quakeforge/libs/gib/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
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <stdio.h>
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#include "QF/qtypes.h"
#include "QF/va.h"
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#include "exp.h"
#include "ops.h"
exp_error_t EXP_ERROR;
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char *exp_error_msg = 0;
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optable_t optable[] = {
{"~", OP_BitInv, 1},
{"!", OP_Not, 1},
{"&", OP_BitAnd, 2},
{"|", OP_BitOr, 2},
{"^", OP_BitXor, 2},
{"**", OP_Exp, 2},
{"/", OP_Div, 2},
{"neg", OP_Negate, 1},
{"*", 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}
};
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functable_t functable[] = {
{"sqrt", Func_Sqrt, 1},
{"abs", Func_Abs, 1},
{"sin", Func_Sin, 1},
{"cos", Func_Cos, 1},
{"tan", Func_Tan, 1},
{"asin", Func_Asin, 1},
{"acos", Func_Acos, 1},
{"atan", Func_Atan, 1},
{"rand", Func_Rand, 2},
{"trunc", Func_Trunc, 1},
{"", 0, 0}
};
// Error handling
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static exp_error_t
EXP_Error (exp_error_t err, const char *msg)
{
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EXP_ERROR = err;
if (exp_error_msg)
free (exp_error_msg);
exp_error_msg = strdup (msg);
return err;
}
const char *
EXP_GetErrorMsg (void)
{
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return exp_error_msg;
}
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static token *
EXP_NewToken (void)
{
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token *new;
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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;
}
*/
static optable_t *
EXP_FindOpByStr (const char *str)
{
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size_t i, len;
int fi;
for (i = 0, len = 0, fi = -1; optable[i].func; i++)
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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)
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return optable + fi;
else
return 0;
}
static functable_t *
EXP_FindFuncByStr (const char *str)
{
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size_t i, len;
int fi;
for (i = 0, len = 0, fi = -1; functable[i].func; i++)
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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)
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return functable + fi;
else
return 0;
}
static int
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EXP_ContainsCommas (token * chain)
{
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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;
}
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return -1; // We should never get here
}
static int
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EXP_DoFunction (token * chain)
{
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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++;
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oplist = realloc (oplist, sizeof (double) * numops);
oplist[numops - 1] = cur->num.value;
}
EXP_RemoveToken (cur);
}
if (numops == chain->func.func->operands) {
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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;
}
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return -2; // We shouldn't get here
}
static int
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EXP_DoUnary (token * chain)
{
if (chain->generic.next->generic.type == TOKEN_OP)
EXP_DoUnary (chain->generic.next);
if (chain->generic.next->generic.type != TOKEN_NUM)
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return -1; // In theory, this should never happen
chain->generic.next->num.value =
chain->op.op->func (chain->generic.next->num.value, 0);
EXP_RemoveToken (chain);
return 0;
}
token *
EXP_ParseString (char *str)
{
char buf[257];
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token *chain, *new, *cur;
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size_t i, m;
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optable_t *op;
functable_t *func;
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cur = chain = EXP_NewToken ();
chain->generic.type = TOKEN_OPAREN;
chain->generic.prev = 0;
chain->generic.next = 0;
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for (i = 0; i < strlen (str); i++) {
m = 0;
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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;
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new = EXP_NewToken ();
new->generic.type = TOKEN_NUM;
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new->num.value = atof (buf);
new->generic.prev = cur;
new->generic.next = 0;
cur->generic.next = new;
cur = new;
i--;
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} 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;
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} 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;
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} 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;
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} 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;
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if (m) {
if ((op = EXP_FindOpByStr (buf))) {
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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;
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} 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);
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EXP_Error (EXP_E_INVOP,
va ("Unknown operator or function '%s'.", buf));
return 0;
}
}
}
}
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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
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EXP_SimplifyTokens (token * chain)
{
exp_error_t res;
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int i;
