/*
* The routine VALconvert transforms a value for interpretation in a
* certain type. It uses some standard cast conventions to do this.
* The result, a pointer to a value, is returned. If there are illegal
* values, or type combinations involved, it gives up with an
* ILLEGALVALUE.
*/
ptr
VALconvert(int typ, ValPtr t)
{
int src_tpe = t->vtype;
ValRecord dst;
dst.vtype = typ;
/* use base types for user types */
if (src_tpe > TYPE_str)
src_tpe = ATOMstorage(src_tpe);
if (dst.vtype > TYPE_str)
dst.vtype = ATOMstorage(dst.vtype);
else if (dst.vtype == TYPE_void)
dst.vtype = TYPE_oid;
/* first convert into a new location */
if (VARconvert(&dst, t, 0) == GDK_FAIL)
return ILLEGALVALUE;
/* then maybe free the old */
if (src_tpe != dst.vtype &&
t->vtype != typ &&
dst.vtype != TYPE_void &&
(src_tpe >= TYPE_str || dst.vtype >= TYPE_str))
VALclear(t);
/* and finally copy the result */
*t = dst;
/* make sure we return the correct type (not the storage type) */
t->vtype = typ;
return VALget(t);
}
/* Convert (cast) the value in T to the type TYP, do this in place.
* Return a pointer to the converted value, or NULL if the conversion
* didn't succeed. If the conversion didn't succeed, the original
* value is not modified. Also see VARconvert. */
ptr
VALconvert(int typ, ValPtr t)
{
int src_tpe = t->vtype;
ValRecord dst;
dst.vtype = typ;
/* first convert into a new location */
if (VARconvert(&dst, t, 0) != GDK_SUCCEED)
return NULL;
/* then maybe free the old */
if (src_tpe != dst.vtype &&
t->vtype != typ &&
dst.vtype != TYPE_void &&
(src_tpe >= TYPE_str || dst.vtype >= TYPE_str))
VALclear(t);
/* and finally copy the result */
*t = dst;
/* make sure we return the correct type (not the storage type) */
t->vtype = typ;
return VALget(t);
}
