hash.cc: improve readability & style

1 files changed, 54 insertions, 72 deletions

diff --git a/vowpalwabbit/hash.cc b/vowpalwabbit/hash.cc
index 690186b1..215f7cef 100644
--- a/vowpalwabbit/hash.cc
+++ b/vowpalwabbit/hash.cc
@@ -14,19 +14,19 @@
 // Adopted for VW and contributed by Ariel Faigon.
 //
 
+#include <sys/types.h>  /* defines size_t */
+
 // Platform-specific functions and macros
 // Microsoft Visual Studio
 #if defined(_MSC_VER)
     typedef unsigned char uint8_t;
-    typedef unsigned long uint32_t; 
+    typedef unsigned long uint32_t;
     typedef unsigned __int64 uint64_t;
 // Other compilers
 #else   // defined(_MSC_VER)
-#  include <stdint.h>	/* defines uint32_t etc */
+#  include <stdint.h>   /* defines uint32_t etc */
 #endif // !defined(_MSC_VER)
 
-#include <sys/types.h>	/* defines size_t */
-
 //-----------------------------------------------------------------------------
 // MurmurHash3 was written by Austin Appleby, and is placed in the public
 // domain. The author hereby disclaims copyright to this source code.
@@ -39,34 +39,26 @@
 //-----------------------------------------------------------------------------
 // Platform-specific functions and macros
 
-// Microsoft Visual Studio
-
-#if defined(_MSC_VER)
-
-#define FORCE_INLINE	__forceinline
-
-#include <stdlib.h>
-
-#define ROTL32(x,y)	_rotl(x,y)
-
-#define BIG_CONSTANT(x) (x)
+#if defined(_MSC_VER)       // Microsoft Visual Studio
 
-// Other compilers
+#   define FORCE_INLINE __forceinline
+#   include <stdlib.h>
+#   define ROTL32(x,y)  _rotl(x,y)
+#   define BIG_CONSTANT(x) (x)
 
-#else	// defined(_MSC_VER)
+#else                       // Other compilers
 
-#define	FORCE_INLINE __attribute__((always_inline))
+#   define FORCE_INLINE	__attribute__((always_inline))
 
-inline uint32_t rotl32 ( uint32_t x, int8_t r )
-{
-  return (x << r) | (x >> (32 - r));
-}
+    inline uint32_t rotl32 ( uint32_t x, int8_t r )
+    {
+        return (x << r) | (x >> (32 - r));
+    }
 
-#define	ROTL32(x,y)	rotl32(x,y)
+#   define ROTL32(x,y)     rotl32(x,y)
+#   define BIG_CONSTANT(x) (x##LLU)
 
-#define BIG_CONSTANT(x) (x##LLU)
-
-#endif // !defined(_MSC_VER)
+#endif
 
 //-----------------------------------------------------------------------------
 // Block read - if your platform needs to do endian-swapping or can only
@@ -74,7 +66,7 @@ inline uint32_t rotl32 ( uint32_t x, int8_t r )
 
 FORCE_INLINE uint32_t getblock ( const uint32_t * p, int i )
 {
-  return p[i];
+    return p[i];
 }
 
 //-----------------------------------------------------------------------------
@@ -82,66 +74,56 @@ FORCE_INLINE uint32_t getblock ( const uint32_t * p, int i )
 
 FORCE_INLINE uint32_t fmix ( uint32_t h )
 {
-  h ^= h >> 16;
-  h *= 0x85ebca6b;
-  h ^= h >> 13;
-  h *= 0xc2b2ae35;
-  h ^= h >> 16;
+    h ^= h >> 16;
+    h *= 0x85ebca6b;
+    h ^= h >> 13;
+    h *= 0xc2b2ae35;
+    h ^= h >> 16;
 
-  return h;
+    return h;
 }
 
 //-----------------------------------------------------------------------------
 uint32_t uniform_hash (const void * key, size_t len, uint32_t seed)
 {
-  const uint8_t * data = (const uint8_t*)key;
-  const int nblocks = len / 4;
+    const uint8_t * data = (const uint8_t*)key;
+    const int nblocks = len / 4;
 
-  uint32_t h1 = seed;
+    uint32_t h1 = seed;
 
-  const uint32_t c1 = 0xcc9e2d51;
-  const uint32_t c2 = 0x1b873593;
+    const uint32_t c1 = 0xcc9e2d51;
+    const uint32_t c2 = 0x1b873593;
 
-  //----------
-  // body
+    // --- body
+    const uint32_t * blocks = (const uint32_t *)(data + nblocks*4);
 
-  const uint32_t * blocks = (const uint32_t *)(data + nblocks*4);
+    for (int i = -nblocks; i; i++) {
+        uint32_t k1 = getblock(blocks,i);
 
-  for(int i = -nblocks; i; i++)
-  {
-    uint32_t k1 = getblock(blocks,i);
+        k1 *= c1;
+        k1 = ROTL32(k1,15);
+        k1 *= c2;
 
-    k1 *= c1;
-    k1 = ROTL32(k1,15);
-    k1 *= c2;
-    
-    h1 ^= k1;
-    h1 = ROTL32(h1,13); 
-    h1 = h1*5+0xe6546b64;
-  }
+        h1 ^= k1;
+        h1 = ROTL32(h1,13);
+        h1 = h1*5+0xe6546b64;
+    }
 
-  //----------
-  // tail
+    // --- tail
+    const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
 
-  const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
+    uint32_t k1 = 0;
 
-  uint32_t k1 = 0;
+    switch(len & 3) {
+        case 3: k1 ^= tail[2] << 16;
+        case 2: k1 ^= tail[1] << 8;
+        case 1: k1 ^= tail[0];
+                k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
+    }
 
-  switch(len & 3)
-  {
-  case 3: k1 ^= tail[2] << 16;
-  case 2: k1 ^= tail[1] << 8;
-  case 1: k1 ^= tail[0];
-          k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
-  };
+    // --- finalization
+    h1 ^= len;
 
-  //----------
-  // finalization
-
-  h1 ^= len;
-
-  h1 = fmix(h1);
-
-  return h1;
-} 
+    return fmix(h1);
+}