566 lines
11 KiB
Plaintext
566 lines
11 KiB
Plaintext
%{
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/*-
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* Written by Pace Willisson (pace@blitz.com)
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* and placed in the public domain.
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*
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* Largely rewritten by J.T. Conklin (jtc@wimsey.com)
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*
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* $FreeBSD$
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*/
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#include <sys/types.h>
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <inttypes.h>
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#include <limits.h>
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#include <locale.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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#include <regex.h>
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#include <unistd.h>
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/*
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* POSIX specifies a specific error code for syntax errors. We exit
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* with this code for all errors.
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*/
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#define ERR_EXIT 2
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enum valtype {
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integer, numeric_string, string
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} ;
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struct val {
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enum valtype type;
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union {
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char *s;
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intmax_t i;
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} u;
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} ;
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char **av;
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int nonposix;
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struct val *result;
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void assert_to_integer(struct val *);
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void assert_div(intmax_t, intmax_t);
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void assert_minus(intmax_t, intmax_t, intmax_t);
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void assert_plus(intmax_t, intmax_t, intmax_t);
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void assert_times(intmax_t, intmax_t, intmax_t);
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int compare_vals(struct val *, struct val *);
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void free_value(struct val *);
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int is_integer(const char *);
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int is_string(struct val *);
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int is_zero_or_null(struct val *);
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struct val *make_integer(intmax_t);
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struct val *make_str(const char *);
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struct val *op_and(struct val *, struct val *);
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struct val *op_colon(struct val *, struct val *);
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struct val *op_div(struct val *, struct val *);
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struct val *op_eq(struct val *, struct val *);
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struct val *op_ge(struct val *, struct val *);
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struct val *op_gt(struct val *, struct val *);
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struct val *op_le(struct val *, struct val *);
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struct val *op_lt(struct val *, struct val *);
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struct val *op_minus(struct val *, struct val *);
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struct val *op_ne(struct val *, struct val *);
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struct val *op_or(struct val *, struct val *);
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struct val *op_plus(struct val *, struct val *);
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struct val *op_rem(struct val *, struct val *);
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struct val *op_times(struct val *, struct val *);
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int to_integer(struct val *);
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void to_string(struct val *);
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int yyerror(const char *);
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int yylex(void);
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%}
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%union
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{
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struct val *val;
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}
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%left <val> '|'
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%left <val> '&'
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%left <val> '=' '>' '<' GE LE NE
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%left <val> '+' '-'
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%left <val> '*' '/' '%'
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%left <val> ':'
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%token <val> TOKEN
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%type <val> start expr
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%%
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start: expr { result = $$; }
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expr: TOKEN
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| '(' expr ')' { $$ = $2; }
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| expr '|' expr { $$ = op_or($1, $3); }
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| expr '&' expr { $$ = op_and($1, $3); }
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| expr '=' expr { $$ = op_eq($1, $3); }
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| expr '>' expr { $$ = op_gt($1, $3); }
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| expr '<' expr { $$ = op_lt($1, $3); }
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| expr GE expr { $$ = op_ge($1, $3); }
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| expr LE expr { $$ = op_le($1, $3); }
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| expr NE expr { $$ = op_ne($1, $3); }
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| expr '+' expr { $$ = op_plus($1, $3); }
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| expr '-' expr { $$ = op_minus($1, $3); }
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| expr '*' expr { $$ = op_times($1, $3); }
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| expr '/' expr { $$ = op_div($1, $3); }
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| expr '%' expr { $$ = op_rem($1, $3); }
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| expr ':' expr { $$ = op_colon($1, $3); }
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;
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%%
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struct val *
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make_integer(intmax_t i)
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{
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struct val *vp;
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vp = (struct val *)malloc(sizeof(*vp));
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if (vp == NULL)
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errx(ERR_EXIT, "malloc() failed");
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vp->type = integer;
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vp->u.i = i;
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return (vp);
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}
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struct val *
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make_str(const char *s)
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{
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struct val *vp;
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vp = (struct val *)malloc(sizeof(*vp));
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if (vp == NULL || ((vp->u.s = strdup(s)) == NULL))
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errx(ERR_EXIT, "malloc() failed");
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if (is_integer(s))
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vp->type = numeric_string;
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else
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vp->type = string;
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return (vp);
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}
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void
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free_value(struct val *vp)
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{
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if (vp->type == string || vp->type == numeric_string)
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free(vp->u.s);
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}
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int
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to_integer(struct val *vp)
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{
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intmax_t i;
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/* we can only convert numeric_string to integer, here */
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if (vp->type == numeric_string) {
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errno = 0;
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i = strtoimax(vp->u.s, (char **)NULL, 10);
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/* just keep as numeric_string, if the conversion fails */
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if (errno != ERANGE) {
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free(vp->u.s);
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vp->u.i = i;
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vp->type = integer;
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}
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}
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return (vp->type == integer);
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}
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void
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assert_to_integer(struct val *vp)
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{
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if (vp->type == string)
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errx(ERR_EXIT, "not a decimal number: '%s'", vp->u.s);
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if (!to_integer(vp))
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errx(ERR_EXIT, "operand too large: '%s'", vp->u.s);
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}
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void
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to_string(struct val *vp)
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{
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char *tmp;
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if (vp->type == string || vp->type == numeric_string)
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return;
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/*
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* log_10(x) ~= 0.3 * log_2(x). Rounding up gives the number
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* of digits; add one each for the sign and terminating null
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* character, respectively.
