public static DbValue CONCAT(DbFunctionTools tools, DbFunctionArguments args)
{
string FunctionName = "CONCAT";
args.EnsureCount(FunctionName, 2);
DbType arg0type;
ByteSlice arg0 = args[0].Eval(out arg0type);
if (Types.IsNullValue(arg0))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg0type.ID != DbTypeID.CHARS)
{
args.Expected(FunctionName, 0, "input CHAR(n), got " + arg0type.Name.ToUpper());
}
DbType arg1type;
ByteSlice arg1 = args[1].Eval(out arg1type);
if (Types.IsNullValue(arg1))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg1type.ID != DbTypeID.CHARS)
{
args.Expected(FunctionName, 0, "input CHAR(n), got " + arg1type.Name.ToUpper());
}
mstring s0 = tools.GetString(arg0);
mstring s1 = tools.GetString(arg1);
s0 = s0.AppendM(s1);
return(tools.AllocValue(s0));
}
public static DbValue REVERSE(DbFunctionTools tools, DbFunctionArguments args)
{
string FunctionName = "REVERSE";
args.EnsureCount(FunctionName, 1);
DbType arg0type;
ByteSlice arg0 = args[0].Eval(out arg0type);
if (Types.IsNullValue(arg0))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg0type.ID != DbTypeID.CHARS)
{
args.Expected(FunctionName, 0, "input CHAR(n), got " + arg0type.Name.ToUpper());
}
mstring x = tools.GetString(arg0);
mstring r = mstring.Prepare();
for (int i = x.Length - 1; i >= 0; i--)
{
r = r.AppendM(x.SubstringM(i, 1));
}
return(tools.AllocValue(r));
}
public static DbValue SPACE(DbFunctionTools tools, DbFunctionArguments args)
{
string FunctionName = "SPACE";
args.EnsureCount(FunctionName, 1);
DbType arg0type;
ByteSlice arg0 = args[0].Eval(out arg0type);
if (Types.IsNullValue(arg0))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg0type.ID != DbTypeID.INT)
{
args.Expected(FunctionName, 0, "input INT, got " + arg0type.Name.ToUpper());
return(null);
}
int len = tools.GetInt(arg0);
if (len < 1)
{
return(tools.AllocValue(mstring.Prepare("")));
}
else
{
mstring s = mstring.Prepare();
for (int i = 0; i < len; i++)
{
s = s.AppendM(" ");
}
return(tools.AllocValue(s));
}
}
private static DbValue _PAD(string functionName, DbFunctionTools tools, DbFunctionArguments args, bool isLeft)
{
args.EnsureCount(functionName, 3);
DbType arg0type;
ByteSlice arg0 = args[0].Eval(out arg0type);
if (Types.IsNullValue(arg0))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg0type.ID != DbTypeID.CHARS)
{
args.Expected(functionName, 0, "input CHAR(n), got " + arg0type.Name.ToUpper());
}
DbType arg1type;
ByteSlice arg1 = args[1].Eval(out arg1type);
if (Types.IsNullValue(arg1))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg1type.ID != DbTypeID.INT)
{
args.Expected(functionName, 0, "input INT, got " + arg1type.Name.ToUpper());
}
DbType arg2type;
ByteSlice arg2 = args[2].Eval(out arg2type);
if (Types.IsNullValue(arg2))
{
return(tools.AllocNullValue()); // Give a null, take a null.
}
if (arg2type.ID != DbTypeID.CHARS)
{
args.Expected(functionName, 0, "input CHAR(n), got " + arg2type.Name.ToUpper());
}
mstring str = tools.GetString(arg0);
int totallen = tools.GetInt(arg1);
mstring padstr = tools.GetString(arg2);
if (str.Length > totallen)
{
str = str.SubstringM(0, totallen);
}
else if (str.Length < totallen)
{
int delta = totallen - str.Length;
int padlen = padstr.Length;
mstring newstr = mstring.Prepare();
for (int remain = delta; remain > 0;)
{
newstr = newstr.AppendM(padstr);
remain -= padlen;
}
//if we go over, truncate.
if (newstr.Length > delta)
{
newstr = newstr.SubstringM(0, delta);
}
if (isLeft)
{
str = newstr.AppendM(str);
}
else
{
str = str.AppendM(newstr);
}
}
return(tools.AllocValue(str));
}
