/**

 * WinPR: Windows Portable Runtime

 * Object Pool

 *

 * Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <winpr/config.h>

#include <winpr/crt.h>

#include <winpr/wlog.h>

#include <winpr/collections.h>

#include "../stream.h"

struct s_wStreamPool

{

  size_t aSize;

  size_t aCapacity;

  wStream** aArray;

  size_t uSize;

  size_t uCapacity;

  wStream** uArray;

  CRITICAL_SECTION lock;

  BOOL synchronized;

  size_t defaultSize;

};

/**

 * Lock the stream pool

 */

static INLINE void StreamPool_Lock(wStreamPool* pool)

{

  WINPR_ASSERT(pool);

  if (pool->synchronized)

    EnterCriticalSection(&pool->lock);

}

/**

 * Unlock the stream pool

 */

static INLINE void StreamPool_Unlock(wStreamPool* pool)

{

  WINPR_ASSERT(pool);

  if (pool->synchronized)

    LeaveCriticalSection(&pool->lock);

}

static BOOL StreamPool_EnsureCapacity(wStreamPool* pool, size_t count, BOOL usedOrAvailable)

{

  size_t new_cap = 0;

  size_t* cap;

  size_t* size;

  wStream*** array;

  WINPR_ASSERT(pool);

  cap = (usedOrAvailable) ? &pool->uCapacity : &pool->aCapacity;

  size = (usedOrAvailable) ? &pool->uSize : &pool->aSize;

  array = (usedOrAvailable) ? &pool->uArray : &pool->aArray;

  if (*cap == 0)

    new_cap = *size + count;

  else if (*size + count > *cap)

    new_cap = *cap * 2;

  else if ((*size + count) < *cap / 3)

    new_cap = *cap / 2;

  if (new_cap > 0)

  {

    wStream** new_arr;

    if (*cap < *size + count)

      *cap += count;

    new_arr = (wStream**)realloc(*array, sizeof(wStream*) * new_cap);

    if (!new_arr)

      return FALSE;

    *cap = new_cap;

    *array = new_arr;

  }

  return TRUE;

}

/**

 * Methods

 */

static void StreamPool_ShiftUsed(wStreamPool* pool, size_t index, INT64 count)

{

  WINPR_ASSERT(pool);

  if (count > 0)

  {

    const size_t pcount = (size_t)count;

    StreamPool_EnsureCapacity(pool, pcount, TRUE);

    MoveMemory(&pool->uArray[index + pcount], &pool->uArray[index],

               (pool->uSize - index) * sizeof(wStream*));

    pool->uSize += pcount;

  }

  else if (count < 0)

  {

    const size_t pcount = (size_t)-count;

    if ((pool->uSize - index - pcount) > 0)

    {

      MoveMemory(&pool->uArray[index], &pool->uArray[index + pcount],

                 (pool->uSize - index - pcount) * sizeof(wStream*));

    }

    pool->uSize -= pcount;

  }

}

/**

 * Adds a used stream to the pool.

 */

static void StreamPool_AddUsed(wStreamPool* pool, wStream* s)

{

  StreamPool_EnsureCapacity(pool, 1, TRUE);

  pool->uArray[(pool->uSize)++] = s;

}

/**

 * Removes a used stream from the pool.

 */

static void StreamPool_RemoveUsed(wStreamPool* pool, wStream* s)

{

  size_t index;

  BOOL found = FALSE;

  WINPR_ASSERT(pool);

  for (index = 0; index < pool->uSize; index++)

  {

    if (pool->uArray[index] == s)

    {

      found = TRUE;

      break;

    }

  }

  if (found)

    StreamPool_ShiftUsed(pool, index, -1);

}

static void StreamPool_ShiftAvailable(wStreamPool* pool, size_t index, INT64 count)

{

  WINPR_ASSERT(pool);

  if (count > 0)

  {

    const size_t pcount = (size_t)count;

    StreamPool_EnsureCapacity(pool, pcount, FALSE);

    MoveMemory(&pool->aArray[index + pcount], &pool->aArray[index],

               (pool->aSize - index) * sizeof(wStream*));

    pool->aSize += pcount;

  }

  else if (count < 0)

  {

    const size_t pcount = (size_t)-count;

    if ((pool->aSize - index - pcount) > 0)

    {

      MoveMemory(&pool->aArray[index], &pool->aArray[index + pcount],

                 (pool->aSize - index - pcount) * sizeof(wStream*));

    }

    pool->aSize -= pcount;

  }

}

/**

 * Gets a stream from the pool.

