private static int SGsub( Thread l )
{
var str = (LString)l[1];
var pat = (LString)l[2];
var subst = l[3];
var subTy = subst.ValueType;
switch( subTy )
{
case LValueType.Number:
l.ConvertToString( ref subst );
break;
case LValueType.String:
case LValueType.Function:
case LValueType.Table:
break;
default:
throw new ArgumentException( "string/function/table expected" );
}
var max = l.StackTop >= 4 ? (int)l[4] : int.MaxValue;
MatchState ms;
InitMatchState( out ms, l );
ms.Str = str.InternalData;
ms.StrInit = LString.BufferDataOffset;
ms.Pat = pat.InternalData;
int patInit = LString.BufferDataOffset;
bool anchor = patInit < ms.Pat.Length && ms.Pat[patInit] == (byte)'^';
if( anchor )
patInit++;
var strBuilder = l.GetStrBuilder( str.Length * 2 );
int sPos = LString.BufferDataOffset;
int n = 0;
while( n < max )
{
ms.Level = 0;
Debug.Assert( ms.MatchDepth == MaxCCalls );
var e = SMatch( ref ms, sPos, patInit );
if( e != -1 )
{
n++;
Value substVal;
switch( subTy )
{
case LValueType.Function:
{
l.Push( subst );
var nCap = PushCaptures( ref ms, sPos, e, false );
l.Call( nCap, 1 );
substVal = l.PopValue();
}
break;
case LValueType.Table:
PushCapture( ref ms, 0, sPos, e );
substVal = l.GetTable( (Table)subst, l.PopValue() );
break;
case LValueType.Number:
//it's already been made a string
substVal = subst;
break;
case LValueType.String:
//need to handle escape sequences
{
var sb = (byte[])subst.RefVal;
for( int i = LString.BufferDataOffset; i < sb.Length; i++ )
{
var ch = sb[i];
if( ch != (byte)'%' )
{
strBuilder.Append( ch );
continue;
}
if( ++i == sb.Length )
throw new ArgumentException( "Invalid use of % in replacement string" );
ch = sb[i];
if( ch == (byte)'%' )
{
strBuilder.Append( ch );
continue;
}
switch( ch )
{
case (byte)'0':
strBuilder.Append( ms.Str, sPos, e - sPos );
break;
case (byte)'1':
case (byte)'2':
case (byte)'3':
case (byte)'4':
case (byte)'5':
case (byte)'6':
case (byte)'7':
case (byte)'8':
case (byte)'9':
{
int idx = ch - (byte)'1';
PushCapture( ref ms, idx, sPos, e );
substVal = l.PopValue();
l.ConvertToString( ref substVal );
strBuilder.Append( (LString)substVal );
}
break;
default:
throw new ArgumentException( "Invalid use o f% in replacement string" );
}
}
}
substVal = new Value(); //hush, little compiler
break;
default:
substVal = new Value();
break;
}
if( subTy != LValueType.String )
{
//strings already appended, need to handle this case now
if( !substVal.ToBool() )
{
strBuilder.Append( ms.Str, sPos, e - sPos );
}
else
{
l.ConvertToString( ref substVal );
strBuilder.Append( (LString)substVal );
}
}
}
if( e != -1 && e > sPos )
sPos = e;
else if( sPos < ms.Str.Length )
strBuilder.Append( ms.Str[sPos++] );
else
break;
if( anchor )
break;
}
strBuilder.Append( ms.Str, sPos, ms.Str.Length - sPos );
var ret = strBuilder.ToLString();
l.RetireStrBuilder( strBuilder );
RetireMatchState( ref ms );
return l.SetReturnValues( ret, n );
}
