/*      $NetBSD: tscroll.c,v 1.15 2021/09/06 07:03:50 rin Exp $ */

/*-
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>

#ifndef lint
#if 0
static char sccsid[] = "@(#)tscroll.c   8.4 (Berkeley) 7/27/94";
#else
__RCSID("$NetBSD: tscroll.c,v 1.15 2021/09/06 07:03:50 rin Exp $");
#endif
#endif                          /* not lint */

#include <string.h>
#include <stdarg.h>
#include "curses.h"
#include "curses_private.h"

#define MAXRETURNSIZE   64

char   *
__tscroll(const char *cap, int n1, int n2)
{

        return __parse_cap(cap, n1, n2);
}

/*
 * Routines to parse capabilities.  Derived from tgoto.c in termcap(3)
 * library.  Cap is a string containing printf type escapes to allow
 * scrolling.  The following escapes are defined for substituting n:
 *
 *      %d      as in printf
 *      %2      like %2d
 *      %3      like %3d
 *      %.      gives %c hacking special case characters
 *      %+x     like %c but adding x first
 *
 *      The codes below affect the state but don't use up a value.
 *
 *      %>xy    if value > x add y
 *      %i      increments n
 *      %%      gives %
 *      %B      BCD (2 decimal digits encoded in one byte)
 *      %D      Delta Data (backwards bcd)
 *
 * all other characters are ``self-inserting''.
 *
 * XXX:
 *      %r      reverse order of two parameters
 * is also defined but we don't support it (yet).
 */
char    *
__parse_cap (char const *cap, ...)
{
        va_list ap;
        static char result[MAXRETURNSIZE];
        int     c, n;
        char   *dp;
        int     have_input;

        va_start (ap, cap);
        n = 0;                  /* XXX gcc -Wuninitialized */

        if (cap == NULL)
                goto err;
#ifdef DEBUG
        {
                int     i;

                __CTRACE(__CTRACE_MISC, "__parse_cap: cap = ");
                for (i = 0; i < strlen(cap); i++)
                        __CTRACE(__CTRACE_MISC, "%s", unctrl(cap[i]));
                __CTRACE(__CTRACE_MISC, "\n");
        }
#endif
        have_input = 0;
        for (dp = result; (c = *cap++) != '\0';) {
                if (c != '%') {
                        *dp++ = c;
                        continue;
                }
                switch (c = *cap++) {
                case 'n':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%n, val = %d\n", n);
                        }
                        n ^= 0140;
                        continue;
                case 'd':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%d, val = %d\n", n);
                        }
                        if (n < 10)
                                goto one;
                        if (n < 100)
                                goto two;
                        /* FALLTHROUGH */
                case '3':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%3, val = %d\n", n);
                        }
                        *dp++ = (n / 100) | '0';
                        n %= 100;
                        /* FALLTHROUGH */
                case '2':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%2, val = %d\n", n);
                        }
        two:            *dp++ = n / 10 | '0';
        one:            *dp++ = n % 10 | '0';
                        have_input = 0;
                        continue;
                case '>':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%>, val = %d\n", n);
                        }
                        if (n > *cap++)
                                n += *cap++;
                        else
                                cap++;
                        continue;
                case '+':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%+, val = %d\n", n);
                        }
                        n += *cap++;
                        /* FALLTHROUGH */
                case '.':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%., val = %d\n", n);
                        }
                        *dp++ = n;
                        have_input = 0;
                        continue;
                case 'i':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%i, val = %d\n", n);
                        }
                        n++;
                        continue;
                case '%':
                        *dp++ = c;
                        continue;
                case 'B':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%B, val = %d\n", n);
                        }
                        n = (n / 10 << 4) + n % 10;
                        continue;
                case 'D':
                        if (!have_input) {
                                n = va_arg(ap, int);
                                have_input = 1;
                                __CTRACE(__CTRACE_MISC,
                                    "__parse_cap: %%D, val = %d\n", n);
                        }
                        n = n - 2 * (n % 16);
                        continue;
                        /*
                         * XXX
                         * System V terminfo files have lots of extra gunk.
                         * The only other one we've seen in capability strings
                         * is %pN, and it seems to work okay if we ignore it.
                         */
                case 'p':
                        ++cap;
                        continue;
                default:
                        goto err;
                }
        }
        *dp = '\0';
        va_end(ap);
        return result;

err:    va_end(ap);
        return (char *)"\0";
}