quakeforge/libs/util/exp.c

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/*
EXP equation evaluation routines
Copyright (C) 2000, 2001 Brian Koropoff
This program 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
of the License, or (at your option) any later version.
This program 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, US
*/
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stdio.h>
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#include "QF/qtypes.h"
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#include "exp.h"
#include "ops.h"
exp_error_t EXP_ERROR;
optable_t optable[] =
{
{"!", OP_Not, 1},
{"**", OP_Exp, 2},
{"/", OP_Div, 2},
{"*", OP_Mult, 2},
{"+", OP_Add, 2},
{"-", OP_Sub, 2},
{"==", OP_Eq, 2},
{"!=", OP_Neq, 2},
{">=", OP_GreaterThanEqual, 2},
{">", OP_GreaterThan, 2},
{"<=", OP_LessThanEqual, 2},
{"<", OP_LessThan, 2},
{"||", OP_Or, 2},
{"or", OP_Or, 2},
{"&&", OP_And, 2},
{"and", OP_And, 2},
{"", 0, 0}
};
functable_t functable[] =
{
{"sin", Func_Sin, 1},
{"cos", Func_Cos, 1},
{"tan", Func_Tan, 1},
{"asin", Func_Asin, 1},
{"acos", Func_Acos, 1},
{"atan", Func_Atan, 1},
{"", 0, 0}
};
token *EXP_NewToken (void)
{
token *new;
new = malloc(sizeof(token));
if (!new)
return 0;
new->generic.type = TOKEN_GENERIC;
return new;
}
/*
int EXP_FindIndexByFunc (opfunc func)
{
int i;
for (i = 0; optable[i].func; i++)
if (func == optable[i].func)
return i;
return -1;
}
*/
optable_t *EXP_FindOpByStr (const char *str)
{
int i, len, fi;
for (i = 0, len = 0, fi = -1; optable[i].func; i++)
if (!strncmp(str, optable[i].str, strlen(optable[i].str)) && strlen(optable[i].str) > len) {
len = strlen(optable[i].str);
fi = i;
}
if (fi >= 0)
return optable+fi;
else
return 0;
}
functable_t *EXP_FindFuncByStr (const char *str)
{
int i, len, fi;
for (i = 0, len = 0, fi = -1; functable[i].func; i++)
if (!strncmp(str, functable[i].str, strlen(functable[i].str)) && strlen(functable[i].str) > len) {
len = strlen(functable[i].str);
fi = i;
}
if (fi >= 0)
return functable+fi;
else
return 0;
}
int EXP_ContainsCommas (token *chain)
{
token *cur;
int paren = 0;
for (cur = chain; cur; cur = cur->generic.next) {
if (cur->generic.type == TOKEN_OPAREN)
paren++;
if (cur->generic.type == TOKEN_CPAREN)
paren--;
if (!paren)
return 0;
if (cur->generic.type == TOKEN_COMMA)
return 1;
}
return -1; // We should never get here
}
int EXP_DoFunction (token *chain)
{
token *cur, *temp;
double *oplist = 0;
double value;
unsigned int numops = 0;
for (cur = chain->generic.next; cur; cur = temp) {
if (cur->generic.type != TOKEN_CPAREN)
temp = cur->generic.next;
else
temp = 0;
if (cur->generic.type == TOKEN_NUM) {
numops++;
oplist = realloc(oplist, sizeof(double)*numops);
oplist[numops-1] = cur->num.value;
}
EXP_RemoveToken (cur);
}
if (numops == chain->func.func->operands) {
value = chain->func.func->func(oplist, numops); // Heh
chain->generic.type = TOKEN_NUM;
chain->num.value = value;
if (oplist)
free (oplist);
return 0;
} else {
if (oplist)
free (oplist);
return -1;
}
return -2; // We shouldn't get here
}
token *EXP_ParseString (char *str)
{
char buf[256];
token *chain, *new, *cur;
int i,m;
optable_t *op;
functable_t *func;
cur = chain = EXP_NewToken();
chain->generic.type = TOKEN_OPAREN;
chain->generic.prev = 0;
chain->generic.next = 0;
for (i = 0; i < strlen(str); i++)
{
m = 0;
while(isspace((byte)str[i]))
i++;
if (!str[i])
break;
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if (isdigit((byte)str[i]) || str[i] == '.')
