584 lines
13 KiB
C
584 lines
13 KiB
C
/** $MirBSD: expr.c,v 1.7 2004/10/28 11:53:41 tg Exp $ */
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/* $OpenBSD: expr.c,v 1.9 2003/10/22 07:40:38 jmc Exp $ */
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/*
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* Korn expression evaluation
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*/
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#include "sh.h"
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#include <ctype.h>
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__RCSID("$MirBSD: expr.c,v 1.7 2004/10/28 11:53:41 tg Exp $");
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/* The order of these enums is constrained by the order of opinfo[] */
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enum token {
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/* some (long) unary operators */
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O_PLUSPLUS = 0, O_MINUSMINUS,
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/* binary operators */
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O_EQ, O_NE,
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/* assignments are assumed to be in range O_ASN .. O_BORASN */
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O_ASN, O_TIMESASN, O_DIVASN, O_MODASN, O_PLUSASN, O_MINUSASN,
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O_LSHIFTASN, O_RSHIFTASN, O_BANDASN, O_BXORASN, O_BORASN,
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O_LSHIFT, O_RSHIFT,
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O_LE, O_GE, O_LT, O_GT,
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O_LAND,
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O_LOR,
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O_TIMES, O_DIV, O_MOD,
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O_PLUS, O_MINUS,
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O_BAND,
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O_BXOR,
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O_BOR,
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O_TERN,
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O_COMMA,
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/* things after this aren't used as binary operators */
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/* unary that are not also binaries */
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O_BNOT, O_LNOT,
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/* misc */
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OPEN_PAREN, CLOSE_PAREN, CTERN,
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/* things that don't appear in the opinfo[] table */
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VAR, LIT, END, BAD
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};
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#define IS_BINOP(op) (((int)op) >= (int)O_EQ && ((int)op) <= (int)O_COMMA)
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#define IS_ASSIGNOP(op) ((int)(op) >= (int)O_ASN && (int)(op) <= (int)O_BORASN)
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enum prec {
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P_PRIMARY = 0, /* VAR, LIT, (), ~ ! - + */
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P_MULT, /* * / % */
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P_ADD, /* + - */
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P_SHIFT, /* << >> */
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P_RELATION, /* < <= > >= */
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P_EQUALITY, /* == != */
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P_BAND, /* & */
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P_BXOR, /* ^ */
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P_BOR, /* | */
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P_LAND, /* && */
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P_LOR, /* || */
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P_TERN, /* ?: */
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P_ASSIGN, /* = *= /= %= += -= <<= >>= &= ^= |= */
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P_COMMA /* , */
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};
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#define MAX_PREC P_COMMA
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struct opinfo {
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char name[4];
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int len; /* name length */
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enum prec prec; /* precedence: lower is higher */
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};
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/* Tokens in this table must be ordered so the longest are first
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* (eg, += before +). If you change something, change the order
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* of enum token too.
