 12: v2 += (U32)key[11] << 24;
-            case 11: v2 += (U32)key[10] << 16;
+            case 12: v2 += (U32)key[11] << 24;  /* FALLTHROUGH */
+            case 11: v2 += (U32)key[10] << 16;  /* FALLTHROUGH */
             case 10: v2 += (U32)U8TO16_LE(key+8);
                      v1 -= U8TO32_LE(key+4);
                      v0 += U8TO32_LE(key+0);
                      goto zaphod32_finalize;
-            case 9: v2 += (U32)key[8];
+            case 9: v2 += (U32)key[8];          /* FALLTHROUGH */
             case 8: v1 -= U8TO32_LE(key+4);
                     v0 += U8TO32_LE(key+0);
                     goto zaphod32_finalize;
-            case 7: v2 += (U32)key[6];
+            case 7: v2 += (U32)key[6];          /* FALLTHROUGH */
             case 6: v0 += (U32)U8TO16_LE(key+4);
                     v1 -= U8TO32_LE(key+0);
                     goto zaphod32_finalize;
-            case 5: v0 += (U32)key[4];
+            case 5: v0 += (U32)key[4];          /* FALLTHROUGH */
             case 4: v1 -= U8TO32_LE(key+0);
                     goto zaphod32_finalize;
-            case 3: v2 += (U32)key[2];
+            case 3: v2 += (U32)key[2];          /* FALLTHROUGH */
             case 2: v0 += (U32)U8TO16_LE(key);
                     break;
             case 1: v0 += (U32)key[0];
@@ -238,7 +269,10 @@ U32 zaphod32_hash_with_state(
         return v0 ^ v2;
     }
 
-    if (len >= 8) {
+/*  if (len >= 8) */ /* this block is only reached by a goto above, so this condition
+                        is commented out, but if the above block is removed it would
+                        be necessary to use this. */
+    {
 zaphod32_read8:
         len = key_len & 0x7;
         end = key + key_len - len;
@@ -257,12 +291,13 @@ zaphod32_read8:
 
     v0 += (U32)(key_len) << 24;
     switch (len & 0x3) {
-        case 3: v2 += (U32)key[2];
+        case 3: v2 += (U32)key[2];          /* FALLTHROUGH */
         case 2: v0 += (U32)U8TO16_LE(key);
                 break;
         case 1: v0 += (U32)key[0];
                 break;
         case 0: v2 ^= 0xFF;
+                break;
     }
 zaphod32_finalize:
     ZAPHOD32_FINALIZE(v0,v1,v2);