NSDecimalNumberPlaceholder added

Foundation/NSDecimal/NSDecimalNumberPlaceholder.h

@@ -0,0 +1,5 @@
+#import <Foundation/NSDecimalNumber.h>
+
+@interface NSDecimalNumberPlaceholder : NSDecimalNumber
+
+@end

Foundation/NSDecimal/NSDecimalNumberPlaceholder.m

@@ -0,0 +1,24 @@
+#import "NSDecimalNumberPlaceholder.h"
+#import <Foundation/NSRaise.h>
+#import <Foundation/NSCoder.h>
+
+@implementation NSDecimalNumberPlaceholder
+
+-initWithCoder:(NSCoder *)coder {
+   if([coder allowsKeyedCoding]){
+    NSInteger exponent=[coder decodeIntegerForKey:@"NS.exponent"];
+    NSInteger length=[coder decodeIntegerForKey:@"NS.length"];
+    BOOL negative=[coder decodeBoolForKey:@"NS.negative"];
+    BOOL compact=[coder decodeBoolForKey:@"NS.compact"];
+    NSInteger mantissaByteOrder=[coder decodeIntegerForKey:@"NS.mantissa.bo"]; // byte order??
+    NSUInteger byteLength=0;
+    const uint8_t *mantissa=[coder decodeBytesForKey:@"NS.mantissa" returnedLength:&byteLength];
+   }
+
+// We should warn here, but this needs to be ignored for an app   
+//   NSUnimplementedMethod();
+   [self dealloc];
+   return [[NSNumber alloc] initWithInteger:0]; // NSNumber is implemented
+}
+
+@end