/****************************************************************************
*
*    Copyright (c) 2017 - 2021 VeriSilicon Inc. All Rights Reserved.
*    Copyright (c) 2007 - 2016 Intel Corporation. All Rights Reserved.
*
*    Permission is hereby granted, free of charge, to any person obtaining
*    a copy of this software and associated documentation files (the
*    'Software'), to deal in the Software without restriction, including
*    without limitation the rights to use, copy, modify, merge, publish,
*    distribute, sub license, and/or sell copies of the Software, and to
*    permit persons to whom the Software is furnished to do so, subject
*    to the following conditions:
*
*    The above copyright notice and this permission notice (including the
*    next paragraph) shall be included in all copies or substantial
*    portions of the Software.
*
*    THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
*    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
*    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
*    IN NO EVENT SHALL VIVANTE AND/OR ITS SUPPLIERS BE LIABLE FOR ANY
*    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
*    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
*    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*****************************************************************************/
#include "object_heap.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "vsi_daemon_debug.h"

#define LAST_FREE -1
#define ALLOCATED -2

/*
 * Expands the heap
 * Return 0 on success, -1 on error
 */
static int object_heap_expand(object_heap_p heap) {
  int i;
  void *new_heap_index;
  int next_free;
  int new_heap_size = heap->heap_size + heap->heap_increment;
  int bucket_index = new_heap_size / heap->heap_increment - 1;

  if (bucket_index >= heap->num_buckets) {
    int new_num_buckets = heap->num_buckets + 8;
    void **new_bucket;

    new_bucket = realloc(heap->bucket, new_num_buckets * sizeof(void *));
    if (NULL == new_bucket) {
      return -1;
    }

    heap->num_buckets = new_num_buckets;
    heap->bucket = new_bucket;
  }

  if (!heap->bucket) {
    return -1;
  }

  new_heap_index = (void *)malloc(heap->heap_increment * heap->object_size);
  if (NULL == new_heap_index) {
    return -1; /* Out of memory */
  }

  heap->bucket[bucket_index] = new_heap_index;
  next_free = heap->next_free;
  for (i = new_heap_size; i-- > heap->heap_size;) {
    object_base_p obj = (object_base_p)(
        new_heap_index + (i - heap->heap_size) * heap->object_size);
    obj->id = i + heap->id_offset;
    obj->next_free = next_free;
    next_free = i;
  }
  heap->next_free = next_free;
  heap->heap_size = new_heap_size;
  return 0; /* Success */
}

/*
 * Return 0 on success, -1 on error
 */
int object_heap_init(object_heap_p heap, int object_size, int id_offset) {
  heap->object_size = object_size;
  heap->id_offset = id_offset & OBJECT_HEAP_OFFSET_MASK;
  heap->heap_size = 0;
  heap->heap_increment = 16;
  heap->next_free = LAST_FREE;
  heap->num_buckets = 0;
  heap->bucket = NULL;

  if (object_heap_expand(heap) == 0) {
    ASSERT(heap->heap_size);
    _hantroInitMutex(&heap->mutex);
    return 0;
  } else {
    ASSERT(!heap->heap_size);
    ASSERT(!heap->bucket || !heap->bucket[0]);

    free(heap->bucket);

    return -1;
  }
}

/*
 * Allocates an object
 * Returns the object ID on success, returns -1 on error
 */
int object_heap_allocate(object_heap_p heap) {
  object_base_p obj;
  int bucket_index, obj_index;

  _hantroLockMutex(&heap->mutex);
  if (LAST_FREE == heap->next_free) {
    if (-1 == object_heap_expand(heap)) {
      _hantroUnlockMutex(&heap->mutex);
      return -1; /* Out of memory */
    }
  }
  ASSERT(heap->next_free >= 0);

  bucket_index = heap->next_free / heap->heap_increment;
  obj_index = heap->next_free % heap->heap_increment;

  obj = (object_base_p)(heap->bucket[bucket_index] +
                        obj_index * heap->object_size);
  heap->next_free = obj->next_free;
  _hantroUnlockMutex(&heap->mutex);

  obj->next_free = ALLOCATED;
  return obj->id;
}

/*
 * Lookup an object by object ID
 * Returns a pointer to the object on success, returns NULL on error
 */
object_base_p object_heap_lookup(object_heap_p heap, int id) {
  object_base_p obj;
  int bucket_index, obj_index;

  _hantroLockMutex(&heap->mutex);
  if ((id < heap->id_offset) || (id > (heap->heap_size + heap->id_offset))) {
    _hantroUnlockMutex(&heap->mutex);
    return NULL;
  }
  id &= OBJECT_HEAP_ID_MASK;
  bucket_index = id / heap->heap_increment;
  obj_index = id % heap->heap_increment;
  obj = (object_base_p)(heap->bucket[bucket_index] +
                        obj_index * heap->object_size);
  _hantroUnlockMutex(&heap->mutex);

  /* Check if the object has in fact been allocated */
  if (obj->next_free != ALLOCATED) {
    return NULL;
  }
  return obj;
}

/*
 * Iterate over all objects in the heap.
 * Returns a pointer to the first object on the heap, returns NULL if heap is
 * empty.
 */
object_base_p object_heap_first(object_heap_p heap,
                                object_heap_iterator *iter) {
  *iter = -1;
  return object_heap_next(heap, iter);
}

/*
 * Iterate over all objects in the heap.
 * Returns a pointer to the next object on the heap, returns NULL if heap is
 * empty.
 */
object_base_p object_heap_next(object_heap_p heap, object_heap_iterator *iter) {
  object_base_p obj;
  int i = *iter + 1;
  int bucket_index, obj_index;

  _hantroLockMutex(&heap->mutex);
  while (i < heap->heap_size) {
    bucket_index = i / heap->heap_increment;
    obj_index = i % heap->heap_increment;

    obj = (object_base_p)(heap->bucket[bucket_index] +
                          obj_index * heap->object_size);
    if (obj->next_free == ALLOCATED) {
      _hantroUnlockMutex(&heap->mutex);
      *iter = i;
      return obj;
    }
    i++;
  }
  _hantroUnlockMutex(&heap->mutex);
  *iter = i;
  return NULL;
}

/*
 * Frees an object
 */
void object_heap_free(object_heap_p heap, object_base_p obj) {
  /* Don't complain about NULL pointers */
  if (NULL != obj) {
    /* Check if the object has in fact been allocated */
    ASSERT(obj->next_free == ALLOCATED);

    _hantroLockMutex(&heap->mutex);
    obj->next_free = heap->next_free;
    heap->next_free = obj->id & OBJECT_HEAP_ID_MASK;
    _hantroUnlockMutex(&heap->mutex);
  }
}

/*
 * Destroys a heap, the heap must be empty.
 */
void object_heap_destroy(object_heap_p heap) {
  object_base_p obj;
  int i;
  int bucket_index, obj_index;

  if (heap->heap_size) {
    _hantroDestroyMutex(&heap->mutex);

    /* Check if heap is empty */
    for (i = 0; i < heap->heap_size; i++) {
      /* Check if object is not still allocated */
      bucket_index = i / heap->heap_increment;
      obj_index = i % heap->heap_increment;
      obj = (object_base_p)(heap->bucket[bucket_index] +
                            obj_index * heap->object_size);
      ASSERT(obj->next_free != ALLOCATED);
    }

    for (i = 0; i < heap->heap_size / heap->heap_increment; i++) {
      free(heap->bucket[i]);
    }

    free(heap->bucket);
  }

  heap->bucket = NULL;
  heap->heap_size = 0;
  heap->next_free = LAST_FREE;
}
