722 lines
22 KiB
C
722 lines
22 KiB
C
/* $Id$
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* Subroutines used to convert an infix expression to a postfix expression
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*
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* Author: Bob Dalesio
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* Date: 12-12-86
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*
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* Experimental Physics and Industrial Control System (EPICS)
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*
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* Copyright 1991, the Regents of the University of California,
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* and the University of Chicago Board of Governors.
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*
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* This software was produced under U.S. Government contracts:
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* (W-7405-ENG-36) at the Los Alamos National Laboratory,
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* and (W-31-109-ENG-38) at Argonne National Laboratory.
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*
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* Initial development by:
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* The Controls and Automation Group (AT-8)
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* Ground Test Accelerator
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* Accelerator Technology Division
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* Los Alamos National Laboratory
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*
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* Co-developed with
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* The Controls and Computing Group
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* Accelerator Systems Division
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* Advanced Photon Source
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* Argonne National Laboratory
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*
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* Modification Log:
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* -----------------
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* .01 01-11-89 lrd added right shift and left shift operations
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* .02 01-13-89 lrd modified to load into IOCs
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* .03 02-01-89 lrd added trigonometric functions
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* .04 04-05-89 lrd fixed the order of some operations in the
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* element table and added a warning label
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* .05 11-26-90 lrd fix SINH, COSH, TANH
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* .06 02-20-92 rcz fixed for vxWorks build
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* .07 02-24-92 jba add EXP and fixed trailing blanks in expression
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* .08 03-03-92 jba added MAX_VAL and MIN_VAL and comma(like close paren)
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* .09 03-06-92 jba added multiple conditional expressions ?
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* .10 04-01-92 jba allowed floating pt constants in expression
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* .11 05-01-92 jba flt pt constant string replaced with double in postfix
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* .12 08-21-92 jba ANSI c changes
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* .13 08-21-92 jba initialized *ppostfix: needed when calc expr not defined
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* .14 12-11-92 mrk Removed include for stdioLib.h
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* .15 11-03-93 jba Added test for extra close paren at end of expression
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* .16 01-24-94 jba Changed seperator test to catch invalid commas
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* .17 05-11-94 jba Added support for CONST_PI, CONST_R2D, and CONST_D2R
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* and conversion of infix expression to uppercase
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* .18 01-22-98 tmm Changed name postfix() to calcPostfix(). Changed arg list
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* from pointer to postfix expression to address of pointer to
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* postfix expression. calcPostfix() frees old expression, allocates
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* space sufficient to hold new expression, and returns pointer to it.
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* Added S2R, R2S (conversions between arc-seconds and radians). Changed
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* CONSTANT to LITERAL to avoid conflict with link.h. Support 26 vars (A-Z).
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* .19 03-18-98 tmm Added string operators
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*/
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/*
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* Subroutines
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*
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* Public
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*
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* sCalcPostfix convert an algebraic expression to symbolic postfix
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* args
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* pinfix the algebraic expression
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* pp_postfix address of the symbolic postfix expression
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* perror error information
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* returns
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* 0 successful
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* -1 not successful
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* Private routines for calcPostfix
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*
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* find_element finds a symbolic element in the expression element tbl
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* args
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* pbuffer pointer to the infix expression element
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* pelement pointer to the expression element table entry
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* pno_bytes pointer to the size of this element
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* parg pointer to arg (used for fetch)
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* returns
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* TRUE element found
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* FALSE element not found
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*
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* get_element finds the next expression element in the infix expr
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* args
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* pinfix pointer into the infix expression
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* pelement pointer to the expression element table
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* pno_bytes size of the element in the infix expression
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* parg pointer to argument (used for fetch)
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* returns
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* FINE found an expression element
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* VARIABLE found a database reference
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* UNKNOWN_ELEMENT unknown element found in the infix expression
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*/
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#ifdef vxWorks
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#include <vxWorks.h>
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#endif
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include "dbDefs.h"
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#define epicsExportSharedSymbols
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#include "sCalcPostfix.h"
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#include "sCalcPostfixPvt.h"
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#define OVERRIDESTDCALC 0
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#define DEBUG 0
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volatile int sCalcPostfixDebug=0;
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/* declarations for postfix */
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/* element types */
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#define OPERAND 0
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#define UNARY_OPERATOR 1
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#define BINARY_OPERATOR 2
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#define EXPR_TERM 3
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#define COND 4
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#define CLOSE_PAREN 5
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#define CONDITIONAL 6
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#define ELSE 7
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#define SEPARATOR 8
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#define TRASH 9
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#define FLOAT_PT_CONST 10
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#define MINUS_OPERATOR 11
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#define STRING_CONST 12
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#define CLOSE_BRACKET 13
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#define CLOSE_CURLY 14
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#define UNARY_MINUS_I_S_P 7
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#define UNARY_MINUS_I_C_P 8
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#define UNARY_MINUS_CODE UNARY_NEG
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#define BINARY_MINUS_I_S_P 4
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#define BINARY_MINUS_I_C_P 4
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#define BINARY_MINUS_CODE SUB
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/* parsing return values */
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#define FINE 0
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#define UNKNOWN_ELEMENT -1
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#define END -2
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/*
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* element table
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*
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* structure of an element
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*/
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struct expression_element{
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char element[10]; /* character representation of an element */
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char in_stack_pri; /* priority in translation stack */
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char in_coming_pri; /* priority when first checking */
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char type; /* element type */
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char code; /* postfix representation */
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};
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/*
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* NOTE: DO NOT CHANGE WITHOUT READING THIS NOTICE !!!!!!!!!!!!!!!!!!!!
