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+/*
+ * arithmetic code ripped out of ash shell for code sharing
+ *
+ * Copyright (c) 1989, 1991, 1993, 1994
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
+ * was re-ported from NetBSD and debianized.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ *
+ * Original BSD copyright notice is retained at the end of this file.
+ */
+/*
+ * rewrite arith.y to micro stack based cryptic algorithm by
+ * Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
+ *
+ * Modified by Paul Mundt <lethal@linux-sh.org> (c) 2004 to support
+ * dynamic variables.
+ *
+ * Modified by Vladimir Oleynik <dzo@simtreas.ru> (c) 2001-2005 to be
+ * used in busybox and size optimizations,
+ * rewrote arith (see notes to this), added locale support,
+ * rewrote dynamic variables.
+ */
+
+#include "busybox.h"
+#include "math.h"
+
+#define a_e_h_t arith_eval_hooks_t
+#define lookupvar (math_hooks->lookupvar)
+#define setvar (math_hooks->setvar)
+#define endofname (math_hooks->endofname)
+
+/* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+/* This is my infix parser/evaluator. It is optimized for size, intended
+ * as a replacement for yacc-based parsers. However, it may well be faster
+ * than a comparable parser written in yacc. The supported operators are
+ * listed in #defines below. Parens, order of operations, and error handling
+ * are supported. This code is thread safe. The exact expression format should
+ * be that which POSIX specifies for shells. */
+
+/* The code uses a simple two-stack algorithm. See
+ * http://www.onthenet.com.au/~grahamis/int2008/week02/lect02.html
+ * for a detailed explanation of the infix-to-postfix algorithm on which
+ * this is based (this code differs in that it applies operators immediately
+ * to the stack instead of adding them to a queue to end up with an
+ * expression). */
+
+/* To use the routine, call it with an expression string and error return
+ * pointer */
+
+/*
+ * Aug 24, 2001 Manuel Novoa III
+ *
+ * Reduced the generated code size by about 30% (i386) and fixed several bugs.
+ *
+ * 1) In arith_apply():
+ * a) Cached values of *numptr and &(numptr[-1]).
+ * b) Removed redundant test for zero denominator.
+ *
+ * 2) In arith():
+ * a) Eliminated redundant code for processing operator tokens by moving
+ * to a table-based implementation. Also folded handling of parens
+ * into the table.
+ * b) Combined all 3 loops which called arith_apply to reduce generated
+ * code size at the cost of speed.
+ *
+ * 3) The following expressions were treated as valid by the original code:
+ * 1() , 0! , 1 ( *3 ) .
+ * These bugs have been fixed by internally enclosing the expression in
+ * parens and then checking that all binary ops and right parens are
+ * preceded by a valid expression (NUM_TOKEN).
+ *
+ * Note: It may be desirable to replace Aaron's test for whitespace with
+ * ctype's isspace() if it is used by another busybox applet or if additional
+ * whitespace chars should be considered. Look below the "#include"s for a
+ * precompiler test.
+ */
+
+/*
+ * Aug 26, 2001 Manuel Novoa III
+ *
+ * Return 0 for null expressions. Pointed out by Vladimir Oleynik.
+ *
+ * Merge in Aaron's comments previously posted to the busybox list,
+ * modified slightly to take account of my changes to the code.
+ *
+ */
+
+/*
+ * (C) 2003 Vladimir Oleynik <dzo@simtreas.ru>
+ *
+ * - allow access to variable,
+ * used recursive find value indirection (c=2*2; a="c"; $((a+=2)) produce 6)
+ * - realize assign syntax (VAR=expr, +=, *= etc)
+ * - realize exponentiation (** operator)
+ * - realize comma separated - expr, expr
+ * - realise ++expr --expr expr++ expr--
+ * - realise expr ? expr : expr (but, second expr calculate always)
+ * - allow hexadecimal and octal numbers
+ * - was restored loses XOR operator
+ * - remove one goto label, added three ;-)
+ * - protect $((num num)) as true zero expr (Manuel`s error)
+ * - always use special isspace(), see comment from bash ;-)
+ */
+
+#define arith_isspace(arithval) \
+ (arithval == ' ' || arithval == '\n' || arithval == '\t')
+
+typedef unsigned char operator;
+
+/* An operator's token id is a bit of a bitfield. The lower 5 bits are the
+ * precedence, and 3 high bits are an ID unique across operators of that
+ * precedence. The ID portion is so that multiple operators can have the
+ * same precedence, ensuring that the leftmost one is evaluated first.
