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+/*
+ * UCW Library -- Memory Pools
+ *
+ * (c) 1997--2005 Martin Mares <mj@ucw.cz>
+ * (c) 2007 Pavel Charvat <pchar@ucw.cz>
+ * (c) 2015, 2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *
+ * This software may be freely distributed and used according to the terms
+ * of the GNU Lesser General Public License.
+ */
+
+#pragma once
+
+#include <string.h>
+#include <stdint.h>
+
+#define CPU_STRUCT_ALIGN (sizeof(void*))
+
+/***
+ * [[defs]]
+ * Definitions
+ * -----------
+ ***/
+
+/**
+ * Memory pool state (see mp_push(), ...).
+ * You should use this one as an opaque handle only, the insides are internal.
+ **/
+struct mempool_state {
+ unsigned free[2];
+ void *last[2];
+};
+
+/**
+ * Memory pool.
+ * You should use this one as an opaque handle only, the insides are internal.
+ **/
+struct mempool {
+ struct mempool_state state;
+ void *unused, *last_big;
+ unsigned chunk_size, threshold, idx;
+};
+
+struct mempool_stats { /** Mempool statistics. See mp_stats(). **/
+ uint64_t total_size; /** Real allocated size in bytes. */
+ unsigned chain_count[3]; /** Number of allocated chunks in small/big/unused chains. */
+ unsigned chain_size[3]; /** Size of allocated chunks in small/big/unused chains. */
+};
+
+/***
+ * [[basic]]
+ * Basic manipulation
+ * ------------------
+ ***/
+
+/**
+ * Initialize a given mempool structure.
+ * \p chunk_size must be in the interval `[1, UINT_MAX / 2]`.
+ * It will allocate memory by this large chunks and take
+ * memory to satisfy requests from them.
+ *
+ * Memory pools can be treated as <<trans:respools,resources>>, see <<trans:res_mempool()>>.
+ **/
+void mp_init(struct mempool *pool, unsigned chunk_size);
+
+/**
+ * Allocate and initialize a new memory pool.
+ * See \ref mp_init() for \p chunk_size limitations.
+ *
+ * The new mempool structure is allocated on the new mempool.
+ *
+ * Memory pools can be treated as <<trans:respools,resources>>, see <<trans:res_mempool()>>.
+ **/
+struct mempool *mp_new(unsigned chunk_size);
+
+/**
+ * Cleanup mempool initialized by mp_init or mp_new.
+ * Frees all the memory allocated by this mempool and,
+ * if created by \ref mp_new(), the \p pool itself.
+ **/
+void mp_delete(struct mempool *pool);
+
+/**
+ * Frees all data on a memory pool, but leaves it working.
+ * It can keep some of the chunks allocated to serve
+ * further allocation requests. Leaves the \p pool alive,
+ * even if it was created with \ref mp_new().
+ **/
+void mp_flush(struct mempool *pool);
+
+/**
+ * Compute some statistics for debug purposes.
+ * See the definition of the <<struct_mempool_stats,mempool_stats structure>>.
+ **/
+void mp_stats(struct mempool *pool, struct mempool_stats *stats);
+uint64_t mp_total_size(struct mempool *pool); /** How many bytes were allocated by the pool. **/
+
+/***
+ * [[alloc]]
+ * Allocation routines
+ * -------------------
+ ***/
+
+/**
+ * The function allocates new \p size bytes on a given memory pool.
+ * If the \p size is zero, the resulting pointer is undefined,
+ * but it may be safely reallocated or used as the parameter
+ * to other functions below.
+ *
+ * The resulting pointer is always aligned to a multiple of
+ * `CPU_STRUCT_ALIGN` bytes and this condition remains true also
+ * after future reallocations.
+ **/
+void *mp_alloc(struct mempool *pool, unsigned size);
+
+/**
+ * The same as \ref mp_alloc(), but the result may be unaligned.
+ **/
+void *mp_alloc_noalign(struct mempool *pool, unsigned size);
+
+/**
+ * The same as \ref mp_alloc(), but fills the newly allocated memory with zeroes.
+ **/
+void *mp_alloc_zero(struct mempool *pool, unsigned size);