contrib: added mempools from libucw

6 files changed, 1490 insertions, 0 deletions

diff --git a/contrib/ucw/LICENSE b/contrib/ucw/LICENSE
new file mode 120000
index 00000000..0cb7f47a
--- /dev/null
+++ b/contrib/ucw/LICENSE
@@ -0,0 +1 @@
+../licenses/LGPL2
\ No newline at end of file
diff --git a/contrib/ucw/alloc.h b/contrib/ucw/alloc.h
new file mode 100644
index 00000000..668c707c
--- /dev/null
+++ b/contrib/ucw/alloc.h
@@ -0,0 +1,36 @@
+/*
+ *	UCW Library -- Generic allocators
+ *
+ *	(c) 2014 Martin Mares <mj@ucw.cz>
+ */
+
+#ifndef _UCW_ALLOC_H
+#define _UCW_ALLOC_H
+
+/**
+ * This structure describes a generic allocator. It provides pointers
+ * to three functions, which handle the actual (re)allocations.
+ **/
+struct ucw_allocator {
+  void * (*alloc)(struct ucw_allocator *alloc, size_t size);
+  void * (*realloc)(struct ucw_allocator *alloc, void *ptr, size_t old_size, size_t new_size);
+  void (*free)(struct ucw_allocator *alloc, void *ptr);
+};
+
+/* alloc-std.c */
+
+/**
+ * [[std]]
+ * This allocator uses <<basics:xmalloc()>>, <<basics:xrealloc()>> and <<basics:xfree()>>. The memory
+ * it allocates is left unitialized.
+ **/
+extern struct ucw_allocator ucw_allocator_std;
+
+/**
+ * [[zeroing]]
+ * This allocator uses <<basics:xmalloc()>>, <<basics:xrealloc()>> and <<basics:xfree()>>. All memory
+ * is zeroed upon allocation.
+ **/
+extern struct ucw_allocator ucw_allocator_zeroed;
+
+#endif
diff --git a/contrib/ucw/config.h b/contrib/ucw/config.h
new file mode 100644
index 00000000..11234f56
--- /dev/null
+++ b/contrib/ucw/config.h
@@ -0,0 +1,53 @@
+/*
+ *	UCW Library -- Configuration-Dependent Definitions
+ *
+ *	(c) 1997--2012 Martin Mares <mj@ucw.cz>
+ *	(c) 2006 Robert Spalek <robert@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+#ifndef _UCW_CONFIG_H
+#define _UCW_CONFIG_H
+
+/* Default page size and pointer alignment */
+#ifndef CPU_PAGE_SIZE
+#define CPU_PAGE_SIZE 4096
+#endif
+#define CPU_STRUCT_ALIGN sizeof(void *)
+
+/* Tell libc we're going to use all extensions available */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+/* Types (based on standard C99 integers) */
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef uint8_t byte;			/** Exactly 8 bits, unsigned **/
+typedef uint8_t u8;			/** Exactly 8 bits, unsigned **/
+typedef int8_t s8;			/** Exactly 8 bits, signed **/
+typedef uint16_t u16;			/** Exactly 16 bits, unsigned **/
+typedef int16_t s16;			/** Exactly 16 bits, signed **/
+typedef uint32_t u32;			/** Exactly 32 bits, unsigned **/
+typedef int32_t s32;			/** Exactly 32 bits, signed **/
+typedef uint64_t u64;			/** Exactly 64 bits, unsigned **/
+typedef int64_t s64;			/** Exactly 64 bits, signed **/
+
+typedef unsigned int uint;		/** A better pronounceable alias for `unsigned int` **/
+typedef s64 timestamp_t;		/** Milliseconds since an unknown epoch **/
+
+// FIXME: This should be removed soon
+typedef uint uns;			/** Backwards compatible alias for `uint' ***/
+
+#ifdef CONFIG_UCW_LARGE_FILES
+typedef s64 ucw_off_t;			/** File position (either 32- or 64-bit, depending on `CONFIG_UCW_LARGE_FILES`). **/
+#else
+typedef s32 ucw_off_t;
+#endif
+
+#endif
diff --git a/contrib/ucw/lib.h b/contrib/ucw/lib.h
new file mode 100644
index 00000000..bd4612f1
--- /dev/null
+++ b/contrib/ucw/lib.h
@@ -0,0 +1,251 @@
+/*
+ *	The UCW Library -- Miscellaneous Functions
+ *
+ *	(c) 1997--2014 Martin Mares <mj@ucw.cz>
+ *	(c) 2005--2014 Tomas Valla <tom@ucw.cz>
+ *	(c) 2006 Robert Spalek <robert@ucw.cz>
+ *	(c) 2007 Pavel Charvat <pchar@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+#ifndef _UCW_LIB_H
+#define _UCW_LIB_H
+
+#include <stdarg.h>
+#include <stdbool.h>
+
+#ifdef CONFIG_UCW_CLEAN_ABI
+#define assert_failed ucw_assert_failed
+#define assert_failed_msg ucw_assert_failed_msg
+#define assert_failed_noinfo ucw_assert_failed_noinfo
+#define big_alloc ucw_big_alloc
+#define big_alloc_zero ucw_big_alloc_zero
+#define big_free ucw_big_free
+#define die ucw_die
+#define log_die_hook ucw_log_die_hook
+#define log_file ucw_log_file
+#define log_fork ucw_log_fork
+#define log_init ucw_log_init
+#define log_pid ucw_log_pid
+#define log_title ucw_log_title
+#define msg ucw_msg
+#define page_alloc ucw_page_alloc
+#define page_alloc_zero ucw_page_alloc_zero
+#define page_free ucw_page_free
+#define page_realloc ucw_page_realloc
+#define random_max ucw_random_max
+#define random_max_u64 ucw_random_max_u64
+#define random_u32 ucw_random_u32
+#define random_u64 ucw_random_u64
+#define vdie ucw_vdie
+#define vmsg ucw_vmsg
+#define xfree ucw_xfree
+#define xmalloc ucw_xmalloc
+#define xmalloc_zero ucw_xmalloc_zero
+#define xrealloc ucw_xrealloc
+#define xstrdup ucw_xstrdup
+#endif
+
+/*** === Macros for handling structures, offsets and alignment ***/
+
+#define CHECK_PTR_TYPE(x, type) ((x)-(type)(x) + (type)(x))		/** Check that a pointer @x is of type @type. Fail compilation if not. **/
+#define PTR_TO(s, i) &((s*)0)->i					/** Return OFFSETOF() in form of a pointer. **/
+#define OFFSETOF(s, i) ((uint)offsetof(s, i))				/** Offset of item @i from the start of structure @s **/
+#define SKIP_BACK(s, i, p) ((s *)((char *)p - OFFSETOF(s, i)))		/** Given a pointer @p to item @i of structure @s, return a pointer to the start of the struct. **/
+
+/** Align an integer @s to the nearest higher multiple of @a (which should be a power of two) **/
+#define ALIGN_TO(s, a) (((s)+a-1)&~(a-1))
+
+/** Align a pointer @p to the nearest higher multiple of @s. **/
+#define ALIGN_PTR(p, s) ((uintptr_t)(p) % (s) ? (typeof(p))((uintptr_t)(p) + (s) - (uintptr_t)(p) % (s)) : (p))
+
+#define UNALIGNED_PART(ptr, type) (((uintptr_t) (ptr)) % sizeof(type))
+
+/*** === Other utility macros ***/
+
+#define MIN(a,b) (((a)<(b))?(a):(b))			/** Minimum of two numbers **/