token *cur;
token *temp;
/* First, get rid of parentheses */
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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;
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if (cur->generic.prev->generic.type == TOKEN_FUNC) {
// These are arguments to a function
cur = cur->generic.prev;
if (EXP_DoFunction (cur))
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return EXP_Error (EXP_E_SYNTAX,
va
("Invalid number of arguments to function '%s'.",
cur->func.func->str));
} else {
if (EXP_ContainsCommas (cur))
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return EXP_Error (EXP_E_SYNTAX,
"Comma used outside of a function argument list.");
temp = cur;
cur = cur->generic.next;
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EXP_RemoveToken (temp); /* Remove parentheses, leaving value
behind */
EXP_RemoveToken (cur->generic.next);
}
}
}
/* Next, evaluate all operators in order of operations */
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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 a unary operator is in our way, it gets evaluated early
if (cur->generic.next->generic.type == TOKEN_OP)
if (EXP_DoUnary (cur->generic.next))
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return EXP_Error (EXP_E_SYNTAX,
va
("Unary operator '%s' not followed by a unary operator or numerical value.",
cur->generic.next->op.op->str));
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;
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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;
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EXP_RemoveToken (temp->generic.next);
EXP_RemoveToken (temp);
}
}
}
}
return EXP_E_NORMAL;
}
void
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EXP_RemoveToken (token * tok)
{
tok->generic.prev->generic.next = tok->generic.next;
tok->generic.next->generic.prev = tok->generic.prev;
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free (tok);
}
void
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EXP_DestroyTokens (token * chain)
{
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token *temp;
for (; chain; chain = temp) {
temp = chain->generic.next;
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free (chain);
}
}
double
EXP_Evaluate (char *str)
{
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token *chain;
double res;
EXP_ERROR = EXP_E_NORMAL;
if (!(chain = EXP_ParseString (str)))
return 0;
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if (EXP_Validate (chain)) {
EXP_DestroyTokens (chain);
return 0;
}
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if (EXP_SimplifyTokens (chain)) {
EXP_DestroyTokens (chain);
return 0;
}
res = chain->generic.next->num.value;
EXP_DestroyTokens (chain);
return res;
}
void
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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
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EXP_Validate (token * chain)
{
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token *cur, *new;
int paren = 0;
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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 */
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if ((cur->generic.type == TOKEN_NUM && (cur->generic.next->generic.type == TOKEN_OPAREN || // 5(1+1)
cur->generic.next->generic.type == TOKEN_FUNC || // 5 sin (1+1)
(cur->generic.next->generic.type == TOKEN_OP && cur->generic.next->op.op->operands == 1))) || // 5!(1+1)
(cur->generic.type == TOKEN_CPAREN && (cur->generic.next->generic.type == TOKEN_NUM || // (1+1)5
cur->generic.next->generic.type == TOKEN_OPAREN))) // (1+1)(1+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
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|| 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->generic.next->op.op = EXP_FindOpByStr ("neg");
else if (cur->generic.next->op.op->operands == 2)
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return EXP_Error (EXP_E_SYNTAX,
va
("Operator '%s' does not follow a number or numerical value.",
cur->generic.next->op.op->str));
} else if (cur->generic.type == TOKEN_FUNC
&& cur->generic.next->generic.type != TOKEN_OPAREN)
return EXP_Error (EXP_E_SYNTAX,
va
("Function '%s' called without an argument list.",
cur->func.func->str));
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_Error (EXP_E_SYNTAX,
"Comma used outside of a function or after a non-number.");
else if (cur->generic.type == TOKEN_OP
&& cur->generic.next->generic.type == TOKEN_CPAREN)
return EXP_Error (EXP_E_SYNTAX,
va ("Operator '%s' is missing an operand.",
cur->op.op->str));
else if (cur->generic.type == TOKEN_NUM
&& cur->generic.next->generic.type == TOKEN_NUM)
return EXP_Error (EXP_E_SYNTAX,
"Double number error (two numbers next two each other without an operator).");
else if (cur->generic.type == TOKEN_OPAREN
&& cur->generic.next->generic.type == TOKEN_CPAREN)
return EXP_Error (EXP_E_PAREN, "Empty parentheses found.");
}
paren--;
if (paren)
return EXP_Error (EXP_E_PAREN, "Parenthesis mismatch.");
return 0;
}
void
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EXP_PrintTokens (token * chain)
{
for (; chain; chain = chain->generic.next)
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switch (chain->generic.type) {
case TOKEN_OPAREN:
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printf ("(");
break;
case TOKEN_CPAREN:
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printf (")");
break;
case TOKEN_COMMA:
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printf (",");
break;
case TOKEN_NUM:
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printf ("%f", chain->num.value);
break;
case TOKEN_OP:
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printf ("%s", chain->op.op->str);
break;
case TOKEN_FUNC:
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printf ("%s", chain->func.func->str);
break;
case TOKEN_GENERIC:
break;
}
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printf ("\n");
}