public static DbValue CAST(DbFunctionTools tools, DbFunctionArguments args)
{
#if DEBUG
//System.Diagnostics.Debugger.Launch();
#endif
string FunctionName = "CAST";
args.EnsureCount(FunctionName, 2);
DbType type;
ByteSlice bs = args[0].Eval(out type);
mstring xas = tools.GetString(args[1]);
if (!xas.StartsWith("AS "))
{
#if DEBUG
throw new Exception("Expected AS <type> in CAST, not: " + xas);
#endif
throw new Exception("Expected AS <type> in CAST");
}
mstring msastype = xas.SubstringM(3);
string sastype = msastype.ToString(); // Alloc.
sastype = DbType.NormalizeName(sastype); // Alloc if char(n).
DbType astype = DbType.Prepare(sastype); // Alloc if char(n).
if (DbTypeID.NULL == astype.ID)
{
throw new Exception("Unknown AS type in CAST: " + sastype);
}
switch (astype.ID)
{
case DbTypeID.INT:
switch (type.ID)
{
case DbTypeID.INT: // as INT
if (astype.Size > type.Size)
{
throw new Exception("CAST: source value buffer too small");
}
return(tools.AllocValue(ByteSlice.Prepare(bs, 0, astype.Size), astype));
case DbTypeID.LONG: // as INT
return(tools.AllocValue((int)tools.GetLong(bs)));
case DbTypeID.DOUBLE: // as INT
return(tools.AllocValue((int)tools.GetDouble(bs)));
case DbTypeID.DATETIME: // as INT
return(tools.AllocValue((int)tools.GetDateTime(bs).Ticks));
case DbTypeID.CHARS: // as INT
{
int to = tools.GetString(bs).NextItemToInt32(' ');
return(tools.AllocValue(to));
}
default:
throw new Exception("Cannot handle CAST value of type " + type.Name + " AS " + astype.Name);
}
break;
case DbTypeID.LONG:
switch (type.ID)
{
case DbTypeID.INT: // as LONG
return(tools.AllocValue((long)tools.GetInt(bs)));
case DbTypeID.LONG: // as LONG
if (astype.Size > type.Size)
{
throw new Exception("CAST: source value buffer too small");
}
return(tools.AllocValue(ByteSlice.Prepare(bs, 0, astype.Size), astype));
case DbTypeID.DOUBLE: // as LONG
return(tools.AllocValue((long)tools.GetDouble(bs)));
case DbTypeID.DATETIME: // as LONG
return(tools.AllocValue((long)tools.GetDateTime(bs).Ticks));
case DbTypeID.CHARS: // as LONG
{
long to = tools.GetString(bs).NextItemToInt64(' ');
return(tools.AllocValue(to));
}
default:
throw new Exception("Cannot handle CAST value of type " + type.Name + " AS " + astype.Name);
}
break;
case DbTypeID.DOUBLE:
switch (type.ID)
{
case DbTypeID.INT: // as DOUBLE
return(tools.AllocValue((double)tools.GetInt(bs)));
case DbTypeID.LONG: // as DOUBLE
return(tools.AllocValue((double)tools.GetLong(bs)));
case DbTypeID.DOUBLE: // as DOUBLE
if (astype.Size > type.Size)
{
throw new Exception("CAST: source value buffer too small");
}
return(tools.AllocValue(ByteSlice.Prepare(bs, 0, astype.Size), astype));
case DbTypeID.DATETIME: // as DOUBLE
return(tools.AllocValue((double)tools.GetDateTime(bs).Ticks));
case DbTypeID.CHARS: // as DOUBLE
{
double to = tools.GetString(bs).NextItemToDouble(' ');
return(tools.AllocValue(to));
}
default:
throw new Exception("Cannot handle CAST value of type " + type.Name + " AS " + astype.Name);
}
break;
case DbTypeID.DATETIME:
switch (type.ID)
{
case DbTypeID.INT: // as DATETIME
return(tools.AllocValue(new DateTime((long)tools.GetInt(bs))));
case DbTypeID.LONG: // as DATETIME
return(tools.AllocValue(new DateTime((long)tools.GetLong(bs))));
case DbTypeID.DOUBLE: // as DATETIME
return(tools.AllocValue(new DateTime((long)tools.GetDouble(bs))));
case DbTypeID.DATETIME: // as DATETIME
if (astype.Size > type.Size)
{
throw new Exception("CAST: source value buffer too small");
}
return(tools.AllocValue(ByteSlice.Prepare(bs, 0, astype.Size), astype));
case DbTypeID.CHARS: // as DATETIME
{
mstring to = tools.GetString(bs);
return(tools.AllocValue(DateTime.Parse(to.ToString())));
}
default:
throw new Exception("Cannot handle CAST value of type " + type.Name + " AS " + astype.Name);
}
break;
case DbTypeID.CHARS:
switch (type.ID)
{
case DbTypeID.INT: // as CHAR(n)
{
mstring ms = mstring.Prepare(tools.GetInt(bs));
return(tools.AllocValue(ms, astype.Size));
}
case DbTypeID.LONG: // as CHAR(n)
{
mstring ms = mstring.Prepare(tools.GetLong(bs));
return(tools.AllocValue(ms, astype.Size));
}
case DbTypeID.DOUBLE: // as CHAR(n)
{
mstring ms = mstring.Prepare(tools.GetDouble(bs));
return(tools.AllocValue(ms, astype.Size));
}
case DbTypeID.DATETIME: // as CHAR(n)
{
mstring ms = mstring.Prepare(tools.GetDateTime(bs).ToString());
return(tools.AllocValue(ms, astype.Size));
}
case DbTypeID.CHARS: // as CHAR(n)
if (astype.Size > type.Size)
{
//throw new Exception("CAST: source value buffer too small");
return(tools.AllocValue(tools.GetString(bs), astype.Size));
}
return(tools.AllocValue(ByteSlice.Prepare(bs, 0, astype.Size), astype));
default:
throw new Exception("Cannot handle CAST value of type " + type.Name + " AS " + astype.Name);
}
break;
default:
throw new Exception("Cannot handle CAST value of type " + type.Name + " AS " + astype.Name);
}
}
