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archived-lcd4linux/evaluator.c
reinelt de2e1d3b69 [lcd4linux @ 2006-01-30 12:53:07 by reinelt] 
replaced strncpy with strcpy where possible

git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@631 3ae390bd-cb1e-0410-b409-cd5a39f66f1f
2006-01-30 12:53:08 +00:00

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/* $Id: evaluator.c,v 1.30 2006/01/30 12:53:08 reinelt Exp $
*
* expression evaluation
*
* Copyright (C) 1999, 2000 Michael Reinelt <reinelt@eunet.at>
* Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
*
* This file is part of LCD4Linux.
*
* LCD4Linux is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* LCD4Linux is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
* $Log: evaluator.c,v $
* Revision 1.30 2006/01/30 12:53:08 reinelt
* replaced strncpy with strcpy where possible
*
* Revision 1.29 2006/01/30 06:11:36 reinelt
* changed Result->length to Result->size
*
* Revision 1.28 2006/01/30 05:47:38 reinelt
* graphic subsystem changed to full-color RGBA
*
* Revision 1.27 2006/01/28 15:36:18 harbaum
* Fix: string termination bug in eval()
*
* Revision 1.26 2006/01/21 09:40:20 reinelt
* Big Memory Leak in Evaluator fixed (thanks to Oliver Gehrke)
*
* Revision 1.25 2005/05/08 04:32:44 reinelt
* CodingStyle added and applied
*
* Revision 1.24 2005/03/30 04:57:50 reinelt
* Evaluator speedup: use bsearch for finding functions and variables
*
* Revision 1.23 2005/01/18 06:30:23 reinelt
* added (C) to all copyright statements
*
* Revision 1.22 2004/06/26 12:04:59 reinelt
*
* uh-oh... the last CVS log message messed up things a lot...
*
* Revision 1.21 2004/06/26 09:27:21 reinelt
*
* added '-W' to CFLAGS
* changed all C++ comments to C ones
* cleaned up a lot of signed/unsigned mistakes
*
* Revision 1.20 2004/06/20 10:09:56 reinelt
*
* 'const'ified the whole source
*
* Revision 1.19 2004/04/12 11:12:25 reinelt
* added plugin_isdn, removed old ISDN client
* fixed some real bad bugs in the evaluator
*
* Revision 1.18 2004/03/11 06:39:58 reinelt
* big patch from Martin:
* - reuse filehandles
* - memory leaks fixed
* - earlier busy-flag checking with HD44780
* - reuse memory for strings in RESULT and hash
* - netdev_fast to wavid time-consuming regex
*
* Revision 1.17 2004/03/08 18:45:52 hejl
* fixed segfault when using string concatenation
*
* Revision 1.16 2004/03/08 04:33:08 reinelt
* string concatenation fixed
*
* Revision 1.15 2004/03/06 20:31:16 reinelt
* Complete rewrite of the evaluator to get rid of the code
* from mark Morley (because of license issues).
* The new Evaluator does a pre-compile of expressions, and
* stores them in trees. Therefore it should be reasonable faster...
*
* Revision 1.14 2004/03/03 03:47:04 reinelt
* big patch from Martin Hejl:
* - use qprintf() where appropriate
* - save CPU cycles on gettimeofday()
* - add quit() functions to free allocated memory
* - fixed lots of memory leaks
*
* Revision 1.13 2004/02/26 21:42:45 reinelt
* memory leak fixes from Martin
*
* Revision 1.12 2004/02/05 07:10:23 reinelt
* evaluator function names are no longer case-sensitive
* Crystalfontz Fan PWM control, Fan RPM monitoring, temperature monitoring
*
* Revision 1.11 2004/01/30 20:57:56 reinelt
* HD44780 patch from Martin Hejl
* dmalloc integrated
*
* Revision 1.10 2004/01/29 04:40:02 reinelt
* every .c file includes "config.h" now
*
* Revision 1.9 2004/01/15 07:47:02 reinelt
* debian/ postinst and watch added (did CVS forget about them?)