+ * Consider * and /. */
+
+#define tok_decl(prec,id) (((id)<<5)|(prec))
+#define PREC(op) ((op) & 0x1F)
+
+#define TOK_LPAREN tok_decl(0,0)
+
+#define TOK_COMMA tok_decl(1,0)
+
+#define TOK_ASSIGN tok_decl(2,0)
+#define TOK_AND_ASSIGN tok_decl(2,1)
+#define TOK_OR_ASSIGN tok_decl(2,2)
+#define TOK_XOR_ASSIGN tok_decl(2,3)
+#define TOK_PLUS_ASSIGN tok_decl(2,4)
+#define TOK_MINUS_ASSIGN tok_decl(2,5)
+#define TOK_LSHIFT_ASSIGN tok_decl(2,6)
+#define TOK_RSHIFT_ASSIGN tok_decl(2,7)
+
+#define TOK_MUL_ASSIGN tok_decl(3,0)
+#define TOK_DIV_ASSIGN tok_decl(3,1)
+#define TOK_REM_ASSIGN tok_decl(3,2)
+
+/* all assign is right associativity and precedence eq, but (7+3)<<5 > 256 */
+#define convert_prec_is_assing(prec) do { if (prec == 3) prec = 2; } while (0)
+
+/* conditional is right associativity too */
+#define TOK_CONDITIONAL tok_decl(4,0)
+#define TOK_CONDITIONAL_SEP tok_decl(4,1)
+
+#define TOK_OR tok_decl(5,0)
+
+#define TOK_AND tok_decl(6,0)
+
+#define TOK_BOR tok_decl(7,0)
+
+#define TOK_BXOR tok_decl(8,0)
+
+#define TOK_BAND tok_decl(9,0)
+
+#define TOK_EQ tok_decl(10,0)
+#define TOK_NE tok_decl(10,1)
+
+#define TOK_LT tok_decl(11,0)
+#define TOK_GT tok_decl(11,1)
+#define TOK_GE tok_decl(11,2)
+#define TOK_LE tok_decl(11,3)
+
+#define TOK_LSHIFT tok_decl(12,0)
+#define TOK_RSHIFT tok_decl(12,1)
+
+#define TOK_ADD tok_decl(13,0)
+#define TOK_SUB tok_decl(13,1)
+
+#define TOK_MUL tok_decl(14,0)
+#define TOK_DIV tok_decl(14,1)
+#define TOK_REM tok_decl(14,2)
+
+/* exponent is right associativity */
+#define TOK_EXPONENT tok_decl(15,1)
+
+/* For now unary operators. */
+#define UNARYPREC 16
+#define TOK_BNOT tok_decl(UNARYPREC,0)
+#define TOK_NOT tok_decl(UNARYPREC,1)
+
+#define TOK_UMINUS tok_decl(UNARYPREC+1,0)
+#define TOK_UPLUS tok_decl(UNARYPREC+1,1)
+
+#define PREC_PRE (UNARYPREC+2)
+
+#define TOK_PRE_INC tok_decl(PREC_PRE, 0)
+#define TOK_PRE_DEC tok_decl(PREC_PRE, 1)
+
+#define PREC_POST (UNARYPREC+3)
+
+#define TOK_POST_INC tok_decl(PREC_POST, 0)
+#define TOK_POST_DEC tok_decl(PREC_POST, 1)
+
+#define SPEC_PREC (UNARYPREC+4)
+
+#define TOK_NUM tok_decl(SPEC_PREC, 0)
+#define TOK_RPAREN tok_decl(SPEC_PREC, 1)
+
+#define NUMPTR (*numstackptr)
+
+static int
+tok_have_assign(operator op)
+{
+ operator prec = PREC(op);
+
+ convert_prec_is_assing(prec);
+ return (prec == PREC(TOK_ASSIGN) ||
+ prec == PREC_PRE || prec == PREC_POST);
+}
+
+static int
+is_right_associativity(operator prec)
+{
+ return (prec == PREC(TOK_ASSIGN) || prec == PREC(TOK_EXPONENT)
+ || prec == PREC(TOK_CONDITIONAL));
+}
+
+typedef struct {
+ arith_t val;
+ arith_t contidional_second_val;
+ char contidional_second_val_initialized;
+ char *var; /* if NULL then is regular number,
+ else is variable name */
+} v_n_t;
+
+typedef struct chk_var_recursive_looped_t {
+ const char *var;