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*/
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static const struct opinfo opinfo[] = {
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{ "++", 2, P_PRIMARY }, /* before + */
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{ "--", 2, P_PRIMARY }, /* before - */
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{ "==", 2, P_EQUALITY }, /* before = */
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{ "!=", 2, P_EQUALITY }, /* before ! */
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{ "=", 1, P_ASSIGN }, /* keep assigns in a block */
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{ "*=", 2, P_ASSIGN },
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{ "/=", 2, P_ASSIGN },
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{ "%=", 2, P_ASSIGN },
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{ "+=", 2, P_ASSIGN },
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{ "-=", 2, P_ASSIGN },
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{ "<<=", 3, P_ASSIGN },
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{ ">>=", 3, P_ASSIGN },
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{ "&=", 2, P_ASSIGN },
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{ "^=", 2, P_ASSIGN },
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{ "|=", 2, P_ASSIGN },
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{ "<<", 2, P_SHIFT },
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{ ">>", 2, P_SHIFT },
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{ "<=", 2, P_RELATION },
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{ ">=", 2, P_RELATION },
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{ "<", 1, P_RELATION },
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{ ">", 1, P_RELATION },
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{ "&&", 2, P_LAND },
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{ "||", 2, P_LOR },
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{ "*", 1, P_MULT },
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{ "/", 1, P_MULT },
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{ "%", 1, P_MULT },
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{ "+", 1, P_ADD },
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{ "-", 1, P_ADD },
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{ "&", 1, P_BAND },
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{ "^", 1, P_BXOR },
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{ "|", 1, P_BOR },
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{ "?", 1, P_TERN },
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{ ",", 1, P_COMMA },
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{ "~", 1, P_PRIMARY },
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{ "!", 1, P_PRIMARY },
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{ "(", 1, P_PRIMARY },
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{ ")", 1, P_PRIMARY },
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{ ":", 1, P_PRIMARY },
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{ "", 0, P_PRIMARY } /* end of table */
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};
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typedef struct expr_state Expr_state;
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struct expr_state {
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const char *expression; /* expression being evaluated */
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const char *tokp; /* lexical position */
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enum token tok; /* token from token() */
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int noassign; /* don't do assigns (for ?:,&&,||) */
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struct tbl *val; /* value from token() */
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struct tbl *evaling; /* variable that is being recursively
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* expanded (EXPRINEVAL flag set)
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*/
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};
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enum error_type { ET_UNEXPECTED, ET_BADLIT, ET_RECURSIVE,
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ET_LVALUE, ET_RDONLY, ET_STR };
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static void evalerr(Expr_state *es, enum error_type type,
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const char *str) GCC_FUNC_ATTR(noreturn);
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static struct tbl *evalexpr(Expr_state *es, enum prec prec);
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static void token(Expr_state *es);
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static struct tbl *do_ppmm(Expr_state *es, enum token op,
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struct tbl *vasn, bool_t is_prefix);
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static void assign_check(Expr_state *es, enum token op,
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struct tbl *vasn);
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static struct tbl *tempvar(void);
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static struct tbl *intvar(Expr_state *es, struct tbl *vp);
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/*
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* parse and evaluate expression
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*/
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int
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evaluate(const char *expr, long int *rval, int error_ok)
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{
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struct tbl v;
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int ret;
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v.flag = DEFINED|INTEGER;
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v.type = 0;
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ret = v_evaluate(&v, expr, error_ok);
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*rval = v.val.i;
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return ret;
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}
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/*
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* parse and evaluate expression, storing result in vp.
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*/
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int
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v_evaluate(struct tbl *vp, const char *expr, volatile int error_ok)
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{
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struct tbl *v;
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Expr_state curstate;
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Expr_state * const es = &curstate;
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int i;
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/* save state to allow recursive calls */
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curstate.expression = curstate.tokp = expr;
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curstate.noassign = 0;
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curstate.evaling = (struct tbl *) 0;
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newenv(E_ERRH);
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i = ksh_sigsetjmp(e->jbuf, 0);
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if (i) {
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/* Clear EXPRINEVAL in of any variables we were playing with */
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if (curstate.evaling)
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curstate.evaling->flag &= ~EXPRINEVAL;
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quitenv();
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if (i == LAEXPR) {
