vtkMultiThreader.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#ifndef vtkMultiThreader_h
#define vtkMultiThreader_h
 
#include "vtkCommonCoreModule.h" // For export macro
#include "vtkObject.h"
#include "vtkThreads.h" // for VTK_MAX_THREADS
 
#include <mutex> // For std::mutex
 
#if defined(VTK_USE_PTHREADS)
#include <pthread.h>   // Needed for PTHREAD implementation of mutex
#include <sys/types.h> // Needed for unix implementation of pthreads
#include <unistd.h>    // Needed for unix implementation of pthreads
#endif
 
// If VTK_USE_PTHREADS is defined, then pthread_create() will be
// used to create multiple threads
 
// If VTK_USE_PTHREADS is defined, then the multithreaded
// function is of type void *, and returns nullptr
// Otherwise the type is void which is correct for WIN32
 
// Defined in vtkThreads.h:
//   VTK_MAX_THREADS
//   VTK_THREAD_RETURN_VALUE
//   VTK_THREAD_RETURN_TYPE
 
#ifdef VTK_USE_PTHREADS
typedef void* (*vtkThreadFunctionType)(void*);
typedef pthread_t vtkThreadProcessIDType;
// #define VTK_THREAD_RETURN_VALUE  nullptr
// #define VTK_THREAD_RETURN_TYPE   void *
typedef pthread_t vtkMultiThreaderIDType;
#endif
 
#ifdef VTK_USE_WIN32_THREADS
typedef vtkWindowsLPTHREAD_START_ROUTINE vtkThreadFunctionType;
typedef vtkWindowsHANDLE vtkThreadProcessIDType;
// #define VTK_THREAD_RETURN_VALUE 0
// #define VTK_THREAD_RETURN_TYPE DWORD __stdcall
typedef vtkWindowsDWORD vtkMultiThreaderIDType;
#endif
 
#if !defined(VTK_USE_PTHREADS) && !defined(VTK_USE_WIN32_THREADS)
typedef void (*vtkThreadFunctionType)(void*);
typedef int vtkThreadProcessIDType;
// #define VTK_THREAD_RETURN_VALUE
// #define VTK_THREAD_RETURN_TYPE void
typedef int vtkMultiThreaderIDType;
#endif
 
VTK_ABI_NAMESPACE_BEGIN
class VTKCOMMONCORE_EXPORT vtkMultiThreader : public vtkObject
{
public:
  static vtkMultiThreader* New();
 
  vtkTypeMacro(vtkMultiThreader, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;
 
  class ThreadInfo
  {
  public:
    int ThreadID;
    int NumberOfThreads;
    int* ActiveFlag;
    std::mutex* ActiveFlagLock;
    void* UserData;
  };
 
 
  vtkSetClampMacro(NumberOfThreads, int, 1, VTK_MAX_THREADS);
  virtual int GetNumberOfThreads();
 
 
  static int GetGlobalStaticMaximumNumberOfThreads();
 
 
  static void SetGlobalMaximumNumberOfThreads(int val);
  static int GetGlobalMaximumNumberOfThreads();
 
 
  static void SetGlobalDefaultNumberOfThreads(int val);
  static int GetGlobalDefaultNumberOfThreads();
 
  // These methods are excluded from wrapping 1) because the
  // wrapper gives up on them and 2) because they really shouldn't be
  // called from a script anyway.
 
  void SingleMethodExecute();
 
  void MultipleMethodExecute();
 
  void SetSingleMethod(vtkThreadFunctionType, void* data);
 
  void SetMultipleMethod(int index, vtkThreadFunctionType, void* data);
 
  int SpawnThread(vtkThreadFunctionType, void* data);
 
  void TerminateThread(int threadId);
 
  vtkTypeBool IsThreadActive(int threadId);
 
  static vtkMultiThreaderIDType GetCurrentThreadID();
 
  static vtkTypeBool ThreadsEqual(vtkMultiThreaderIDType t1, vtkMultiThreaderIDType t2);
 
protected:
  vtkMultiThreader();
  ~vtkMultiThreader() override;
 
  // The number of threads to use
  int NumberOfThreads;
 
  // An array of thread info containing a thread id
  // (0, 1, 2, .. VTK_MAX_THREADS-1), the thread count, and a pointer
  // to void so that user data can be passed to each thread
  ThreadInfo ThreadInfoArray[VTK_MAX_THREADS];
 
  // The methods
  vtkThreadFunctionType SingleMethod;
  vtkThreadFunctionType MultipleMethod[VTK_MAX_THREADS];
 
  // Storage of MutexFunctions and ints used to control spawned
  // threads and the spawned thread ids
  int SpawnedThreadActiveFlag[VTK_MAX_THREADS];
  std::mutex* SpawnedThreadActiveFlagLock[VTK_MAX_THREADS];
  vtkThreadProcessIDType SpawnedThreadProcessID[VTK_MAX_THREADS];
  ThreadInfo SpawnedThreadInfoArray[VTK_MAX_THREADS];
 
  // Internal storage of the data
  void* SingleData;
  void* MultipleData[VTK_MAX_THREADS];
 
private:
  vtkMultiThreader(const vtkMultiThreader&) = delete;
  void operator=(const vtkMultiThreader&) = delete;
};
 
using ThreadInfoStruct = vtkMultiThreader::ThreadInfo;
 
VTK_ABI_NAMESPACE_END
#endif