+ struct chk_var_recursive_looped_t *next;
+} chk_var_recursive_looped_t;
+
+static chk_var_recursive_looped_t *prev_chk_var_recursive;
+
+static int
+arith_lookup_val(v_n_t *t, a_e_h_t *math_hooks)
+{
+ if (t->var) {
+ const char * p = lookupvar(t->var);
+
+ if (p) {
+ int errcode;
+
+ /* recursive try as expression */
+ chk_var_recursive_looped_t *cur;
+ chk_var_recursive_looped_t cur_save;
+
+ for (cur = prev_chk_var_recursive; cur; cur = cur->next) {
+ if (strcmp(cur->var, t->var) == 0) {
+ /* expression recursion loop detected */
+ return -5;
+ }
+ }
+ /* save current lookuped var name */
+ cur = prev_chk_var_recursive;
+ cur_save.var = t->var;
+ cur_save.next = cur;
+ prev_chk_var_recursive = &cur_save;
+
+ t->val = arith (p, &errcode, math_hooks);
+ /* restore previous ptr after recursiving */
+ prev_chk_var_recursive = cur;
+ return errcode;
+ }
+ /* allow undefined var as 0 */
+ t->val = 0;
+ }
+ return 0;
+}
+
+/* "applying" a token means performing it on the top elements on the integer
+ * stack. For a unary operator it will only change the top element, but a
+ * binary operator will pop two arguments and push a result */
+static int
+arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr, a_e_h_t *math_hooks)
+{
+ v_n_t *numptr_m1;
+ arith_t numptr_val, rez;
+ int ret_arith_lookup_val;
+
+ /* There is no operator that can work without arguments */
+ if (NUMPTR == numstack) goto err;
+ numptr_m1 = NUMPTR - 1;
+
+ /* check operand is var with noninteger value */
+ ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
+ if (ret_arith_lookup_val)
+ return ret_arith_lookup_val;
+
+ rez = numptr_m1->val;
+ if (op == TOK_UMINUS)
+ rez *= -1;
+ else if (op == TOK_NOT)
+ rez = !rez;
+ else if (op == TOK_BNOT)
+ rez = ~rez;
+ else if (op == TOK_POST_INC || op == TOK_PRE_INC)
+ rez++;
+ else if (op == TOK_POST_DEC || op == TOK_PRE_DEC)
+ rez--;
+ else if (op != TOK_UPLUS) {
+ /* Binary operators */
+
+ /* check and binary operators need two arguments */
+ if (numptr_m1 == numstack) goto err;
+
+ /* ... and they pop one */
+ --NUMPTR;
+ numptr_val = rez;
+ if (op == TOK_CONDITIONAL) {
+ if (!numptr_m1->contidional_second_val_initialized) {
+ /* protect $((expr1 ? expr2)) without ": expr" */
+ goto err;
+ }
+ rez = numptr_m1->contidional_second_val;
+ } else if (numptr_m1->contidional_second_val_initialized) {
+ /* protect $((expr1 : expr2)) without "expr ? " */
+ goto err;
+ }
+ numptr_m1 = NUMPTR - 1;
+ if (op != TOK_ASSIGN) {
+ /* check operand is var with noninteger value for not '=' */
+ ret_arith_lookup_val = arith_lookup_val(numptr_m1, math_hooks);
+ if (ret_arith_lookup_val)
+ return ret_arith_lookup_val;
+ }
+ if (op == TOK_CONDITIONAL) {
+ numptr_m1->contidional_second_val = rez;
+ }
+ rez = numptr_m1->val;
+ if (op == TOK_BOR || op == TOK_OR_ASSIGN)
+ rez |= numptr_val;
