Queue.c

 
#include <winpr/config.h>
 
#include <winpr/crt.h>
#include <winpr/assert.h>
 
#include <winpr/collections.h>
 
struct s_wQueue
{
  size_t capacity;
  size_t growthFactor;
  BOOL synchronized;
 
  BYTE padding[4];
 
  size_t head;
  size_t tail;
  size_t size;
  void** array;
  CRITICAL_SECTION lock;
  HANDLE event;
 
  wObject object;
  BOOL haveLock;
 
  BYTE padding2[4];
};
 
size_t Queue_Count(wQueue* queue)
{
  size_t ret = 0;
 
  Queue_Lock(queue);
 
  ret = queue->size;
 
  Queue_Unlock(queue);
 
  return ret;
}
 
void Queue_Lock(wQueue* queue)
{
  WINPR_ASSERT(queue);
  if (queue->synchronized)
    EnterCriticalSection(&queue->lock);
}
 
void Queue_Unlock(wQueue* queue)
{
  WINPR_ASSERT(queue);
  if (queue->synchronized)
    LeaveCriticalSection(&queue->lock);
}
 
HANDLE Queue_Event(wQueue* queue)
{
  WINPR_ASSERT(queue);
  return queue->event;
}
 
wObject* Queue_Object(wQueue* queue)
{
  WINPR_ASSERT(queue);
  return &queue->object;
}
 
void Queue_Clear(wQueue* queue)
{
  Queue_Lock(queue);
 
  for (size_t index = queue->head; index != queue->tail; index = (index + 1) % queue->capacity)
  {
    if (queue->object.fnObjectFree)
      queue->object.fnObjectFree(queue->array[index]);
 
    queue->array[index] = NULL;
  }
 
  queue->size = 0;
  queue->head = queue->tail = 0;
  (void)ResetEvent(queue->event);
  Queue_Unlock(queue);
}
 
BOOL Queue_Contains(wQueue* queue, const void* obj)
{
  BOOL found = FALSE;
 
  Queue_Lock(queue);
 
  for (size_t index = 0; index < queue->tail; index++)
  {
    if (queue->object.fnObjectEquals(queue->array[index], obj))
    {
      found = TRUE;
      break;
    }
  }
 
  Queue_Unlock(queue);
 
  return found;
}
 
static BOOL Queue_EnsureCapacity(wQueue* queue, size_t count)
{
  WINPR_ASSERT(queue);
 
  if (queue->size + count >= queue->capacity)
  {
    const size_t old_capacity = queue->capacity;
    size_t new_capacity = queue->capacity * queue->growthFactor;
    void** newArray = NULL;
    if (new_capacity < queue->size + count)
      new_capacity = queue->size + count;
    newArray = (void**)realloc(queue->array, sizeof(void*) * new_capacity);
 
    if (!newArray)
      return FALSE;
 
    queue->capacity = new_capacity;
    queue->array = newArray;
    ZeroMemory(&(queue->array[old_capacity]), (new_capacity - old_capacity) * sizeof(void*));
 
    /* rearrange wrapped entries */
    if (queue->tail <= queue->head)
    {
      CopyMemory(&(queue->array[old_capacity]), queue->array, queue->tail * sizeof(void*));
      queue->tail += old_capacity;
    }
  }
  return TRUE;
}
 
BOOL Queue_Enqueue(wQueue* queue, const void* obj)
{
  BOOL ret = TRUE;
 
  Queue_Lock(queue);
 
  if (!Queue_EnsureCapacity(queue, 1))
    goto out;
 
  if (queue->object.fnObjectNew)
    queue->array[queue->tail] = queue->object.fnObjectNew(obj);
  else
  {
    union
    {
      const void* cv;
      void* v;
    } cnv;
    cnv.cv = obj;
    queue->array[queue->tail] = cnv.v;
  }
  queue->tail = (queue->tail + 1) % queue->capacity;
 
  const BOOL signalSet = queue->size == 0;
  queue->size++;
 
  if (signalSet)
    (void)SetEvent(queue->event);
out:
 
  Queue_Unlock(queue);
 
  return ret;
}
 
void* Queue_Dequeue(wQueue* queue)
{
  void* obj = NULL;
 
  Queue_Lock(queue);
 
  if (queue->size > 0)
  {
    obj = queue->array[queue->head];
    queue->array[queue->head] = NULL;
    queue->head = (queue->head + 1) % queue->capacity;
    queue->size--;
  }
 
  if (queue->size < 1)
    (void)ResetEvent(queue->event);
 
  Queue_Unlock(queue);
 
  return obj;
}
 
void* Queue_Peek(wQueue* queue)
{
  void* obj = NULL;
 
  Queue_Lock(queue);
 
  if (queue->size > 0)
    obj = queue->array[queue->head];
 
  Queue_Unlock(queue);
 
  return obj;
}
 
void Queue_Discard(wQueue* queue)
{
  void* obj = NULL;
 
  Queue_Lock(queue);
  obj = Queue_Dequeue(queue);
 
  if (queue->object.fnObjectFree)
    queue->object.fnObjectFree(obj);
  Queue_Unlock(queue);
}
 
static BOOL default_queue_equals(const void* obj1, const void* obj2)
{
  return (obj1 == obj2);
}
 
wQueue* Queue_New(BOOL synchronized, SSIZE_T capacity, SSIZE_T growthFactor)
{
  wObject* obj = NULL;
  wQueue* queue = NULL;
  queue = (wQueue*)calloc(1, sizeof(wQueue));
 
  if (!queue)
    return NULL;
 
  queue->synchronized = synchronized;
 
  queue->growthFactor = 2;
  if (growthFactor > 0)
    queue->growthFactor = (size_t)growthFactor;
 
  if (capacity <= 0)
    capacity = 32;
  if (!InitializeCriticalSectionAndSpinCount(&queue->lock, 4000))
    goto fail;
  queue->haveLock = TRUE;
  if (!Queue_EnsureCapacity(queue, (size_t)capacity))
    goto fail;
 
  queue->event = CreateEvent(NULL, TRUE, FALSE, NULL);
 
  if (!queue->event)
    goto fail;
 
  obj = Queue_Object(queue);
  obj->fnObjectEquals = default_queue_equals;
 
  return queue;
fail:
  WINPR_PRAGMA_DIAG_PUSH
  WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC
  Queue_Free(queue);
  WINPR_PRAGMA_DIAG_POP
  return NULL;
}
 
void Queue_Free(wQueue* queue)
{
  if (!queue)
    return;
 
  if (queue->haveLock)
  {
    Queue_Clear(queue);
    DeleteCriticalSection(&queue->lock);
  }
  (void)CloseHandle(queue->event);
  free(queue->array);
  free(queue);
}