/************************************************************************
The memory management

(c) 1994, 1995 Innobase Oy

Created 6/8/1994 Heikki Tuuri
*************************************************************************/

#include "mem0dbg.ic"

#include "mem0pool.h"

/*******************************************************************
Creates a memory heap block where data can be allocated. */

mem_block_t*
mem_heap_create_block(
/*==================*/
				/* out, own: memory heap block, NULL if
				did not succeed (only possible for
				MEM_HEAP_BTR_SEARCH type heaps) */
	mem_heap_t*	heap,	/* in: memory heap or NULL if first block
				should be created */
	ulint		n,	/* in: number of bytes needed for user data, or
				if init_block is not NULL, its size in bytes */
	void*		init_block, /* in: init block in fast create,
				type must be MEM_HEAP_DYNAMIC */
	ulint		type,	/* in: type of heap: MEM_HEAP_DYNAMIC or
				MEM_HEAP_BUFFER */
	const char*	file_name,/* in: file name where created */
	ulint		line);	/* in: line where created */
/**********************************************************************
Frees a block from a memory heap. */

void
mem_heap_block_free(
/*================*/
	mem_heap_t*	heap,	/* in: heap */
	mem_block_t*	block);	/* in: block to free */
/**********************************************************************
Frees the free_block field from a memory heap. */

void
mem_heap_free_block_free(
/*=====================*/
	mem_heap_t*	heap);	/* in: heap */
/*******************************************************************
Adds a new block to a memory heap. */

mem_block_t*
mem_heap_add_block(
/*===============*/
				/* out: created block, NULL if did not
				succeed (only possible for
				MEM_HEAP_BTR_SEARCH type heaps)*/
	mem_heap_t*	heap,	/* in: memory heap */
	ulint		n);	/* in: number of bytes user needs */

UNIV_INLINE
void
mem_block_set_len(mem_block_t* block, ulint len)
{
	ut_ad(len > 0);

	block->len = len;
}

UNIV_INLINE
ulint
mem_block_get_len(mem_block_t* block)
{
	return(block->len);
}

UNIV_INLINE
void
mem_block_set_type(mem_block_t* block, ulint type)
{
	ut_ad((type == MEM_HEAP_DYNAMIC) || (type == MEM_HEAP_BUFFER)
	      || (type == MEM_HEAP_BUFFER + MEM_HEAP_BTR_SEARCH));

	block->type = type;
}

UNIV_INLINE
ulint
mem_block_get_type(mem_block_t* block)
{
	return(block->type);
}

UNIV_INLINE
void
mem_block_set_free(mem_block_t* block, ulint free)
{
	ut_ad(free > 0);
	ut_ad(free <= mem_block_get_len(block));

	block->free = free;
}

UNIV_INLINE
ulint
mem_block_get_free(mem_block_t* block)
{
	return(block->free);
}

UNIV_INLINE
void
mem_block_set_start(mem_block_t* block, ulint start)
{
	ut_ad(start > 0);

	block->start = start;
}

UNIV_INLINE
ulint
mem_block_get_start(mem_block_t* block)
{
	return(block->start);
}

/*******************************************************************
Allocates n bytes of memory from a memory heap. */
UNIV_INLINE
void*
mem_heap_alloc(
/*===========*/
				/* out: allocated storage, NULL if did not
				succeed (only possible for
				MEM_HEAP_BTR_SEARCH type heaps) */
	mem_heap_t*	heap,	/* in: memory heap */
	ulint		n)	/* in: number of bytes; if the heap is allowed
				to grow into the buffer pool, this must be
				<= MEM_MAX_ALLOC_IN_BUF */
{
	mem_block_t*	block;
	void*		buf;
	ulint		free;

	ut_ad(mem_heap_check(heap));

	block = UT_LIST_GET_LAST(heap->base);

	ut_ad(!(block->type & MEM_HEAP_BUFFER) || (n <= MEM_MAX_ALLOC_IN_BUF));

	/* Check if there is enough space in block. If not, create a new
	block to the heap */

	if (mem_block_get_len(block)
	    < mem_block_get_free(block) + MEM_SPACE_NEEDED(n)) {

		block = mem_heap_add_block(heap, n);

		if (block == NULL) {

			return(NULL);
		}
	}

	free = mem_block_get_free(block);

	buf = (byte*)block + free;

	mem_block_set_free(block, free + MEM_SPACE_NEEDED(n));

