/*****************************************************************************

Copyright (c) 1994, 2018, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License, version 2.0, as published by the
Free Software Foundation.

This program is also distributed with certain software (including but not
limited to OpenSSL) that is licensed under separate terms, as designated in a
particular file or component or in included license documentation. The authors
of MySQL hereby grant you an additional permission to link the program and
your derivative works with the separately licensed software that they have
included with MySQL.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

*****************************************************************************/

/** @file include/mem0mem.ic
 The memory management

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

#include "ut0new.h"

#ifdef UNIV_DEBUG
#define mem_heap_create_block(heap, n, type, file_name, line) \
  mem_heap_create_block_func(heap, n, file_name, line, type)
#define mem_heap_create_at(N, file_name, line) \
  mem_heap_create_func(N, file_name, line, MEM_HEAP_DYNAMIC)
#else /* UNIV_DEBUG */
#define mem_heap_create_block(heap, n, type, file_name, line) \
  mem_heap_create_block_func(heap, n, type)
#define mem_heap_create_at(N, file_name, line) \
  mem_heap_create_func(N, MEM_HEAP_DYNAMIC)
#endif /* UNIV_DEBUG */
/** Creates a memory heap block where data can be allocated.
 @return own: memory heap block, NULL if did not succeed (only possible
 for MEM_HEAP_BTR_SEARCH type heaps) */
mem_block_t *mem_heap_create_block_func(
    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 */
#ifdef UNIV_DEBUG
    const char *file_name, /*!< in: file name where created */
    ulint line,            /*!< in: line where created */
#endif                     /* UNIV_DEBUG */
    ulint type);           /*!< in: type of heap: MEM_HEAP_DYNAMIC or
                           MEM_HEAP_BUFFER */

/** 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 */

#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
/** Frees the free_block field from a memory heap. */
void mem_heap_free_block_free(mem_heap_t *heap); /*!< in: heap */
#endif                                           /* !UNIV_LIBRARY */
#endif                                           /* !UNIV_HOTBACKUP */

/** Adds a new block to a memory heap.
 @param[in]	heap	memory heap
 @param[in]	n	number of bytes needed
 @return created block, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
mem_block_t *mem_heap_add_block(mem_heap_t *heap, ulint n);

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 >= block->start);
  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); }

/** Checks that an object is a memory heap block
@param[in]	block	Memory block to check. */
UNIV_INLINE
void mem_block_validate(const mem_block_t *block) {
  if (block->magic_n != MEM_BLOCK_MAGIC_N) {
    ib::fatal error;
    error << "Memory block is invalid (correctness field value"
             " should be "
          << MEM_BLOCK_MAGIC_N << ", but it is " << block->magic_n
          << ") in a block of size " << block->len;
    ut_d(error << ", allocated at " << block->file_name << ":" << block->line);
  }
}

/** Allocates and zero-fills n bytes of memory from a memory heap.
@param[in]	heap	memory heap
@param[in]	n	number of bytes; if the heap is allowed to grow into
the buffer pool, this must be <= MEM_MAX_ALLOC_IN_BUF
@return allocated, zero-filled storage */
UNIV_INLINE
void *mem_heap_zalloc(mem_heap_t *heap, ulint n) {
  ut_ad(heap);
  ut_ad(!(heap->type & MEM_HEAP_BTR_SEARCH));
  return (memset(mem_heap_alloc(heap, n), 0, n));
}

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

  ut_d(mem_block_validate(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_NO_MANS_LAND;

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

  ut_ad(mem_block_get_len(block) >= mem_block_get_free(block));

  UNIV_MEM_ALLOC(buf - MEM_NO_MANS_LAND, MEM_SPACE_NEEDED(n));

#ifdef UNIV_DEBUG
  byte *start_no_mans_land = buf - MEM_NO_MANS_LAND;
  byte *end_no_mans_land =
      start_no_mans_land + MEM_SPACE_NEEDED(n) - MEM_NO_MANS_LAND;
  memset(start_no_mans_land, MEM_NO_MANS_LAND_BEFORE_BYTE, MEM_NO_MANS_LAND);
  UNIV_MEM_FREE(start_no_mans_land, MEM_NO_MANS_LAND);

  memset(end_no_mans_land, MEM_NO_MANS_LAND_AFTER_BYTE, MEM_NO_MANS_LAND);
  UNIV_MEM_FREE(end_no_mans_land, MEM_NO_MANS_LAND);
#endif

  return (buf);
}

#ifdef UNIV_DEBUG
UNIV_INLINE
void validate_no_mans_land(byte *no_mans_land_begin,
                           byte mem_no_mans_land_byte) {
  UNIV_MEM_VALID(no_mans_land_begin, MEM_NO_MANS_LAND);
  for (byte *no_mans_land_it = no_mans_land_begin;
       no_mans_land_it < no_mans_land_begin + MEM_NO_MANS_LAND;
       ++no_mans_land_it) {
    ut_a(*no_mans_land_it == mem_no_mans_land_byte);
  }
}
#endif