+ else if (op == TOK_OR)
+ rez = numptr_val || rez;
+ else if (op == TOK_BAND || op == TOK_AND_ASSIGN)
+ rez &= numptr_val;
+ else if (op == TOK_BXOR || op == TOK_XOR_ASSIGN)
+ rez ^= numptr_val;
+ else if (op == TOK_AND)
+ rez = rez && numptr_val;
+ else if (op == TOK_EQ)
+ rez = (rez == numptr_val);
+ else if (op == TOK_NE)
+ rez = (rez != numptr_val);
+ else if (op == TOK_GE)
+ rez = (rez >= numptr_val);
+ else if (op == TOK_RSHIFT || op == TOK_RSHIFT_ASSIGN)
+ rez >>= numptr_val;
+ else if (op == TOK_LSHIFT || op == TOK_LSHIFT_ASSIGN)
+ rez <<= numptr_val;
+ else if (op == TOK_GT)
+ rez = (rez > numptr_val);
+ else if (op == TOK_LT)
+ rez = (rez < numptr_val);
+ else if (op == TOK_LE)
+ rez = (rez <= numptr_val);
+ else if (op == TOK_MUL || op == TOK_MUL_ASSIGN)
+ rez *= numptr_val;
+ else if (op == TOK_ADD || op == TOK_PLUS_ASSIGN)
+ rez += numptr_val;
+ else if (op == TOK_SUB || op == TOK_MINUS_ASSIGN)
+ rez -= numptr_val;
+ else if (op == TOK_ASSIGN || op == TOK_COMMA)
+ rez = numptr_val;
+ else if (op == TOK_CONDITIONAL_SEP) {
+ if (numptr_m1 == numstack) {
+ /* protect $((expr : expr)) without "expr ? " */
+ goto err;
+ }
+ numptr_m1->contidional_second_val_initialized = op;
+ numptr_m1->contidional_second_val = numptr_val;
+ } else if (op == TOK_CONDITIONAL) {
+ rez = rez ?
+ numptr_val : numptr_m1->contidional_second_val;
+ } else if (op == TOK_EXPONENT) {
+ if (numptr_val < 0)
+ return -3; /* exponent less than 0 */
+ else {
+ arith_t c = 1;
+
+ if (numptr_val)
+ while (numptr_val--)
+ c *= rez;
+ rez = c;
+ }
+ } else if (numptr_val==0) /* zero divisor check */
+ return -2;
+ else if (op == TOK_DIV || op == TOK_DIV_ASSIGN)
+ rez /= numptr_val;
+ else if (op == TOK_REM || op == TOK_REM_ASSIGN)
+ rez %= numptr_val;
+ }
+ if (tok_have_assign(op)) {
+ char buf[sizeof(arith_t_type)*3 + 2];
+
+ if (numptr_m1->var == NULL) {
+ /* Hmm, 1=2 ? */
+ goto err;
+ }
+ /* save to shell variable */
+ snprintf(buf, sizeof(buf), arith_t_fmt, (arith_t_type) rez);
+ setvar(numptr_m1->var, buf, 0);
+ /* after saving, make previous value for v++ or v-- */
+ if (op == TOK_POST_INC)
+ rez--;
+ else if (op == TOK_POST_DEC)
+ rez++;
+ }
+ numptr_m1->val = rez;
+ /* protect geting var value, is number now */
+ numptr_m1->var = NULL;
+ return 0;
+ err:
+ return -1;
+}
+
+/* longest must be first */
+static const char op_tokens[] ALIGN1 = {
+ '<','<','=',0, TOK_LSHIFT_ASSIGN,
+ '>','>','=',0, TOK_RSHIFT_ASSIGN,
+ '<','<', 0, TOK_LSHIFT,
+ '>','>', 0, TOK_RSHIFT,
+ '|','|', 0, TOK_OR,
+ '&','&', 0, TOK_AND,
+ '!','=', 0, TOK_NE,
+ '<','=', 0, TOK_LE,
+ '>','=', 0, TOK_GE,
+ '=','=', 0, TOK_EQ,
+ '|','=', 0, TOK_OR_ASSIGN,
+ '&','=', 0, TOK_AND_ASSIGN,
+ '*','=', 0, TOK_MUL_ASSIGN,
+ '/','=', 0, TOK_DIV_ASSIGN,
+ '%','=', 0, TOK_REM_ASSIGN,
+ '+','=', 0, TOK_PLUS_ASSIGN,
