tparm.c

i386的bootloader源码grub

     * if they appear as a %l or %s format following an explicit parameter
     * reference (e.g., %p2%s).  All other parameters are numbers.
     *
     * 'number' counts coarsely the number of pop's we see in the string, and
     * 'popcount' shows the highest parameter number in the string.  We would
     * like to simply use the latter count, but if we are reading termcap
     * strings, there may be cases that we cannot see the explicit parameter
     * numbers.
     */
    for (cp = string; (cp - string) < (int) len2;) {
	if (*cp == '%') {
	    cp++;
	    cp = parse_format(cp, format, &len);
	    switch (*cp) {
	    default:
		break;

	    case 'd':		/* FALLTHRU */
	    case 'o':		/* FALLTHRU */
	    case 'x':		/* FALLTHRU */
	    case 'X':		/* FALLTHRU */
	    case 'c':		/* FALLTHRU */
		number++;
		lastpop = -1;
		break;

	    case 'l':
	    case 's':
		if (lastpop > 0)
		    p_is_s[lastpop - 1] = dummy;
		++number;
		break;

	    case 'p':
		cp++;
		i = (*cp - '0');
		if (i >= 0 && i <= 9) {
		    lastpop = i;
		    if (lastpop > popcount)
			popcount = lastpop;
		}
		break;

	    case 'P':
	    case 'g':
		cp++;
		break;

	    case '\'':
		cp += 2;
		lastpop = -1;
		break;

	    case '{':
		cp++;
		while (*cp >= '0' && *cp <= '9') {
		    cp++;
		}
		break;

	    case '+':
	    case '-':
	    case '*':
	    case '/':
	    case 'm':
	    case 'A':
	    case 'O':
	    case '&':
	    case '|':
	    case '^':
	    case '=':
	    case '<':
	    case '>':
	    case '!':
	    case '~':
		lastpop = -1;
		number += 2;
		break;

	    case 'i':
		lastpop = -1;
		if (popcount < 2)
		    popcount = 2;
		break;
	    }
	}
	if (*cp != '\0')
	    cp++;
    }

    if (number > 9)
	number = 9;
    for (i = 0; i < max(popcount, number); i++) {
	/*
	 * A few caps (such as plab_norm) have string-valued parms.
	 * We'll have to assume that the caller knows the difference, since
	 * a char* and an int may not be the same size on the stack.
	 */
	if (p_is_s[i] != 0) {
	  p_is_s[i] = (char *)(*(dataptr++));
	} else {
	  param[i] = (int)(*(dataptr++));
	}
    }

    /*
     * This is a termcap compatibility hack.  If there are no explicit pop
     * operations in the string, load the stack in such a way that
     * successive pops will grab successive parameters.  That will make
     * the expansion of (for example) \E[%d;%dH work correctly in termcap
     * style, which means tparam() will expand termcap strings OK.
     */
    stack_ptr = 0;
    if (popcount == 0) {
	popcount = number;
	for (i = number - 1; i >= 0; i--)
	    npush(param[i]);
    }

    while (*string) {
        /* skip delay timings */
	if (*string == '$' && *(string + 1) == '<') {
	    while( *string && *string != '>') 
	        string++;
	    if ( *string == '>' ) string++;
	} else if ( *string == '%') {
	    string++;
	    string = parse_format(string, format, &len);
	    switch (*string) {
	    default:
		break;
	    case '%':
		save_char('%');
		break;

	    case 'd':		/* FALLTHRU */
	    case 'o':		/* FALLTHRU */
	    case 'x':		/* FALLTHRU */
	    case 'X':		/* FALLTHRU */
	    case 'c':		/* FALLTHRU */
		save_number(format, npop(), len);
		break;

	    case 'l':
		save_number("%d", strlen(spop()), 0);
		break;

	    case 's':
		save_text(format, spop(), len);
		break;

	    case 'p':
		string++;
		i = (*string - '1');
		if (i >= 0 && i < 9) {
		    if (p_is_s[i])
			spush(p_is_s[i]);
		    else
			npush(param[i]);
		}
		break;

	    case 'P':
		string++;
		if (isUPPER(*string)) {
		    i = (*string - 'A');
		    static_vars[i] = npop();
		} else if (isLOWER(*string)) {
		    i = (*string - 'a');
		    dynamic_var[i] = npop();
		}
		break;

	    case 'g':
		string++;
		if (isUPPER(*string)) {
		    i = (*string - 'A');
		    npush(static_vars[i]);
		} else if (isLOWER(*string)) {
		    i = (*string - 'a');
		    npush(dynamic_var[i]);
		}
		break;

	    case '\'':
		string++;
		npush(*string);
		string++;
		break;

	    case '{':
		number = 0;
		string++;
		while (*string >= '0' && *string <= '9') {
		    number = number * 10 + *string - '0';
		    string++;
		}
		npush(number);
		break;

	    case '+':
		npush(npop() + npop());
		break;

	    case '-':
		y = npop();
		x = npop();
		npush(x - y);
		break;

	    case '*':
		npush(npop() * npop());
		break;

	    case '/':
		y = npop();
		x = npop();
		npush(y ? (x / y) : 0);
		break;

	    case 'm':
		y = npop();
		x = npop();
		npush(y ? (x % y) : 0);
		break;

	    case 'A':
		npush(npop() && npop());
		break;

	    case 'O':
		npush(npop() || npop());
		break;

	    case '&':
		npush(npop() & npop());
		break;

	    case '|':
		npush(npop() | npop());
		break;

	    case '^':
		npush(npop() ^ npop());
		break;

	    case '=':
		y = npop();
		x = npop();
		npush(x == y);
		break;

	    case '<':
		y = npop();
		x = npop();
		npush(x < y);
		break;

	    case '>':
		y = npop();
		x = npop();
		npush(x > y);
		break;

	    case '!':
		npush(!npop());
		break;

	    case '~':
		npush(~npop());
		break;

	    case 'i':
		if (p_is_s[0] == 0)
		    param[0]++;
		if (p_is_s[1] == 0)
		    param[1]++;
		break;

	    case '?':
		break;

	    case 't':
		x = npop();
		if (!x) {
		    /* scan forward for %e or %; at level zero */
		    string++;
		    level = 0;
		    while (*string) {
			if (*string == '%') {
			    string++;
			    if (*string == '?')
				level++;
			    else if (*string == ';') {
				if (level > 0)
				    level--;
				else
				    break;
			    } else if (*string == 'e' && level == 0)
				break;
			}

			if (*string)
			    string++;
		    }
		}
		break;

	    case 'e':
		/* scan forward for a %; at level zero */
		string++;
		level = 0;
		while (*string) {
		    if (*string == '%') {
			string++;
			if (*string == '?')
			    level++;
			else if (*string == ';') {
			    if (level > 0)
				level--;
			    else
				break;
			}
		    }

		    if (*string)
			string++;
		}
		break;

	    case ';':
		break;

	    }			/* endswitch (*string) */
	} else {             	/* endelse (*string == '%') */
	    save_char(*string);
	}

	if (*string == '\0')
	    break;

	string++;
    }				/* endwhile (*string) */

    get_space(1);
    out_buff[out_used] = '\0';

    return (out_buff);
}

char *
grub_tparm(const char *string,...)
{
    char *result;
    int *dataptr = (int *) &string;

    dataptr++;

    result = tparam_internal(string, dataptr);

    return result;
}