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*/
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#define NDIGITS(x) (3 * (sizeof(x) * CHAR_BIT) / 10 + 1 + 1 + 1)
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tmp = malloc(NDIGITS(vp->u.i));
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if (tmp == NULL)
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errx(ERR_EXIT, "malloc() failed");
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sprintf(tmp, "%jd", vp->u.i);
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vp->type = string;
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vp->u.s = tmp;
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}
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int
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is_integer(const char *s)
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{
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if (nonposix) {
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if (*s == '\0')
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return (1);
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while (isspace((unsigned char)*s))
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s++;
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}
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if (*s == '-' || (nonposix && *s == '+'))
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s++;
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if (*s == '\0')
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return (0);
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while (isdigit((unsigned char)*s))
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s++;
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return (*s == '\0');
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}
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int
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is_string(struct val *vp)
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{
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/* only TRUE if this string is not a valid integer */
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return (vp->type == string);
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}
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int
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yylex(void)
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{
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char *p;
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if (*av == NULL)
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return (0);
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p = *av++;
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if (strlen(p) == 1) {
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if (strchr("|&=<>+-*/%:()", *p))
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return (*p);
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} else if (strlen(p) == 2 && p[1] == '=') {
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switch (*p) {
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case '>': return (GE);
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case '<': return (LE);
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case '!': return (NE);
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}
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}
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yylval.val = make_str(p);
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return (TOKEN);
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}
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int
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is_zero_or_null(struct val *vp)
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{
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if (vp->type == integer)
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return (vp->u.i == 0);
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return (*vp->u.s == 0 || (to_integer(vp) && vp->u.i == 0));
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}
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int
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main(int argc, char *argv[])
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{
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int c;
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setlocale(LC_ALL, "");
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if (getenv("EXPR_COMPAT") != NULL
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|| check_utility_compat("expr")) {
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av = argv + 1;
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nonposix = 1;
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} else {
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while ((c = getopt(argc, argv, "e")) != -1) {
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switch (c) {
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case 'e':
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nonposix = 1;
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break;
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default:
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errx(ERR_EXIT,
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"usage: expr [-e] expression\n");
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}
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}
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av = argv + optind;
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}
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yyparse();
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if (result->type == integer)
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printf("%jd\n", result->u.i);
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else
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printf("%s\n", result->u.s);
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return (is_zero_or_null(result));
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}
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int
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yyerror(const char *s __unused)
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{
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errx(ERR_EXIT, "syntax error");
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}
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struct val *
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op_or(struct val *a, struct val *b)
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{
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if (!is_zero_or_null(a)) {
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free_value(b);
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return (a);
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}
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free_value(a);
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if (!is_zero_or_null(b))
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return (b);
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free_value(b);
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return (make_integer((intmax_t)0));
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}
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struct val *
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op_and(struct val *a, struct val *b)
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{
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if (is_zero_or_null(a) || is_zero_or_null(b)) {
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free_value(a);
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free_value(b);
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return (make_integer((intmax_t)0));
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} else {
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free_value(b);
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return (a);
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}
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}
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int
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compare_vals(struct val *a, struct val *b)
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{
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int r;
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if (is_string(a) || is_string(b)) {
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to_string(a);
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to_string(b);
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r = strcoll(a->u.s, b->u.s);
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} else {
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assert_to_integer(a);
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assert_to_integer(b);
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if (a->u.i > b->u.i)
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r = 1;
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else if (a->u.i < b->u.i)
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r = -1;
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else
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r = 0;
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}
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free_value(a);
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free_value(b);
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return (r);
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}
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struct val *
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op_eq(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) == 0)));
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}
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struct val *
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op_gt(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) > 0)));
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}
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struct val *
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op_lt(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) < 0)));
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}
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struct val *
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op_ge(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) >= 0)));
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}
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struct val *
