459 lines
10 KiB
Text
459 lines
10 KiB
Text
/* $NetBSD: expr.y,v 1.38 2012/03/15 02:02:20 joerg Exp $ */
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/*_
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* Copyright (c) 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jaromir Dolecek <jdolecek@NetBSD.org> and J.T. Conklin <jtc@NetBSD.org>.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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%{
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: expr.y,v 1.38 2012/03/15 02:02:20 joerg Exp $");
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#endif /* not lint */
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#include <sys/types.h>
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#include <err.h>
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#include <errno.h>
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#include <limits.h>
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#include <locale.h>
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#include <regex.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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static const char * const *av;
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static void yyerror(const char *, ...) __dead;
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static int yylex(void);
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static int is_zero_or_null(const char *);
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static int is_integer(const char *);
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static int64_t perform_arith_op(const char *, const char *, const char *);
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int main(int, const char * const *);
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#define YYSTYPE const char *
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%}
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%token STRING
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%left SPEC_OR
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%left SPEC_AND
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%left COMPARE
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%left ADD_SUB_OPERATOR
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%left MUL_DIV_MOD_OPERATOR
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%left SPEC_REG
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%left LENGTH
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%left LEFT_PARENT RIGHT_PARENT
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%%
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exp: expr = {
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(void) printf("%s\n", $1);
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return (is_zero_or_null($1));
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}
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;
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expr: item { $$ = $1; }
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| expr SPEC_OR expr = {
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/*
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* Return evaluation of first expression if it is neither
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* an empty string nor zero; otherwise, returns the evaluation
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* of second expression.
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*/
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if (!is_zero_or_null($1))
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$$ = $1;
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else
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$$ = $3;
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}
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| expr SPEC_AND expr = {
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/*
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* Returns the evaluation of first expr if neither expression
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* evaluates to an empty string or zero; otherwise, returns
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* zero.
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*/
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if (!is_zero_or_null($1) && !is_zero_or_null($3))
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$$ = $1;
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else
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$$ = "0";
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}
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| expr SPEC_REG expr = {
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/*
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* The ``:'' operator matches first expr against the second,
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* which must be a regular expression.
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*/
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regex_t rp;
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regmatch_t rm[2];
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int eval;
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/* compile regular expression */
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if ((eval = regcomp(&rp, $3, REG_BASIC)) != 0) {
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char errbuf[256];
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(void)regerror(eval, &rp, errbuf, sizeof(errbuf));
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yyerror("%s", errbuf);
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/* NOT REACHED */
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}
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/* compare string against pattern -- remember that patterns
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are anchored to the beginning of the line */
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if (regexec(&rp, $1, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
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char *val;
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if (rm[1].rm_so >= 0) {
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(void) asprintf(&val, "%.*s",
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(int) (rm[1].rm_eo - rm[1].rm_so),
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$1 + rm[1].rm_so);
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} else {
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(void) asprintf(&val, "%d",
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(int)(rm[0].rm_eo - rm[0].rm_so));
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}
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if (val == NULL)
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err(1, NULL);
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$$ = val;
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} else {
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if (rp.re_nsub == 0) {
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$$ = "0";
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} else {
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$$ = "";
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}
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}
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}
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| expr ADD_SUB_OPERATOR expr = {
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/* Returns the results of addition, subtraction */
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char *val;
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int64_t res;
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res = perform_arith_op($1, $2, $3);
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(void) asprintf(&val, "%lld", (long long int) res);
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if (val == NULL)
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err(1, NULL);
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$$ = val;
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}
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| expr MUL_DIV_MOD_OPERATOR expr = {
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/*
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* Returns the results of multiply, divide or remainder of
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* numeric-valued arguments.
