heap.h

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/*
 *  COPYRIGHT (c) 1989-2006.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.org/license/LICENSE.
 */

#ifndef _RTEMS_SCORE_HEAP_H
#define _RTEMS_SCORE_HEAP_H

#include <rtems/score/cpu.h>
#include <rtems/score/heapinfo.h>

#ifdef __cplusplus
extern "C" {
#endif

#ifdef RTEMS_DEBUG
  #define HEAP_PROTECTION
#endif

typedef struct Heap_Control Heap_Control;

typedef struct Heap_Block Heap_Block;

typedef enum {
  HEAP_ERROR_BROKEN_PROTECTOR,

  HEAP_ERROR_FREE_PATTERN,

  HEAP_ERROR_DOUBLE_FREE,

  HEAP_ERROR_BAD_USED_BLOCK,

  HEAP_ERROR_BAD_FREE_BLOCK
} Heap_Error_reason;

typedef struct {
  Heap_Control *heap;

  Heap_Block *block;

  Heap_Error_reason reason;
} Heap_Error_context;

#ifndef HEAP_PROTECTION
  #define HEAP_PROTECTION_HEADER_SIZE 0
#else
  #define HEAP_PROTECTOR_COUNT 2

  #define HEAP_BEGIN_PROTECTOR_0 ((uintptr_t) 0xfd75a98f)
  #define HEAP_BEGIN_PROTECTOR_1 ((uintptr_t) 0xbfa1f177)
  #define HEAP_END_PROTECTOR_0 ((uintptr_t) 0xd6b8855e)
  #define HEAP_END_PROTECTOR_1 ((uintptr_t) 0x13a44a5b)

  #define HEAP_FREE_PATTERN ((uintptr_t) 0xe7093cdf)

  #define HEAP_PROTECTION_OBOLUS ((Heap_Block *) 1)

  typedef void (*_Heap_Protection_handler)(
     Heap_Control *heap,
     Heap_Block *block
  );

  typedef void (*_Heap_Protection_error_handler)(
     Heap_Control *heap,
     Heap_Block *block,
     Heap_Error_reason reason
  );

  typedef struct {
    _Heap_Protection_handler block_initialize;
    _Heap_Protection_handler block_check;
    _Heap_Protection_error_handler block_error;
    void *handler_data;
    Heap_Block *first_delayed_free_block;
    Heap_Block *last_delayed_free_block;
    uintptr_t delayed_free_block_count;
    uintptr_t delayed_free_fraction;
  } Heap_Protection;

  struct _Thread_Control;

  typedef struct {
    uintptr_t protector [HEAP_PROTECTOR_COUNT];
    Heap_Block *next_delayed_free_block;
    struct _Thread_Control *task;
    void *tag;
  } Heap_Protection_block_begin;

  typedef struct {
    uintptr_t protector [HEAP_PROTECTOR_COUNT];
  } Heap_Protection_block_end;

  #define HEAP_PROTECTION_HEADER_SIZE \
    (sizeof(Heap_Protection_block_begin) + sizeof(Heap_Protection_block_end))
#endif

#define HEAP_BLOCK_HEADER_SIZE \
  (2 * sizeof(uintptr_t) + HEAP_PROTECTION_HEADER_SIZE)

struct Heap_Block {
  uintptr_t prev_size;

  #ifdef HEAP_PROTECTION
    Heap_Protection_block_begin Protection_begin;
  #endif

  uintptr_t size_and_flag;

  #ifdef HEAP_PROTECTION
    Heap_Protection_block_end Protection_end;
  #endif

  Heap_Block *next;

  Heap_Block *prev;
};

struct Heap_Control {
  Heap_Block free_list;
  uintptr_t page_size;
  uintptr_t min_block_size;
  uintptr_t area_begin;
  uintptr_t area_end;
  Heap_Block *first_block;
  Heap_Block *last_block;
  Heap_Statistics stats;
  #ifdef HEAP_PROTECTION
    Heap_Protection Protection;
  #endif
};

typedef struct {
  void *begin;
  uintptr_t size;
} Heap_Area;

typedef uintptr_t (*Heap_Initialization_or_extend_handler)(
  Heap_Control *heap,
  void *area_begin,
  uintptr_t area_size,
  uintptr_t page_size_or_unused
);

uintptr_t _Heap_Extend(
  Heap_Control *heap,
  void *area_begin,
  uintptr_t area_size,
  uintptr_t unused
);

uintptr_t _Heap_No_extend(
  Heap_Control *unused_0,
  void *unused_1,
  uintptr_t unused_2,
  uintptr_t unused_3
);

RTEMS_INLINE_ROUTINE uintptr_t _Heap_Align_up(
  uintptr_t value,
  uintptr_t alignment
)
{
  uintptr_t remainder = value % alignment;

  if ( remainder != 0 ) {
    return value - remainder + alignment;
  } else {
    return value;
  }
}

RTEMS_INLINE_ROUTINE uintptr_t _Heap_Min_block_size( uintptr_t page_size )
{
  return _Heap_Align_up( sizeof( Heap_Block ), page_size );
}

RTEMS_INLINE_ROUTINE uintptr_t _Heap_Area_overhead(
  uintptr_t page_size
)
{
  if ( page_size != 0 ) {
    page_size = _Heap_Align_up( page_size, CPU_ALIGNMENT );
  } else {
    page_size = CPU_ALIGNMENT;
  }

  return 2 * (page_size - 1) + HEAP_BLOCK_HEADER_SIZE;
}

RTEMS_INLINE_ROUTINE uintptr_t _Heap_Size_with_overhead(
  uintptr_t page_size,
  uintptr_t size,
  uintptr_t alignment
)
{
  if ( page_size != 0 ) {
    page_size = _Heap_Align_up( page_size, CPU_ALIGNMENT );
  } else {
    page_size = CPU_ALIGNMENT;
  }

  if ( page_size < alignment ) {
    page_size = alignment;
  }

  return HEAP_BLOCK_HEADER_SIZE + page_size - 1 + size;
}

#ifdef __cplusplus
}
#endif

#endif
/* end of include file */