+#define MAX(a,b) (((a)>(b))?(a):(b))			/** Maximum of two numbers **/
+#define CLAMP(x,min,max) ({ typeof(x) _t=x; (_t < min) ? min : (_t > max) ? max : _t; })	/** Clip a number @x to interval [@min,@max] **/
+#define ABS(x) ((x) < 0 ? -(x) : (x))			/** Absolute value **/
+#define ARRAY_SIZE(a) (sizeof(a)/sizeof(*(a)))		/** The number of elements of an array **/
+#define STRINGIFY(x) #x					/** Convert macro parameter to a string **/
+#define STRINGIFY_EXPANDED(x) STRINGIFY(x)		/** Convert an expanded macro parameter to a string **/
+#define GLUE(x,y) x##y					/** Glue two tokens together **/
+#define GLUE_(x,y) x##_##y				/** Glue two tokens together, separating them by an underscore **/
+
+#define COMPARE(x,y) do { if ((x)<(y)) return -1; if ((x)>(y)) return 1; } while(0)		/** Numeric comparison function for qsort() **/
+#define REV_COMPARE(x,y) COMPARE(y,x)								/** Reverse numeric comparison **/
+#define COMPARE_LT(x,y) do { if ((x)<(y)) return 1; if ((x)>(y)) return 0; } while(0)
+#define COMPARE_GT(x,y) COMPARE_LT(y,x)
+
+#define	ROL(x, bits) (((x) << (bits)) | ((uint)(x) >> (sizeof(uint)*8 - (bits))))		/** Bitwise rotation of an unsigned int to the left **/
+#define	ROR(x, bits) (((uint)(x) >> (bits)) | ((x) << (sizeof(uint)*8 - (bits))))		/** Bitwise rotation of an unsigned int to the right **/
+
+/*** === Shortcuts for GCC Extensions ***/
+
+#ifdef __GNUC__
+
+#undef inline
+#define NONRET __attribute__((noreturn))				/** Function does not return **/
+#define UNUSED __attribute__((unused))					/** Variable/parameter is knowingly unused **/
+#define CONSTRUCTOR __attribute__((constructor))			/** Call function upon start of program **/
+#define CONSTRUCTOR_WITH_PRIORITY(p) __attribute__((constructor(p)))	/** Define constructor with a given priority **/
+#define PACKED __attribute__((packed))					/** Structure should be packed **/
+#define CONST __attribute__((const))					/** Function depends only on arguments **/
+#define PURE __attribute__((pure))					/** Function depends only on arguments and global vars **/
+#define FORMAT_CHECK(x,y,z) __attribute__((format(x,y,z)))		/** Checking of printf-like format strings **/
+#define likely(x) __builtin_expect((x),1)				/** Use `if (likely(@x))` if @x is almost always true **/
+#define unlikely(x) __builtin_expect((x),0)				/** Use `if (unlikely(@x))` to hint that @x is almost always false **/
+
+#if __GNUC__ >= 4 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3
+#define ALWAYS_INLINE inline __attribute__((always_inline))		/** Forcibly inline **/
+#define NO_INLINE __attribute__((noinline))				/** Forcibly uninline **/
+#else
+#define ALWAYS_INLINE inline
+#endif
+
+#if __GNUC__ >= 4
+#define LIKE_MALLOC __attribute__((malloc))				/** Function returns a "new" pointer **/
+#define SENTINEL_CHECK __attribute__((sentinel))			/** The last argument must be NULL **/
+#else
+#define LIKE_MALLOC
+#define SENTINEL_CHECK
+#endif
+
+#else
+#error This program requires the GNU C compiler.
+#endif
+
+/***
+ * [[logging]]
+ *
+ * === Basic logging functions (see <<log:,Logging>> and <ucw/log.h> for more)
+ ***/
+
+enum log_levels {			/** The available log levels to pass to msg() and friends. **/
+  L_DEBUG=0,				// 'D' - Debugging
+  L_INFO,				// 'I' - Informational
+  L_WARN,				// 'W' - Warning
+  L_ERROR,				// 'E' - Error, but non-critical
+  L_INFO_R,				// 'i' - An alternative set of levels for messages caused by remote events
+  L_WARN_R,				// 'w'   (e.g., a packet received via network)
+  L_ERROR_R,				// 'e'
+  L_FATAL,				// '!' - Fatal error
+  L_MAX
+};
+
+#define LOG_LEVEL_NAMES P(DEBUG) P(INFO) P(WARN) P(ERROR) P(INFO_R) P(WARN_R) P(ERROR_R) P(FATAL)
+
+// Return the letter associated with a given severity level
+#define LS_LEVEL_LETTER(level) ("DIWEiwe!###"[( level )])
+
+#define L_SIGHANDLER	0x80000000	/** Avoid operations that are unsafe in signal handlers **/
+#define L_LOGGER_ERR	0x40000000	/** Used internally to avoid infinite reporting of logging errors **/
+
+/**
+ * This is the basic printf-like function for logging a message.
+ * The @flags contain the log level and possibly other flag bits (like `L_SIGHANDLER`).
+ **/
+void msg(uint flags, const char *fmt, ...) FORMAT_CHECK(printf,2,3);
+void vmsg(uint flags, const char *fmt, va_list args);		/** A vararg version of msg(). **/
+void die(const char *, ...) NONRET FORMAT_CHECK(printf,1,2);	/** Log a fatal error message and exit the program. **/
+void vdie(const char *fmt, va_list args) NONRET;		/** va_list version of die() **/
+
+extern char *log_title;			/** An optional log message title. Set to program name by log_init(). **/
+extern int log_pid;			/** An optional PID printed in each log message. Set to 0 if it shouldn't be logged. **/
+extern void (*log_die_hook)(void);	/** An optional function called just before die() exists. **/	// API: log_die_hook
+
+void log_init(const char *argv0);	/** Set @log_title to the program name extracted from @argv[0]. **/
+void log_fork(void);			/** Call after fork() to update @log_pid. **/
+void log_file(const char *name);	/** Establish logging to the named file. Also redirect stderr there. **/
+
+void assert_failed(const char *assertion, const char *file, int line) NONRET;
+void assert_failed_msg(const char *assertion, const char *file, int line, const char *fmt, ...) NONRET FORMAT_CHECK(printf,4,5);
+void assert_failed_noinfo(void) NONRET;
+
+#ifdef DEBUG_ASSERTS
+/**
+ * Check an assertion. If the condition @x is false, stop the program with a fatal error.
+ * Assertion checks are compiled only when `DEBUG_ASSERTS` is defined.
+ **/
+#define ASSERT(x) ({ if (unlikely(!(x))) assert_failed(#x, __FILE__, __LINE__); 1; })
+
+/**
+ * Check an assertion with a debug message. If the condition @cond is false,
+ * print the message and stop the program with fatal error.
