C/C++ Users Group Library 1996 July/C-C++ Users Group Library July 1996.iso/vol_100/109_01/vartabs.c

C/C++ Source or Header | 1985-03-09 | 4.5 KB | 196 lines

/*
    Program to copy a file replacing:
        spaces with tabs and spaces 'entab'
        or tabs and spaces with spaces 'detab'
    optional fourth argument allows the tab stop modulus
    to be user specified instead of 8.
*/

/*
    Macros for constant definitions
*/

#define ERROR -1    /* error flag returned by buffered i/o routines */
#define EOFF -1        /* end of file marker returned by getc() */
#define EOF 0x1A    /* CP/M's end file char for ascii files */
#define NOFILE -1    /* no such file indication given by fopen() */
#define TAB 0x09    /* tab character */
#define MAXLINE 79    /* max column number in a line */

/*
    Argument vector indices
*/

#define XFER_TYPE 1    /* entab or detab transfer */
#define FROM_FILE 2
#define TO_FILE   3
#define MODULUS   4

/*
    main to open the files for entab() or detab()
    and handle invocation errors.
*/

main(argc,argv)
    int argc;
    char *argv[];
    {
    int fdin,fdout;
    char inbuf[134],outbuf[134];

    if(argc != 4 && argc != 5) {
      printf("Correct invocation form is:\n\n");
      printf("VARTABS <detab or entab> <from file> <to file>");
      printf(" [<tab stop modulus>]\n");
      }
    else if( (fdin = fopen(argv[FROM_FILE],inbuf)) == NOFILE )
      printf("No such file %s\n",argv[FROM_FILE]);
    else if( (fdout  = fcreat(argv[TO_FILE],outbuf)) == ERROR )
      printf("Can't open %s\n",argv[TO_FILE]);
    else if( argc == 4) {
      if( tolower(*argv[XFER_TYPE]) == 'e' )
        entab(inbuf,outbuf,8);
      else if( tolower(*argv[XFER_TYPE]) == 'd')
        detab(inbuf,outbuf,8);
      else
        printf("What !!\n");
      }
    else {
      if( tolower(*argv[XFER_TYPE]) == 'e' )
        entab(inbuf,outbuf,atoi(argv[MODULUS]));
      else if( tolower(*argv[XFER_TYPE]) == 'd' )
        detab(inbuf,outbuf,atoi(argv[MODULUS]));
      else
        printf("What !!\n");
      }
    exit();
    }

/*
    procedure detab --copy file to file translating tabs to spaces
*/

detab(filein,fileout,modulo)
    char filein[];    /* the input file buffer */
    char fileout[];    /* the output file buffer */
    int  modulo;        /* modulus for tab stops */
    {
    int col;        /* column counter */
    char tabs[MAXLINE];    /* vector of tab_stops */
    int c;        /* 1 char buffer */

    settab(tabs,MAXLINE,modulo);    /* init the tab_stops to mod modulo cols */
    col = 0;
    while( (c = getc(filein)) != EOFF )
      if( c == TAB ) {
        do {
    putchr(' ',fileout);
    col++;
    } while( ! tabpos(col,tabs,MAXLINE) );
        }
      else if( c == '\n' ) {
        putc(c,fileout);
        col = 0;
        }
      else {
        putc(c,fileout);
        col++;
        }
    if( fflush(fileout) == ERROR)
      err_exit("output file flush error");
    return;
    }    /* end detab */


/*
    procedure entab --copy file to file translating
            spaces to tabs and spaces
*/

entab(filein,fileout,modulo)
    char filein[];    /* the input file buffer */
    char fileout[];    /* the output file buffer */
    int  modulo;        /* modulus for tab stops */
    {
    int col,newcol;    /* column counters */
    char tabs[MAXLINE];    /* vector of tab_stops */
    int c;        /* 1 char buffer */

    settab(tabs,MAXLINE,modulo);    /* init the tab_stops to mod modulo */
    col = 0;
    while(1) {
      newcol = col;
      while( (c = getc(filein)) == ' ' ) { /* collect blanks */
        newcol++;
        if( tabpos(newcol,tabs,MAXLINE) ) {
    putchr(TAB,fileout);
    col = newcol;
    }    /* end if */
        }        /* end while */
      for(; col<newcol; col++)
        putchr(' ',fileout);
      if(c == ERROR)
        err_exit("error in reading file\n");
      putchr(c,fileout);
      if(c == EOF)
        break;
      if( c == '\n' )
        col = 0;
      else
        col++;
      }    /* end while(1) */
    if( fflush(fileout) == ERROR )
      err_exit("error in flushing output buffer\n");
    return;
    }    /* end entab */

/*
    procedure -- putchr write a char to an output file and
        error exit with message if error occurrs
*/

putchr(c,buf)
    char c,buf[];
    {
    int stat;

    stat = putc(c,buf);
    if(stat == ERROR) err_exit("error during buffered write\n");
    return;
    }


/* procedure err_exit -- print error message and exit to CP/M */

err_exit(msg)
    char *msg;
    {
    printf("%s",*msg);
    exit();
    }

/*
function tabpos -- return true if past end of MAXLINE or at a tab_stop
        false otherwise
*/

tabpos(col,tabs,max)
    int col,max;
    char tabs[];
    {
    return ( col >max || tabs[col] );
    }

/* procedure settab -- initialize the array of tab_stops to mod 8 values */

settab(tabs,max,modulo)
    int max,modulo;
    char tabs[];
    {
    int i;

    for(i=0; i<=max; i++)
      tabs[i] = (i % modulo == 0);
    return;
    }