07-09-10 - Backspace

#define _WIN32_WINNT 0x0501 
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <psapi.h>

static bool strsame(const char * s1,const char * s2)
{
    for(int i=0;;i++)
    {
        if ( s1[i] != s2[i] )
            return false;
        if ( s1[i] == 0 )
            return true;
    }
}

// __declspec(dllimport) void RtlFillMemory( void *, size_t count, char );
extern "C" 
void * __cdecl memset(void *buf,int val,size_t count)
{
    char * p = (char *) buf;
    for(size_t i=0;i < count;i++)
    {
        p[i] = val;
    }
    return buf;
}

//#undef RtlCopyMemory
//NTSYSAPI void NTAPI RtlCopyMemory( void *, const void *, size_t count );
extern "C" 
void * __cdecl memcpy(void *dst,const void *src,size_t count)
{
    char * d = (char *) dst;
    char * s = (char *) src;
    for(size_t i=0;i < count;i++)
    {
        d[i] = s[i];
    }
    return dst;
}

//int CALLBACK WinMain ( IN HINSTANCE hInstance, IN HINSTANCE hPrevInstance, IN LPSTR lpCmdLine, IN int nShowCmd )
int my_WinMain(void)
{
    bool isExplorer = false;
    
    HWND active = GetForegroundWindow();
    
    DWORD procid;
    DWORD otherThread = GetWindowThreadProcessId(active,&procid);
            
    if ( active )
    {   
        HWND cur = active;
        for(;;)
        {
            HWND p = GetParent(cur);
            if ( ! p ) break;
            cur = p;
        }
        
        char name[1024];
        name[0] = 0;
        
        if ( GetClassNameA(cur,name,sizeof(name)) )
        {
            //lprintf("name : %s\n",name);
        
            isExplorer = strsame(name,"CabinetWClass") ||
                strsame(name,"ExploreWClass"); 
        }
    }
    
    if ( isExplorer )
    {   
        //lprintf("sending alt-up\n");
    
        INPUT inputs[4] = { 0 }; // this calls memset
        inputs[0].type = INPUT_KEYBOARD;
        inputs[0].ki.wVk = VK_LMENU;
        inputs[1].type = INPUT_KEYBOARD;
        inputs[1].ki.wVk = VK_UP;
        
        // send keyups in reverse order :
        inputs[2] = inputs[1]; // this generates memcpy
        inputs[3] = inputs[0];
        inputs[2].ki.dwFlags |= KEYEVENTF_KEYUP;
        inputs[3].ki.dwFlags |= KEYEVENTF_KEYUP;
        
        SendInput(4,inputs,sizeof(INPUT));
    }
    else
    {
        //lprintf("sending backspace\n");
        // can't use SendInput here cuz it will run me again
        
        // find the actual window and send a message :
        
        DWORD myThread = GetCurrentThreadId();
        
        AttachThreadInput(otherThread,myThread,TRUE);
        
        HWND focus = GetFocus();
        
        if ( ! focus )
            focus = active;
            
        // the HotKey thingy that I use will still send the KeyUp for Backspace,
        //  so I only need to send the key down :
        //  (some apps respond to keys on KeyUp and would process backspace twice- eg. Firefox)
        // also, if I send the KeyDown/Up together the WM_CHAR gets out of order oddly
        //PostMessageKeyUpDown(focus,VK_BACK);
        int vk = VK_BACK;
        int ScanKey = MapVirtualKey(vk, 0);
        const LPARAM lpKD = 1 | (ScanKey << 16);
        //const LPARAM lpKU = lpKD | (1UL << 31) | (1UL << 30);
        
        PostMessage(focus,WM_KEYDOWN,vk,lpKD);
        //PostMessage(w,WM_KEYUP,vk,lpKU);  
        
        AttachThreadInput(otherThread,myThread,FALSE);
    }   
    
    return 0;
}

extern "C"
{
int WinMainCRTStartup(void)
{
    return my_WinMain();
}
}

Bug fixed 07/12 : don't send key up message. Also, build without CRT and the EXE size is under 4k.

Download the EXE