+ * Assertion checks are compiled only when `DEBUG_ASSERTS` is defined.
+ **/
+#define ASSERT_MSG(cond,str,x...) ({ if (unlikely(!(cond))) assert_failed_msg(#cond, __FILE__, __LINE__, str,##x); 1; })
+
+#else
+#define ASSERT(x) ({ if (__builtin_constant_p(x) && !(x)) assert_failed_noinfo(); 1; })
+#define ASSERT_MSG(cond,str,x...) ASSERT(cond)
+#endif
+
+#define COMPILE_ASSERT(name,x) typedef char _COMPILE_ASSERT_##name[!!(x)-1]
+
+#ifdef LOCAL_DEBUG
+#define DBG(x,y...) msg(L_DEBUG, x,##y)	/** If `LOCAL_DEBUG` is defined before including <ucw/lib.h>, log a debug message. Otherwise do nothing. **/
+/**
+ * If `LOCAL_DEBUG` is defined before including <ucw/lib.h>, log current
+ * file name and line number. Otherwise do nothing.
+ **/
+#define DBG_SPOT msg(L_DEBUG, "%s:%d (%s)", __FILE__, __LINE__, __func__)
+#else
+#define DBG(x,y...) do { } while(0)
+#define DBG_SPOT do { } while(0)
+#endif
+
+#ifdef DEBUG_ASSERTS
+/**
+ * Sometimes, we may want to check that a pointer points to a valid memory
+ * location before we start using it for anything more complicated. This
+ * macro checks pointer validity by reading the byte it points to.
+ **/
+#define ASSERT_READABLE(ptr) ({ volatile char *__p = (ptr); *__p; })
+/** Like the previous macro, but it checks writeability, too. **/
+#define ASSERT_WRITEABLE(ptr) ({ volatile char *__p = (ptr); *__p = *__p; })
+#else
+#define ASSERT_READABLE(ptr) do { } while(0)
+#define ASSERT_WRITEABLE(ptr) do { } while(0)
+#endif
+
+/*** === Memory allocation ***/
+
+/*
+ * Unfortunately, several libraries we might want to link to define
+ * their own xmalloc and we don't want to interfere with them, hence
+ * the renaming.
+ */
+#define xmalloc ucw_xmalloc
+#define xrealloc ucw_xrealloc
+#define xfree ucw_xfree
+
+void *xmalloc(size_t) LIKE_MALLOC;		/** Allocate memory and die() if there is none. **/
+void *xrealloc(void *, size_t);			/** Reallocate memory and die() if there is none. **/
+void xfree(void *);				/** Free memory allocated by xmalloc() or xrealloc(). **/
+
+void *xmalloc_zero(size_t) LIKE_MALLOC;		/** Allocate memory and fill it by zeroes. **/
+char *xstrdup(const char *) LIKE_MALLOC;	/** Make a xmalloc()'ed copy of a string. Returns NULL for NULL string. **/
+
+/* bigalloc.c */
+
+void *page_alloc(u64 len) LIKE_MALLOC;		// Internal: allocates a multiple of CPU_PAGE_SIZE bytes with mmap
+void *page_alloc_zero(u64 len) LIKE_MALLOC;
+void page_free(void *start, u64 len);
+void *page_realloc(void *start, u64 old_len, u64 new_len);
+
+void *big_alloc(u64 len) LIKE_MALLOC;		/** Allocate a large memory block in the most efficient way available. **/
+void *big_alloc_zero(u64 len) LIKE_MALLOC;	/** Allocate and clear a large memory block. **/
+void big_free(void *start, u64 len);		/** Free block allocated by @big_alloc() or @big_alloc_zero(). **/
+
+/*** === Random numbers (random.c) ***/
+
+uint random_u32(void);				/** Return a pseudorandom 32-bit number. **/
+uint random_max(uint max);			/** Return a pseudorandom 32-bit number in range [0,@max). **/
+u64 random_u64(void);				/** Return a pseudorandom 64-bit number. **/
+u64 random_max_u64(u64 max);			/** Return a pseudorandom 64-bit number in range [0,@max). **/
+
+#endif
diff --git a/contrib/ucw/mempool.c b/contrib/ucw/mempool.c
new file mode 100644
index 00000000..b0d203db
--- /dev/null
+++ b/contrib/ucw/mempool.c
@@ -0,0 +1,586 @@
+/*
+ *	UCW Library -- Memory Pools (One-Time Allocation)
+ *
+ *	(c) 1997--2014 Martin Mares <mj@ucw.cz>
+ *	(c) 2007--2015 Pavel Charvat <pchar@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+#undef LOCAL_DEBUG
+
+#include <ucw/config.h>
+#include <ucw/lib.h>
+#include <ucw/alloc.h>
+#include <ucw/mempool.h>
+
+#include <string.h>
+
+#define MP_CHUNK_TAIL ALIGN_TO(sizeof(struct mempool_chunk), CPU_STRUCT_ALIGN)
+#define MP_SIZE_MAX (SIZE_MAX - MP_CHUNK_TAIL - CPU_PAGE_SIZE)
+
+struct mempool_chunk {
+#ifdef CONFIG_DEBUG
+  struct mempool *pool;		// Can be useful when analysing coredump for memory leaks
+#endif
+  struct mempool_chunk *next;
+  size_t size;
+};
+
+static size_t
+mp_align_size(size_t size)
+{
+#ifdef CONFIG_UCW_POOL_IS_MMAP
+  size = MAX(size, 64 + MP_CHUNK_TAIL);
+  return ALIGN_TO(size, CPU_PAGE_SIZE) - MP_CHUNK_TAIL;
+#else
+  return ALIGN_TO(size, CPU_STRUCT_ALIGN);
+#endif
+}
+
+static void *mp_allocator_alloc(struct ucw_allocator *a, size_t size)
+{
+  struct mempool *mp = (struct mempool *) a;
+  return mp_alloc_fast(mp, size);
+}
+
+static void *mp_allocator_realloc(struct ucw_allocator *a, void *ptr, size_t old_size, size_t new_size)
+{
+  if (new_size <= old_size)
+    return ptr;
+
+  /*
+   *  In the future, we might want to do something like mp_realloc(),
+   *  but we have to check that it is indeed the last block in the pool.