#ifdef UNIV_MEM_DEBUG
	UNIV_MEM_ALLOC(buf,
		       n + MEM_FIELD_HEADER_SIZE + MEM_FIELD_TRAILER_SIZE);

	/* In the debug version write debugging info to the field */
	mem_field_init((byte*)buf, n);

	/* Advance buf to point at the storage which will be given to the
	caller */
	buf = (byte*)buf + MEM_FIELD_HEADER_SIZE;

#endif
#ifdef UNIV_SET_MEM_TO_ZERO
	UNIV_MEM_ALLOC(buf, n);
	memset(buf, '\0', n);
#endif
	UNIV_MEM_ALLOC(buf, n);
	return(buf);
}

/*********************************************************************
Returns a pointer to the heap top. */
UNIV_INLINE
byte*
mem_heap_get_heap_top(
/*==================*/
				/* out: pointer to the heap top */
	mem_heap_t*	heap)	/* in: memory heap */
{
	mem_block_t*	block;
	byte*		buf;

	ut_ad(mem_heap_check(heap));

	block = UT_LIST_GET_LAST(heap->base);

	buf = (byte*)block + mem_block_get_free(block);

	return(buf);
}

/*********************************************************************
Frees the space in a memory heap exceeding the pointer given. The
pointer must have been acquired from mem_heap_get_heap_top. The first
memory block of the heap is not freed. */
UNIV_INLINE
void
mem_heap_free_heap_top(
/*===================*/
	mem_heap_t*	heap,	/* in: heap from which to free */
	byte*		old_top)/* in: pointer to old top of heap */
{
	mem_block_t*	block;
	mem_block_t*	prev_block;
#ifdef UNIV_MEM_DEBUG
	ibool		error;
	ulint		total_size;
	ulint		size;
#endif

	ut_ad(mem_heap_check(heap));

#ifdef UNIV_MEM_DEBUG

	/* Validate the heap and get its total allocated size */
	mem_heap_validate_or_print(heap, NULL, FALSE, &error, &total_size,
				   NULL, NULL);
	ut_a(!error);

	/* Get the size below top pointer */
	mem_heap_validate_or_print(heap, old_top, FALSE, &error, &size, NULL,
				   NULL);
	ut_a(!error);

#endif

	block = UT_LIST_GET_LAST(heap->base);

	while (block != NULL) {
		if (((byte*)block + mem_block_get_free(block) >= old_top)
		    && ((byte*)block <= old_top)) {
			/* Found the right block */

			break;
		}

		/* Store prev_block value before freeing the current block
		(the current block will be erased in freeing) */

		prev_block = UT_LIST_GET_PREV(list, block);

		mem_heap_block_free(heap, block);

		block = prev_block;
	}

	ut_ad(block);

	/* Set the free field of block */
	mem_block_set_free(block, old_top - (byte*)block);

#ifdef UNIV_MEM_DEBUG
	ut_ad(mem_block_get_start(block) <= mem_block_get_free(block));

	/* In the debug version erase block from top up */

	mem_erase_buf(old_top, (byte*)block + block->len - old_top);

	/* Update allocated memory count */
	mutex_enter(&mem_hash_mutex);
	mem_current_allocated_memory -= (total_size - size);
	mutex_exit(&mem_hash_mutex);

#endif

	/* If free == start, we may free the block if it is not the first
	one */

	if ((heap != block) && (mem_block_get_free(block)
				== mem_block_get_start(block))) {
		mem_heap_block_free(heap, block);
	}
}

/*********************************************************************
Empties a memory heap. The first memory block of the heap is not freed. */
UNIV_INLINE
void
mem_heap_empty(
/*===========*/
	mem_heap_t*	heap)	/* in: heap to empty */
{
	mem_heap_free_heap_top(heap, (byte*)heap + mem_block_get_start(heap));

	if (heap->free_block) {
		mem_heap_free_block_free(heap);
	}
}

/*********************************************************************
Returns a pointer to the topmost element in a memory heap. The size of the
element must be given. */
UNIV_INLINE
void*
mem_heap_get_top(
/*=============*/
				/* out: pointer to the topmost element */
	mem_heap_t*	heap,	/* in: memory heap */
	ulint		n)	/* in: size of the topmost element */
{
	mem_block_t*	block;
	void*		buf;

	ut_ad(mem_heap_check(heap));

	block = UT_LIST_GET_LAST(heap->base);

	buf = (byte*)block + mem_block_get_free(block) - MEM_SPACE_NEEDED(n);

