readline.c

guide and some example with visualC++

		redraw_line(prompt);
		break;
	      case 0177:	/* DEL */
	      case 010:		/* ^H */
		if(cur_pos > 0) {
		    cur_pos -= 1;
		    backspace();
		    for(i=cur_pos; i<max_pos; i++)
			cur_line[i] = cur_line[i+1];
		    max_pos -= 1;
		    fix_line();
		}
		break;
	      case 004:		/* ^D */
		if(max_pos == 0) {
		    reset_termio();
		    return((char *)NULL);
		}
		if(cur_pos < max_pos) {
		    for(i=cur_pos; i<max_pos; i++)
			cur_line[i] = cur_line[i+1];
		    max_pos -= 1;
		    fix_line();
		}
		break;
	      case 025:		/* ^U */
		clear_line(prompt);
		break;
	      case 027:		/* ^W */
		while((cur_pos > 0) &&
		      (cur_line[cur_pos-1] == SPACE)) {
		    cur_pos -= 1;
		    backspace();
		}
		while((cur_pos > 0) &&
		      (cur_line[cur_pos-1] != SPACE)) {
		    cur_pos -= 1;
		    backspace();
		}
		clear_eoline();
		max_pos = cur_pos;
		break;
	    case '\n':	/* ^J */
	    case '\r':	/* ^M */
		user_putc(NEWLINE);
		cur_line[max_pos+1] = '\0';
		cur_line = (char *)ralloc(cur_line,
					  (unsigned
					   long)(strlen(cur_line)+2),
					  "line resize");
		line_len=0;
		
		reset_termio();
		return cur_line;
	      default:
		break;
	    }
	}
    }
}


/* fix up the line from cur_pos to max_pos */
/* do not need any terminal capabilities except backspace, */
/* and space overwrites a character */
static void fix_line()
{
    int i;

    /* write tail of string */
    user_putsn(&cur_line[cur_pos],max_pos - cur_pos);
    
    
    /* write a space at the end of the line in case we deleted one */
    user_putc(SPACE);

    /* backup to original position */
    for(i=max_pos+1; i>cur_pos; i--)
	backspace();

}

/* redraw the entire line, putting the cursor where it belongs */
static void redraw_line(char *prompt)
{
    int i;

    user_puts(prompt);
    user_puts(cur_line);

    /* put the cursor where it belongs */
    for(i=max_pos; i>cur_pos; i--)
	backspace();
}

/* clear cur_line and the screen line */
static void clear_line(char *prompt)
{
    int i;

    memset(cur_line,0,max_pos);

    for(i=cur_pos; i>0; i--)
	backspace();

    for(i=0; i<max_pos; i++)
	user_putc(SPACE);

    user_putc('\r');
    user_puts(prompt);

    cur_pos = 0;
    max_pos = 0;
}

static void backupTo(char to, char from)
{
    int cmode = 0;
    int k = 1,i = cur_pos-1;

    backspace();
    while(i-- > 0) {
	backspace();
	if(cur_line[i] == '\'') {
	    if(cmode & 1)
		cmode &= ~1;
	    else
		cmode |= 1;
	    continue;
	}else if(cur_line[i] == '\"') {
	    if(cmode & 2)
		cmode &= ~2;
	    else
		cmode |= 2;
	    continue;
	}
	    
	if(cur_line[i] == to && !cmode) {
	    if(!--k)
		break;
	}else if(cur_line[i] == from && !cmode)
	    k++;
    }
    if(k) {
	user_putc(BELL);
	i = 0;
    } else
	delay(CLOCKS_PER_SEC / 2);

    user_putsn(&cur_line[i],cur_pos - i);

}
    
/* clear to end of line and the screen end of line */
static void clear_eoline()
{
    int i;
    for(i=cur_pos; i<max_pos; i++)
	cur_line[i] = '\0';

    for(i=cur_pos; i<max_pos; i++)
	user_putc(SPACE);
    for(i=cur_pos; i<max_pos; i++)
	backspace();
}

/* copy line to cur_line, draw it and set cur_pos and max_pos */
static void copy_line(char *line)
{
    while(strlen(line)+1>line_len) {
	extend_cur_line();
    }
    strcpy(cur_line, line);
    user_puts(cur_line);
    cur_pos = max_pos = strlen(cur_line);
}

/* add line to the history */
#ifndef _HistLimit       /* history limiter */
#define _HistLimit 500
#endif

void EiC_add_history(unsigned char *line)
{
    static unsigned int limit = 0;
    struct hist *entry;

    if(limit == _HistLimit && EndHist) {
	free(EndHist->line);
	entry = EndHist;
	EndHist = EndHist->next;
	EndHist->prev = NULL;
    } else {
	entry = (struct hist *)alloc((unsigned long)sizeof(struct hist),"history");
	limit++;
    }
    entry->line = alloc((unsigned long)(strlen(line)+1),"history");
    strcpy(entry->line, line);
    
    entry->prev = history;
    entry->next = NULL;
    if(history != NULL) {
	history->next = entry;
    } else /* get first entry */
	EndHist = entry;
    
    history = entry;
    HistLineNo++;
}

int  EiC_getHistLineNo()
{
    return HistLineNo;
}
	    
void EiC_save_history(FILE *to, int from)
{
    int cl = HistLineNo - 1;
    struct hist *p;
    p = history;
    while(cl-- > from)
	p = p->prev;
    while(p) {
	fprintf(to,"%s\n",p->line);
	p = p->next;
    }
}