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*/
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char *val;
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int64_t res;
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res = perform_arith_op($1, $2, $3);
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(void) asprintf(&val, "%lld", (long long int) res);
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if (val == NULL)
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err(1, NULL);
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$$ = val;
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}
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| expr COMPARE expr = {
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/*
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* Returns the results of integer comparison if both arguments
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* are integers; otherwise, returns the results of string
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* comparison using the locale-specific collation sequence.
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* The result of each comparison is 1 if the specified relation
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* is true, or 0 if the relation is false.
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*/
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int64_t l, r;
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int res;
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res = 0;
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/*
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* Slight hack to avoid differences in the compare code
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* between string and numeric compare.
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*/
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if (is_integer($1) && is_integer($3)) {
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/* numeric comparison */
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l = strtoll($1, NULL, 10);
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r = strtoll($3, NULL, 10);
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} else {
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/* string comparison */
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l = strcoll($1, $3);
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r = 0;
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}
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switch($2[0]) {
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case '=': /* equal */
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res = (l == r);
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break;
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case '>': /* greater or greater-equal */
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if ($2[1] == '=')
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res = (l >= r);
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else
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res = (l > r);
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break;
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case '<': /* lower or lower-equal */
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if ($2[1] == '=')
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res = (l <= r);
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else
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res = (l < r);
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break;
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case '!': /* not equal */
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/* the check if this is != was done in yylex() */
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res = (l != r);
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}
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$$ = (res) ? "1" : "0";
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}
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| LEFT_PARENT expr RIGHT_PARENT { $$ = $2; }
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| LENGTH expr {
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/*
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* Return length of 'expr' in bytes.
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*/
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char *ln;
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asprintf(&ln, "%ld", (long) strlen($2));
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if (ln == NULL)
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err(1, NULL);
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$$ = ln;
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}
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;
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item: STRING
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| ADD_SUB_OPERATOR
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| MUL_DIV_MOD_OPERATOR
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| COMPARE
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| SPEC_OR
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| SPEC_AND
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| SPEC_REG
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| LENGTH
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;
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%%
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/*
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* Returns 1 if the string is empty or contains only numeric zero.
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*/
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static int
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is_zero_or_null(const char *str)
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{
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char *endptr;
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return str[0] == '\0'
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|| ( strtoll(str, &endptr, 10) == 0LL
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&& endptr[0] == '\0');
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}
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/*
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* Returns 1 if the string is an integer.
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*/
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static int
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is_integer(const char *str)
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{
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char *endptr;
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(void) strtoll(str, &endptr, 10);
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/* note we treat empty string as valid number */
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return (endptr[0] == '\0');
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}
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static int64_t
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perform_arith_op(const char *left, const char *op, const char *right)
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{
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int64_t res, sign, l, r;
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u_int64_t temp;
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res = 0;
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if (!is_integer(left)) {
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yyerror("non-integer argument '%s'", left);
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/* NOTREACHED */
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}
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if (!is_integer(right)) {
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yyerror("non-integer argument '%s'", right);
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/* NOTREACHED */
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}
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errno = 0;
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l = strtoll(left, NULL, 10);
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if (errno == ERANGE) {
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yyerror("value '%s' is %s is %lld", left,
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(l > 0) ? "too big, maximum" : "too small, minimum",
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(l > 0) ? LLONG_MAX : LLONG_MIN);
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/* NOTREACHED */
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}
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errno = 0;
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r = strtoll(right, NULL, 10);
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if (errno == ERANGE) {
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yyerror("value '%s' is %s is %lld", right,
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(l > 0) ? "too big, maximum" : "too small, minimum",
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(l > 0) ? LLONG_MAX : LLONG_MIN);
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/* NOTREACHED */
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}
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switch(op[0]) {
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case '+':
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/*
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* Do the op into an unsigned to avoid overflow and then cast
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* back to check the resulting signage.