#ifdef UNIV_MEM_DEBUG
	ut_ad(mem_block_get_start(block) <=(ulint)((byte*)buf - (byte*)block));

	/* In the debug version, advance buf to point at the storage which
	was given to the caller in the allocation*/

	buf = (byte*)buf + MEM_FIELD_HEADER_SIZE;

	/* Check that the field lengths agree */
	ut_ad(n == (ulint)mem_field_header_get_len(buf));
#endif

	return(buf);
}

/*********************************************************************
Frees the topmost element in a memory heap. The size of the element must be
given. */
UNIV_INLINE
void
mem_heap_free_top(
/*==============*/
	mem_heap_t*	heap,	/* in: memory heap */
	ulint		n)	/* in: size of the topmost element */
{
	mem_block_t*	block;

	ut_ad(mem_heap_check(heap));

	block = UT_LIST_GET_LAST(heap->base);

	/* Subtract the free field of block */
	mem_block_set_free(block, mem_block_get_free(block)
			   - MEM_SPACE_NEEDED(n));
#ifdef UNIV_MEM_DEBUG

	ut_ad(mem_block_get_start(block) <= mem_block_get_free(block));

	/* In the debug version check the consistency, and erase field */
	mem_field_erase((byte*)block + mem_block_get_free(block), n);
#endif

	/* If free == start, we may free the block if it is not the first
	one */

	if ((heap != block) && (mem_block_get_free(block)
				== mem_block_get_start(block))) {
		mem_heap_block_free(heap, block);
	} else {
		UNIV_MEM_FREE((byte*) block + mem_block_get_free(block), n);
	}
}

/*********************************************************************
NOTE: Use the corresponding macros instead of this function. Creates a
memory heap. For debugging purposes, takes also the file name and line as
argument. */
UNIV_INLINE
mem_heap_t*
mem_heap_create_func(
/*=================*/
					/* out, own: memory heap, NULL if
					did not succeed (only possible for
					MEM_HEAP_BTR_SEARCH type heaps)*/
	ulint		n,		/* in: desired start block size,
					this means that a single user buffer
					of size n will fit in the block,
					0 creates a default size block;
					if init_block is not NULL, n tells
					its size in bytes */
	void*		init_block,	/* in: if very fast creation is
					wanted, the caller can reserve some
					memory from its stack, for example,
					and pass it as the the initial block
					to the heap: then no OS call of malloc
					is needed at the creation. CAUTION:
					the caller must make sure the initial
					block is not unintentionally erased
					(if allocated in the stack), before
					the memory heap is explicitly freed. */
	ulint		type,		/* in: heap type */
	const char*	file_name,	/* in: file name where created */
	ulint		line)		/* in: line where created */
{
	mem_block_t*   block;

	if (n > 0) {
		block = mem_heap_create_block(NULL, n, init_block, type,
					      file_name, line);
	} else {
		block = mem_heap_create_block(NULL, MEM_BLOCK_START_SIZE,
					      init_block, type,
					      file_name, line);
	}

	if (block == NULL) {

		return(NULL);
	}

	UT_LIST_INIT(block->base);

	/* Add the created block itself as the first block in the list */
	UT_LIST_ADD_FIRST(list, block->base, block);

#ifdef UNIV_MEM_DEBUG

	mem_hash_insert(block, file_name, line);

#endif

	return(block);
}

/*********************************************************************
NOTE: Use the corresponding macro instead of this function. Frees the space
occupied by a memory heap. In the debug version erases the heap memory
blocks. */
UNIV_INLINE
void
mem_heap_free_func(
/*===============*/
	mem_heap_t*	heap,		/* in, own: heap to be freed */
	const char*	file_name __attribute__((unused)),
					/* in: file name where freed */
	ulint		line  __attribute__((unused)))
{
	mem_block_t*	block;
	mem_block_t*	prev_block;

	ut_ad(mem_heap_check(heap));

	block = UT_LIST_GET_LAST(heap->base);

