Cat.c

/* Chapter 2. cat. */
/* cat [options] [files]
    Only the -s option is used. Others are ignored.
    -s suppresses error report when a file does not exist */

#include "Everything.h"

#define BUF_SIZE 0x200

static VOID CatFile (HANDLE, HANDLE);
int _tmain (int argc, LPTSTR argv [])
{
    HANDLE hInFile, hStdIn = GetStdHandle (STD_INPUT_HANDLE);
    HANDLE hStdOut = GetStdHandle (STD_OUTPUT_HANDLE);
    BOOL dashS;
    int iArg, iFirstFile;

    /*  dashS will be set only if "-s" is on the command line. */
    /*  iFirstFile is the argv [] index of the first input file. */
    iFirstFile = Options (argc, argv, _T("s"), &dashS, NULL);

    if (iFirstFile == argc) { /* No files in arg list. */
        CatFile (hStdIn, hStdOut);
        return 0;
    }

    /* Process the input files. */
    for (iArg = iFirstFile; iArg < argc; iArg++) {
        hInFile = CreateFile (argv [iArg], GENERIC_READ,
                0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
        if (hInFile == INVALID_HANDLE_VALUE) {
            if (!dashS) ReportError (_T ("Cat Error: File does not exist."), 0, TRUE);
        } else {
            CatFile (hInFile, hStdOut);
            if (GetLastError() != 0 && !dashS) {
                ReportError (_T ("Cat Error: Could not process file completely."), 0, TRUE);
            }
            CloseHandle (hInFile);
        }
    }
    return 0;
}

static VOID CatFile (HANDLE hInFile, HANDLE hOutFile)
{
    DWORD nIn, nOut;
    BYTE buffer [BUF_SIZE];

    while (ReadFile (hInFile, buffer, BUF_SIZE, &nIn, NULL) && (nIn != 0)
            && WriteFile (hOutFile, buffer, nIn, &nOut, NULL));

    return;
}