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* Because the routine that looks for a match in this table takes the first
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* match it finds, elements whose designations are contained in other elements
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* MUST come first in this list. (e.g. ABS will match A if A preceeds ABS and
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* then try to find BS therefore ABS must be first in this list
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*/
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static struct expression_element elements[] = {
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/*
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element i_s_p i_c_p type_element internal_rep */
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"ABS", 7, 8, UNARY_OPERATOR, ABS_VAL, /* absolute value */
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"NOT", 7, 8, UNARY_OPERATOR, UNARY_NEG, /* unary negate */
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"-", 7, 8, MINUS_OPERATOR, UNARY_NEG, /* unary negate (or binary op) */
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"SQRT", 7, 8, UNARY_OPERATOR, SQU_RT, /* square root */
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"SQR", 7, 8, UNARY_OPERATOR, SQU_RT, /* square root */
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"EXP", 7, 8, UNARY_OPERATOR, EXP, /* exponential function */
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"LOGE", 7, 8, UNARY_OPERATOR, LOG_E, /* log E */
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"LN", 7, 8, UNARY_OPERATOR, LOG_E, /* log E */
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"LOG", 7, 8, UNARY_OPERATOR, LOG_10, /* log 10 */
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"ACOS", 7, 8, UNARY_OPERATOR, ACOS, /* arc cosine */
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"ASIN", 7, 8, UNARY_OPERATOR, ASIN, /* arc sine */
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"ATAN2", 7, 8, UNARY_OPERATOR, ATAN2, /* arc tangent */
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"ATAN", 7, 8, UNARY_OPERATOR, ATAN, /* arc tangent */
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"MAX", 7, 8, UNARY_OPERATOR, MAX_VAL, /* maximum of 2 args */
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"MIN", 7, 8, UNARY_OPERATOR, MIN_VAL, /* minimum of 2 args */
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"CEIL", 7, 8, UNARY_OPERATOR, CEIL, /* smallest integer >= */
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"FLOOR", 7, 8, UNARY_OPERATOR, FLOOR, /* largest integer <= */
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"NINT", 7, 8, UNARY_OPERATOR, NINT, /* nearest integer */
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"INT", 7, 8, UNARY_OPERATOR, NINT, /* nearest integer */
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"COSH", 7, 8, UNARY_OPERATOR, COSH, /* hyperbolic cosine */
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"COS", 7, 8, UNARY_OPERATOR, COS, /* cosine */
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"SINH", 7, 8, UNARY_OPERATOR, SINH, /* hyperbolic sine */
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"SIN", 7, 8, UNARY_OPERATOR, SIN, /* sine */
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"TANH", 7, 8, UNARY_OPERATOR, TANH, /* hyperbolic tangent*/
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"TAN", 7, 8, UNARY_OPERATOR, TAN, /* tangent */
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"!=", 3, 3, BINARY_OPERATOR,NOT_EQ, /* not equal */
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"!", 7, 8, UNARY_OPERATOR, REL_NOT, /* not */
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"~", 7, 8, UNARY_OPERATOR, BIT_NOT, /* bitwise not */
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"DBL", 7, 8, UNARY_OPERATOR, TO_DOUBLE, /* convert to double */
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"STR", 7, 8, UNARY_OPERATOR, TO_STRING, /* convert to string */
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"$P", 7, 8, UNARY_OPERATOR, PRINTF, /* formatted print to string */
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"PRINTF", 7, 8, UNARY_OPERATOR, PRINTF, /* formatted print to string */
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"$S", 7, 8, UNARY_OPERATOR, SSCANF, /* scan string argument */
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"SSCANF", 7, 8, UNARY_OPERATOR, SSCANF, /* scan string argument */
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"RNDM", 0, 0, OPERAND, RANDOM, /* Random Number */
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"OR", 1, 1, BINARY_OPERATOR,BIT_OR, /* or */
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"AND", 2, 2, BINARY_OPERATOR,BIT_AND, /* and */
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"XOR", 1, 1, BINARY_OPERATOR,BIT_EXCL_OR, /* exclusive or */
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"PI", 0, 0, OPERAND, CONST_PI, /* pi */
