source: buchla-68k/orig/GP/GETLINE.C

/*
   =============================================================================
        getline.c -- get a line from stdin
        Version 1 -- 1988-05-03 -- D.N. Lynx Crowe
        Does line editing.  Acts like gets().
   =============================================================================
*/

#include "stdio.h"
#include "ascii.h"
#include "stddefs.h"

char *
getline(buf, nb)
char *buf;      /* buffer pointer */
int nb;         /* buffer limit */
{
        register char *bp;
        register int c;
        register int bc;

        bc = 0;         /* number of characters currently in buffer */
        bp = buf;       /* current buffer pointer */
        *bp = '\0';     /* initial null into buffer */

        while (bc < nb) {               /* read up to limit */

                c = getchar();

                switch (c) {

                case A_BS:
                case A_DEL:

                        if (bc EQ 0) {

                                putchar(A_BEL); /* complain -- nothing there */
                                break;

                        } else {

                                bc--;           /* decrement byte count */
                                bp--;           /* back-up the pointer */
                                *bp = '\0';     /* terminate the string */

                                putchar(A_BS);  /* erase character from screen */
                                putchar(' ');
                                putchar(A_BS);

                                break;
                        }

                case A_CR:
                case A_LF:

                        *bp = '\0';             /* terminate line with null */
                        return(buf);            /* return -- CR or LF hit */

/* 
 */

                case CTL('X'):

                        *buf = '\0';            /* clear the buffer */

                        while (bc--) {

                                putchar(A_BS);
                                putchar(' ');
                                putchar(A_BS);
                        }

                        bc = 0;         /* reset byte count */
                        bp = buf;       /* reset buffer pointer */
                        break;

                case EOF:

                        return(NULL);

                default:

                        *bp++ = (char)c;        /* put character in buffer */
                        *bp = '\0';             /* terminate line with null */
                        putchar(c);             /* echo the character */
                        bc++;                   /* update character count */
                }
        }

        buf[nb - 1] = '\0';     /* terminate buffer */
        return(buf);            /* buffer full error */
}