 */

wStream* StreamPool_Take(wStreamPool* pool, size_t size)

{

  size_t index;

  SSIZE_T foundIndex;

  wStream* s = NULL;

  StreamPool_Lock(pool);

  if (size == 0)

    size = pool->defaultSize;

  foundIndex = -1;

  for (index = 0; index < pool->aSize; index++)

  {

    s = pool->aArray[index];

    if (Stream_Capacity(s) >= size)

    {

      foundIndex = index;

      break;

    }

  }

  if (foundIndex < 0)

  {

    s = Stream_New(NULL, size);

    if (!s)

      goto out_fail;

  }

  else

  {

    Stream_SetPosition(s, 0);

    Stream_SetLength(s, Stream_Capacity(s));

    StreamPool_ShiftAvailable(pool, foundIndex, -1);

  }

  if (s)

  {

    s->pool = pool;

    s->count = 1;

    StreamPool_AddUsed(pool, s);

  }

out_fail:

  StreamPool_Unlock(pool);

  return s;

}

/**

 * Returns an object to the pool.

 */

static void StreamPool_Remove(wStreamPool* pool, wStream* s)

{

  StreamPool_EnsureCapacity(pool, 1, FALSE);

  Stream_EnsureValidity(s);

  for (size_t x = 0; x < pool->aSize; x++)

  {

    wStream* cs = pool->aArray[x];

    WINPR_ASSERT(cs != s);

  }

  pool->aArray[(pool->aSize)++] = s;

  StreamPool_RemoveUsed(pool, s);

}

static void StreamPool_ReleaseOrReturn(wStreamPool* pool, wStream* s)

{

  StreamPool_Lock(pool);

  if (s->count > 0)

    s->count--;

  if (s->count == 0)

    StreamPool_Remove(pool, s);

  StreamPool_Unlock(pool);

}

void StreamPool_Return(wStreamPool* pool, wStream* s)

{

  WINPR_ASSERT(pool);

  if (!s)

    return;

  StreamPool_Lock(pool);

  StreamPool_Remove(pool, s);

  StreamPool_Unlock(pool);

}

/**

 * Increment stream reference count

 */

void Stream_AddRef(wStream* s)

{

  WINPR_ASSERT(s);

  if (s->pool)

  {

    StreamPool_Lock(s->pool);

    s->count++;

    StreamPool_Unlock(s->pool);

  }

}

/**

 * Decrement stream reference count

 */

void Stream_Release(wStream* s)

{

  WINPR_ASSERT(s);

  if (s->pool)

    StreamPool_ReleaseOrReturn(s->pool, s);

}

/**

 * Find stream in pool using pointer inside buffer

 */

wStream* StreamPool_Find(wStreamPool* pool, BYTE* ptr)

{

  size_t index;

  wStream* s = NULL;

  BOOL found = FALSE;

  StreamPool_Lock(pool);

  for (index = 0; index < pool->uSize; index++)

  {

    s = pool->uArray[index];

    if ((ptr >= Stream_Buffer(s)) && (ptr < (Stream_Buffer(s) + Stream_Capacity(s))))

    {

      found = TRUE;

      break;

    }

  }

  StreamPool_Unlock(pool);

  return (found) ? s : NULL;

}

/**

 * Releases the streams currently cached in the pool.

 */

void StreamPool_Clear(wStreamPool* pool)

{

  StreamPool_Lock(pool);

  while (pool->aSize > 0)

  {

    wStream* s = pool->aArray[--pool->aSize];

    Stream_Free(s, s->isAllocatedStream);

  }

  while (pool->uSize > 0)

  {

    wStream* s = pool->uArray[--pool->uSize];

    Stream_Free(s, s->isAllocatedStream);

  }

  StreamPool_Unlock(pool);

}

/**

 * Construction, Destruction

 */

wStreamPool* StreamPool_New(BOOL synchronized, size_t defaultSize)

{

  wStreamPool* pool = NULL;

  pool = (wStreamPool*)calloc(1, sizeof(wStreamPool));

  if (pool)

  {

    pool->synchronized = synchronized;

    pool->defaultSize = defaultSize;

    if (!StreamPool_EnsureCapacity(pool, 32, FALSE))

      goto fail;

    if (!StreamPool_EnsureCapacity(pool, 32, TRUE))

      goto fail;

    InitializeCriticalSectionAndSpinCount(&pool->lock, 4000);

  }

  return pool;

fail:

  StreamPool_Free(pool);

  return NULL;

}

void StreamPool_Free(wStreamPool* pool)

{

  if (pool)

  {

    StreamPool_Clear(pool);

    DeleteCriticalSection(&pool->lock);

    free(pool->aArray);

    free(pool->uArray);

    free(pool);

  }

}

char* StreamPool_GetStatistics(wStreamPool* pool, char* buffer, size_t size)

{

  WINPR_ASSERT(pool);

  if (!buffer || (size < 1))

    return NULL;

  _snprintf(buffer, size - 1,

            "aSize    =%" PRIuz ", uSize    =%" PRIuz "aCapacity=%" PRIuz ", uCapacity=%" PRIuz,

            pool->aSize, pool->uSize, pool->aCapacity, pool->uCapacity);

  buffer[size - 1] = '\0';

  return buffer;

}