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if (error_ok == KSH_RETURN_ERROR)
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return 0;
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errorf(null);
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}
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unwind(i);
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/*NOTREACHED*/
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}
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token(es);
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if (es->tok == END) {
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es->tok = LIT;
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es->val = tempvar();
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}
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v = intvar(es, evalexpr(es, MAX_PREC));
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if (es->tok != END)
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evalerr(es, ET_UNEXPECTED, (char *) 0);
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if (vp->flag & INTEGER)
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setint_v(vp, v);
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else
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/* can fail if readonly */
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setstr(vp, str_val(v), error_ok);
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quitenv();
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return 1;
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}
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static void
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evalerr(Expr_state *es, enum error_type type, const char *str)
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{
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char tbuf[2];
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const char *s;
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switch (type) {
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case ET_UNEXPECTED:
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switch (es->tok) {
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case VAR:
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s = es->val->name;
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break;
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case LIT:
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s = str_val(es->val);
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break;
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case END:
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s = "end of expression";
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break;
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case BAD:
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tbuf[0] = *es->tokp;
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tbuf[1] = '\0';
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s = tbuf;
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break;
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default:
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s = opinfo[(int)es->tok].name;
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}
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warningf(TRUE, "%s: unexpected '%s'", es->expression, s);
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break;
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case ET_BADLIT:
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warningf(TRUE, "%s: bad number '%s'", es->expression, str);
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break;
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case ET_RECURSIVE:
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warningf(TRUE, "%s: expression recurses on parameter '%s'",
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es->expression, str);
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break;
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case ET_LVALUE:
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warningf(TRUE, "%s: %s requires lvalue",
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es->expression, str);
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break;
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case ET_RDONLY:
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warningf(TRUE, "%s: %s applied to read only variable",
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es->expression, str);
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break;
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default: /* keep gcc happy */
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case ET_STR:
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warningf(TRUE, "%s: %s", es->expression, str);
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break;
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}
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unwind(LAEXPR);
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}
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static struct tbl *
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evalexpr(Expr_state *es, enum prec prec)
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{
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struct tbl *vl, UNINITIALIZED(*vr), *vasn;
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enum token op;
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long UNINITIALIZED(res);
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if (prec == P_PRIMARY) {
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op = es->tok;
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if (op == O_BNOT || op == O_LNOT || op == O_MINUS
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|| op == O_PLUS)
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{
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token(es);
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vl = intvar(es, evalexpr(es, P_PRIMARY));
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if (op == O_BNOT)
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vl->val.i = ~vl->val.i;
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else if (op == O_LNOT)
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vl->val.i = !vl->val.i;
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else if (op == O_MINUS)
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vl->val.i = -vl->val.i;
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/* op == O_PLUS is a no-op */
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} else if (op == OPEN_PAREN) {
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token(es);
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vl = evalexpr(es, MAX_PREC);
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if (es->tok != CLOSE_PAREN)
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evalerr(es, ET_STR, "missing )");
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token(es);
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} else if (op == O_PLUSPLUS || op == O_MINUSMINUS) {
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token(es);
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vl = do_ppmm(es, op, es->val, TRUE);
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token(es);
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} else if (op == VAR || op == LIT) {
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vl = es->val;
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token(es);
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} else {
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evalerr(es, ET_UNEXPECTED, (char *) 0);
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/*NOTREACHED*/
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}
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if (es->tok == O_PLUSPLUS || es->tok == O_MINUSMINUS) {