* evaluator: conditional expressions (a?b:c) added
* text widget nearly finished
*
* Revision 1.8 2004/01/12 03:51:01 reinelt
* evaluating the 'Variables' section in the config file
*
* Revision 1.7 2004/01/07 10:15:41 reinelt
* small glitch in evaluator fixed
* made config table sorted and access with bsearch(),
* which should be much faster
*
* Revision 1.6 2004/01/06 23:01:37 reinelt
* more copyright issues
*
* Revision 1.5 2004/01/06 17:33:45 reinelt
* Evaluator: functions with variable argument lists
* Evaluator: plugin_sample.c and README.Plugins added
*
* Revision 1.4 2004/01/06 15:19:12 reinelt
* Evaluator rearrangements...
*
* Revision 1.3 2003/10/11 06:01:52 reinelt
* renamed expression.{c,h} to client.{c,h}
* added config file client
* new functions 'AddNumericVariable()' and 'AddStringVariable()'
* new parameter '-i' for interactive mode
*
* Revision 1.2 2003/10/06 05:47:27 reinelt
* operators: ==, \!=, <=, >=
*
* Revision 1.1 2003/10/06 04:34:06 reinelt
* expression evaluator added
*
*/
/*
* exported functions:
*
* int SetVariable (char *name, RESULT *value)
* adds a generic variable to the evaluator
*
* int SetVariableNumeric (char *name, double value)
* adds a numerical variable to the evaluator
*
* int SetVariableString (char *name, char *value)
* adds a numerical variable to the evaluator
*
* int AddFunction (char *name, int argc, void (*func)())
* adds a function to the evaluator
*
* void DeleteVariables (void);
* frees all allocated variables
*
* void DeleteFunctions (void);
* frees all allocated functions
*
* void DelResult (RESULT *result)
* sets a result to none
* frees a probably allocated memory
*
* RESULT* SetResult (RESULT **result, int type, void *value)
* initializes a result
*
* double R2N (RESULT *result)
* converts a result into a number
*
* char* R2S (RESULT *result)
* converts a result into a string
*
*
* int Compile (char* expression, void **tree)
* compiles a expression into a tree
*
* int Eval (void *tree, RESULT *result)
* evaluates an expression
*
* void DelTree (void *tree)
* frees a compiled tree
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <setjmp.h>
#include "debug.h"
#include "evaluator.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif
/* string buffer chunk size */
#define CHUNK_SIZE 16
typedef enum {
T_UNDEF,
T_NAME,
T_NUMBER,
T_STRING,
T_OPERATOR,
T_VARIABLE,
T_FUNCTION
} TOKEN;
typedef enum {
O_UNDEF, /* undefined */
O_LST, /* expression lists */
O_SET, /* variable assignements */
O_CND, /* conditional a?b:c */
O_COL, /* colon in a?b:c */
O_OR, /* logical OR */
O_AND, /* logical AND */
O_EQ, /* equal */
O_NE, /* not equal */
O_LT, /* less than */
O_LE, /* less or equal */
O_GT, /* greater than */
O_GE, /* greater or equal */
O_ADD, /* addition */
O_SUB, /* subtraction */
O_SGN, /* sign '-' */
O_CAT, /* string concatenation */
O_MUL, /* multiplication */
O_DIV, /* division */
O_MOD, /* modulo */
O_POW, /* power */
O_NOT, /* logical NOT */
O_BRO, /* open brace */
O_COM, /* comma (argument seperator) */
O_BRC /* closing brace */
} OPERATOR;
typedef struct {
char *pattern;
int len;
OPERATOR op;
} PATTERN;
typedef struct {
char *name;
RESULT *value;
} VARIABLE;
typedef struct {
char *name;
int argc;
void (*func) ();
} FUNCTION;
typedef struct _NODE {
TOKEN Token;
OPERATOR Operator;
RESULT *Result;
VARIABLE *Variable;
FUNCTION *Function;
int Children;
struct _NODE **Child;
} NODE;
