Add bench of hash computation library (XXHASH)

bench/Makefile

@@ -238,6 +238,14 @@ bench-concurrentqueue0:
 	@./bench-concurrentqueue.exe 60
 
 
+# XXHASH shall point to the source directory of xxhash
+bench-xxhash:
+	@if test -n "$${XXHASH}" ; then $(MAKE) bench-xxhash0 ; else echo "Nothing to be done for XXHASH." ; fi
+
+bench-xxhash0:
+	$(CC) $(CFLAGS) $(CPPFLAGS) -I "$${XXHASH}/" bench-xxhash.c "$${XXHASH}/libxxhash.a" -o bench-xxhash.exe
+	@./bench-xxhash.exe 70
+
 # BOOST is assumed to be installed in the system
 bench-boost:
 	$(CXX) $(CFLAGS) $(CPPFLAGS) bench-boost.cpp -o bench-boost.exe -lpthread

bench/bench-xxhash.c

@@ -0,0 +1,47 @@
+#define NDEBUG
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+
+#include "xxhash.h"
+
+#include "common.h"
+
+static unsigned long *g_p;
+
+static void test_hash_prepare(size_t n)
+{
+  g_p = malloc (n * sizeof(unsigned long));
+  if (g_p == NULL) abort();
+  for(size_t i = 0; i < n ; i++)
+    g_p[i] = ((rand_get()*RAND_MAX + rand_get())*RAND_MAX+rand_get())*RAND_MAX + rand_get();
+}
+
+
+static void test_hash_final(void)
+{
+  free(g_p);
+}
+
+static void test_hash(size_t n)
+{
+  g_result = XXH64(g_p, sizeof(unsigned long)*n, 0);
+}
+
+/********************************************************************************************/
+
+
+int main(int argc, const char *argv[])
+{
+  int n = (argc > 1) ? atoi(argv[1]) : 0;
+  if (n == 70) {
+    n = (argc > 2) ? atoi(argv[2]) : 100000000;
+    test_hash_prepare(n);
+    test_function("XXHASH64 time", n, test_hash);
+    test_hash_final();
+  }
+  
+  exit(0);
+}
+