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vl = do_ppmm(es, es->tok, vl, FALSE);
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token(es);
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}
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return vl;
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}
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vl = evalexpr(es, ((int) prec) - 1);
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for (op = es->tok; IS_BINOP(op) && opinfo[(int) op].prec == prec;
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op = es->tok)
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{
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token(es);
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vasn = vl;
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if (op != O_ASN) /* vl may not have a value yet */
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vl = intvar(es, vl);
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if (IS_ASSIGNOP(op)) {
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assign_check(es, op, vasn);
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vr = intvar(es, evalexpr(es, P_ASSIGN));
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} else if (op != O_TERN && op != O_LAND && op != O_LOR)
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vr = intvar(es, evalexpr(es, ((int) prec) - 1));
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if ((op == O_DIV || op == O_MOD || op == O_DIVASN
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|| op == O_MODASN) && vr->val.i == 0)
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{
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if (es->noassign)
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vr->val.i = 1;
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else
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evalerr(es, ET_STR, "zero divisor");
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}
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switch ((int) op) {
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case O_TIMES:
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case O_TIMESASN:
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res = vl->val.i * vr->val.i;
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break;
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case O_DIV:
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case O_DIVASN:
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res = vl->val.i / vr->val.i;
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break;
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case O_MOD:
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case O_MODASN:
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res = vl->val.i % vr->val.i;
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break;
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case O_PLUS:
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case O_PLUSASN:
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res = vl->val.i + vr->val.i;
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break;
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case O_MINUS:
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case O_MINUSASN:
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res = vl->val.i - vr->val.i;
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break;
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case O_LSHIFT:
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case O_LSHIFTASN:
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res = vl->val.i << vr->val.i;
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break;
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case O_RSHIFT:
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case O_RSHIFTASN:
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res = vl->val.i >> vr->val.i;
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break;
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case O_LT:
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res = vl->val.i < vr->val.i;
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break;
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case O_LE:
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res = vl->val.i <= vr->val.i;
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break;
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case O_GT:
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res = vl->val.i > vr->val.i;
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break;
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case O_GE:
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res = vl->val.i >= vr->val.i;
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break;
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case O_EQ:
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res = vl->val.i == vr->val.i;
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break;
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case O_NE:
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res = vl->val.i != vr->val.i;
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break;
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case O_BAND:
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case O_BANDASN:
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res = vl->val.i & vr->val.i;
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break;
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case O_BXOR:
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case O_BXORASN:
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res = vl->val.i ^ vr->val.i;
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break;
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case O_BOR:
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case O_BORASN:
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res = vl->val.i | vr->val.i;
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break;
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case O_LAND:
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if (!vl->val.i)
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es->noassign++;
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vr = intvar(es, evalexpr(es, ((int) prec) - 1));
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res = vl->val.i && vr->val.i;
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if (!vl->val.i)
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es->noassign--;
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break;
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case O_LOR:
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if (vl->val.i)
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es->noassign++;
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vr = intvar(es, evalexpr(es, ((int) prec) - 1));
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res = vl->val.i || vr->val.i;
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if (vl->val.i)
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es->noassign--;
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break;
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case O_TERN:
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{
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int e = vl->val.i != 0;
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if (!e)
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es->noassign++;
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vl = evalexpr(es, MAX_PREC);
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if (!e)
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es->noassign--;
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if (es->tok != CTERN)
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evalerr(es, ET_STR, "missing :");
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token(es);
