parser5.c

早期freebsd实现

/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Edward Wang at The University of California, Berkeley.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static char sccsid[] = "@(#)parser5.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#include "parser.h"
#include "var.h"

/*
 * unary $ $? + - ! ~
 */
p_expr11(v, flag)
register struct value *v;
char flag;
{
	int op;
	char *opname;

	switch (token) {
	case T_DOLLAR:
		opname = "$";
		break;
	case T_DQ:
		opname = "$?";
		break;
	case T_PLUS:
		opname = "unary +";
		break;
	case T_MINUS:
		opname = "unary -";
		break;
	case T_NOT:
		opname = "!";
		break;
	case T_COMP:
		opname = "~";
		break;
	default:
		return p_expr12(v, flag);
	}
	op = token;
	(void) s_gettok();
	if (p_expr11(v, flag) < 0)
		return -1;
	switch (v->v_type) {
	case V_NUM:
		break;
	case V_STR:
		switch (op) {
		case T_MINUS:
		case T_NOT:
		case T_COMP:
			p_error("%s: Numeric operand required.", opname);
			str_free(v->v_str);
			v->v_type = V_ERR;
			return 0;
		}
		break;
	case V_ERR:
		return 0;
	}
	switch (op) {
	case T_DOLLAR:
	case T_DQ:
		if (v->v_type == V_NUM) {
			int tmp = cx.x_type == X_BUF && cx.x_arg != 0 &&
				v->v_num > 0 && v->v_num <= cx.x_narg;
			if (op == T_DQ)
				v->v_num = tmp;
			else if (tmp)
				*v = cx.x_arg[v->v_num - 1];
			else {
				p_error("%d: No such argument.", v->v_num);
				v->v_type = V_ERR;
			}
		} else {
			char *name = v->v_str;
			struct var *r = var_lookup(name);
			if (op == T_DQ) {
				v->v_type = V_NUM;
				v->v_num = r != 0;
			} else if (r != 0)
				*v = r->r_val;
			else {
				p_error("%s: Undefined variable.", name);
				v->v_type = V_ERR;
			}
			str_free(name);
		}
		if (v->v_type == V_STR && (v->v_str = str_cpy(v->v_str)) == 0) {
			p_memerror();
			return -1;
		}
		break;
	case T_MINUS:
		v->v_num = - v->v_num;
		break;
	case T_NOT:
		v->v_num = ! v->v_num;
		break;
	case T_COMP:
		v->v_num = ~ v->v_num;
		break;
	}
	return 0;
}

/*
 * string, number, ( expr )
 * Plus function calls.
 *
 * Always return v_type == V_ERR when flag == 0.
 */
p_expr12(v, flag)
register struct value *v;
char flag;
{
	v->v_type = V_ERR;
	switch (token) {
	case T_NUM:
		if (flag) {
			v->v_type = V_NUM;
			v->v_num = token_num;
		}
		(void) s_gettok();
		break;
	case T_STR:
		if (flag) {
			v->v_type = V_STR;
			v->v_str = token_str;
		} else
			str_free(token_str);
		(void) s_gettok();
		break;
	case T_LP:
		(void) s_gettok();
		if (p_expr(v, flag) < 0) {
			p_synerror();
			return -1;
		}
		if (token != T_RP) {
			p_synerror();
			val_free(*v);
			return -1;
		}
		(void) s_gettok();
		break;
	default:
		return -1;
	}
	while (token == T_LP) {
		char *cmd;

		if (p_convstr(v) < 0)
			return -1;
		cmd = v->v_type == V_STR ? v->v_str : 0;
		if (p_function(cmd, v, flag) < 0) {
			if (cmd)
				str_free(cmd);
			return -1;
		}
		if (cmd)
			str_free(cmd);
	}
	return 0;
}