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"D2R", 0, 0, OPERAND, CONST_D2R, /* pi/180 */
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"R2D", 0, 0, OPERAND, CONST_R2D, /* 180/pi */
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"S2R", 0, 0, OPERAND, CONST_S2R, /* arc-sec to radians: pi/(180*3600) */
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"R2S", 0, 0, OPERAND, CONST_R2S, /* radians to arc-sec: (180*3600)/pi */
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"0", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"1", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"2", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"3", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"4", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"5", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"6", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"7", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"8", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"9", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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".", 0, 0, FLOAT_PT_CONST, LITERAL, /* flt pt constant */
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"\"", 0, 0, STRING_CONST, SLITERAL, /* string constant */
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"'", 0, 0, STRING_CONST, SLITERAL, /* string constant */
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"?", 0, 0, CONDITIONAL, COND_IF, /* conditional */
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":", 0, 0, CONDITIONAL, COND_ELSE, /* else */
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"(", 0, 8, UNARY_OPERATOR, PAREN, /* open paren */
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"[", 0, 8, BINARY_OPERATOR,SUBRANGE, /* string subrange */
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"{", 0, 8, BINARY_OPERATOR,REPLACE, /* string replace */
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"^", 6, 6, BINARY_OPERATOR,EXPON, /* exponentiation */
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"**", 6, 6, BINARY_OPERATOR,EXPON, /* exponentiation */
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"+", 4, 4, BINARY_OPERATOR,ADD, /* addition */
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#if 0 /* "-" operator is overloaded; may be unary or binary */
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"-", 4, 4, BINARY_OPERATOR,SUB, /* subtraction */
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#endif
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"*", 5, 5, BINARY_OPERATOR,MULT, /* multiplication */
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"/", 5, 5, BINARY_OPERATOR,DIV, /* division */
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"%", 5, 5, BINARY_OPERATOR,MODULO, /* modulo */
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",", 0, 0, SEPARATOR, COMMA, /* comma */
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")", 0, 0, CLOSE_PAREN, PAREN, /* close paren */
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"]", 0, 0, CLOSE_BRACKET, SUBRANGE, /* close bracket */
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"}", 0, 0, CLOSE_CURLY, REPLACE, /* close curly bracket */
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"||", 1, 1, BINARY_OPERATOR,REL_OR, /* logical or */
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"|", 1, 1, BINARY_OPERATOR,BIT_OR, /* bitwise or */
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"&&", 2, 2, BINARY_OPERATOR,REL_AND, /* logical and */
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"&", 2, 2, BINARY_OPERATOR,BIT_AND, /* bitwise and */
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">>", 2, 2, BINARY_OPERATOR,RIGHT_SHIFT, /* right shift */
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">=", 3, 3, BINARY_OPERATOR,GR_OR_EQ, /* greater or equal*/
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">", 3, 3, BINARY_OPERATOR,GR_THAN, /* greater than */
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"<<", 2, 2, BINARY_OPERATOR,LEFT_SHIFT, /* left shift */
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"<=", 3, 3, BINARY_OPERATOR,LESS_OR_EQ,/* less or equal to*/
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"<", 3, 3, BINARY_OPERATOR,LESS_THAN, /* less than */
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"#", 3, 3, BINARY_OPERATOR,NOT_EQ, /* not equal */
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"==", 3, 3, BINARY_OPERATOR,EQUAL, /* equal */
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"=", 3, 3, BINARY_OPERATOR,EQUAL, /* equal */
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""
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};
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/*
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* Element-table entry for "fetch" operation. This element is used for all
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* named variables. Currently, letters A-Z (double) and AA-ZZ (string) are
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* allowed. Lower and upper case letters mean the same thing.
