Add hash table helper functions for using pointers as hash keys

2 files changed, 38 insertions, 0 deletions

diff --git a/src/mesa/shader/hash_table.c b/src/mesa/shader/hash_table.c
index fa6ba2bfdf..933e300abd 100644
--- a/src/mesa/shader/hash_table.c
+++ b/src/mesa/shader/hash_table.c
@@ -157,3 +157,17 @@ hash_table_string_hash(const void *key)
 
     return hash;
 }
+
+
+unsigned
+hash_table_pointer_hash(const void *key)
+{
+   return (unsigned)((uintptr_t) key / sizeof(void *));
+}
+
+
+int
+hash_table_pointer_compare(const void *key1, const void *key2)
+{
+   return key1 == key2 ? 0 : 1;
+}
diff --git a/src/mesa/shader/hash_table.h b/src/mesa/shader/hash_table.h
index 881e756f08..0552691464 100644
--- a/src/mesa/shader/hash_table.h
+++ b/src/mesa/shader/hash_table.h
@@ -118,6 +118,30 @@ extern unsigned hash_table_string_hash(const void *key);
  */
 #define hash_table_string_compare ((hash_compare_func_t) strcmp)
 
+
+/**
+ * Compute hash value of a pointer
+ *
+ * \param key  Pointer to be used as a hash key
+ *
+ * \note
+ * The memory pointed to by \c key is \b never accessed.  The value of \c key
+ * itself is used as the hash key
+ *
+ * \sa hash_table_pointer_compare
+ */
+unsigned
+hash_table_pointer_hash(const void *key);
+
+
+/**
+ * Compare two pointers used as keys
+ *
+ * \sa hash_table_pointer_hash
+ */
+int
+hash_table_pointer_compare(const void *key1, const void *key2);
+
 #ifdef __cplusplus
 };
 #endif