Read-only BFs and XXHash

setup.py

@@ -6,6 +6,7 @@
 ext_files = ["src/mmapbitarray.c",
              "src/bloomfilter.c",
              "src/md5.c",
+             "src/xxhash.c",
              "src/primetester.c",
              "src/MurmurHash3.c",
              ]

src/bloomfilter.c

@@ -156,9 +156,10 @@ BTYPE _hash_long(uint32_t hash_seed, Key * key) {
 
 /*
 CODE TO USE SHA512..
+
 #include <openssl/evp.h>
 
-uint32_t _hash_char(uint32_t hash_seed, Key * key) {
+BTYPE _hash_char(uint32_t hash_seed, Key * key) {
     EVP_MD_CTX ctx;
     unsigned char result_buffer[64];
 
@@ -171,9 +172,9 @@ uint32_t _hash_char(uint32_t hash_seed, Key * key) {
     EVP_MD_CTX_cleanup(&ctx);
     return *(uint32_t *)result_buffer;
 }
-*/
 
-/* Code for MurmurHash3 */
+CODE TO USE MurmurHash3
+
 #include "MurmurHash3.h"
 BTYPE _hash_char(uint32_t hash_seed, Key * key) {
     BTYPE hashed_pieces[2];
@@ -183,6 +184,22 @@ BTYPE _hash_char(uint32_t hash_seed, Key * key) {
 }
 
 
+CODE TO USE SuperFast
+
+#include "superfast.h"
+BYPTE _hash_char(uint32_t hash_seed, Key * key) {
+	return SuperFastHash(key->shash, key->nhash, hash_seed);
+}
+*/
+
+/* CODE TO USE xxHash */
+
+#include "xxhash.h"
+BTYPE _hash_char(uint32_t hash_seed, Key * key) {
+    return XXH32(key->shash, key->nhash, hash_seed);
+}
+
+
 #if 0
 int main(int argc, char **argv)
 {

src/mmapbitarray.c

@@ -148,9 +148,13 @@ MBArray * mbarray_Create_Mmap(BTYPE num_bits, const char * file, const char * he
     }
 
     errno = 0;
+
+    int mmap_flags = PROT_READ;
+    mmap_flags |= (oflag & O_RDWR) ? PROT_WRITE : 0; //add PROT_WRITE if we have write permissions
+
     array->vector = (DTYPE *)mmap(NULL,
                                   _mmap_size(array),
-                                  PROT_READ | PROT_WRITE,
+                                  mmap_flags,
                                   MAP_SHARED, 
                                   array->fd,
                                   0);