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*/
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static struct expression_element fetch_element = {
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"A", 0, 0, OPERAND, FETCH, /* fetch var */
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};
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static struct expression_element fetch_string_element = {
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"AA", 0, 0, OPERAND, SFETCH, /* fetch var */
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};
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static int strncasecmp(char *s1, char *s2, size_t n)
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{
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short i;
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for (i=0; i<(short)n && (*s1 || *s2); i++, s1++, s2++) {
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if (toupper((int)*s1) > toupper((int)*s2)) return(1);
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if (toupper((int)*s1) < toupper((int)*s2)) return(-1);
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}
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return(0);
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}
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/*
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* FIND_ELEMENT
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*
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* find the pointer to an entry in the element table
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*/
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static int find_element(pbuffer, pelement, pno_bytes, parg)
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register char *pbuffer;
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register struct expression_element **pelement;
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register short *pno_bytes, *parg;
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{
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*parg = 0;
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/* compare the string to each element in the element table */
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*pelement = &elements[0];
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while ((*pelement)->element[0] != NULL){
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if (strncasecmp(pbuffer,(*pelement)->element, strlen((*pelement)->element)) == 0){
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*pno_bytes += strlen((*pelement)->element);
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return(TRUE);
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}
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*pelement += 1;
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}
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/* look for a variable reference */
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/* double variables: ["a" - "z"], numbered 1-26 */
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if (isalpha((int)*pbuffer)) {
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*pelement = &fetch_element; /* fetch means "variable reference" (fetch or store) */
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*parg = *pbuffer - (isupper((int)*pbuffer) ? 'A' : 'a');
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*pno_bytes += 1;
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/* string variables: ["aa" - "zz"], numbered 1-26 */
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if (pbuffer[1] == pbuffer[0]) {
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*pelement = &fetch_string_element;
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*pno_bytes += 1;
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}
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return(TRUE);
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}
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if (sCalcPostfixDebug) printf("find_element: can't find '%s'\n", pbuffer);
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return(FALSE);
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}
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/*
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* GET_ELEMENT
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*
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* get an expression element
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*/
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static int get_element(pinfix, pelement, pno_bytes, parg)
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register char *pinfix;
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register struct expression_element **pelement;
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register short *pno_bytes, *parg;
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{
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/* get the next expression element from the infix expression */
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if (*pinfix == NULL) return(END);
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*pno_bytes = 0;
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while (*pinfix == 0x20){
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*pno_bytes += 1;
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pinfix++;
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}
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if (*pinfix == NULL) return(END);
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if (!find_element(pinfix, pelement, pno_bytes, parg))
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return(UNKNOWN_ELEMENT);
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if (sCalcPostfixDebug > 5) printf("get_element: found element '%s', arg=%d\n", (*pelement)->element, *parg);
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return(FINE);
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}
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#if OVERRIDESTDCALC
