ExprNode* ReadExpr (FILE* F, ObjData* O)
/* Read an expression from the given file */
{
ExprNode* Expr;
/* Read the node tag and handle NULL nodes */
unsigned char Op = Read8 (F);
if (Op == EXPR_NULL) {
return 0;
}
/* Create a new node */
Expr = NewExprNode (O, Op);
/* Check the tag and handle the different expression types */
if (EXPR_IS_LEAF (Op)) {
switch (Op) {
case EXPR_LITERAL:
Expr->V.IVal = Read32Signed (F);
break;
case EXPR_SYMBOL:
/* Read the import number */
Expr->V.ImpNum = ReadVar (F);
break;
case EXPR_SECTION:
/* Read the section number */
Expr->V.SecNum = ReadVar (F);
break;
default:
Error ("Invalid expression op: %02X", Op);
}
} else {
/* Not a leaf node */
Expr->Left = ReadExpr (F, O);
Expr->Right = ReadExpr (F, O);
}
/* Return the tree */
return Expr;
}
static void SkipExpr (FILE* F)
/* Skip an expression from the given file */
{
/* Read the node tag and handle NULL nodes */
unsigned char Op = Read8 (F);
if (Op == EXPR_NULL) {
return;
}
/* Check the tag and handle the different expression types */
if (EXPR_IS_LEAF (Op)) {
switch (Op) {
case EXPR_LITERAL:
(void) Read32Signed (F);
break;
case EXPR_SYMBOL:
/* Read the import number */
(void) ReadVar (F);
break;
case EXPR_SECTION:
case EXPR_BANK:
/* Read the segment number */
(void) ReadVar (F);
break;
default:
Error ("Invalid expression op: %02X", Op);
}
} else {
/* Not a leaf node */
SkipExpr (F);
SkipExpr (F);
}
}