int Preprocessor_expr(DOH *s, int *error) {
int token = 0;
int op = 0;
sp = 0;
assert(s);
assert(scan);
Seek(s, 0, SEEK_SET);
/* Printf(stdout,"evaluating : '%s'\n", s); */
*error = 0;
Scanner_clear(scan);
Scanner_push(scan, s);
/* Put initial state onto the stack */
stack[sp].op = EXPR_TOP;
stack[sp].value = 0;
while (1) {
/* Look at the top of the stack */
switch (stack[sp].op) {
case EXPR_TOP:
/* An expression. Can be a number or another expression enclosed in parens */
token = expr_token(scan);
if (!token) {
errmsg = "Expected an expression";
*error = 1;
return 0;
}
if ((token == SWIG_TOKEN_INT) || (token == SWIG_TOKEN_UINT) || (token == SWIG_TOKEN_LONG) || (token == SWIG_TOKEN_ULONG)) {
/* A number. Reduce EXPR_TOP to an EXPR_VALUE */
char *c = Char(Scanner_text(scan));
stack[sp].value = (long) strtol(c, 0, 0);
stack[sp].svalue = 0;
/* stack[sp].value = (long) atol(Char(Scanner_text(scan))); */
stack[sp].op = EXPR_VALUE;
} else if (token == SWIG_TOKEN_PLUS) {
} else if ((token == SWIG_TOKEN_MINUS) || (token == SWIG_TOKEN_LNOT) || (token == SWIG_TOKEN_NOT)) {
if (token == SWIG_TOKEN_MINUS)
token = EXPR_UMINUS;
stack[sp].value = token;
stack[sp++].op = EXPR_OP;
stack[sp].op = EXPR_TOP;
stack[sp].svalue = 0;
} else if ((token == SWIG_TOKEN_LPAREN)) {
stack[sp++].op = EXPR_GROUP;
stack[sp].op = EXPR_TOP;
stack[sp].value = 0;
stack[sp].svalue = 0;
} else if (token == SWIG_TOKEN_ENDLINE) {
} else if ((token == SWIG_TOKEN_STRING)) {
stack[sp].svalue = NewString(Scanner_text(scan));
stack[sp].op = EXPR_VALUE;
} else if ((token == SWIG_TOKEN_ID)) {
stack[sp].value = 0;
stack[sp].svalue = 0;
stack[sp].op = EXPR_VALUE;
} else
goto syntax_error;
break;
case EXPR_VALUE:
/* A value is on the stack. We may reduce or evaluate depending on what the next token is */
token = expr_token(scan);
if (!token) {
/* End of input. Might have to reduce if an operator is on stack */
while (sp > 0) {
if (stack[sp - 1].op == EXPR_OP) {
if (!reduce_op())
goto reduce_error;
} else if (stack[sp - 1].op == EXPR_GROUP) {
errmsg = "Missing \')\'";
*error = 1;
return 0;
} else
goto syntax_error;
}
return stack[sp].value;
}
/* Token must be an operator */
switch (token) {
case SWIG_TOKEN_STAR:
case SWIG_TOKEN_EQUALTO:
case SWIG_TOKEN_NOTEQUAL:
case SWIG_TOKEN_PLUS:
case SWIG_TOKEN_MINUS:
case SWIG_TOKEN_AND:
case SWIG_TOKEN_LAND:
case SWIG_TOKEN_OR:
case SWIG_TOKEN_LOR:
case SWIG_TOKEN_XOR:
case SWIG_TOKEN_LESSTHAN:
case SWIG_TOKEN_GREATERTHAN:
case SWIG_TOKEN_LTEQUAL:
case SWIG_TOKEN_GTEQUAL:
case SWIG_TOKEN_SLASH:
case SWIG_TOKEN_PERCENT:
case SWIG_TOKEN_LSHIFT:
case SWIG_TOKEN_RSHIFT:
if ((sp == 0) || (stack[sp - 1].op == EXPR_GROUP)) {
/* No possibility of reduce. Push operator and expression */
sp++;
stack[sp].op = EXPR_OP;
stack[sp].value = token;
sp++;
stack[sp].op = EXPR_TOP;
stack[sp].value = 0;
} else {
if (stack[sp - 1].op != EXPR_OP)
goto syntax_error_expected_operator;
op = stack[sp - 1].value; /* Previous operator */
/* Now, depending on the precedence relationship between the last operator and the current
we will reduce or push */
if (prec[op] <= prec[token]) {
/* Reduce the previous operator */
if (!reduce_op())
goto reduce_error;
}
sp++;
stack[sp].op = EXPR_OP;
stack[sp].value = token;
sp++;
stack[sp].op = EXPR_TOP;
stack[sp].value = 0;
}
break;
case SWIG_TOKEN_RPAREN:
if (sp == 0)
goto extra_rparen;
/* Might have to reduce operators first */
while ((sp > 0) && (stack[sp - 1].op == EXPR_OP)) {
if (!reduce_op())
goto reduce_error;
}
if ((sp == 0) || (stack[sp - 1].op != EXPR_GROUP))
goto extra_rparen;
stack[sp - 1].op = EXPR_VALUE;
stack[sp - 1].value = stack[sp].value;
sp--;
break;
default:
goto syntax_error_expected_operator;
break;
}
break;
default:
fprintf(stderr, "Internal error in expression evaluator.\n");
abort();
}
}
syntax_error:
errmsg = "Syntax error";
*error = 1;
return 0;
syntax_error_expected_operator:
errmsg = "Syntax error: expected operator";
*error = 1;
return 0;
reduce_error:
/* errmsg has been set by reduce_op */
*error = 1;
return 0;
extra_rparen:
errmsg = "Extra \')\'";
*error = 1;
return 0;
}
/* ----------------------------------------------------------------------------
* scanner_file(DOHFile *f)
*
* Start reading from new file
* ------------------------------------------------------------------------- */
void scanner_file(DOHFile * f) {
if (!scan_init) scanner_init();
Scanner_clear(scan);
Scanner_push(scan,f);
}
