hashtable: More options about memory management.

diff --git a/ucw/hashtable.h b/ucw/hashtable.h
index f480fe95ab15b3253f3ee773236750debcebf311..364ee255cdc2511fa3786564855b6dd6295898c2 100644 (file)
--- a/ucw/hashtable.h
+++ b/ucw/hashtable.h
@@ -79,8 +79,11 @@
  *                     newly created node. Very useful for lookup operations.
  *  HASH_GIVE_ALLOC    void *alloc(unsigned int size) -- allocate space for
  *                     a node. Default is xmalloc() or pooled allocation, depending
- *                     on HASH_USE_POOL and HASH_AUTO_POOL switches.
- *                     void free(void *) -- the converse.
+ *                     on HASH_USE_POOL, HASH_AUTO_POOL, HASH_USE_ELTPOOL
+ *                     and HASH_AUTO_ELTPOOL switches. void free(void *) -- the converse.
+ * HASH_GIVE_TABLE_ALLOC void *table_alloc(unsigned int size), void *table_free(void *)
+ *                     Allocate or free space for the table itself. Default is xmalloc()
+ *                     or the functions defined by HASH_GIVE_ALLOC if HASH_TABLE_ALLOC is set.
  *
  *  ... and a couple of extra parameters:
  *
@@ -93,10 +96,15 @@
  *                     deallocation is not supported by mempools, so delete/remove
  *                     will leak pool memory.
  *  HASH_AUTO_POOL=size        Create a pool of the given block size automatically.
+ *  HASH_USE_ELTPOOL=pool Allocate all nodes from given eltpool.
+ *                     Only works for nodes of limited size.
+ *  HASH_AUTO_ELTPOOL=count Create an eltpool of the given number of elements in each chunk.
+ *                     Only works for fixed-sized nodes and zero HASH_GIVE_EXTRA_SIZE.
  *  HASH_ZERO_FILL     New entries should be initialized to all zeroes.
  *  HASH_TABLE_ALLOC   The hash table itself will be allocated and freed using
  *                     the same allocation functions as the nodes instead of
  *                     the default xmalloc().
+ *  HASH_TABLE_GROW    Never decrease the size of the hash table itself
  *  HASH_TABLE_DYNAMIC Support multiple hash tables; the first parameter of all
  *                     hash table operations is struct HASH_PREFIX(table) *.
  *  HASH_TABLE_VARS    Extra variables to be defined in table structure
@@ -160,6 +168,9 @@ struct P(table) {
 #ifdef HASH_AUTO_POOL
   struct mempool *pool;
 #endif
+#ifdef HASH_AUTO_ELTPOOL
+  struct eltpool *eltpool;
+#endif
 #ifdef HASH_TABLE_VARS
   HASH_TABLE_VARS
 #endif
@@ -345,6 +356,26 @@ static inline void P(init_alloc) (TAU) { T.pool = mp_new(HASH_AUTO_POOL); }
 static inline void P(cleanup_alloc) (TAU) { mp_delete(T.pool); }
 #define HASH_USE_POOL
 
+#elif defined(HASH_USE_ELTPOOL)
+/* If the caller has requested to use his eltpool, do so */
+#include "ucw/eltpool.h"
+static inline void * P(alloc) (TAUC unsigned int size) { ASSERT(size <= (HASH_USE_ELTPOOL)->elt_size); return ep_alloc(HASH_USE_ELTPOOL); }
+static inline void P(free) (TAUC void *x) { ep_free(HASH_USE_ELTPOOL, x); }
+static inline void P(init_alloc) (TAU) { }
+static inline void P(cleanup_alloc) (TAU) { }
+
+#elif defined(HASH_AUTO_ELTPOOL)
+/* Use our own eltpools */
+#ifdef HASH_GIVE_EXTRA_SIZE
+#error HASH_AUTO_ELTPOOL not supported in combination with variable-sized nodes
+#endif
+#include "ucw/eltpool.h"
+static inline void * P(alloc) (TAUC unsigned int size UNUSED) { return ep_alloc(T.eltpool); }
+static inline void P(free) (TAUC void *x) { ep_free(T.eltpool, x); }
+static inline void P(init_alloc) (TAU) { T.eltpool = ep_new(sizeof(P(bucket)), HASH_AUTO_ELTPOOL); }
+static inline void P(cleanup_alloc) (TAU) { ep_delete(T.eltpool); }
+#define HASH_USE_ELTPOOL
+
 #else
 /* The default allocation method */
 static inline void * P(alloc) (TAUC unsigned int size) { return xmalloc(size); }
@@ -354,7 +385,12 @@ static inline void P(cleanup_alloc) (TAU) { }
 
