readline.c

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/* -*-C-*-
 *
 * $Revision: 1.2 $
 *   $Author: mechavar $
 *     $Date: 2000/05/01 19:37:08 $
 *
 * Copyright (c) 2000 ARM, INC.
 * All Rights Reserved.
 *
 *   Project: BootStrap Loader
 *
 *   
 */

#include <string.h>

#include "swis.h"

#define START		('A'-'@')
#define BACK		('B'-'@')
#define ERASE_FWD	('D'-'@')
#define END		('E'-'@')
#define FORWARD		('F'-'@')
#define ERASE		('H'-'@')
#define ERASE_EOL	('K'-'@')
#define ENTER		('M'-'@')
#define REDRAW		('R'-'@')
#define ERASE_LINE	('U'-'@')
#define ERASE_SOL	('W'-'@')

#define BACKSPACE	('H'-'@')
#define DELETE		(0x7f)
#define LF		('\n')
#define CR		('\r')
#define CTRL_D		('D'-'@')

extern int ReadC(void);
extern void WriteC(int c);

static void backspace(int n)
{
    while (n--) WriteC(BACKSPACE);
}

static void backup(char *buffer, int pos)
{
    backspace(strlen(&buffer[pos]));
}

static void redraw_eol(char *buffer, int pos)
{
    int c;

    while (c = buffer[pos++]) WriteC(c);
}

static void redraw_line(char *prompt, char *buffer, int pos)
{
    int c;

    WriteC(CR);
    while (c = *prompt++) WriteC(c);
    redraw_eol(buffer, 0);
    backup(buffer, pos);
}

static void delete(char *buffer, int pos)
{
    if (buffer[pos] == 0) return;
    strcpy(&buffer[pos], &buffer[pos+1]);
    redraw_eol(buffer, pos);
    WriteC(' ');
    WriteC(BACKSPACE);
    backup(buffer, pos);
    return;
}

static int insert(char *buffer, int pos, int c)
{
    char *s = &buffer[pos];

    memmove(s+1, s, strlen(s)+1);
    buffer[pos] = c;
    redraw_eol(buffer, pos);
    pos++;
    backup(buffer, pos);
    return pos;
}

int ReadLineZ(char *buffer, int maxlen)
{
    int pos = 0;
    int c;

    do {
	c =ReadC();
	if (c == CR || c == LF) {
	    buffer[pos] = 0;
	    return pos;
	}
	if (c == CTRL_D) {
	    buffer[0] = 0;
	    return -1;
	}
	if (c >= ' ' && pos < maxlen)
	    buffer[pos++] = c;
    } while (1);
}

int ReadLine(char *prompt, char *buffer, int maxlen)
{
    int i;
    int pos = 0;
    int c;

    *buffer = 0;
    Write0(prompt);
    do {
	c = ReadC();
	if (c == DELETE) c = ERASE;
	if (c < ' ') {
	    switch (c) {
		case START:
		    backspace(pos);
		    pos = 0;
		    break;
		case BACK:
		    if (pos > 0) {
			WriteC(BACKSPACE);
			pos--;
		    }
		    break;
		case ERASE_FWD:
		    if (strlen(buffer) == 0) {
			Write0("*EOF*\r\n");
			return -1;
		    }
		    delete(buffer, pos);
		    break;
		case END:
		    redraw_eol(buffer, pos);
		    pos = strlen(buffer);
		    break;
		case FORWARD:
		    if (buffer[pos]) {
			WriteC(buffer[pos]);
			pos++;
		    }
		    break;
		case ERASE:
		    if (pos > 0) {
			WriteC(BACKSPACE);
			pos--;
			delete(buffer, pos);
		    }
		    break;
		case ENTER:
		    WriteC(CR);
		    WriteC(LF);
		    return strlen(buffer);
		case REDRAW:
		    WriteC(LF);
		    redraw_line(prompt, buffer, pos);
		    break;
		case ERASE_LINE:
		    backspace(pos);
		    i = pos = strlen(buffer);
		    while (i--) WriteC(' ');
		    backspace(pos);
		    pos = 0;
		    buffer[0] = 0;
		    break;
	    }
	} else if (strlen(buffer) < maxlen)
	    pos = insert(buffer, pos, c);
    } while (1);
}