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if (e)
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es->noassign++;
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vr = evalexpr(es, P_TERN);
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if (e)
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es->noassign--;
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vl = e ? vl : vr;
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}
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break;
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case O_ASN:
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res = vr->val.i;
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break;
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case O_COMMA:
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res = vr->val.i;
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break;
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}
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if (IS_ASSIGNOP(op)) {
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vr->val.i = res;
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if (vasn->flag & INTEGER)
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setint_v(vasn, vr);
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else
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setint(vasn, res);
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vl = vr;
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} else if (op != O_TERN)
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vl->val.i = res;
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}
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return vl;
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}
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static void
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token(Expr_state *es)
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{
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const char *cp;
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int c;
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char *tvar;
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/* skip white space */
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for (cp = es->tokp; (c = *cp), isspace(c); cp++)
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;
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es->tokp = cp;
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if (c == '\0')
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es->tok = END;
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else if (letter(c)) {
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for (; letnum(c); c = *cp)
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cp++;
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if (c == '[') {
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int len;
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len = array_ref_len(cp);
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if (len == 0)
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evalerr(es, ET_STR, "missing ]");
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cp += len;
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}
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#ifdef KSH
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else if (c == '(' /*)*/ ) {
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/* todo: add math functions (all take single argument):
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* abs acos asin atan cos cosh exp int log sin sinh sqrt
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* tan tanh
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*/
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;
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}
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#endif /* KSH */
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if (es->noassign) {
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es->val = tempvar();
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es->val->flag |= EXPRLVALUE;
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} else {
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tvar = str_nsave(es->tokp, cp - es->tokp, ATEMP);
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es->val = global(tvar);
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afree(tvar, ATEMP);
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}
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es->tok = VAR;
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} else if (digit(c)) {
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for (; c != '_' && (letnum(c) || c == '#'); c = *cp++)
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;
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tvar = str_nsave(es->tokp, --cp - es->tokp, ATEMP);
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es->val = tempvar();
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es->val->flag &= ~INTEGER;
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es->val->type = 0;
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es->val->val.s = tvar;
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if (setint_v(es->val, es->val) == NULL)
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evalerr(es, ET_BADLIT, tvar);
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afree(tvar, ATEMP);
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es->tok = LIT;
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} else {
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int i, n0;
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for (i = 0; (n0 = opinfo[i].name[0]); i++)
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if (c == n0
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&& strncmp(cp, opinfo[i].name, opinfo[i].len) == 0)
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{
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es->tok = (enum token) i;
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cp += opinfo[i].len;
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break;
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}
|
|
if (!n0)
|
|
es->tok = BAD;
|
|
}
|
|
es->tokp = cp;
|
|
}
|
|
|
|
/* Do a ++ or -- operation */
|
|
static struct tbl *
|
|
do_ppmm(Expr_state *es, enum token op, struct tbl *vasn, bool_t is_prefix)
|
|
{
|
|
struct tbl *vl;
|
|
int oval;
|
|
|
|
assign_check(es, op, vasn);
|
|
|
|
vl = intvar(es, vasn);
|
|
oval = op == O_PLUSPLUS ? vl->val.i++ : vl->val.i--;
|
|
if (vasn->flag & INTEGER)
|
|
setint_v(vasn, vl);
|
|
else
|
|
setint(vasn, vl->val.i);
|
|
if (!is_prefix) /* undo the inc/dec */
|
|
vl->val.i = oval;
|
|
|
|
return vl;
|
|
}
|
|
|
|
static void
|
|
assign_check(Expr_state *es, enum token op, struct tbl *vasn)
|
|
{
|
|
if (vasn->name[0] == '\0' && !(vasn->flag & EXPRLVALUE))
|
|
evalerr(es, ET_LVALUE, opinfo[(int) op].name);
|
|
else if (vasn->flag & RDONLY)
|
|
evalerr(es, ET_RDONLY, opinfo[(int) op].name);
|
|
}
|
|
|
|
static struct tbl *
|
|
tempvar(void)
|
|
{
|
|
struct tbl *vp;
|
|
|
|
vp = (struct tbl*) alloc(sizeof(struct tbl), ATEMP);
|
|
vp->flag = ISSET|INTEGER;
|
|
vp->type = 0;
|
|
vp->areap = ATEMP;
|
|
vp->val.i = 0;
|
|
vp->name[0] = '\0';
|
|
return vp;
|
|
}
|
|
|
|
/* cast (string) variable to temporary integer variable */
|
|
static struct tbl *
|
|
intvar(Expr_state *es, struct tbl *vp)
|
|
{
|
|
struct tbl *vq;
|
|
|
|
/* try to avoid replacing a temp var with another temp var */
|
|
if (vp->name[0] == '\0'
|
|
&& (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER))
|
|
return vp;
|
|
|
|
vq = tempvar();
|
|
if (setint_v(vq, vp) == NULL) {
|
|
if (vp->flag & EXPRINEVAL)
|
|
evalerr(es, ET_RECURSIVE, vp->name);
|
|
es->evaling = vp;
|
|
vp->flag |= EXPRINEVAL;
|
|
v_evaluate(vq, str_val(vp), KSH_UNWIND_ERROR);
|
|
vp->flag &= ~EXPRINEVAL;
|
|
es->evaling = (struct tbl *) 0;
|
|
}
|
|
return vq;
|
|
}
|