/* operators */
/* IMPORTANT! list must be sorted by length! */
static PATTERN Pattern[] = {
{";", 1, O_LST}, /* expression lists */
{"=", 1, O_SET}, /* variable assignements */
{"?", 1, O_CND}, /* conditional a?b:c */
{":", 1, O_COL}, /* colon a?b:c */
{"|", 1, O_OR}, /* logical OR */
{"&", 1, O_AND}, /* logical AND */
{"<", 1, O_LT}, /* less than */
{">", 1, O_GT}, /* greater than */
{"+", 1, O_ADD}, /* addition */
{"-", 1, O_SUB}, /* subtraction or sign */
{".", 1, O_CAT}, /* string concatenation */
{"*", 1, O_MUL}, /* multiplication */
{"/", 1, O_DIV}, /* division */
{"%", 1, O_MOD}, /* modulo */
{"^", 1, O_POW}, /* power */
{"!", 1, O_NOT}, /* logical NOT */
{"(", 1, O_BRO}, /* open brace */
{",", 1, O_COM}, /* comma (argument seperator) */
{")", 1, O_BRC}, /* closing brace */
{"==", 2, O_EQ}, /* equal */
{"!=", 2, O_NE}, /* not equal */
{"<=", 2, O_LE}, /* less or equal */
{">=", 2, O_GE} /* greater or equal */
};
static char *Expression = NULL;
static char *ExprPtr = NULL;
static char *Word = NULL;
static TOKEN Token = T_UNDEF;
static OPERATOR Operator = O_UNDEF;
static VARIABLE *Variable = NULL;
static int nVariable = 0;
static FUNCTION *Function = NULL;
static int nFunction = 0;
void DelResult(RESULT * result)
{
result->type = 0;
result->size = 0;
result->number = 0.0;
if (result->string) {
free(result->string);
result->string = NULL;
}
}
static void FreeResult(RESULT * result)
{
if (result != NULL) {
DelResult(result);
free(result);
}
}
static RESULT *NewResult(void)
{
RESULT *result = malloc(sizeof(RESULT));
if (result == NULL) {
error("Evaluator: cannot allocate result: out of memory!");
return NULL;
}
result->type = 0;
result->size = 0;
result->number = 0.0;
result->string = NULL;
return result;
}
RESULT *SetResult(RESULT ** result, const int type, const void *value)
{
if (*result == NULL) {
if ((*result = NewResult()) == NULL)
return NULL;
} else if (type == R_NUMBER) {
DelResult(*result);
}
if (type == R_NUMBER) {
(*result)->type = R_NUMBER;
(*result)->size = 0;
(*result)->number = *(double *) value;
(*result)->string = NULL;
}
else if (type == R_STRING) {
int len = strlen((char *) value);
(*result)->type = R_STRING;
(*result)->number = 0.0;
if ((*result)->string == NULL || len >= (*result)->size) {
/* buffer is either empty or too small */
if ((*result)->string)
free((*result)->string);
/* allocate memory in multiples of CHUNK_SIZE */
(*result)->size = CHUNK_SIZE * ((len+1) / CHUNK_SIZE + 1);
(*result)->string = malloc((*result)->size);
}
strcpy((*result)->string, value);
} else {
error("Evaluator: internal error: invalid result type %d", type);
return NULL;
}
return *result;
}
static RESULT *CopyResult(RESULT ** result, RESULT * value)
{
if (*result == NULL) {
if ((*result = NewResult()) == NULL)
return NULL;
}
(*result)->type = value->type;
(*result)->number = value->number;
if (value->string == NULL) {
(*result)->size = 0;
if ((*result)->string)
free((*result)->string);
(*result)->string = NULL;
} else {
/* is buffer large enough? */
if ((*result)->string == NULL || value->size > (*result)->size) {
if ((*result)->string)
free((*result)->string);
(*result)->size = value->size;
(*result)->string = malloc((*result)->size);
}
strcpy((*result)->string, value->string);
}
return *result;
}
double R2N(RESULT * result)
{
if (result == NULL) {
error("Evaluator: internal error: NULL result");
return 0.0;
}
if (result->type & R_NUMBER) {
