remove duplicated implementations of log2

src/stasis/CMakeLists.txt

@@ -5,7 +5,6 @@ ADD_LIBRARY(stasis util/crc32.c
                    util/rw.c
                    util/doubleLinkedList.c
                    util/linkedlist.c
-                   util/hash.c
                    util/log2.c
                    util/histogram.c
                    util/hashFunctions.c

src/stasis/util/hash.c

@@ -1,91 +0,0 @@
-#include <stasis/util/hash.h>
-#include <assert.h>
-//#include <stdio.h>
-/**
- @todo Make hash.c 32/64bit little/big-endian clean...
-
- @file Hash functions for stasis' in memory and persistent hash tables.
-*/
-
-#ifdef THOMAS_WANG_32
-static inline int thomasWangs32BitMixFunction(int key)
-{
-  key += ~(key << 15);
-  key ^=  (key >> 10);
-  key +=  (key << 3);
-  key ^=  (key >> 6);
-  key += ~(key << 11);
-  key ^=  (key >> 16);
-  return key;
-}
-#else 
-#ifdef THOMAS_WANG_64
-
-static inline unsigned long thomasWangs64BitMixFunction(unsigned long key) 
-{
-  key += ~(key << 32L);
-  key ^= (key >> 22L);
-  key += ~(key << 13L);
-  key ^= (key >> 8L);
-  key += (key << 3L);
-  key ^= (key >> 15L);
-  key += ~(key << 27L);
-  key ^= (key >> 31L);
-  return key;
-}
-
-#endif
-#endif
-
-static const char LogTable256[] = 
-{
-  0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
-  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
-  5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
-  5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
-  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
-  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
-  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
-  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
-  7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
-};
-
-/*Taken from 
-  http://graphics.stanford.edu/~seander/bithacks.html
-
-  @todo extend to handle unsigned long (this will mean 64bit on 64bit
-  platforms; need compiler macro to test for sizeof(long), test
-  harness to compare logBase2Slow's output with logBase2's output,
-  etc...)
-*/
-uint32_t logBase2(uint64_t v) { 
-  uint32_t r = 0; // r will be lg(v)
-  uint32_t t, tt; // temporaries
-  
-  if ((tt = v >> 16))
-    {
-      r = (t = v >> 24) ? 24 + LogTable256[t] : 16 + LogTable256[tt & 0xFF];
-    }
-  else 
-    {
-      r = (t = v >> 8) ? 8 + LogTable256[t] : LogTable256[v];
-    }
-  return r;
-}
-
-uint32_t logBase2Slow(uint64_t v) { 
-  uint32_t r = 0; // r will be lg(v)
-
-  while (v >>= 1) // unroll for more speed...
-    {
-      r++;
-    }
-  return r;
-}

stasis/util/hash.h

@@ -1,5 +1,6 @@
 
 #include <stasis/util/crc32.h>
+#include <stasis/util/log2.h>
 #include <stasis/common.h>
 
 #ifndef __HASH_H
@@ -13,7 +14,6 @@
 static inline unsigned long stasis_util_two_to_the (char x) {
   return (1 << ((long)x));
 }
-uint32_t logBase2(uint64_t value);
 
 /**
    This function maps from the length of the bucket list to a appropriate set
@@ -21,7 +21,7 @@ uint32_t logBase2(uint64_t value);
 */
 static inline void HASH_ENTRY(_get_size_params)(uint64_t desiredSize,
 		      unsigned char * tableBits, uint64_t* nextExtension) {
-  *tableBits = logBase2(desiredSize)+1;
+  *tableBits = stasis_log_2_64(desiredSize)+1;
   *nextExtension = ((desiredSize) - stasis_util_two_to_the(*tableBits-1));
 }
 

stasis/util/log2.h

@@ -21,6 +21,15 @@
 
 extern const uint8_t LogTable256[256];
 
+/*Taken from
+  http://graphics.stanford.edu/~seander/bithacks.html
+
+  @todo extend to handle unsigned long (this will mean 64bit on 64bit
+  platforms; need compiler macro to test for sizeof(long), test
+  harness to compare logBase2Slow's output with logBase2's output,
+  etc...)
+*/
+
 /**
  * @param v 32-bit word to find the log of
  * @return lg_2(v)
@@ -31,11 +40,11 @@ static inline uint8_t stasis_log_2_32(uint32_t v) {
 
   if ((tt = v >> 16))
   {
-    r = (t = tt >> 8) ? 24 + LogTable256[t] : 16 + LogTable256[tt];
+    r = ((t = tt >> 8)) ? 24 + LogTable256[t] : 16 + LogTable256[tt];
   }
   else
   {
-    r = (t = v >> 8) ? 8 + LogTable256[t] : LogTable256[v];
+    r = ((t = v >> 8)) ? 8 + LogTable256[t] : LogTable256[v];
   }
   return r;
 }