+   */
+  struct mempool *mp = (struct mempool *) a;
+  void *new = mp_alloc_fast(mp, new_size);
+  memcpy(new, ptr, old_size);
+  return new;
+}
+
+static void mp_allocator_free(struct ucw_allocator *a UNUSED, void *ptr UNUSED)
+{
+  // Does nothing
+}
+
+void
+mp_init(struct mempool *pool, size_t chunk_size)
+{
+  chunk_size = mp_align_size(MAX(sizeof(struct mempool), chunk_size));
+  *pool = (struct mempool) {
+    .allocator = {
+      .alloc = mp_allocator_alloc,
+      .realloc = mp_allocator_realloc,
+      .free = mp_allocator_free,
+    },
+    .chunk_size = chunk_size,
+    .threshold = chunk_size >> 1,
+    .last_big = &pool->last_big
+  };
+}
+
+static void *
+mp_new_big_chunk(struct mempool *pool, size_t size)
+{
+  struct mempool_chunk *chunk;
+  chunk = xmalloc(size + MP_CHUNK_TAIL) + size;
+  chunk->size = size;
+  if (pool)
+    pool->total_size += size + MP_CHUNK_TAIL;
+  return chunk;
+}
+
+static void
+mp_free_big_chunk(struct mempool *pool, struct mempool_chunk *chunk)
+{
+  pool->total_size -= chunk->size + MP_CHUNK_TAIL;
+  xfree((void *)chunk - chunk->size);
+}
+
+static void *
+mp_new_chunk(struct mempool *pool, size_t size)
+{
+#ifdef CONFIG_UCW_POOL_IS_MMAP
+  struct mempool_chunk *chunk;
+  chunk = page_alloc(size + MP_CHUNK_TAIL) + size;
+  chunk->size = size;
+  if (pool)
+    pool->total_size += size + MP_CHUNK_TAIL;
+  return chunk;
+#else
+  return mp_new_big_chunk(pool, size);
+#endif
+}
+
+static void
+mp_free_chunk(struct mempool *pool, struct mempool_chunk *chunk)
+{
+#ifdef CONFIG_UCW_POOL_IS_MMAP
+  pool->total_size -= chunk->size + MP_CHUNK_TAIL;
+  page_free((void *)chunk - chunk->size, chunk->size + MP_CHUNK_TAIL);
+#else
+  mp_free_big_chunk(pool, chunk);
+#endif
+}
+
+struct mempool *
+mp_new(size_t chunk_size)
+{
+  chunk_size = mp_align_size(MAX(sizeof(struct mempool), chunk_size));
+  struct mempool_chunk *chunk = mp_new_chunk(NULL, chunk_size);
+  struct mempool *pool = (void *)chunk - chunk_size;
+  DBG("Creating mempool %p with %u bytes long chunks", pool, chunk_size);
+  chunk->next = NULL;
+#ifdef CONFIG_DEBUG
+  chunk->pool = pool;
+#endif
+  *pool = (struct mempool) {
+    .allocator = {
+      .alloc = mp_allocator_alloc,
+      .realloc = mp_allocator_realloc,
+      .free = mp_allocator_free,
+    },
+    .state = { .free = { chunk_size - sizeof(*pool) }, .last = { chunk } },
+    .chunk_size = chunk_size,
+    .threshold = chunk_size >> 1,
+    .last_big = &pool->last_big,
+    .total_size = chunk->size + MP_CHUNK_TAIL,
+  };
+  return pool;
+}
+
+static void
+mp_free_chain(struct mempool *pool, struct mempool_chunk *chunk)
+{
+  while (chunk)
+    {
+      struct mempool_chunk *next = chunk->next;
+      mp_free_chunk(pool, chunk);
+      chunk = next;
+    }
+}
+
+static void
+mp_free_big_chain(struct mempool *pool, struct mempool_chunk *chunk)
+{
+  while (chunk)
+    {
+      struct mempool_chunk *next = chunk->next;
+      mp_free_big_chunk(pool, chunk);
+      chunk = next;
+    }
+}
+
+void
+mp_delete(struct mempool *pool)
+{
+  DBG("Deleting mempool %p", pool);
+  mp_free_big_chain(pool, pool->state.last[1]);
+  mp_free_chain(pool, pool->unused);
+  mp_free_chain(pool, pool->state.last[0]); // can contain the mempool structure
+}
+
+void
+mp_flush(struct mempool *pool)
+{
+  mp_free_big_chain(pool, pool->state.last[1]);
+  struct mempool_chunk *chunk, *next;
+  for (chunk = pool->state.last[0]; chunk && (void *)chunk - chunk->size != pool; chunk = next)
+    {
+      next = chunk->next;
+      chunk->next = pool->unused;
+      pool->unused = chunk;
+    }
+  pool->state.last[0] = chunk;
+  pool->state.free[0] = chunk ? chunk->size - sizeof(*pool) : 0;
+  pool->state.last[1] = NULL;
+  pool->state.free[1] = 0;
+  pool->state.next = NULL;
+  pool->last_big = &pool->last_big;
+}
+
+static void
+mp_stats_chain(struct mempool *pool, struct mempool_chunk *chunk, struct mempool_stats *stats, uint idx)
+{
+  while (chunk)
+    {
+      stats->chain_size[idx] += chunk->size + MP_CHUNK_TAIL;
+      stats->chain_count[idx]++;
+      if (idx < 2)
+	{
+	  stats->used_size += chunk->size;
+	  if ((byte *)pool == (byte *)chunk - chunk->size)
+	    stats->used_size -= sizeof(*pool);
+	}
+      chunk = chunk->next;
+    }
+  stats->total_size += stats->chain_size[idx];
+}
+
+void
+mp_stats(struct mempool *pool, struct mempool_stats *stats)
+{
+  bzero(stats, sizeof(*stats));
+  mp_stats_chain(pool, pool->state.last[0], stats, 0);
+  mp_stats_chain(pool, pool->state.last[1], stats, 1);
+  mp_stats_chain(pool, pool->unused, stats, 2);
+  stats->used_size -= pool->state.free[0] + pool->state.free[1];
+  ASSERT(stats->total_size == pool->total_size);
+  ASSERT(stats->used_size <= stats->total_size);
+}
+
+u64
+mp_total_size(struct mempool *pool)
+{
+  return pool->total_size;
+}
+
+void
+mp_shrink(struct mempool *pool, u64 min_total_size)
+{
+  while (1)
+    {
+      struct mempool_chunk *chunk = pool->unused;
+      if (!chunk || pool->total_size - (chunk->size + MP_CHUNK_TAIL) < min_total_size)
+	break;
+      pool->unused = chunk->next;
+      mp_free_chunk(pool, chunk);
+    }
+}
+
+void *
+mp_alloc_internal(struct mempool *pool, size_t size)
+{
+  struct mempool_chunk *chunk;
+  if (size <= pool->threshold)
+    {
+      pool->idx = 0;
+      if (pool->unused)
+        {
+	  chunk = pool->unused;
+	  pool->unused = chunk->next;
+	}
+      else
+	{
+	  chunk = mp_new_chunk(pool, pool->chunk_size);
+#ifdef CONFIG_DEBUG
+	  chunk->pool = pool;
+#endif
+	}
+      chunk->next = pool->state.last[0];
+      pool->state.last[0] = chunk;
+      pool->state.free[0] = pool->chunk_size - size;
+      return (void *)chunk - pool->chunk_size;
+    }
+  else if (likely(size <= MP_SIZE_MAX))
+    {
+      pool->idx = 1;
