#include "ifparser.h"
#include <ctype.h>
#define DO(val) if (!(val)) return NULL
#define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
#define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++
#define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_')
static const char *
parse_variable (g, cp, varp)
IfParser *g;
const char *cp;
const char **varp;
{
SKIPSPACE (cp);
if (!isvarfirstletter (*cp))
return CALLFUNC(g, handle_error) (g, cp, "variable name");
*varp = cp;
for (cp++; isalnum(*cp) || *cp == '_'; cp++) ;
return cp;
}
static const char *
parse_number (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
SKIPSPACE (cp);
if (!isdigit(*cp))
return CALLFUNC(g, handle_error) (g, cp, "number");
#ifdef WIN32
*valp = strtol(cp, &cp, 0);
#else
*valp = atoi (cp);
for (cp++; isdigit(*cp); cp++) ;
#endif
return cp;
}
static const char *
parse_value (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
const char *var;
*valp = 0;
SKIPSPACE (cp);
if (!*cp)
return cp;
switch (*cp) {
case '(':
DO (cp = ParseIfExpression (g, cp + 1, valp));
SKIPSPACE (cp);
if (*cp != ')')
return CALLFUNC(g, handle_error) (g, cp, ")");
return cp + 1;
case '!':
DO (cp = parse_value (g, cp + 1, valp));
*valp = !(*valp);
return cp;
case '-':
DO (cp = parse_value (g, cp + 1, valp));
*valp = -(*valp);
return cp;
case '#':
DO (cp = parse_variable (g, cp + 1, &var));
SKIPSPACE (cp);
if (*cp != '(')
return CALLFUNC(g, handle_error) (g, cp, "(");
do {
DO (cp = parse_variable (g, cp + 1, &var));
SKIPSPACE (cp);
} while (*cp && *cp != ')');
if (*cp != ')')
return CALLFUNC(g, handle_error) (g, cp, ")");
*valp = 1;
return cp + 1;
case 'd':
if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) {
int paren = 0;
cp += 7;
SKIPSPACE (cp);
if (*cp == '(') {
paren = 1;
cp++;
}
DO (cp = parse_variable (g, cp, &var));
SKIPSPACE (cp);
if (paren && *cp != ')')
return CALLFUNC(g, handle_error) (g, cp, ")");
*valp = (*(g->funcs.eval_defined)) (g, var, cp - var);
return cp + paren;
}
}
if (isdigit(*cp)) {
DO (cp = parse_number (g, cp, valp));
} else if (!isvarfirstletter(*cp))
return CALLFUNC(g, handle_error) (g, cp, "variable or number");
else {
DO (cp = parse_variable (g, cp, &var));
*valp = (*(g->funcs.eval_variable)) (g, var, cp - var);
}
return cp;
}
static const char *
parse_product (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_value (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '*':
DO (cp = parse_product (g, cp + 1, &rightval));
*valp = (*valp * rightval);
break;
case '/':
DO (cp = parse_product (g, cp + 1, &rightval));
*valp = (*valp / rightval);
break;
case '%':
DO (cp = parse_product (g, cp + 1, &rightval));
*valp = (*valp % rightval);
break;
}
return cp;
}
static const char *
parse_sum (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_product (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '+':
DO (cp = parse_sum (g, cp + 1, &rightval));
*valp = (*valp + rightval);
break;
case '-':
DO (cp = parse_sum (g, cp + 1, &rightval));
*valp = (*valp - rightval);
break;
}
return cp;
}
static const char *
parse_shift (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_sum (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '<':
if (cp[1] == '<') {
DO (cp = parse_shift (g, cp + 2, &rightval));
*valp = (*valp << rightval);
}
break;
case '>':
if (cp[1] == '>') {
DO (cp = parse_shift (g, cp + 2, &rightval));
*valp = (*valp >> rightval);
}
break;
}
return cp;
}
static const char *
parse_inequality (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_shift (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '<':
if (cp[1] == '=') {
DO (cp = parse_inequality (g, cp + 2, &rightval));
*valp = (*valp <= rightval);
} else {
DO (cp = parse_inequality (g, cp + 1, &rightval));
*valp = (*valp < rightval);
}
break;
case '>':
if (cp[1] == '=') {
DO (cp = parse_inequality (g, cp + 2, &rightval));
*valp = (*valp >= rightval);
} else {
DO (cp = parse_inequality (g, cp + 1, &rightval));
*valp = (*valp > rightval);
}
break;
}
return cp;
}
static const char *
parse_equality (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_inequality (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '=':
if (cp[1] == '=')
cp++;
DO (cp = parse_equality (g, cp + 1, &rightval));
*valp = (*valp == rightval);
break;
case '!':
if (cp[1] != '=')
break;
DO (cp = parse_equality (g, cp + 2, &rightval));
*valp = (*valp != rightval);
break;
}
return cp;
}
static const char *
parse_band (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_equality (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '&':
if (cp[1] != '&') {
DO (cp = parse_band (g, cp + 1, &rightval));
*valp = (*valp & rightval);
}
break;
}
return cp;
}
static const char *
parse_bor (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_band (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '|':
if (cp[1] != '|') {
DO (cp = parse_bor (g, cp + 1, &rightval));
*valp = (*valp | rightval);
}
break;
}
return cp;
}
static const char *
parse_land (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_bor (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '&':
if (cp[1] != '&')
return CALLFUNC(g, handle_error) (g, cp, "&&");
DO (cp = parse_land (g, cp + 2, &rightval));
*valp = (*valp && rightval);
break;
}
return cp;
}
static const char *
parse_lor (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
int rightval;
DO (cp = parse_land (g, cp, valp));
SKIPSPACE (cp);
switch (*cp) {
case '|':
if (cp[1] != '|')
return CALLFUNC(g, handle_error) (g, cp, "||");
DO (cp = parse_lor (g, cp + 2, &rightval));
*valp = (*valp || rightval);
break;
}
return cp;
}
const char *
ParseIfExpression (g, cp, valp)
IfParser *g;
const char *cp;
int *valp;
{
return parse_lor (g, cp, valp);
}