/** Returns a pointer to the heap top.
@param[in]	heap	memory heap
@return pointer to the heap top */
UNIV_INLINE
byte *mem_heap_get_heap_top(mem_heap_t *heap) {
  mem_block_t *block;
  byte *buf;

  ut_d(mem_block_validate(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.
@param[in]	heap		heap from which to free
@param[in]	old_top		pointer to old top of heap */
UNIV_INLINE
void mem_heap_free_heap_top(mem_heap_t *heap, byte *old_top) {
  mem_block_t *block;
  mem_block_t *prev_block;

  ut_d(mem_heap_validate(heap));

  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);

  if (old_top == (byte *)block + mem_block_get_free(block)) {
    return;
  }

#ifdef UNIV_DEBUG
  validate_no_mans_land(old_top, MEM_NO_MANS_LAND_BEFORE_BYTE);
  validate_no_mans_land(
      (byte *)block + mem_block_get_free(block) - MEM_NO_MANS_LAND,
      MEM_NO_MANS_LAND_AFTER_BYTE);
#endif
  /* Set the free field of block */
  mem_block_set_free(block, old_top - (byte *)block);

  ut_ad(mem_block_get_start(block) <= mem_block_get_free(block));
  UNIV_MEM_FREE(old_top, (byte *)block + block->len - old_top);

  /* 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.
@param[in]	heap	heap to empty */
UNIV_INLINE
void mem_heap_empty(mem_heap_t *heap) {
  mem_heap_free_heap_top(heap, (byte *)heap + mem_block_get_start(heap));
#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
  if (heap->free_block) {
    mem_heap_free_block_free(heap);
  }
#endif /* !UNIV_LIBRARY */
#endif /* !UNIV_HOTBACKUP */
}

/** Returns a pointer to the topmost element in a memory heap.
The size of the element must be given.
@param[in]	heap	memory heap
@param[in]	n	size of the topmost element
@return pointer to the topmost element */
UNIV_INLINE
void *mem_heap_get_top(mem_heap_t *heap, ulint n) {
  mem_block_t *block;
  byte *buf;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

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

  return ((void *)buf);
}

/** Checks if a given chunk of memory is the topmost element stored in the
heap. If this is the case, then calling mem_heap_free_top() would free
that element from the heap.
@param[in]	heap	memory heap
@param[in]	buf	presumed topmost element
@param[in]	buf_sz	size of buf in bytes
@return true if topmost */
UNIV_INLINE
bool mem_heap_is_top(mem_heap_t *heap, const void *buf, ulint buf_sz) {
  const byte *first_free_byte;
  const byte *presumed_start_of_buf;

  ut_d(mem_block_validate(heap));

  first_free_byte = mem_heap_get_heap_top(heap);

  presumed_start_of_buf =
      first_free_byte - MEM_SPACE_NEEDED(buf_sz) + MEM_NO_MANS_LAND;

  return (presumed_start_of_buf == buf);
}

/** Allocate a new chunk of memory from a memory heap, possibly discarding
 the topmost element. If the memory chunk specified with (top, top_sz)
 is the topmost element, then it will be discarded, otherwise it will
 be left untouched and this function will be equivallent to
 mem_heap_alloc().
 @return allocated storage, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
void *mem_heap_replace(mem_heap_t *heap, /*!< in/out: memory heap */
                       const void *top, /*!< in: chunk to discard if possible */
                       ulint top_sz,    /*!< in: size of top in bytes */
                       ulint new_sz) /*!< in: desired size of the new chunk */
{
  if (mem_heap_is_top(heap, top, top_sz)) {
    mem_heap_free_top(heap, top_sz);
  }