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op_le(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) <= 0)));
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}
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struct val *
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op_ne(struct val *a, struct val *b)
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{
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return (make_integer((intmax_t)(compare_vals(a, b) != 0)));
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}
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void
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assert_plus(intmax_t a, intmax_t b, intmax_t r)
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{
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/*
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* sum of two positive numbers must be positive,
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* sum of two negative numbers must be negative
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*/
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if ((a > 0 && b > 0 && r <= 0) ||
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(a < 0 && b < 0 && r >= 0))
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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op_plus(struct val *a, struct val *b)
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{
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struct val *r;
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer(a->u.i + b->u.i);
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assert_plus(a->u.i, b->u.i, r->u.i);
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free_value(a);
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free_value(b);
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return (r);
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}
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void
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assert_minus(intmax_t a, intmax_t b, intmax_t r)
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{
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if ((a >= 0 && b < 0 && r <= 0) ||
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(a < 0 && b > 0 && r >= 0))
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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op_minus(struct val *a, struct val *b)
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{
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struct val *r;
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer(a->u.i - b->u.i);
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assert_minus(a->u.i, b->u.i, r->u.i);
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free_value(a);
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free_value(b);
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return (r);
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}
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/*
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* We depend on undefined behaviour giving a result (in r).
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* To test this result, pass it as volatile. This prevents
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* optimizing away of the test based on the undefined behaviour.
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*/
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void
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assert_times(intmax_t a, intmax_t b, volatile intmax_t r)
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{
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/*
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* If the first operand is 0, no overflow is possible,
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* else the result of the division test must match the
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* second operand.
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*
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* Be careful to avoid overflow in the overflow test, as
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* in assert_div(). Overflow in division would kill us
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* with a SIGFPE before getting the test wrong. In old
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* buggy versions, optimization used to give a null test
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* instead of a SIGFPE.
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*/
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if ((a == -1 && b == INTMAX_MIN) || (a != 0 && r / a != b))
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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op_times(struct val *a, struct val *b)
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{
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struct val *r;
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assert_to_integer(a);
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assert_to_integer(b);
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r = make_integer(a->u.i * b->u.i);
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assert_times(a->u.i, b->u.i, r->u.i);
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free_value(a);
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free_value(b);
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return (r);
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}
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void
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assert_div(intmax_t a, intmax_t b)
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{
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if (b == 0)
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errx(ERR_EXIT, "division by zero");
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/* only INTMAX_MIN / -1 causes overflow */
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if (a == INTMAX_MIN && b == -1)
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errx(ERR_EXIT, "overflow");
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}
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struct val *
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op_div(struct val *a, struct val *b)
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{
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struct val *r;
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assert_to_integer(a);
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assert_to_integer(b);
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/* assert based on operands only, not on result */
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assert_div(a->u.i, b->u.i);
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r = make_integer(a->u.i / b->u.i);
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free_value(a);
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free_value(b);
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return (r);
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}
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struct val *
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op_rem(struct val *a, struct val *b)
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{
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struct val *r;
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assert_to_integer(a);
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assert_to_integer(b);
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/* pass a=1 to only check for div by zero */
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assert_div(1, b->u.i);
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r = make_integer(a->u.i % b->u.i);
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free_value(a);
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free_value(b);
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return (r);
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}
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struct val *
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op_colon(struct val *a, struct val *b)
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{
|
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regex_t rp;
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regmatch_t rm[2];
|
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char errbuf[256];
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int eval;
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struct val *v;
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/* coerce both arguments to strings */
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to_string(a);
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to_string(b);
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/* compile regular expression */
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if ((eval = regcomp(&rp, b->u.s, 0)) != 0) {
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regerror(eval, &rp, errbuf, sizeof(errbuf));
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errx(ERR_EXIT, "%s", errbuf);
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}
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/* compare string against pattern */
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/* remember that patterns are anchored to the beginning of the line */
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if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0)
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if (rm[1].rm_so >= 0) {
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*(a->u.s + rm[1].rm_eo) = '\0';
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v = make_str(a->u.s + rm[1].rm_so);
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} else
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v = make_integer((intmax_t)(rm[0].rm_eo));
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else
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if (rp.re_nsub == 0)
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v = make_integer((intmax_t)0);
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else
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v = make_str("");
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/* free arguments and pattern buffer */
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free_value(a);
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free_value(b);
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regfree(&rp);
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|
|
|
return (v);
|
|
}
|