DynamicLib.cpp

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// -*- C++ -*-
#define TEST_DYNAMIC_LIB  1   // Test for DLL export.
#include <coil/DynamicLib.h>

namespace coil
{
  DynamicLib::DynamicLib(int close_handle_on_destruction)
    : m_closeflag(close_handle_on_destruction)
  {
  }

  DynamicLib::DynamicLib(const char* dynlib_name,
                         int open_mode,
                         int close_handle_on_destruction)
    : m_name(dynlib_name), m_mode(open_mode),
      m_closeflag(close_handle_on_destruction)
  {
    if (open(m_name.c_str(), m_mode, m_closeflag) != 0)
      {
        throw std::bad_alloc();
      }
  }

  DynamicLib::~DynamicLib()
  {
    close();
  }

  DynamicLib::DynamicLib(const DynamicLib& rhs)
    : m_name(""), m_mode(0), m_closeflag(0), m_handle(0)
  {
    if (!rhs.m_name.empty() &&
        open(rhs.m_name.c_str(), rhs.m_mode, rhs.m_closeflag) == 0)
      return;
    throw std::bad_alloc();
  }

  DynamicLib& DynamicLib::operator=(const DynamicLib& rhs)
  {
    DynamicLib tmp(rhs);
    std::swap(this->m_name, tmp.m_name);
    std::swap(this->m_mode, tmp.m_mode);
    std::swap(this->m_closeflag, tmp.m_closeflag);
    std::swap(this->m_handle, tmp.m_handle);
    return *this;
  }

  int DynamicLib::open(const char* dll_name,
                   int open_mode,
                   int close_handle_on_destruction)
  {
    HINSTANCE handle = ::LoadLibraryEx(dll_name, NULL, open_mode);
    if (handle == NULL)
      {
        return -1;
      }
    m_handle = handle;
    m_name = dll_name;
    return 0;
  }

  int DynamicLib::close(void)
  {
    if (m_handle == NULL)
      return -1;
    ::FreeLibrary(m_handle);
    return 0;
  }

  void* DynamicLib::symbol (const char* symbol_name)
  {
    if (m_handle == NULL) return NULL;
    return ::GetProcAddress(m_handle, symbol_name);
  }

  const char* DynamicLib::error(void) const
  {
    DWORD dwcode;
    static char cstr[256] = "";

    /* Get the error code. */
    dwcode = ::GetLastError();

    /* Clear the error code. */
    ::SetLastError(ERROR_SUCCESS);

    /* Because it is a normal termination when the error code is 0, */
    /* return NULL. */
    if(dwcode == 0 ) 
    {
      return NULL;
    }

    /* Convert the error code into the message. */
        ::FormatMessage(
                FORMAT_MESSAGE_FROM_SYSTEM |
                FORMAT_MESSAGE_IGNORE_INSERTS,
                NULL,
                dwcode,
                MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                (char *)cstr,
                256,
                NULL
        );
    return cstr;
  }
};

extern "C"
{
  int ForExternTest(void) { return coil::DynamicLib::ForExternTest(); }
}