hashmap: try to use the existing 64bit hash functions for dev_t if it is 64bit

2 files changed, 29 insertions, 0 deletions

diff --git a/src/shared/hashmap.c b/src/shared/hashmap.c
index 5c3efa8dd3..dbf91c439e 100644
--- a/src/shared/hashmap.c
+++ b/src/shared/hashmap.c
@@ -164,6 +164,21 @@ int uint64_compare_func(const void *_a, const void *_b) {
         return a < b ? -1 : (a > b ? 1 : 0);
 }
 
+#if SIZEOF_DEV_T != 8
+unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+        uint64_t u;
+        siphash24((uint8_t*) &u, p, sizeof(dev_t), hash_key);
+        return (unsigned long) u;
+}
+
+int devt_compare_func(const void *_a, const void *_b) {
+        dev_t a, b;
+        a = *(const dev_t*) _a;
+        b = *(const dev_t*) _b;
+        return a < b ? -1 : (a > b ? 1 : 0);
+}
+#endif
+
 static unsigned bucket_hash(Hashmap *h, const void *p) {
         return (unsigned) (h->hash_func(p, h->hash_key) % h->n_buckets);
 }
diff --git a/src/shared/hashmap.h b/src/shared/hashmap.h
index bfad970078..f89e7e8fbc 100644
--- a/src/shared/hashmap.h
+++ b/src/shared/hashmap.h
@@ -52,9 +52,23 @@ int string_compare_func(const void *a, const void *b) _pure_;
 unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
 int trivial_compare_func(const void *a, const void *b) _const_;
 
+/* 32bit values we can always just embedd in the pointer itself, but
+ * in order to support 32bit archs we need store 64bit values
+ * indirectly, since they don't fit in a pointer. */
 unsigned long uint64_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
 int uint64_compare_func(const void *a, const void *b) _pure_;
 
+/* On some archs dev_t is 32bit, and on others 64bit. And sometimes
+ * it's 64bit on 32bit archs, and sometimes 32bit on 64bit archs. Yuck! */
+#if SIZEOF_DEV_T != 8
+unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
+int devt_compare_func(const void *a, const void *b) _pure_;
+#else
+/* No need to define a second version of this... */
+#define devt_hash_func uint64_hash_func
+#define devt_compare_func uint64_compare_func
+#endif
+
 Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func);
 void hashmap_free(Hashmap *h);
 void hashmap_free_free(Hashmap *h);