{
while ((isdigit((byte)str[i]) // A number
|| str[i] == '.' // A decimal point
|| str[i] == 'e' // An exponent
|| ((str[i] == '-' || str[i] == '+') && str[i-1] == 'e')) // A + or - after an exponent
&& i < strlen(str) // We are within the string
&& m < 256) // And there is space in the buffer
buf[m++] = str[i++];
buf[m] = 0;
new = EXP_NewToken();
new->generic.type = TOKEN_NUM;
new->num.value = atof(buf);
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
i--;
}
else if (str[i] == ',')
{
new = EXP_NewToken();
new->generic.type = TOKEN_COMMA;
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
}
else if (str[i] == '(')
{
new = EXP_NewToken();
new->generic.type = TOKEN_OPAREN;
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
}
else if (str[i] == ')')
{
new = EXP_NewToken();
new->generic.type = TOKEN_CPAREN;
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
}
else
{
while(!(isdigit((byte)str[i])) && !isspace((byte)str[i])
&& str[i] != '.' && str[i] != '(' && str[i] != ')'
&& str[i] != ',' && m < 256) {
buf[m++] = str[i++];
}
buf[m] = 0;
if (m)
{
if ((op = EXP_FindOpByStr (buf))) {
i -= (m - strlen(op->str) + 1);
new = EXP_NewToken();
new->generic.type = TOKEN_OP;
new->op.op = op;
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
} else if ((func = EXP_FindFuncByStr(buf))) {
i -= (m - strlen(func->str) + 1);
new = EXP_NewToken();
new->generic.type = TOKEN_FUNC;
new->func.func = func;
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
} else {
EXP_DestroyTokens (chain);
return 0;
}
}
}
}
new = EXP_NewToken();
new->generic.type = TOKEN_CPAREN;
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
return chain;
}
exp_error_t EXP_SimplifyTokens (token *chain)
{
exp_error_t res;
int i;
token *cur;
token *temp;
/* First, get rid of parentheses */
for (cur = chain->generic.next; cur->generic.type != TOKEN_CPAREN; cur = cur->generic.next)
{
if (cur->generic.type == TOKEN_OPAREN)
{
res = EXP_SimplifyTokens(cur); /* Call ourself to simplify parentheses content */
if (res)
return res;
if (cur->generic.prev->generic.type == TOKEN_FUNC) { // These are arguments to a function
cur = cur->generic.prev;
if (EXP_DoFunction (cur))
return EXP_E_SYNTAX;
} else {
if (EXP_ContainsCommas (cur))
return EXP_E_SYNTAX;
temp = cur;
cur = cur->generic.next;
EXP_RemoveToken(temp); /* Remove parentheses, leaving value behind */
EXP_RemoveToken(cur->generic.next);
}
}
}
/* Next, evaluate all operators in order of operations */
for (i = 0; optable[i].func; i++)
{
for (cur = chain->generic.next; cur->generic.type != TOKEN_CPAREN; cur = cur->generic.next)
{
if (cur->generic.type == TOKEN_OP && cur->op.op == optable + i && cur->generic.next) {
if (optable[i].operands == 1 && cur->generic.next->generic.type == TOKEN_NUM) {
cur->generic.next->num.value = optable[i].func(cur->generic.next->num.value, 0);
temp = cur;
cur = cur->generic.next;
EXP_RemoveToken(temp);
}
else if (cur->generic.prev->generic.type == TOKEN_NUM && cur->generic.next->generic.type == TOKEN_NUM)
{
cur->generic.prev->num.value = optable[i].func(cur->generic.prev->num.value, cur->generic.next->num.value);
temp = cur;
cur = cur->generic.prev;
EXP_RemoveToken(temp->generic.next);
EXP_RemoveToken(temp);
}
}
}
}
return EXP_E_NORMAL;
}
void EXP_RemoveToken (token *tok)
{
tok->generic.prev->generic.next = tok->generic.next;
tok->generic.next->generic.prev = tok->generic.prev;