/* show all history lines */
void EiC_show_history(FILE *fp)
{
    struct hist *p;
    p = EndHist;
    while(p) {
	fputs(p->line,fp);
	putc(NEWLINE,fp);
	p = p->next;
    }
    fflush(fp);
}

int EiC_load_history(char * fname, int prompt)
{
#define BufSz  512

    int i;
    char buff[BufSz];
    char *line;
    
    FILE *fp = fopen(fname,"r");
    if(prompt)
	set_termio();    
    if(fp) {
	while(fgets(buff,BufSz-2,fp)) {
	    for(i=0;buff[i] && buff[i] != '\n';++i)
		;
	    if(!buff[i])
		buff[i++] = '\\';
	    buff[i] = 0;
	    if(prompt) {
		printf("Re-enter [%s] (Y/N/E)?",buff);
		switch(special_getc()) {
		case 'y':
		case 'Y':
		    user_puts(" Y\n");
		    break;
		case 'e':
		case 'E':
		    user_puts(" E\n");
		    copy_line(buff);
		    line = editLine("edit: ");
		    if(*line)
			EiC_add_history(line);
		    free(line);
		    set_termio();
		    continue;
		default:
		    user_puts(" N\n");
		    continue;
		    
		}
	    }
	    EiC_add_history(buff);
	}
	fclose(fp);
	i = 1;
    } else
	i = 0;
    if(prompt)
	reset_termio();
    printf("added %d lines\n",HistLineNo);
    return i;

#undef BufSz
}
    

#if defined(WIN32)

/* Convert Arrow keystrokes to Control characters: */
static char msdos_getch()
{
    int c = _getch();
    if (c == 224 || c== 0) {
		c = _getch();		/* Get the extended code. */
		switch (c) {
		case 75:		/* Left Arrow. */
			c = 002;
		 break;
		case 77:		/* Right Arrow. */
			c = 006;
			break;
		case 72:		/* Up Arrow. */
			c = 020;
			break;
		case 80:		/* Down Arrow. */
			c = 016;
			break;
		case 115:		/* Ctl Left Arrow. */
		case 71:		/* Home */
			c = 001;
			break;
		case 116:		/* Ctl Right Arrow. */
		case 79:		/* End */
			c = 005;
			break;
		case 83:		/* Delete */
			c = 004;
			break;
		default:
			c = 0;
	    break;
		}
	} else if (c == 033) {	/* ESC */
		c = 025;
    }
    return c;
}

static void set_termio() {} 
static void reset_termio() {}

#else

/* Convert ANSI arrow keys to control characters */
static int ansi_getc()
{
  int c = getc(stdin);
  if (c == 033) {
    c = getc(stdin); /* check for CSI */
    if (c == '[') {
      c = getc(stdin); /* get command character */
      switch (c) {
      case 'D': /* left arrow key */
	c = 002;
	break;
      case 'C': /* right arrow key */
	c = 006;
	break;
      case 'A': /* up arrow key */
	c = 020;
	break;
	
      case 'B': /* down arrow key */
	c = 016;
	break;
      }
    }
  }
  return c;
}

/* set termio so we can do our own input processing */
static void set_termio()
{
    if(term_set == 0) {
	tcgetattr(0, &orig_termio);
	rl_termio = orig_termio;
	rl_termio.c_iflag &= ~(BRKINT|PARMRK|INPCK/*|IUCLC*/|IXON|IXOFF);
	rl_termio.c_iflag |=  (IGNBRK|IGNPAR);
	/* rl_termio.c_oflag &= ~(ONOCR); Costas Sphocleous Irvine,CA */
	rl_termio.c_lflag &= ~(ICANON|ECHO|ECHOE|ECHOK|ECHONL|NOFLSH);
	rl_termio.c_lflag |=  (ISIG);
	rl_termio.c_cc[VMIN] = 1;
	rl_termio.c_cc[VTIME] = 0;
	term_chars[VERASE]   = orig_termio.c_cc[VERASE];
	term_chars[VEOF]     = orig_termio.c_cc[VEOF];
	term_chars[VKILL]    = orig_termio.c_cc[VKILL];
	term_chars[VWERASE]  = orig_termio.c_cc[VWERASE];
	term_chars[VREPRINT] = orig_termio.c_cc[VREPRINT];
	term_chars[VSUSP]    = orig_termio.c_cc[VSUSP];
	/* disable suspending process on ^Z */
	rl_termio.c_cc[VSUSP] = 0;
	tcsetattr(0, TCSADRAIN, &rl_termio);
	term_set = 1;
    }
    
}
  
static void reset_termio()
{
    if(term_set == 1) {
	tcsetattr(0, TCSADRAIN, &orig_termio);
	term_set = 0;
    }
}

#endif

#ifdef _STANDALONE
int main()
{
    char * line = NULL;
    printf("**Press ^D in empty line to exit**\n");
    do {
	line = EiC_readline("$$> ");
	if (line) {
	    if(*line)
		EiC_add_history(line);
	    free(line);
	}
    } while(line);
    printf("\n-----------------\n");
    EiC_show_history(stdout);
    return 0;
}
#endif

#endif