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/* Override standard EPICS expression evaluator (if we're loaded after it). */
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long epicsShareAPI postfix(char *pinfix,char *ppostfix,short *perror)
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{
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char *my_ppostfix = NULL, *s, *d;
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long retval;
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retval = sCalcPostfix(pinfix, &my_ppostfix, perror);
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if (*my_ppostfix == BAD_EXPRESSION) {
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*ppostfix = BAD_EXPRESSION;
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} else {
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for (s = my_ppostfix, d = ppostfix; *s != END_STACK; ) {
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*d++=*s++;
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}
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*d = *s;
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}
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free(my_ppostfix);
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return(retval);
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}
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#endif
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/*
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* sCalcPostFix
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*
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* convert an infix expression to a postfix expression
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*/
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long epicsShareAPI sCalcPostfix(char *pinfix, char **pp_postfix, short *perror)
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{
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short no_bytes;
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register short operand_needed;
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register short new_expression;
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struct expression_element stack[80];
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struct expression_element *pelement;
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register struct expression_element *pstacktop;
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double constant;
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register char c, *pposthold;
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char in_stack_pri, in_coming_pri, code;
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char *ppostfix, *ppostfixStart;
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short arg;
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if (sCalcPostfixDebug) printf("sCalcPostfix: entry\n");
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/* Allocate a buffer for the postfix expression. */
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if (*pp_postfix) free(*pp_postfix); /* Free old buffer. */
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ppostfix = calloc(5*strlen(pinfix)+7, 1);
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*pp_postfix = ppostfix;
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ppostfixStart = ppostfix++;
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*ppostfixStart = BAD_EXPRESSION;
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*ppostfix = END_STACK;
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/* place the expression elements into postfix */
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operand_needed = TRUE;
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new_expression = TRUE;
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*perror = 0;
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if (*pinfix == 0) {
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return(0);
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}
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pstacktop = &stack[0];
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while (get_element(pinfix, &pelement, &no_bytes, &arg) != END){
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pinfix += no_bytes;
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code = pelement->code;
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if ((*ppostfixStart != USES_STRING) && ((code == TO_STRING) ||
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(code == PRINTF) || (code == SSCANF) || (code == SLITERAL) ||
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(code == SUBRANGE) || (code == SFETCH))) {
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*ppostfixStart = USES_STRING;
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}
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switch (pelement->type){
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case OPERAND:
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if (!operand_needed){
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*perror = 5;
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*ppostfixStart = BAD_EXPRESSION; return(-1);
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}
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/* add operand to the expression */
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*ppostfix++ = pelement->code;
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/* if this is a variable reference, append variable number */
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if ((pelement->code == (char)FETCH) || (pelement->code == (char)SFETCH)) {
|
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*ppostfix++ = arg;
|
||
}
|
||
|
||
operand_needed = FALSE;
|
||
new_expression = FALSE;
|
||
break;
|
||
|
||
case FLOAT_PT_CONST:
|
||
if (!operand_needed){
|
||
*perror = 5;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add constant to postfix expression */
|
||
*ppostfix++ = pelement->code;
|
||
pposthold = ppostfix;
|
||
|
||
pinfix-=no_bytes;
|
||