+ '-','=', 0, TOK_MINUS_ASSIGN,
+ '-','-', 0, TOK_POST_DEC,
+ '^','=', 0, TOK_XOR_ASSIGN,
+ '+','+', 0, TOK_POST_INC,
+ '*','*', 0, TOK_EXPONENT,
+ '!', 0, TOK_NOT,
+ '<', 0, TOK_LT,
+ '>', 0, TOK_GT,
+ '=', 0, TOK_ASSIGN,
+ '|', 0, TOK_BOR,
+ '&', 0, TOK_BAND,
+ '*', 0, TOK_MUL,
+ '/', 0, TOK_DIV,
+ '%', 0, TOK_REM,
+ '+', 0, TOK_ADD,
+ '-', 0, TOK_SUB,
+ '^', 0, TOK_BXOR,
+ /* uniq */
+ '~', 0, TOK_BNOT,
+ ',', 0, TOK_COMMA,
+ '?', 0, TOK_CONDITIONAL,
+ ':', 0, TOK_CONDITIONAL_SEP,
+ ')', 0, TOK_RPAREN,
+ '(', 0, TOK_LPAREN,
+ 0
+};
+/* ptr to ")" */
+#define endexpression (&op_tokens[sizeof(op_tokens)-7])
+
+arith_t
+arith(const char *expr, int *perrcode, a_e_h_t *math_hooks)
+{
+ char arithval; /* Current character under analysis */
+ operator lasttok, op;
+ operator prec;
+ operator *stack, *stackptr;
+ const char *p = endexpression;
+ int errcode;
+ v_n_t *numstack, *numstackptr;
+ unsigned datasizes = strlen(expr) + 2;
+
+ /* Stack of integers */
+ /* The proof that there can be no more than strlen(startbuf)/2+1 integers
+ * in any given correct or incorrect expression is left as an exercise to
+ * the reader. */
+ numstackptr = numstack = alloca((datasizes / 2) * sizeof(numstack[0]));
+ /* Stack of operator tokens */
+ stackptr = stack = alloca(datasizes * sizeof(stack[0]));
+
+ *stackptr++ = lasttok = TOK_LPAREN; /* start off with a left paren */
+ *perrcode = errcode = 0;
+
+ while (1) {
+ arithval = *expr;
+ if (arithval == 0) {
+ if (p == endexpression) {
+ /* Null expression. */
+ return 0;
+ }
+
+ /* This is only reached after all tokens have been extracted from the
+ * input stream. If there are still tokens on the operator stack, they
+ * are to be applied in order. At the end, there should be a final
+ * result on the integer stack */
+
+ if (expr != endexpression + 1) {
+ /* If we haven't done so already, */
+ /* append a closing right paren */
+ expr = endexpression;
+ /* and let the loop process it. */
+ continue;
+ }
+ /* At this point, we're done with the expression. */
+ if (numstackptr != numstack+1) {
+ /* ... but if there isn't, it's bad */
+ err:
+ *perrcode = -1;
+ return *perrcode;
+ }
+ if (numstack->var) {
+ /* expression is $((var)) only, lookup now */
+ errcode = arith_lookup_val(numstack, math_hooks);
+ }
+ ret:
+ *perrcode = errcode;
+ return numstack->val;
+ }
+
+ /* Continue processing the expression. */
+ if (arith_isspace(arithval)) {
+ /* Skip whitespace */
+ goto prologue;
+ }
+ p = endofname(expr);
+ if (p != expr) {
+ size_t var_name_size = (p-expr) + 1; /* trailing zero */
+
+ numstackptr->var = alloca(var_name_size);
+ safe_strncpy(numstackptr->var, expr, var_name_size);
+ expr = p;
+ num:
+ numstackptr->contidional_second_val_initialized = 0;
+ numstackptr++;
+ lasttok = TOK_NUM;
+ continue;
+ }
+ if (isdigit(arithval)) {