  return (mem_heap_alloc(heap, new_sz));
}

/** Allocate a new chunk of memory from a memory heap, possibly discarding
 the topmost element and then copy the specified data to it. If the memory
 chunk specified with (top, top_sz) is the topmost element, then it will be
 discarded, otherwise it will be left untouched and this function will be
 equivallent to mem_heap_dup().
 @return allocated storage, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
void *mem_heap_dup_replace(
    mem_heap_t *heap, /*!< in/out: memory heap */
    const void *top,  /*!< in: chunk to discard if possible */
    ulint top_sz,     /*!< in: size of top in bytes */
    const void *data, /*!< in: new data to duplicate */
    ulint data_sz)    /*!< in: size of data in bytes */
{
  void *p = mem_heap_replace(heap, top, top_sz, data_sz);

  memcpy(p, data, data_sz);

  return (p);
}

/** Allocate a new chunk of memory from a memory heap, possibly discarding
 the topmost element and then copy the specified string to it. If the memory
 chunk specified with (top, top_sz) is the topmost element, then it will be
 discarded, otherwise it will be left untouched and this function will be
 equivallent to mem_heap_strdup().
 @return allocated string, NULL if did not succeed (only possible for
 MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
char *mem_heap_strdup_replace(
    mem_heap_t *heap, /*!< in/out: memory heap */
    const void *top,  /*!< in: chunk to discard if possible */
    ulint top_sz,     /*!< in: size of top in bytes */
    const char *str)  /*!< in: new data to duplicate */
{
  return (reinterpret_cast<char *>(
      mem_heap_dup_replace(heap, top, top_sz, str, strlen(str) + 1)));
}

/** 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_d(mem_block_validate(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));
  UNIV_MEM_ASSERT_W(
      (byte *)block + mem_block_get_free(block) + MEM_NO_MANS_LAND, n);
#ifdef UNIV_DEBUG
  validate_no_mans_land((byte *)block + mem_block_get_free(block),
                        MEM_NO_MANS_LAND_BEFORE_BYTE);
  validate_no_mans_land((byte *)block + mem_block_get_free(block) +
                            MEM_SPACE_NEEDED(n) - MEM_NO_MANS_LAND,
                        MEM_NO_MANS_LAND_AFTER_BYTE);
#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),
                  MEM_SPACE_NEEDED(n));
  }
}

/** Creates a memory heap.
NOTE: Use the corresponding macros instead of this function.
A single user buffer of 'size' will fit in the block.
0 creates a default size block.
@param[in]	size		Desired start block size.
@param[in]	file_name	File name where created
@param[in]	line		Line where created
@param[in]	type		Heap type
@return own: memory heap, NULL if did not succeed (only possible for
MEM_HEAP_BTR_SEARCH type heaps) */
UNIV_INLINE
mem_heap_t *mem_heap_create_func(ulint size,
#ifdef UNIV_DEBUG
                                 const char *file_name, ulint line,
#endif /* UNIV_DEBUG */
                                 ulint type) {
  mem_block_t *block;

  if (!size) {
    size = MEM_BLOCK_START_SIZE;
  }

  block = mem_heap_create_block(NULL, size, type, file_name, line);

  if (block == NULL) {
    return (NULL);
  }

#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
  /* The first block should not be in buffer pool,
  because it might be relocated to resize buffer pool. */
  ut_ad(block->buf_block == NULL);
#endif /* !UNIV_LIBRARY */
#endif /* UNIV_HOTBACKUP */

  UT_LIST_INIT(block->base, &mem_block_t::list);

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

  return (block);
}

/** Frees the space occupied by a memory heap.
NOTE: Use the corresponding macro instead of this function.
@param[in]	heap	Heap to be freed */
UNIV_INLINE
void mem_heap_free(mem_heap_t *heap) {
  mem_block_t *block;
  mem_block_t *prev_block;

  ut_d(mem_block_validate(heap));

  block = UT_LIST_GET_LAST(heap->base);

#ifndef UNIV_HOTBACKUP
#ifndef UNIV_LIBRARY
  if (heap->free_block) {
    mem_heap_free_block_free(heap);
  }
#endif /* !UNIV_LIBRARY */
#endif /* !UNIV_HOTBACKUP */

  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;
  }
}

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

  ut_d(mem_block_validate(heap));

  size = heap->total_size;

#ifndef UNIV_LIBRARY
  if (heap->free_block) {
    size += UNIV_PAGE_SIZE;
  }
#endif /* !UNIV_LIBRARY */

  return (size);
}

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

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

/** Makes a NUL-terminated copy of a nonterminated string,
 allocated from a memory heap.
 @return own: a copy of the string */
UNIV_INLINE
char *mem_heap_strdupl(
    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 = (char *)mem_heap_alloc(heap, len + 1);
  s[len] = 0;
  if (len > 0) {
    memcpy(s, str, len);
  }
  return s;
}