vtkMultiThreader.h

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/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkMultiThreader.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#ifndef vtkMultiThreader_h
#define vtkMultiThreader_h

#include "vtkCommonCoreModule.h" // For export macro
#include "vtkObject.h"

#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

// Defined in vtkSystemIncludes.h:
//   VTK_MAX_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 vtkSystemIncludes.h:
//   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

class vtkMutexLock;

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;
    vtkMutexLock        *ActiveFlagLock;
    void                *UserData;
  };


  vtkSetClampMacro( NumberOfThreads, int, 1, VTK_MAX_THREADS );
  virtual int GetNumberOfThreads();


  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 thread_id );

  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];
  vtkMutexLock               *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;

#endif