/**
 * =========================================================================
 * File        : winit.cpp
 * Project     : 0 A.D.
 * Description : windows-specific module init and shutdown mechanism
 * =========================================================================
 */

// license: GPL; see lib/license.txt

#include "precompiled.h"
#include "winit.h"

#include "win.h"    // GetTickCount for quick'n dirty timing

// see http://blogs.msdn.com/larryosterman/archive/2004/09/27/234840.aspx
// for discussion of a similar mechanism.
//
// note: this module is kept distinct from the CRT's init/shutdown mechanism
// to insulate against changes there. another advantage is that callbacks
// can return LibError instead of int.

typedef LibError (*PfnLibErrorVoid)(void);

// pointers to start and end of function tables.
// notes:
// - COFF tosses out empty segments, so we have to put in one value
//   (zero, because CallFunctionPointers has to ignore entries =0 anyway).
// - ASCII '$' and 'Z' come before resp. after '0'..'9', so use that to
//   bound the section names.
__declspec(allocate(".WINIT$I$")) PfnLibErrorVoid initBegin = 0;
__declspec(allocate(".WINIT$IZ")) PfnLibErrorVoid initEnd = 0;
__declspec(allocate(".WINIT$S$")) PfnLibErrorVoid shutdownBegin = 0;
__declspec(allocate(".WINIT$SZ")) PfnLibErrorVoid shutdownEnd = 0;
// note: #pragma comment(linker, "/include") is not necessary since
// these are referenced below.


/**
 * call into a range of function pointers.
 * @param [begin, end): STL-style range
 *
 * note: pointers = 0 are ignored. this is because the above placeholders
 * are initialized to 0 and because the range may be larger than
 * expected due to COFF section padding (with zeroes).
 **/
static void CallFunctionPointers(PfnLibErrorVoid* begin, PfnLibErrorVoid* end)
{
    const DWORD t0 = GetTickCount();

    for(PfnLibErrorVoid* ppfunc = begin; ppfunc < end; ppfunc++)
    {
        if(*ppfunc)
            (*ppfunc)();
    }

    const DWORD t1 = GetTickCount();
    debug_printf("WINIT| total elapsed time in callbacks %d ms (+-10)\n", t1-t0);
}


void winit_CallInitFunctions()
{
    CallFunctionPointers(&initBegin, &initEnd);
}

void winit_CallShutdownFunctions()
{
    CallFunctionPointers(&shutdownBegin, &shutdownEnd);
}