+      size_t aligned = ALIGN_TO(size, CPU_STRUCT_ALIGN);
+      chunk = mp_new_big_chunk(pool, aligned);
+      chunk->next = pool->state.last[1];
+#ifdef CONFIG_DEBUG
+      chunk->pool = pool;
+#endif
+      pool->state.last[1] = chunk;
+      pool->state.free[1] = aligned - size;
+      return pool->last_big = (void *)chunk - aligned;
+    }
+  else
+    die("Cannot allocate %zu bytes from a mempool", size);
+}
+
+void *
+mp_alloc(struct mempool *pool, size_t size)
+{
+  return mp_alloc_fast(pool, size);
+}
+
+void *
+mp_alloc_noalign(struct mempool *pool, size_t size)
+{
+  return mp_alloc_fast_noalign(pool, size);
+}
+
+void *
+mp_alloc_zero(struct mempool *pool, size_t size)
+{
+  void *ptr = mp_alloc_fast(pool, size);
+  bzero(ptr, size);
+  return ptr;
+}
+
+void *
+mp_start_internal(struct mempool *pool, size_t size)
+{
+  void *ptr = mp_alloc_internal(pool, size);
+  pool->state.free[pool->idx] += size;
+  return ptr;
+}
+
+void *
+mp_start(struct mempool *pool, size_t size)
+{
+  return mp_start_fast(pool, size);
+}
+
+void *
+mp_start_noalign(struct mempool *pool, size_t size)
+{
+  return mp_start_fast_noalign(pool, size);
+}
+
+void *
+mp_grow_internal(struct mempool *pool, size_t size)
+{
+  if (unlikely(size > MP_SIZE_MAX))
+    die("Cannot allocate %zu bytes of memory", size);
+  size_t avail = mp_avail(pool);
+  void *ptr = mp_ptr(pool);
+  if (pool->idx)
+    {
+      size_t amortized = likely(avail <= MP_SIZE_MAX / 2) ? avail * 2 : MP_SIZE_MAX;
+      amortized = MAX(amortized, size);
+      amortized = ALIGN_TO(amortized, CPU_STRUCT_ALIGN);
+      struct mempool_chunk *chunk = pool->state.last[1], *next = chunk->next;
+      pool->total_size = pool->total_size - chunk->size + amortized;
+      ptr = xrealloc(ptr, amortized + MP_CHUNK_TAIL);
+      chunk = ptr + amortized;
+      chunk->next = next;
+      chunk->size = amortized;
+      pool->state.last[1] = chunk;
+      pool->state.free[1] = amortized;
+      pool->last_big = ptr;
+      return ptr;
+    }
+  else
+    {
+      void *p = mp_start_internal(pool, size);
+      memcpy(p, ptr, avail);
+      return p;
+    }
+}
+
+size_t
+mp_open(struct mempool *pool, void *ptr)
+{
+  return mp_open_fast(pool, ptr);
+}
+
+void *
+mp_realloc(struct mempool *pool, void *ptr, size_t size)
+{
+  return mp_realloc_fast(pool, ptr, size);
+}
+
+void *
+mp_realloc_zero(struct mempool *pool, void *ptr, size_t size)
+{
+  size_t old_size = mp_open_fast(pool, ptr);
+  ptr = mp_grow(pool, size);
+  if (size > old_size)
+    bzero(ptr + old_size, size - old_size);
+  mp_end(pool, ptr + size);
+  return ptr;
+}
+
+void *
+mp_spread_internal(struct mempool *pool, void *p, size_t size)
+{
+  void *old = mp_ptr(pool);
+  void *new = mp_grow_internal(pool, p-old+size);
+  return p-old+new;
+}
+
+void
+mp_restore(struct mempool *pool, struct mempool_state *state)
+{
+  struct mempool_chunk *chunk, *next;
+  struct mempool_state s = *state;
+  for (chunk = pool->state.last[0]; chunk != s.last[0]; chunk = next)
+    {
+      next = chunk->next;
+      chunk->next = pool->unused;
+      pool->unused = chunk;
+    }
+  for (chunk = pool->state.last[1]; chunk != s.last[1]; chunk = next)
+    {
+      next = chunk->next;
+      mp_free_big_chunk(pool, chunk);
+    }
+  pool->state = s;
+  pool->last_big = &pool->last_big;
+}
+
+struct mempool_state *
+mp_push(struct mempool *pool)
+{
+  struct mempool_state state = pool->state;
+  struct mempool_state *p = mp_alloc_fast(pool, sizeof(*p));
+  *p = state;
+  pool->state.next = p;
+  return p;
+}
+
+void
+mp_pop(struct mempool *pool)
+{
+  ASSERT(pool->state.next);
+  mp_restore(pool, pool->state.next);
+}
+
+#ifdef TEST
+
+#include <ucw/getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+static void
+fill(byte *ptr, uint len, uint magic)
+{
+  while (len--)
+    *ptr++ = (magic++ & 255);
+}
+
+static void
+check(byte *ptr, uint len, uint magic, uint align)
+{
+  ASSERT(!((uintptr_t)ptr & (align - 1)));
+  while (len--)
+    if (*ptr++ != (magic++ & 255))
+      ASSERT(0);
+}
+
+int main(int argc, char **argv)
+{
+  srand(time(NULL));
+  log_init(argv[0]);
+  cf_def_file = NULL;
+  if (cf_getopt(argc, argv, CF_SHORT_OPTS, CF_NO_LONG_OPTS, NULL) >= 0 || argc != optind)
+    die("Invalid usage");
+
+  uint max = 1000, n = 0, m = 0, can_realloc = 0;
+  void *ptr[max];
+  struct mempool_state *state[max];
+  uint len[max], num[max], align[max];
+  struct mempool *mp = mp_new(128), mp_static;
+
+  for (uint i = 0; i < 5000; i++)
+    {
+      for (uint j = 0; j < n; j++)
+	check(ptr[j], len[j], j, align[j]);
+#if 0
+      DBG("free_small=%u free_big=%u idx=%u chunk_size=%u last_big=%p", mp->state.free[0], mp->state.free[1], mp->idx, mp->chunk_size, mp->last_big);
+      for (struct mempool_chunk *ch = mp->state.last[0]; ch; ch = ch->next)
+	DBG("small %p %p %p %d", (byte *)ch - ch->size, ch, ch + 1, ch->size);
+      for (struct mempool_chunk *ch = mp->state.last[1]; ch; ch = ch->next)
+	DBG("big %p %p %p %d", (byte *)ch - ch->size, ch, ch + 1, ch->size);
+#endif
+      int r = random_max(100);
+      if ((r -= 1) < 0)
+        {
+	  DBG("flush");
+	  mp_flush(mp);
+	  n = m = 0;
+	}
+      else if ((r -= 1) < 0)
+        {
+	  DBG("delete & new");
+	  mp_delete(mp);
+	  if (random_max(2))
+	    mp = mp_new(random_max(0x1000) + 1);
+	  else
+	    mp = &mp_static, mp_init(mp, random_max(512) + 1);
+	  n = m = 0;
+	}
+      else if (n < max && (r -= 30) < 0)
+        {
+	  len[n] = random_max(0x2000);
+	  DBG("alloc(%u)", len[n]);
+	  align[n] = random_max(2) ? CPU_STRUCT_ALIGN : 1;
+	  ptr[n] = (align[n] == 1) ? mp_alloc_fast_noalign(mp, len[n]) : mp_alloc_fast(mp, len[n]);
+	  DBG(" -> (%p)", ptr[n]);
+	  fill(ptr[n], len[n], n);
+	  n++;
+	  can_realloc = 1;