return result->number;
}
if (result->type & R_STRING) {
result->type |= R_NUMBER;
result->number = atof(result->string);
return result->number;
}
error("Evaluator: internal error: invalid result type %d", result->type);
return 0.0;
}
char *R2S(RESULT * result)
{
if (result == NULL) {
error("Evaluator: internal error: NULL result");
return NULL;
}
if (result->type & R_STRING) {
return result->string;
}
if (result->type & R_NUMBER) {
result->type |= R_STRING;
if (result->string)
free(result->string);
result->size = CHUNK_SIZE;
result->string = malloc(result->size);
snprintf(result->string, result->size, "%g", result->number);
return result->string;
}
error("Evaluator: internal error: invalid result type %d", result->type);
return NULL;
}
/* bsearch compare function for variables */
static int LookupVariable(const void *a, const void *b)
{
char *key = (char *) a;
VARIABLE *var = (VARIABLE *) b;
return strcmp(key, var->name);
}
/* qsort compare function for variables */
static int SortVariable(const void *a, const void *b)
{
VARIABLE *va = (VARIABLE *) a;
VARIABLE *vb = (VARIABLE *) b;
return strcmp(va->name, vb->name);
}
static VARIABLE *FindVariable(const char *name)
{
return bsearch(name, Variable, nVariable, sizeof(VARIABLE), LookupVariable);
}
int SetVariable(const char *name, RESULT * value)
{
VARIABLE *V;
V = FindVariable(name);
if (V != NULL) {
CopyResult(&V->value, value);
return 1;
}
nVariable++;
Variable = realloc(Variable, nVariable * sizeof(VARIABLE));
Variable[nVariable - 1].name = strdup(name);
Variable[nVariable - 1].value = NULL;
CopyResult(&Variable[nVariable - 1].value, value);
qsort(Variable, nVariable, sizeof(VARIABLE), SortVariable);
return 0;
}
int SetVariableNumeric(const char *name, const double value)
{
RESULT result = { 0, 0, 0, NULL };
RESULT *rp = &result;
SetResult(&rp, R_NUMBER, &value);
return SetVariable(name, rp);
}
int SetVariableString(const char *name, const char *value)
{
RESULT result = { 0, 0, 0, NULL };
RESULT *rp = &result;
SetResult(&rp, R_STRING, value);
return SetVariable(name, rp);
}
void DeleteVariables(void)
{
int i;
for (i = 0; i < nVariable; i++) {
free(Variable[i].name);
FreeResult(Variable[i].value);
}
free(Variable);
Variable = NULL;
nVariable = 0;
}
/* bsearch compare function for functions */
static int LookupFunction(const void *a, const void *b)
{
char *n = (char *) a;
FUNCTION *f = (FUNCTION *) b;
return strcmp(n, f->name);
}
/* qsort compare function for functions */
static int SortFunction(const void *a, const void *b)
{
FUNCTION *fa = (FUNCTION *) a;
FUNCTION *fb = (FUNCTION *) b;
return strcmp(fa->name, fb->name);
}
static FUNCTION *FindFunction(const char *name)
{
return bsearch(name, Function, nFunction, sizeof(FUNCTION), LookupFunction);
}
int AddFunction(const char *name, const int argc, void (*func) ())
{
nFunction++;
Function = realloc(Function, nFunction * sizeof(FUNCTION));
Function[nFunction - 1].name = strdup(name);
Function[nFunction - 1].argc = argc;
Function[nFunction - 1].func = func;
qsort(Function, nFunction, sizeof(FUNCTION), SortFunction);
return 0;
}
void DeleteFunctions(void)
{
int i;
for (i = 0; i < nFunction; i++) {
free(Function[i].name);
}
free(Function);
Function = NULL;
nFunction = 0;
}
#define is_space(c) ((c) == ' ' || (c) == '\t')
#define is_digit(c) ((c) >= '0' && (c) <= '9')
#define is_alpha(c) (((c) >= 'A' && (c) <= 'Z') || ((c) >= 'a' && (c) <= 'z') || ((c) == '_'))
