/* TimeMem.c - Windows port of Unix time utility */

#include <Windows.h>
#include <Psapi.h>
#include <stdio.h>
#include <tchar.h>

/* Displays usage help for this program. */
static void usage()
{
    _tprintf(_T("Usage: TimeMem command [args...]\n"));
}

/* Converts FILETIME to ULONGLONG. */
static ULONGLONG ConvertFileTime(const FILETIME *t)
{
    ULARGE_INTEGER i;
    CopyMemory(&i, t, sizeof(ULARGE_INTEGER));
    return i.QuadPart;
}

/* Displays information about a process. */
static int info(HANDLE hProcess)
{
    DWORD dwExitCode;
    FILETIME ftCreation, ftExit, ftKernel, ftUser;
    double tElapsed, tKernel, tUser;
    PROCESS_MEMORY_COUNTERS pmc = { sizeof(PROCESS_MEMORY_COUNTERS) };

    /* Exit code */
    if (!GetExitCodeProcess(hProcess, &dwExitCode))
        return 1;

    /* CPU info */
    if (!GetProcessTimes(hProcess, &ftCreation, &ftExit, &ftKernel, &ftUser))
    {
        return 1;
    }
    tElapsed = 1.0e-7 * (ConvertFileTime(&ftExit) - ConvertFileTime(&ftCreation));
    tKernel = 1.0e-7 * ConvertFileTime(&ftKernel);
    tUser = 1.0e-7 * ConvertFileTime(&ftUser);

    /* Memory info */
    // Print information about the memory usage of the process.
    if (!GetProcessMemoryInfo(hProcess, &pmc, sizeof(pmc)))
        return 1;

    /* Display info. */
    _tprintf(_T("Exit code      : %u\n"), dwExitCode);

    _tprintf(_T("Elapsed time   : %.2lf\n"), tElapsed);
    _tprintf(_T("Kernel time    : %.2lf (%.1lf%%)\n"), tKernel, 100.0*tKernel/tElapsed);
    _tprintf(_T("User time      : %.2lf (%.1lf%%)\n"), tUser, 100.0*tUser/tElapsed);

    _tprintf(_T("page fault #   : %u\n"), pmc.PageFaultCount);
    _tprintf(_T("Working set    : %u KB\n"), pmc.PeakWorkingSetSize/1024);
    _tprintf(_T("Paged pool     : %u KB\n"), pmc.QuotaPeakPagedPoolUsage/1024);
    _tprintf(_T("Non-paged pool : %u KB\n"), pmc.QuotaPeakNonPagedPoolUsage/1024);
    _tprintf(_T("Page file size : %u KB\n"), pmc.PeakPagefileUsage/1024);

    return 0;
}

/* Todo:
 * - mimic linux time utility interface; e.g. see http://linux.die.net/man/1/time
 * - build under 64-bit
 * - display detailed error message
 */

int _tmain(
#ifndef NDEBUG
    int argc, _TCHAR *argv[]
#endif
    )
{
    LPTSTR szCmdLine;
    LPTSTR szBegin;
    STARTUPINFO si = { sizeof(STARTUPINFO) };
    PROCESS_INFORMATION pi;
    int ret;

    /* Read the command line. */
    szCmdLine = GetCommandLine();

    /* Strip the first token from the command line. */
    if (szCmdLine[0] == '"')
    {
        /* The first token is double-quoted. Note that we don't need to
         * worry about escaped quote, because a quote is not a valid
         * path name under Windows.
         */
        LPTSTR p = szCmdLine + 1;
        while (*p && *p != '"')
            ++p;
        szBegin = (*p == '"')? p + 1 : p;
    }
    else
    {
        /* The first token is deliminated by a space or tab.
         * See "Parsing C++ Command Line Arguments" below:
         * http://msdn.microsoft.com/en-us/library/windows/desktop/17w5ykft(v=vs.85).aspx
         */
        LPTSTR p = szCmdLine;
        while (*p && *p != ' ' && *p != '\t')
            ++p;
        szBegin = p;
    }

    /* Skip white spaces. */
    while (*szBegin == ' ' || *szBegin == '\t')
        ++szBegin;

    /* If we have no more arguments, display usage info and exit. */
    if (*szBegin == 0)
    {
        usage();
        return 1;
    }

    /* Display argc,argv and command line for debugging purpose. */
#ifndef NDEBUG
    {
        int i;
        for (i = 0; i < argc; i++)
            _tprintf(_T("argv[%d]=%s\n"), i, argv[i]);
        _tprintf(_T("CmdLine=%s\n"), szCmdLine);
        _tprintf(_T("Invoked=%s\n"), szBegin);
    }
#endif

    /* Create the process. */
    if (!CreateProcess(NULL, szBegin, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi))
    {
        _tprintf(_T("Error: Cannot create process.\n"));
        return 1;
    }

    /* Wait for the process to finish. */
    if (WaitForSingleObject(pi.hProcess, INFINITE) != WAIT_OBJECT_0)
    {
        _tprintf(_T("Error: Cannot wait for process.\n"));
        return 1;
    }

    /* Display process statistics. */
    ret = info(pi.hProcess);

    /* Close process handles. */
    CloseHandle(pi.hThread);
    CloseHandle(pi.hProcess);

#ifndef NDEBUG
    _tprintf(_T("\nPress any key to exit...\n"));
    getch();
#endif

    return ret;
}