+	}
+      else if (n < max && (r -= 20) < 0)
+        {
+	  len[n] = random_max(0x2000);
+	  DBG("start(%u)", len[n]);
+	  align[n] = random_max(2) ? CPU_STRUCT_ALIGN : 1;
+	  ptr[n] = (align[n] == 1) ? mp_start_fast_noalign(mp, len[n]) : mp_start_fast(mp, len[n]);
+	  DBG(" -> (%p)", ptr[n]);
+	  fill(ptr[n], len[n], n);
+	  n++;
+	  can_realloc = 1;
+	  goto grow;
+	}
+      else if (can_realloc && n && (r -= 10) < 0)
+        {
+	  if (mp_open(mp, ptr[n - 1]) != len[n - 1])
+	    ASSERT(0);
+grow:
+	  {
+	    uint k = n - 1;
+	    for (uint i = random_max(4); i--; )
+	      {
+	        uint l = len[k];
+	        len[k] = random_max(0x2000);
+	        DBG("grow(%u)", len[k]);
+	        ptr[k] = mp_grow(mp, len[k]);
+	        DBG(" -> (%p)", ptr[k]);
+	        check(ptr[k], MIN(l, len[k]), k, align[k]);
+	        fill(ptr[k], len[k], k);
+	      }
+	    mp_end(mp, ptr[k] + len[k]);
+	  }
+	}
+      else if (can_realloc && n && (r -= 20) < 0)
+        {
+	  uint i = n - 1, l = len[i];
+	  DBG("realloc(%p, %u)", ptr[i], len[i]);
+	  ptr[i] = mp_realloc(mp, ptr[i], len[i] = random_max(0x2000));
+	  DBG(" -> (%p, %u)", ptr[i], len[i]);
+	  check(ptr[i],  MIN(len[i], l), i, align[i]);
+	  fill(ptr[i], len[i], i);
+	}
+      else if (m < max && (r -= 5) < 0)
+        {
+	  DBG("push(%u)", m);
+	  num[m] = n;
+	  state[m++] = mp_push(mp);
+	  can_realloc = 0;
+	}
+      else if (m && (r -= 2) < 0)
+        {
+	  m--;
+	  DBG("pop(%u)", m);
+	  mp_pop(mp);
+	  n = num[m];
+	  can_realloc = 0;
+	}
+      else if (m && (r -= 1) < 0)
+        {
+	  uint i = random_max(m);
+	  DBG("restore(%u)", i);
+	  mp_restore(mp, state[i]);
+	  n = num[m = i];
+	  can_realloc = 0;
+	}
+      else if (can_realloc && n && (r -= 5) < 0)
+        ASSERT(mp_size(mp, ptr[n - 1]) == len[n - 1]);
+      else
+	{
+	  struct mempool_stats stats;
+	  mp_stats(mp, &stats);
+	}
+    }
+
+  mp_delete(mp);
+  return 0;
+}
+
+#endif
diff --git a/contrib/ucw/mempool.h b/contrib/ucw/mempool.h
new file mode 100644
index 00000000..44595ea7
--- /dev/null
+++ b/contrib/ucw/mempool.h
@@ -0,0 +1,563 @@
+/*
+ *	UCW Library -- Memory Pools
+ *
+ *	(c) 1997--2015 Martin Mares <mj@ucw.cz>
+ *	(c) 2007 Pavel Charvat <pchar@ucw.cz>
+ *
+ *	This software may be freely distributed and used according to the terms
+ *	of the GNU Lesser General Public License.
+ */
+
+#ifndef _UCW_POOLS_H
+#define _UCW_POOLS_H
+
+#include <ucw/alloc.h>
+#include <string.h>
+
+#ifdef CONFIG_UCW_CLEAN_ABI
+#define mp_alloc ucw_mp_alloc
+#define mp_alloc_internal ucw_mp_alloc_internal
+#define mp_alloc_noalign ucw_mp_alloc_noalign
+#define mp_alloc_zero ucw_mp_alloc_zero
+#define mp_delete ucw_mp_delete
+#define mp_flush ucw_mp_flush
+#define mp_grow_internal ucw_mp_grow_internal
+#define mp_init ucw_mp_init
+#define mp_memdup ucw_mp_memdup
+#define mp_multicat ucw_mp_multicat
+#define mp_new ucw_mp_new
+#define mp_open ucw_mp_open
+#define mp_pop ucw_mp_pop
+#define mp_printf ucw_mp_printf
+#define mp_printf_append ucw_mp_printf_append
+#define mp_push ucw_mp_push
+#define mp_realloc ucw_mp_realloc
+#define mp_realloc_zero ucw_mp_realloc_zero
+#define mp_restore ucw_mp_restore
+#define mp_shrink ucw_mp_shrink
+#define mp_spread_internal ucw_mp_spread_internal
+#define mp_start ucw_mp_start
+#define mp_start_internal ucw_mp_start_internal
+#define mp_start_noalign ucw_mp_start_noalign
+#define mp_stats ucw_mp_stats
+#define mp_str_from_mem ucw_mp_str_from_mem
+#define mp_strdup ucw_mp_strdup
+#define mp_strjoin ucw_mp_strjoin
+#define mp_total_size ucw_mp_total_size
+#define mp_vprintf ucw_mp_vprintf
+#define mp_vprintf_append ucw_mp_vprintf_append
+#endif
+
+/***
+ * [[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 {
+  size_t free[2];
+  void *last[2];
+  struct mempool_state *next;
+};
+
+/**
+ * Memory pool.
+ * You should use this one as an opaque handle only, the insides are internal.
+ **/
+struct mempool {
+  struct ucw_allocator allocator;	// This must be the first element
+  struct mempool_state state;
+  void *unused, *last_big;
+  size_t chunk_size, threshold;
+  uint idx;
+  u64 total_size;
+};
+
+struct mempool_stats {			/** Mempool statistics. See @mp_stats(). **/
+  u64 total_size;			/* Real allocated size in bytes */
+  u64 used_size;			/* Estimated size allocated from mempool to application */
+  uint chain_count[3];			/* Number of allocated chunks in small/big/unused chains */
+  u64 chain_size[3];			/* Size of allocated chunks in small/big/unused chains */
+};
+
+/***
+ * [[basic]]
+ * Basic manipulation
+ * ------------------
+ ***/
+
+/**
+ * Initialize a given mempool structure.
+ * @chunk_size must be in the interval `[1, SIZE_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, size_t chunk_size);
+
+/**
+ * Allocate and initialize a new memory pool.
+ * See @mp_init() for @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(size_t chunk_size);
+
+/**
+ * Cleanup mempool initialized by mp_init or mp_new.
+ * Frees all the memory allocated by this mempool and,
+ * if created by @mp_new(), the @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 @pool alive,
+ * even if it was created with @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>>.
+ * This function scans the chunk list, so it can be slow. If you are interested
+ * in total memory consumption only, mp_total_size() is faster.
+ **/
+void mp_stats(struct mempool *pool, struct mempool_stats *stats);
+
+/**
+ * Return how many bytes were allocated by the pool, including unused parts
+ * of chunks. This function runs in constant time.
+ **/
+u64 mp_total_size(struct mempool *pool);
+
+/**
+ * Release unused chunks of memory reserved for further allocation
+ * requests, but stop if mp_total_size() would drop below @min_total_size.