#define is_alnum(c) (is_alpha(c) || is_digit(c))
static void Parse(void)
{
Token = T_UNDEF;
Operator = O_UNDEF;
if (Word) {
free(Word);
Word = NULL;
}
/* NULL expression? */
if (ExprPtr == NULL) {
Word = strdup("");
return;
}
/* skip leading whitespace */
while (is_space(*ExprPtr))
ExprPtr++;
/* names */
if (is_alpha(*ExprPtr)) {
char *start = ExprPtr;
while (is_alnum(*ExprPtr))
ExprPtr++;
if (*ExprPtr == ':' && *(ExprPtr + 1) == ':' && is_alpha(*(ExprPtr + 2))) {
ExprPtr += 3;
while (is_alnum(*ExprPtr))
ExprPtr++;
}
Word = strndup(start, ExprPtr - start);
Token = T_NAME;
}
/* numbers */
else if (is_digit(*ExprPtr) || (*ExprPtr == '.' && is_digit(*(ExprPtr + 1)))) {
char *start = ExprPtr;
while (is_digit(*ExprPtr))
ExprPtr++;
if (*ExprPtr == '.') {
ExprPtr++;
while (is_digit(*ExprPtr))
ExprPtr++;
}
Word = strndup(start, ExprPtr - start);
Token = T_NUMBER;
}
/* strings */
else if (*ExprPtr == '\'') {
char *start = ++ExprPtr;
while (*ExprPtr != '\0' && *ExprPtr != '\'')
ExprPtr++;
Word = strndup(start, ExprPtr - start);
Token = T_STRING;
if (*ExprPtr == '\'')
ExprPtr++;
}
/* operators */
else {
int i;
for (i = sizeof(Pattern) / sizeof(Pattern[0]) - 1; i >= 0; i--) {
int len = Pattern[i].len;
if (strncmp(ExprPtr, Pattern[i].pattern, Pattern[i].len) == 0) {
Word = strndup(ExprPtr, len);
Token = T_OPERATOR;
Operator = Pattern[i].op;
ExprPtr += len;
break;
}
}
}
/* syntax check */
if (Token == T_UNDEF && *ExprPtr != '\0') {
error("Evaluator: parse error in <%s>: garbage <%s>", Expression, ExprPtr);
}
/* skip trailing whitespace */
while (is_space(*ExprPtr))
ExprPtr++;
/* empty token */
if (Word == NULL)
Word = strdup("");
}
static NODE *NewNode(NODE * Child)
{
NODE *N;
N = malloc(sizeof(NODE));
if (N == NULL)
return NULL;
memset(N, 0, sizeof(NODE));
N->Token = Token;
N->Operator = Operator;
if (Child != NULL) {
N->Children = 1;
N->Child = malloc(sizeof(NODE *));
N->Child[0] = Child;
}
return N;
}
static NODE *JunkNode(void)
{
NODE *Junk;
Junk = NewNode(NULL);
Junk->Token = T_STRING;
SetResult(&Junk->Result, R_STRING, "");
return Junk;
}
static void LinkNode(NODE * Root, NODE * Child)
{
if (Child == NULL)
return;
Root->Children++;
Root->Child = realloc(Root->Child, Root->Children * sizeof(NODE *));
if (Root->Child == NULL)
return;
Root->Child[Root->Children - 1] = Child;
}
/* forward declaration */
static NODE *Level01(void);
/* literal numbers, variables, functions */
static NODE *Level12(void)
{
NODE *Root = NULL;
if (Token == T_OPERATOR && Operator == O_BRO) {
Parse();
Root = Level01();
if (Token != T_OPERATOR || Operator != O_BRC) {
error("Evaluator: unbalanced parentheses in <%s>", Expression);
LinkNode(Root, JunkNode());
}
}
else if (Token == T_NUMBER) {
double value = atof(Word);
Root = NewNode(NULL);
SetResult(&Root->Result, R_NUMBER, &value);
}
else if (Token == T_STRING) {
Root = NewNode(NULL);
SetResult(&Root->Result, R_STRING, Word);
}
else if (Token == T_NAME) {
/* look-ahead for opening brace */
if (*ExprPtr == '(') {
int argc = 0;
Root = NewNode(NULL);
Root->Token = T_FUNCTION;
Root->Result = NewResult();
Root->Function = FindFunction(Word);
if (Root->Function == NULL) {
error("Evaluator: unknown function '%s' in <%s>", Word, Expression);
Root->Token = T_STRING;
SetResult(&Root->Result, R_STRING, "");
}
/* opening brace */
Parse();
do {
Parse(); /* read argument */
if (Token == T_OPERATOR && Operator == O_BRC) {