 #endif
 
-#ifdef HASH_TABLE_ALLOC
+#ifdef HASH_GIVE_TABLE_ALLOC
+/* If the caller has requested to use his own allocation functions, do so */
+#elif defined(HASH_TABLE_ALLOC)
+#ifdef HASH_USE_ELTPOOL
+#error HASH_TABLE_ALLOC not supported in combination with eltpools
+#endif
 static inline void * P(table_alloc) (TAUC unsigned int size) { return P(alloc)(TTC size); }
 static inline void P(table_free) (TAUC void *x) { P(free)(TTC x); }
 #else
@@ -362,6 +398,10 @@ static inline void * P(table_alloc) (TAUC unsigned int size) { return xmalloc(si
 static inline void P(table_free) (TAUC void *x) { xfree(x); }
 #endif
 
+#if defined(HASH_USE_POOL) && defined(HASH_TABLE_ALLOC) && !defined(HASH_TABLE_GROW)
+#define HASH_TABLE_GROW
+#endif
+
 #ifndef HASH_DEFAULT_SIZE
 #define HASH_DEFAULT_SIZE 32
 #endif
@@ -392,9 +432,11 @@ static void P(alloc_table) (TAU)
     T.hash_max = 2*T.hash_size;
   else
     T.hash_max = ~0U;
+#ifndef HASH_TABLE_GROW
   if (T.hash_size/2 > HASH_DEFAULT_SIZE)
     T.hash_min = T.hash_size/4;
   else
+#endif
     T.hash_min = 0;
 }
 
@@ -613,8 +655,10 @@ static int HASH_PREFIX(delete)(TAC HASH_KEY_DECL)
        {
          *bb = b->next;
          P(free)(TTC b);
+#ifndef HASH_TABLE_GROW
          if (--T.hash_count < T.hash_min)
            P(rehash)(TTC T.hash_size/2);
+#endif
          return 1;
        }
     }
@@ -642,8 +686,10 @@ static void HASH_PREFIX(remove)(TAC HASH_NODE *n)
   ASSERT(b);
   *bb = b->next;
   P(free)(TTC b);
+#ifndef HASH_TABLE_GROW
   if (--T.hash_count < T.hash_min)
     P(rehash)(TTC T.hash_size/2);
+#endif
 }
 #endif
 
@@ -683,6 +729,7 @@ do {                                                                                        \
 #undef HASH_EXTRA_SIZE
 #undef HASH_FN_BITS
 #undef HASH_GIVE_ALLOC
+#undef HASH_GIVE_TABLE_ALLOC
 #undef HASH_GIVE_EQ
 #undef HASH_GIVE_EXTRA_SIZE
 #undef HASH_GIVE_HASHFN
@@ -701,6 +748,8 @@ do {                                                                                        \
 #undef HASH_PREFIX
 #undef HASH_USE_POOL
 #undef HASH_AUTO_POOL
+#undef HASH_USE_ELTPOOL
+#undef HASH_AUTO_ELTPOOL
 #undef HASH_WANT_CLEANUP
 #undef HASH_WANT_DELETE
 #undef HASH_WANT_FIND
@@ -709,5 +758,7 @@ do {                                                                                        \
 #undef HASH_WANT_NEW
 #undef HASH_WANT_REMOVE
 #undef HASH_TABLE_ALLOC
+#undef HASH_TABLE_GROW
 #undef HASH_TABLE_DYNAMIC
+#undef HASH_TABLE_VARS
 #undef HASH_ZERO_FILL