+ **/
+void mp_shrink(struct mempool *pool, u64 min_total_size);
+
+/***
+ * [[alloc]]
+ * Allocation routines
+ * -------------------
+ ***/
+
+/* For internal use only, do not call directly */
+void *mp_alloc_internal(struct mempool *pool, size_t size) LIKE_MALLOC;
+
+/**
+ * The function allocates new @size bytes on a given memory pool.
+ * If the @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, size_t size);
+
+/**
+ * The same as @mp_alloc(), but the result may be unaligned.
+ **/
+void *mp_alloc_noalign(struct mempool *pool, size_t size);
+
+/**
+ * The same as @mp_alloc(), but fills the newly allocated memory with zeroes.
+ **/
+void *mp_alloc_zero(struct mempool *pool, size_t size);
+
+/**
+ * Inlined version of @mp_alloc().
+ **/
+static inline void *mp_alloc_fast(struct mempool *pool, size_t size)
+{
+  size_t avail = pool->state.free[0] & ~(size_t)(CPU_STRUCT_ALIGN - 1);
+  if (size <= avail)
+    {
+      pool->state.free[0] = avail - size;
+      return (byte *)pool->state.last[0] - avail;
+    }
+  else
+    return mp_alloc_internal(pool, size);
+}
+
+/**
+ * Inlined version of @mp_alloc_noalign().
+ **/
+static inline void *mp_alloc_fast_noalign(struct mempool *pool, size_t size)
+{
+  if (size <= pool->state.free[0])
+    {
+      void *ptr = (byte *)pool->state.last[0] - pool->state.free[0];
+      pool->state.free[0] -= size;
+      return ptr;
+    }
+  else
+    return mp_alloc_internal(pool, size);
+}
+
+/**
+ * Return a generic allocator representing the given mempool.
+ **/
+static inline struct ucw_allocator *mp_get_allocator(struct mempool *mp)
+{
+  return &mp->allocator;
+}
+
+/***
+ * [[gbuf]]
+ * Growing buffers
+ * ---------------
+ *
+ * You do not need to know, how a buffer will need to be large,
+ * you can grow it incrementally to needed size. You can grow only
+ * one buffer at a time on a given mempool.
+ *
+ * Similar functionality is provided by <<growbuf:,growing buffes>> module.
+ ***/
+
+/* For internal use only, do not call directly */
+void *mp_start_internal(struct mempool *pool, size_t size) LIKE_MALLOC;
+void *mp_grow_internal(struct mempool *pool, size_t size);
+void *mp_spread_internal(struct mempool *pool, void *p, size_t size);
+
+static inline uint mp_idx(struct mempool *pool, void *ptr)
+{
+  return ptr == pool->last_big;
+}
+
+/**
+ * Open a new growing buffer (at least @size bytes long).
+ * If the @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. There is an unaligned version as well.
+ *
+ * Keep in mind that you can't make any other pool allocations
+ * before you "close" the growing buffer with @mp_end().
+ */
+void *mp_start(struct mempool *pool, size_t size);
+void *mp_start_noalign(struct mempool *pool, size_t size);
+
+/**
+ * Inlined version of @mp_start().
+ **/
+static inline void *mp_start_fast(struct mempool *pool, size_t size)
+{
+  size_t avail = pool->state.free[0] & ~(size_t)(CPU_STRUCT_ALIGN - 1);
+  if (size <= avail)
+    {
+      pool->idx = 0;
+      pool->state.free[0] = avail;
+      return (byte *)pool->state.last[0] - avail;
+    }
+  else
+    return mp_start_internal(pool, size);
+}
+
+/**
+ * Inlined version of @mp_start_noalign().
+ **/
+static inline void *mp_start_fast_noalign(struct mempool *pool, size_t size)
+{
+  if (size <= pool->state.free[0])
+    {
+      pool->idx = 0;
+      return (byte *)pool->state.last[0] - pool->state.free[0];
+    }
+  else
+    return mp_start_internal(pool, size);
+}
+
+/**
+ * Return start pointer of the growing buffer allocated by latest @mp_start() or a similar function.
+ **/
+static inline void *mp_ptr(struct mempool *pool)
+{
+  return (byte *)pool->state.last[pool->idx] - pool->state.free[pool->idx];
+}
+
+/**
+ * Return the number of bytes available for extending the growing buffer.
+ * (Before a reallocation will be needed).
+ **/
+static inline size_t mp_avail(struct mempool *pool)
+{
+  return pool->state.free[pool->idx];
+}
+
+/**
+ * Grow the buffer allocated by @mp_start() to be at least @size bytes long
+ * (@size may be less than @mp_avail(), even zero). Reallocated buffer may
+ * change its starting position. The content will be unchanged to the minimum
+ * of the old and new sizes; newly allocated memory will be uninitialized.
+ * Multiple calls to mp_grow() have amortized linear cost wrt. the maximum value of @size. */
+static inline void *mp_grow(struct mempool *pool, size_t size)
+{
+  return (size <= mp_avail(pool)) ? mp_ptr(pool) : mp_grow_internal(pool, size);
+}
+
+/**
+ * Grow the buffer by at least one byte -- equivalent to <<mp_grow(),`mp_grow`>>`(@pool, @mp_avail(pool) + 1)`.
+ **/
+static inline void *mp_expand(struct mempool *pool)
+{
+  return mp_grow_internal(pool, mp_avail(pool) + 1);
+}
+
+/**
+ * Ensure that there is at least @size bytes free after @p,
+ * if not, reallocate and adjust @p.
+ **/
+static inline void *mp_spread(struct mempool *pool, void *p, size_t size)
+{
+  return (((size_t)((byte *)pool->state.last[pool->idx] - (byte *)p) >= size) ? p : mp_spread_internal(pool, p, size));
+}
+
+/**
+ * Append a character to the growing buffer. Called with @p pointing after
+ * the last byte in the buffer, returns a pointer after the last byte
+ * of the new (possibly reallocated) buffer.
+ **/
+static inline char *mp_append_char(struct mempool *pool, char *p, uint c)
+{
+  p = mp_spread(pool, p, 1);
+  *p++ = c;
+  return p;
+}
+
+/**
+ * Append a memory block to the growing buffer. Called with @p pointing after
+ * the last byte in the buffer, returns a pointer after the last byte
+ * of the new (possibly reallocated) buffer.
+ **/
+static inline void *mp_append_block(struct mempool *pool, void *p, const void *block, size_t size)
+{
+  char *q = mp_spread(pool, p, size);
+  memcpy(q, block, size);
+  return q + size;
+}
+
+/**
+ * Append a string to the growing buffer. Called with @p pointing after
+ * the last byte in the buffer, returns a pointer after the last byte
+ * of the new (possibly reallocated) buffer.
+ **/
+static inline void *mp_append_string(struct mempool *pool, void *p, const char *str)
+{
+  return mp_append_block(pool, p, str, strlen(str));
+}
+
+/**
+ * Close the growing buffer. The @end must point just behind the data, you want to keep
+ * allocated (so it can be in the interval `[@mp_ptr(@pool), @mp_ptr(@pool) + @mp_avail(@pool)]`).
+ * Returns a pointer to the beginning of the just closed block.