break;
} else if (Token == T_OPERATOR && Operator == O_COM) {
error("Evaluator: empty argument in <%s>", Expression);
LinkNode(Root, JunkNode());
} else {
LinkNode(Root, Level01());
}
argc++;
} while (Token == T_OPERATOR && Operator == O_COM);
/* check for closing brace */
if (Token != T_OPERATOR || Operator != O_BRC) {
error("Evaluator: missing closing brace in <%s>", Expression);
}
/* check number of arguments */
if (Root->Function != NULL && Root->Function->argc >= 0 && Root->Function->argc != argc) {
error("Evaluator: wrong number of arguments in <%s>", Expression);
while (argc < Root->Function->argc) {
LinkNode(Root, JunkNode());
argc++;
}
}
} else {
Root = NewNode(NULL);
Root->Token = T_VARIABLE;
Root->Result = NewResult();
Root->Variable = FindVariable(Word);
if (Root->Variable == NULL) {
SetVariableString(Word, "");
Root->Variable = FindVariable(Word);
}
}
}
else {
error("Evaluator: syntax error in <%s>: <%s>", Expression, Word);
Root = NewNode(NULL);
Root->Token = T_STRING;
SetResult(&Root->Result, R_STRING, "");
}
Parse();
return Root;
}
/* unary + or - signs or logical 'not' */
static NODE *Level11(void)
{
NODE *Root;
TOKEN sign = T_UNDEF;
if (Token == T_OPERATOR && (Operator == O_ADD || Operator == O_SUB || Operator == O_NOT)) {
sign = Operator;
if (sign == O_SUB)
sign = O_SGN;
Parse();
}
Root = Level12();
if (sign == O_SGN || sign == O_NOT) {
Root = NewNode(Root);
Root->Token = T_OPERATOR;
Root->Operator = sign;
}
return Root;
}
/* x^y */
static NODE *Level10(void)
{
NODE *Root;
Root = Level11();
while (Token == T_OPERATOR && Operator == O_POW) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level11());
}
return Root;
}
/* multiplication, division, modulo */
static NODE *Level09(void)
{
NODE *Root;
Root = Level10();
while (Token == T_OPERATOR && (Operator == O_MUL || Operator == O_DIV || Operator == O_MOD)) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level10());
}
return Root;
}
/* addition, subtraction, string concatenation */
static NODE *Level08(void)
{
NODE *Root;
Root = Level09();
while (Token == T_OPERATOR && (Operator == O_ADD || Operator == O_SUB || Operator == O_CAT)) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level09());
}
return Root;
}
/* relational operators */
static NODE *Level07(void)
{
NODE *Root;
Root = Level08();
while (Token == T_OPERATOR && (Operator == O_GT || Operator == O_GE || Operator == O_LT || Operator == O_LE)) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level08());
}
return Root;
}
/* equal, not equal */
static NODE *Level06(void)
{
NODE *Root;
Root = Level07();
while (Token == T_OPERATOR && (Operator == O_EQ || Operator == O_NE)) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level07());
}
return Root;
}
/* logical 'and' */
static NODE *Level05(void)
{
NODE *Root;
Root = Level06();
while (Token == T_OPERATOR && Operator == O_AND) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level06());
}
return Root;
}
/* logical 'or' */
static NODE *Level04(void)
{
NODE *Root;
Root = Level05();
while (Token == T_OPERATOR && Operator == O_OR) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level05());
}
return Root;
}
/* conditional expression a?b:c */
static NODE *Level03(void)
{
NODE *Root;
Root = Level04();
if (Token == T_OPERATOR && Operator == O_CND) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level04());
if (Token == T_OPERATOR && Operator == O_COL) {