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*/
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temp = l + r;
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res = (int64_t) temp;
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/* very simplistic check for over-& underflow */
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if ((res < 0 && l > 0 && r > 0)
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|| (res > 0 && l < 0 && r < 0))
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yyerror("integer overflow or underflow occurred for "
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"operation '%s %s %s'", left, op, right);
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break;
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case '-':
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/*
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* Do the op into an unsigned to avoid overflow and then cast
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* back to check the resulting signage.
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*/
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temp = l - r;
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res = (int64_t) temp;
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/* very simplistic check for over-& underflow */
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if ((res < 0 && l > 0 && l > r)
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|| (res > 0 && l < 0 && l < r) )
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yyerror("integer overflow or underflow occurred for "
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"operation '%s %s %s'", left, op, right);
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break;
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case '/':
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if (r == 0)
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yyerror("second argument to '%s' must not be zero", op);
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res = l / r;
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break;
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case '%':
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if (r == 0)
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yyerror("second argument to '%s' must not be zero", op);
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res = l % r;
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break;
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case '*':
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/* shortcut */
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if ((l == 0) || (r == 0)) {
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res = 0;
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break;
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}
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sign = 1;
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if (l < 0)
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sign *= -1;
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if (r < 0)
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sign *= -1;
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res = l * r;
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/*
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* XXX: not the most portable but works on anything with 2's
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* complement arithmetic. If the signs don't match or the
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* result was 0 on 2's complement this overflowed.
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*/
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if ((res < 0 && sign > 0) || (res > 0 && sign < 0) ||
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(res == 0))
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yyerror("integer overflow or underflow occurred for "
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"operation '%s %s %s'", left, op, right);
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/* NOTREACHED */
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break;
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}
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return res;
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}
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static const char *x = "|&=<>+-*/%:()";
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static const int x_token[] = {
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SPEC_OR, SPEC_AND, COMPARE, COMPARE, COMPARE, ADD_SUB_OPERATOR,
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ADD_SUB_OPERATOR, MUL_DIV_MOD_OPERATOR, MUL_DIV_MOD_OPERATOR,
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MUL_DIV_MOD_OPERATOR, SPEC_REG, LEFT_PARENT, RIGHT_PARENT
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};
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static int handle_ddash = 1;
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int
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yylex(void)
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{
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const char *p = *av++;
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int retval;
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if (!p)
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retval = 0;
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else if (p[1] == '\0') {
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const char *w = strchr(x, p[0]);
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if (w) {
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retval = x_token[w-x];
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} else {
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retval = STRING;
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}
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} else if (p[1] == '=' && p[2] == '\0'
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&& (p[0] == '>' || p[0] == '<' || p[0] == '!'))
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retval = COMPARE;
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else if (handle_ddash && p[0] == '-' && p[1] == '-' && p[2] == '\0') {
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/* ignore "--" if passed as first argument and isn't followed
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* by another STRING */
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retval = yylex();
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if (retval != STRING && retval != LEFT_PARENT
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&& retval != RIGHT_PARENT) {
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/* is not followed by string or parenthesis, use as
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* STRING */
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retval = STRING;
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av--; /* was increased in call to yylex() above */
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p = "--";
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} else {
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/* "--" is to be ignored */
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p = yylval;
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}
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} else if (strcmp(p, "length") == 0)
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retval = LENGTH;
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else
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retval = STRING;
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handle_ddash = 0;
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yylval = p;
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return retval;
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}
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/*
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* Print error message and exit with error 2 (syntax error).
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*/
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static __printflike(1, 2) void
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yyerror(const char *fmt, ...)
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{
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va_list arg;
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va_start(arg, fmt);
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verrx(2, fmt, arg);
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va_end(arg);
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}
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int
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main(int argc, const char * const *argv)
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{
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setprogname(argv[0]);
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(void)setlocale(LC_ALL, "");
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if (argc == 1) {
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(void)fprintf(stderr, "usage: %s expression\n",
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getprogname());
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exit(2);
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}
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av = argv + 1;
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exit(yyparse());
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/* NOTREACHED */
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}
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