+ **/
+static inline void *mp_end(struct mempool *pool, void *end)
+{
+  void *p = mp_ptr(pool);
+  pool->state.free[pool->idx] = (byte *)pool->state.last[pool->idx] - (byte *)end;
+  return p;
+}
+
+/**
+ * Close the growing buffer as a string. That is, append a zero byte and call mp_end().
+ **/
+static inline char *mp_end_string(struct mempool *pool, void *end)
+{
+  end = mp_append_char(pool, end, 0);
+  return mp_end(pool, end);
+}
+
+/**
+ * Return size in bytes of the last allocated memory block (with @mp_alloc() or @mp_end()).
+ **/
+static inline size_t mp_size(struct mempool *pool, void *ptr)
+{
+  uint idx = mp_idx(pool, ptr);
+  return ((byte *)pool->state.last[idx] - (byte *)ptr) - pool->state.free[idx];
+}
+
+/**
+ * Open the last memory block (allocated with @mp_alloc() or @mp_end())
+ * for growing and return its size in bytes. The contents and the start pointer
+ * remain unchanged. Do not forget to call @mp_end() to close it.
+ **/
+size_t mp_open(struct mempool *pool, void *ptr);
+
+/**
+ * Inlined version of @mp_open().
+ **/
+static inline size_t mp_open_fast(struct mempool *pool, void *ptr)
+{
+  pool->idx = mp_idx(pool, ptr);
+  size_t size = ((byte *)pool->state.last[pool->idx] - (byte *)ptr) - pool->state.free[pool->idx];
+  pool->state.free[pool->idx] += size;
+  return size;
+}
+
+/**
+ * Reallocate the last memory block (allocated with @mp_alloc() or @mp_end())
+ * to the new @size. Behavior is similar to @mp_grow(), but the resulting
+ * block is closed.
+ **/
+void *mp_realloc(struct mempool *pool, void *ptr, size_t size);
+
+/**
+ * The same as @mp_realloc(), but fills the additional bytes (if any) with zeroes.
+ **/
+void *mp_realloc_zero(struct mempool *pool, void *ptr, size_t size);
+
+/**
+ * Inlined version of @mp_realloc().
+ **/
+static inline void *mp_realloc_fast(struct mempool *pool, void *ptr, size_t size)
+{
+  mp_open_fast(pool, ptr);
+  ptr = mp_grow(pool, size);
+  mp_end(pool, (byte *)ptr + size);
+  return ptr;
+}
+
+/***
+ * [[store]]
+ * Storing and restoring state
+ * ---------------------------
+ *
+ * Mempools can remember history of what was allocated and return back
+ * in time.
+ ***/
+
+/**
+ * Save the current state of a memory pool.
+ * Do not call this function with an opened growing buffer.
+ **/
+static inline void mp_save(struct mempool *pool, struct mempool_state *state)
+{
+  *state = pool->state;
+  pool->state.next = state;
+}
+
+/**
+ * Save the current state to a newly allocated mempool_state structure.
+ * Do not call this function with an opened growing buffer.
+ **/
+struct mempool_state *mp_push(struct mempool *pool);
+
+/**
+ * Restore the state saved by @mp_save() or @mp_push() and free all
+ * data allocated after that point (including the state structure itself).
+ * You can't reallocate the last memory block from the saved state.
+ **/
+void mp_restore(struct mempool *pool, struct mempool_state *state);
+
+/**
+ * Inlined version of @mp_restore().
+ **/
+static inline void mp_restore_fast(struct mempool *pool, struct mempool_state *state)
+{
+  if (pool->state.last[0] != state->last[0] || pool->state.last[1] != state->last[1])
+    mp_restore(pool, state);
+  else
+    {
+      pool->state = *state;
+      pool->last_big = &pool->last_big;
+    }
+}
+
+/**
+ * Restore the state saved by the last call to @mp_push().
+ * @mp_pop() and @mp_push() works as a stack so you can push more states safely.
+ **/
+void mp_pop(struct mempool *pool);
+
+
+/***
+ * [[string]]
+ * String operations
+ * -----------------
+ ***/
+
+char *mp_strdup(struct mempool *, const char *) LIKE_MALLOC;		/** Makes a copy of a string on a mempool. Returns NULL for NULL string. **/
+void *mp_memdup(struct mempool *, const void *, size_t) LIKE_MALLOC;	/** Makes a copy of a memory block on a mempool. **/
+/**
+ * Concatenates all passed strings. The last parameter must be NULL.
+ * This will concatenate two strings:
+ *
+ *   char *message = mp_multicat(pool, "hello ", "world", NULL);
+ **/
+char *mp_multicat(struct mempool *, ...) LIKE_MALLOC SENTINEL_CHECK;
+/**
+ * Concatenates two strings and stores result on @mp.
+ */
+static inline char *LIKE_MALLOC mp_strcat(struct mempool *mp, const char *x, const char *y)
+{
+  return mp_multicat(mp, x, y, NULL);
+}
+/**
+ * Join strings and place @sep between each two neighboring.
+ * @p is the mempool to provide memory, @a is array of strings and @n
+ * tells how many there is of them.
+ **/
+char *mp_strjoin(struct mempool *p, char **a, uint n, uint sep) LIKE_MALLOC;
+/**
+ * Convert memory block to a string. Makes a copy of the given memory block
+ * in the mempool @p, adding an extra terminating zero byte at the end.
+ **/
+char *mp_str_from_mem(struct mempool *p, const void *mem, size_t len) LIKE_MALLOC;
+
+
+/***
+ * [[format]]
+ * Formatted output
+ * ---------------
+ ***/
+
+/**
+ * printf() into a in-memory string, allocated on the memory pool.
+ **/
+char *mp_printf(struct mempool *mp, const char *fmt, ...) FORMAT_CHECK(printf,2,3) LIKE_MALLOC;
+/**
+ * Like @mp_printf(), but uses `va_list` for parameters.
+ **/
+char *mp_vprintf(struct mempool *mp, const char *fmt, va_list args) LIKE_MALLOC;
+/**
+ * Like @mp_printf(), but it appends the data at the end of string
+ * pointed to by @ptr. The string is @mp_open()ed, so you have to
+ * provide something that can be.
+ *
+ * Returns pointer to the beginning of the string (the pointer may have
+ * changed due to reallocation).
+ *
+ * In some versions of LibUCW, this function was called mp_append_printf(). However,
+ * this name turned out to be confusing -- unlike other appending functions, this one is
+ * not called on an opened growing buffer. The old name will be preserved for backward
+ * compatibility for the time being.
+ **/
+char *mp_printf_append(struct mempool *mp, char *ptr, const char *fmt, ...) FORMAT_CHECK(printf,3,4);
+#define mp_append_printf mp_printf_append
+/**
+ * Like @mp_printf_append(), but uses `va_list` for parameters.
+ *
+ * In some versions of LibUCW, this function was called mp_append_vprintf(). However,
+ * this name turned out to be confusing -- unlike other appending functions, this one is
+ * not called on an opened growing buffer. The old name will be preserved for backward
+ * compatibility for the time being.
+ **/
+char *mp_vprintf_append(struct mempool *mp, char *ptr, const char *fmt, va_list args);
+#define mp_append_vprintf mp_vprintf_append
+
+#endif