Parse();
LinkNode(Root, Level04());
} else {
error("Evaluator: syntax error in <%s>: expecting ':' got '%s'", Expression, Word);
LinkNode(Root, JunkNode());
}
}
return Root;
}
/* variable assignments */
static NODE *Level02(void)
{
NODE *Root;
/* we have to do a look-ahead if it's really an assignment */
if ((Token == T_NAME) && (*ExprPtr == '=') && (*(ExprPtr + 1) != '=')) {
char *name = strdup(Word);
VARIABLE *V = FindVariable(name);
if (V == NULL) {
SetVariableString(name, "");
V = FindVariable(name);
}
Parse();
Root = NewNode(NULL);
Root->Variable = V;
Parse();
LinkNode(Root, Level03());
free(name);
} else {
Root = Level03();
}
return Root;
}
/* expression lists */
static NODE *Level01(void)
{
NODE *Root;
Root = Level02();
while (Token == T_OPERATOR && Operator == O_LST) {
Root = NewNode(Root);
Parse();
LinkNode(Root, Level02());
}
return Root;
}
static int EvalTree(NODE * Root)
{
int i;
int argc;
int type = -1;
double number = 0.0;
double dummy;
int freeme = 0;
char *string = NULL;
char *s1, *s2;
RESULT *param[10];
for (i = 0; i < Root->Children; i++) {
EvalTree(Root->Child[i]);
}
switch (Root->Token) {
case T_NUMBER:
case T_STRING:
/* Root->Result already contains the value */
return 0;
case T_VARIABLE:
CopyResult(&Root->Result, Root->Variable->value);
return 0;
case T_FUNCTION:
DelResult(Root->Result);
/* prepare parameter list */
argc = Root->Children;
if (argc > 10)
argc = 10;
for (i = 0; i < argc; i++) {
param[i] = Root->Child[i]->Result;
}
if (Root->Function->argc < 0) {
/* Function with variable argument list: */
/* pass number of arguments as first parameter */
Root->Function->func(Root->Result, argc, &param);
} else {
Root->Function->func(Root->Result, param[0], param[1], param[2], param[3], param[4], param[5], param[6],
param[7], param[8], param[9]);
}
return 0;
case T_OPERATOR:
switch (Root->Operator) {
case O_LST: /* expression list: result is last expression */
i = Root->Children - 1;
type = Root->Child[i]->Result->type;
number = Root->Child[i]->Result->number;
string = Root->Child[i]->Result->string;
break;
case O_SET: /* variable assignment */
CopyResult(&Root->Variable->value, Root->Child[0]->Result);
type = Root->Child[0]->Result->type;
number = Root->Child[0]->Result->number;
string = Root->Child[0]->Result->string;
break;
case O_CND: /* conditional expression */
i = 1 + (R2N(Root->Child[0]->Result) == 0.0);
type = Root->Child[i]->Result->type;
number = Root->Child[i]->Result->number;
string = Root->Child[i]->Result->string;
break;
case O_OR: /* logical OR */
type = R_NUMBER;
number = ((R2N(Root->Child[0]->Result) != 0.0) || (R2N(Root->Child[1]->Result) != 0.0));
break;
case O_AND: /* logical AND */
type = R_NUMBER;
number = ((R2N(Root->Child[0]->Result) != 0.0) && (R2N(Root->Child[1]->Result) != 0.0));
break;
case O_EQ: /* numeric equal */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) == R2N(Root->Child[1]->Result));
break;
case O_NE: /* numeric not equal */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) != R2N(Root->Child[1]->Result));
break;
case O_LT: /* numeric less than */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) < R2N(Root->Child[1]->Result));
break;
case O_LE: /* numeric less equal */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) <= R2N(Root->Child[1]->Result));
break;
case O_GT: /* numeric greater than */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) > R2N(Root->Child[1]->Result));