free(tok);
}
void EXP_DestroyTokens (token *chain)
{
token *temp;
for (;chain; chain = temp)
{
temp = chain->generic.next;
free(chain);
}
}
double EXP_Evaluate (char *str)
{
token *chain;
double res;
EXP_ERROR = EXP_E_NORMAL;
if (!(chain = EXP_ParseString (str)))
{
EXP_ERROR = EXP_E_PARSE;
return 0;
}
res = EXP_Validate (chain);
if (res)
{
EXP_DestroyTokens (chain);
EXP_ERROR = res;
return 0;
}
res = EXP_SimplifyTokens (chain);
if (res)
{
EXP_DestroyTokens (chain);
EXP_ERROR = res;
return 0;
}
res = chain->generic.next->num.value;
EXP_DestroyTokens (chain);
return res;
}
void EXP_InsertTokenAfter (token *spot, token *new)
{
spot->generic.next->generic.prev = new;
new->generic.next = spot->generic.next;
new->generic.prev = spot;
spot->generic.next = new;
}
exp_error_t EXP_Validate (token *chain)
{
token *cur, *new;
int paren = 0;
for (cur = chain; cur->generic.next; cur = cur->generic.next)
{
if (cur->generic.type == TOKEN_OPAREN)
paren++;
if (cur->generic.type == TOKEN_CPAREN)
paren--;
/* Implied multiplication */
if ((cur->generic.type == TOKEN_NUM && cur->generic.next->generic.type == TOKEN_OPAREN) || /* 5(1+1) */
(cur->generic.type == TOKEN_CPAREN && cur->generic.next->generic.type == TOKEN_NUM) || /* (1+1)5 */
(cur->generic.type == TOKEN_CPAREN && cur->generic.next->generic.type == TOKEN_OPAREN) || /* (1+1)(1+1) */
(cur->generic.type == TOKEN_NUM && cur->generic.next->generic.type == TOKEN_FUNC)) /* 4sin(1) */
{
new = EXP_NewToken ();
new->generic.type = TOKEN_OP;
new->op.op = EXP_FindOpByStr ("*");
EXP_InsertTokenAfter (cur, new);
}
else if ((cur->generic.type == TOKEN_OP || cur->generic.type == TOKEN_OPAREN) && cur->generic.next->generic.type == TOKEN_OP)
{
if (cur->generic.next->op.op->func == OP_Sub) /* Stupid hack for negation */
{
cur = cur->generic.next;
cur->generic.type = TOKEN_NUM;
cur->num.value = -1.0;
new = EXP_NewToken();
new->generic.type = TOKEN_OP;
new->op.op = EXP_FindOpByStr ("*");
EXP_InsertTokenAfter (cur, new);
}
else if (cur->generic.next->op.op->operands == 2)
return EXP_E_SYNTAX; /* Operator misuse */
}
else if (cur->generic.type == TOKEN_FUNC && cur->generic.next->generic.type != TOKEN_OPAREN)
return EXP_E_SYNTAX; /* No arguments to funcion */
else if (cur->generic.type == TOKEN_COMMA && ((cur->generic.prev->generic.type != TOKEN_CPAREN
&& cur->generic.prev->generic.type != TOKEN_NUM) || paren <= 1))
return EXP_E_SYNTAX; /* Misused comma */
else if (cur->generic.type == TOKEN_OP && cur->generic.next->generic.type == TOKEN_CPAREN)
return EXP_E_SYNTAX; /* Missing operand */
else if (cur->generic.type == TOKEN_NUM && cur->generic.next->generic.type == TOKEN_NUM)
return EXP_E_SYNTAX; /* Double number error */
else if (cur->generic.type == TOKEN_OPAREN && cur->generic.next->generic.type == TOKEN_CPAREN)
return EXP_E_PAREN; /* Pointless parentheses */
}
paren--;
if (paren)
return EXP_E_PAREN; /* Paren mismatch */
return 0;
}
void EXP_PrintTokens (token *chain)
{
for (; chain; chain = chain->generic.next)
switch (chain->generic.type)
{
case TOKEN_OPAREN:
printf("(");
break;
case TOKEN_CPAREN:
printf(")");
break;
case TOKEN_COMMA:
printf(",");
break;
case TOKEN_NUM:
printf("%f", chain->num.value);
break;
case TOKEN_OP:
printf("%s", chain->op.op->str);
break;
case TOKEN_FUNC:
printf("%s", chain->func.func->str);
break;
case TOKEN_GENERIC:
break;
}
printf("\n");
}