#ifdef UNIV_MEM_DEBUG

	/* In the debug version remove the heap from the hash table of heaps
	and check its consistency */

	mem_hash_remove(heap, file_name, line);

#endif

	if (heap->free_block) {
		mem_heap_free_block_free(heap);
	}

	while (block != NULL) {
		/* Store the contents of info before freeing current block
		(it is erased in freeing) */

		prev_block = UT_LIST_GET_PREV(list, block);

		mem_heap_block_free(heap, block);

		block = prev_block;
	}
}

/*******************************************************************
NOTE: Use the corresponding macro instead of this function.
Allocates a single buffer of memory from the dynamic memory of
the C compiler. Is like malloc of C. The buffer must be freed
with mem_free. */
UNIV_INLINE
void*
mem_alloc_func(
/*===========*/
					/* out, own: free storage */
	ulint		n,		/* in: desired number of bytes */
	const char*	file_name,	/* in: file name where created */
	ulint		line		/* in: line where created */
	)
{
	mem_heap_t*	heap;
	void*		buf;

	heap = mem_heap_create_func(n, NULL, MEM_HEAP_DYNAMIC, file_name,
				    line);

	/* Note that as we created the first block in the heap big enough
	for the buffer requested by the caller, the buffer will be in the
	first block and thus we can calculate the pointer to the heap from
	the pointer to the buffer when we free the memory buffer. */

	buf = mem_heap_alloc(heap, n);

	ut_a((byte*)heap == (byte*)buf - MEM_BLOCK_HEADER_SIZE
	     - MEM_FIELD_HEADER_SIZE);
	return(buf);
}

/*******************************************************************
NOTE: Use the corresponding macro instead of this function. Frees a single
buffer of storage from the dynamic memory of the C compiler. Similar to the
free of C. */
UNIV_INLINE
void
mem_free_func(
/*==========*/
	void*		ptr,		/* in, own: buffer to be freed */
	const char*	file_name,	/* in: file name where created */
	ulint		line		/* in: line where created */
	)
{
	mem_heap_t*   heap;

	heap = (mem_heap_t*)((byte*)ptr - MEM_BLOCK_HEADER_SIZE
			     - MEM_FIELD_HEADER_SIZE);
	mem_heap_free_func(heap, file_name, line);
}

/*********************************************************************
Returns the space in bytes occupied by a memory heap. */
UNIV_INLINE
ulint
mem_heap_get_size(
/*==============*/
	mem_heap_t*	heap)	/* in: heap */
{
	mem_block_t*	block;
	ulint		size	= 0;

	ut_ad(mem_heap_check(heap));

	block = heap;

	while (block != NULL) {

		size += mem_block_get_len(block);
		block = UT_LIST_GET_NEXT(list, block);
	}

	if (heap->free_block) {
		size += UNIV_PAGE_SIZE;
	}

	return(size);
}

/**************************************************************************
Duplicates a NUL-terminated string. */
UNIV_INLINE
char*
mem_strdup(
/*=======*/
				/* out, own: a copy of the string,
				must be deallocated with mem_free */
	const char*	str)	/* in: string to be copied */
{
	ulint	len = strlen(str) + 1;
	return(memcpy(mem_alloc(len), str, len));
}

/**************************************************************************
Makes a NUL-terminated copy of a nonterminated string. */
UNIV_INLINE
char*
mem_strdupl(
/*========*/
				/* out, own: a copy of the string,
				must be deallocated with mem_free */
	const char*	str,	/* in: string to be copied */
	ulint		len)	/* in: length of str, in bytes */
{
	char*	s = mem_alloc(len + 1);
	s[len] = 0;
	return(memcpy(s, str, len));
}

/**************************************************************************
Makes a NUL-terminated copy of a nonterminated string,
allocated from a memory heap. */
UNIV_INLINE
char*
mem_heap_strdupl(
/*=============*/
				/* out, own: a copy of the string */
	mem_heap_t*	heap,	/* in: memory heap where string is allocated */
	const char*	str,	/* in: string to be copied */
	ulint		len)	/* in: length of str, in bytes */
{
	char*	s = mem_heap_alloc(heap, len + 1);
	s[len] = 0;
	return(memcpy(s, str, len));
}