break;
case O_GE: /* numeric greater equal */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) >= R2N(Root->Child[1]->Result));
break;
case O_ADD: /* addition */
type = R_NUMBER;
number = R2N(Root->Child[0]->Result) + R2N(Root->Child[1]->Result);
break;
case O_SUB: /* subtraction */
type = R_NUMBER;
number = R2N(Root->Child[0]->Result) - R2N(Root->Child[1]->Result);
break;
case O_SGN: /* sign */
type = R_NUMBER;
number = -R2N(Root->Child[0]->Result);
break;
case O_CAT: /* string concatenation */
type = R_STRING;
s1 = R2S(Root->Child[0]->Result);
s2 = R2S(Root->Child[1]->Result);
string = malloc(strlen(s1) + strlen(s2) + 1);
strcpy(string, s1);
strcat(string, s2);
freeme = 1;
break;
case O_MUL: /* multiplication */
type = R_NUMBER;
number = R2N(Root->Child[0]->Result) * R2N(Root->Child[1]->Result);
break;
case O_DIV: /* division */
type = R_NUMBER;
dummy = R2N(Root->Child[1]->Result);
if (dummy == 0) {
error("Evaluator: warning: division by zero");
number = 0.0;
} else {
number = R2N(Root->Child[0]->Result) / R2N(Root->Child[1]->Result);
}
break;
case O_MOD: /* modulo */
type = R_NUMBER;
dummy = R2N(Root->Child[1]->Result);
if (dummy == 0) {
error("Evaluator: warning: division by zero");
number = 0.0;
} else {
number = fmod(R2N(Root->Child[0]->Result), R2N(Root->Child[1]->Result));
}
break;
case O_POW: /* x^y */
type = R_NUMBER;
number = pow(R2N(Root->Child[0]->Result), R2N(Root->Child[1]->Result));
break;
case O_NOT: /* logical NOT */
type = R_NUMBER;
number = (R2N(Root->Child[0]->Result) == 0.0);
break;
default:
error("Evaluator: internal error: unhandled operator <%d>", Root->Operator);
SetResult(&Root->Result, R_STRING, "");
return -1;
}
if (type == R_NUMBER) {
SetResult(&Root->Result, R_NUMBER, &number);
return 0;
}
if (type == R_STRING) {
SetResult(&Root->Result, R_STRING, string);
if (freeme)
free(string);
return 0;
}
error("Evaluator: internal error: unhandled type <%d>", type);
SetResult(&Root->Result, R_STRING, "");
return -1;
default:
error("Evaluator: internal error: unhandled token <%d>", Root->Token);
SetResult(&Root->Result, R_STRING, "");
return -1;
}
return 0;
}
int Compile(const char *expression, void **tree)
{
NODE *Root;
*tree = NULL;
Expression = (char *) expression;
ExprPtr = Expression;
Parse();
if (*Word == '\0') {
/* error ("Evaluator: empty expression <%s>", Expression); */
free(Word);
Word = NULL;
return -1;
}
Root = Level01();
if (*Word != '\0') {
error("Evaluator: syntax error in <%s>: garbage <%s>", Expression, Word);
free(Word);
Word = NULL;
return -1;
}
free(Word);
Word = NULL;
*(NODE **) tree = Root;
return 0;
}
int Eval(void *tree, RESULT * result)
{
int ret;
NODE *Tree = (NODE *) tree;
DelResult(result);
if (Tree == NULL) {
SetResult(&result, R_STRING, "");
return 0;
}
ret = EvalTree(Tree);
result->type = Tree->Result->type;
result->size = Tree->Result->size;
result->number = Tree->Result->number;
if (result->size > 0) {
result->string = malloc(result->size);
if (Tree->Result->string != NULL) {
strcpy(result->string, Tree->Result->string);
} else
result->string[0] = '\0';
} else {
result->string = NULL;
}
return ret;
}
void DelTree(void *tree)
{
int i;
NODE *Tree = (NODE *) tree;
if (Tree == NULL)
return;
for (i = 0; i < Tree->Children; i++) {
DelTree(Tree->Child[i]);
}
if (Tree->Result)
FreeResult(Tree->Result);
free(Tree);
}
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