+ numstackptr->var = NULL;
+ numstackptr->val = strto_arith_t(expr, (char **) &expr, 0);
+ goto num;
+ }
+ for (p = op_tokens; ; p++) {
+ const char *o;
+
+ if (*p == 0) {
+ /* strange operator not found */
+ goto err;
+ }
+ for (o = expr; *p && *o == *p; p++)
+ o++;
+ if (!*p) {
+ /* found */
+ expr = o - 1;
+ break;
+ }
+ /* skip tail uncompared token */
+ while (*p)
+ p++;
+ /* skip zero delim */
+ p++;
+ }
+ op = p[1];
+
+ /* post grammar: a++ reduce to num */
+ if (lasttok == TOK_POST_INC || lasttok == TOK_POST_DEC)
+ lasttok = TOK_NUM;
+
+ /* Plus and minus are binary (not unary) _only_ if the last
+ * token was as number, or a right paren (which pretends to be
+ * a number, since it evaluates to one). Think about it.
+ * It makes sense. */
+ if (lasttok != TOK_NUM) {
+ switch (op) {
+ case TOK_ADD:
+ op = TOK_UPLUS;
+ break;
+ case TOK_SUB:
+ op = TOK_UMINUS;
+ break;
+ case TOK_POST_INC:
+ op = TOK_PRE_INC;
+ break;
+ case TOK_POST_DEC:
+ op = TOK_PRE_DEC;
+ break;
+ }
+ }
+ /* We don't want a unary operator to cause recursive descent on the
+ * stack, because there can be many in a row and it could cause an
+ * operator to be evaluated before its argument is pushed onto the
+ * integer stack. */
+ /* But for binary operators, "apply" everything on the operator
+ * stack until we find an operator with a lesser priority than the
+ * one we have just extracted. */
+ /* Left paren is given the lowest priority so it will never be
+ * "applied" in this way.
+ * if associativity is right and priority eq, applied also skip
+ */
+ prec = PREC(op);
+ if ((prec > 0 && prec < UNARYPREC) || prec == SPEC_PREC) {
+ /* not left paren or unary */
+ if (lasttok != TOK_NUM) {
+ /* binary op must be preceded by a num */
+ goto err;
+ }
+ while (stackptr != stack) {
+ if (op == TOK_RPAREN) {
+ /* The algorithm employed here is simple: while we don't
+ * hit an open paren nor the bottom of the stack, pop
+ * tokens and apply them */
+ if (stackptr[-1] == TOK_LPAREN) {
+ --stackptr;
+ /* Any operator directly after a */
+ lasttok = TOK_NUM;
+ /* close paren should consider itself binary */
+ goto prologue;
+ }
+ } else {
+ operator prev_prec = PREC(stackptr[-1]);
+
+ convert_prec_is_assing(prec);
+ convert_prec_is_assing(prev_prec);
+ if (prev_prec < prec)
+ break;
+ /* check right assoc */
+ if (prev_prec == prec && is_right_associativity(prec))
+ break;
+ }
+ errcode = arith_apply(*--stackptr, numstack, &numstackptr, math_hooks);
+ if (errcode) goto ret;
+ }
+ if (op == TOK_RPAREN) {
+ goto err;
+ }
+ }
+
+ /* Push this operator to the stack and remember it. */
+ *stackptr++ = lasttok = op;
+ prologue:
+ ++expr;
+ } /* while */
+}
+
+/*-
+ * Copyright (c) 1989, 1991, 1993, 1994
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
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