while (*pinfix == ' ') *ppostfix++ = *pinfix++;
|
||
while (TRUE) {
|
||
if ( ( *pinfix >= '0' && *pinfix <= '9' ) || *pinfix == '.' ) {
|
||
*ppostfix++ = *pinfix;
|
||
pinfix++;
|
||
} else if ( *pinfix == 'E' || *pinfix == 'e' ) {
|
||
*ppostfix++ = *pinfix;
|
||
pinfix++;
|
||
if (*pinfix == '+' || *pinfix == '-' ) {
|
||
*ppostfix++ = *pinfix;
|
||
pinfix++;
|
||
}
|
||
} else break;
|
||
}
|
||
*ppostfix++ = '\0';
|
||
|
||
ppostfix = pposthold;
|
||
if ( sscanf(ppostfix,"%lg",&constant) != 1) {
|
||
*ppostfix = '\0';
|
||
} else {
|
||
memcpy(ppostfix,(void *)&constant,8);
|
||
}
|
||
ppostfix+=8;
|
||
|
||
operand_needed = FALSE;
|
||
new_expression = FALSE;
|
||
break;
|
||
|
||
case STRING_CONST:
|
||
if (!operand_needed){
|
||
*perror = 5;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add string literal to the postfix expression */
|
||
*ppostfix++ = pelement->code;
|
||
c = pinfix[-1];
|
||
while (*pinfix != c && *pinfix) *ppostfix++ = *pinfix++;
|
||
*ppostfix++ = '\0';
|
||
if (*pinfix) pinfix++;
|
||
|
||
operand_needed = FALSE;
|
||
new_expression = FALSE;
|
||
break;
|
||
|
||
case BINARY_OPERATOR:
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators of higher or equal priority to postfix expression */
|
||
while ((pstacktop->in_stack_pri >= pelement->in_coming_pri)
|
||
&& (pstacktop >= &stack[1])){
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
|
||
/* add new operator to stack */
|
||
pstacktop++;
|
||
*pstacktop = *pelement;
|
||
|
||
operand_needed = TRUE;
|
||
break;
|
||
|
||
case UNARY_OPERATOR:
|
||
if (!operand_needed){
|
||
*perror = 5;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators of higher or equal priority to postfix expression */
|
||
while ((pstacktop->in_stack_pri >= pelement->in_coming_pri)
|
||
&& (pstacktop >= &stack[1])){
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
|
||
/* add new operator to stack */
|
||
pstacktop++;
|
||
*pstacktop = *pelement;
|
||
|
||
new_expression = FALSE;
|
||
break;
|
||
|
||
case MINUS_OPERATOR:
|
||
if (operand_needed) {
|
||
/* then assume minus was intended as a unary operator */
|
||
in_coming_pri = UNARY_MINUS_I_C_P;
|
||
in_stack_pri = UNARY_MINUS_I_S_P;
|
||
code = UNARY_MINUS_CODE;
|
||
new_expression = FALSE;
|
||
} else {
|
||
/* then assume minus was intended as a binary operator */
|
||
in_coming_pri = BINARY_MINUS_I_C_P;
|
||
in_stack_pri = BINARY_MINUS_I_S_P;
|
||
code = BINARY_MINUS_CODE;
|
||
operand_needed = TRUE;
|
||
}
|
||
|
||
/* add operators of higher or equal priority to postfix expression */
|
||
while ((pstacktop->in_stack_pri >= in_coming_pri)
|
||
&& (pstacktop >= &stack[1])){
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
|
||
/* add new operator to stack */
|
||
pstacktop++;
|
||
*pstacktop = *pelement;
|
||
pstacktop->in_stack_pri = in_stack_pri;
|
||
pstacktop->code = code;
|
||
|
||
break;
|
||
|
||
case SEPARATOR:
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators to postfix until open paren */
|
||
while ((pstacktop->element[0] != '(') && (pstacktop->element[0] != '[')
|
||
&& (pstacktop->element[0] != '{')) {
|
||
if (pstacktop == &stack[1] || pstacktop == &stack[0]){
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
operand_needed = TRUE;
|
||
break;
|
||
|
||
case CLOSE_PAREN:
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators to postfix until matching paren */
|
||
while (pstacktop->element[0] != '(') {
|
||
if (pstacktop == &stack[1] || pstacktop == &stack[0]) {
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
pstacktop--; /* remove ( from stack */
|
||
break;
|
||
|
||
case CLOSE_BRACKET:
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators to postfix until matching bracket */
|
||
while (pstacktop->element[0] != '[') {
|
||
if (pstacktop == &stack[1] || pstacktop == &stack[0]) {
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
/* add SUBRANGE operator to postfix */
|
||
if (pstacktop == &stack[0]) {
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
break;
|
||
|
||
case CLOSE_CURLY:
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators to postfix until matching bracket */
|
||
while (pstacktop->element[0] != '{') {
|
||
if (pstacktop == &stack[1] || pstacktop == &stack[0]) {
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
/* add REPLACE operator to postfix */
|
||
if (pstacktop == &stack[0]) {
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
break;
|
||
|
||
case CONDITIONAL:
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add operators of higher priority to postfix expression */
|
||
while ((pstacktop->in_stack_pri > pelement->in_coming_pri)
|
||
&& (pstacktop >= &stack[1])){
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
|
||
/* add new element to the postfix expression */
|
||
*ppostfix++ = pelement->code;
|
||
|
||
/* add : operator with COND_END code to stack */
|
||
if (pelement->element[0] == ':'){
|
||
pstacktop++;
|
||
*pstacktop = *pelement;
|
||
pstacktop->code = COND_END;
|
||
}
|
||
|
||
operand_needed = TRUE;
|
||
break;
|
||
|
||
case EXPR_TERM:
|
||
if (operand_needed && !new_expression){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add all operators on stack to postfix */
|
||
while (pstacktop >= &stack[1]){
|
||
if (pstacktop->element[0] == '('){
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
|
||
/* add new element to the postfix expression */
|
||
*ppostfix++ = pelement->code;
|
||
|
||
operand_needed = TRUE;
|
||
new_expression = TRUE;
|
||
break;
|
||
|
||
default:
|
||
*perror = 8;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
}
|
||
if (operand_needed){
|
||
*perror = 4;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
|
||
/* add all operators on stack to postfix */
|
||
while (pstacktop >= &stack[1]){
|
||
if (pstacktop->element[0] == '('){
|
||
*perror = 6;
|
||
*ppostfixStart = BAD_EXPRESSION; return(-1);
|
||
}
|
||
*ppostfix++ = pstacktop->code;
|
||
pstacktop--;
|
||
}
|
||
*ppostfix++ = END_STACK;
|
||
*ppostfix = '\0';
|
||
|
||
if (ppostfixStart[1] == END_STACK)
|
||
*ppostfixStart = BAD_EXPRESSION;
|
||
else if (*ppostfixStart != USES_STRING)
|
||
*ppostfixStart = NO_STRING;
|
||
|
||
return(0);
|
||
}
|