Add debug flag Cbor_Debug that enables checking data length that is b…

…eing encoded. Helps to find cases when buffer is not big enough.

Make numEncodableMembers public.
Make error message when number of deserialized members is mismatched more informative.

cbor.d

@@ -22,6 +22,8 @@ private import std.string : format;
 private import std.traits;
 private import std.typecons : Flag;
 
+//version = Cbor_Debug;
+
 /// Thrown in a case of decoding error.
 class CborException : Exception
 {
@@ -326,19 +328,29 @@ align(1) struct CborValue
 
 		T obj;
 
+		size_t arrLength = via.array.length;
+		size_t numMembers;
+
 		static if (isTuple!T)
+			numMembers = T.Types.length;
+		else
+			numMembers = numEncodableMembers!T;
+
+		if (arrLength != numMembers)
 		{
-			if (via.array.length != T.Types.length)
-				throw new CborException("The number of deserialized Tuple element is mismatched");
+			throw new CborException(
+				format("The number of deserialized members of %s is mismatched."~
+					" Got %s, while expected %s members",
+						T.stringof, numMembers, arrLength));
+		}
 
+		static if (isTuple!T)
+		{
 			foreach (i, Type; T.Types)
 				obj.field[i] = via.array[i].as!(Type);
 		}
 		else 
 		{  // simple struct
-			if (via.array.length != numEncodableMembers!T)
-				throw new CborException("The number of deserialized struct member is mismatched");
-
 			static if (is(T == class))
 				obj = new T();
 
@@ -579,7 +591,7 @@ align(1) struct CborValue
 //------------------------------------------------------------------------------
 
 
-private import std.range : isInputRange, isOutputRange, ElementType, put;
+private import std.range : isInputRange, isOutputRange, ElementType;
 private import std.typecons : isTuple;
 
 /// Encodes value E into output range sink.
@@ -637,23 +649,23 @@ private size_t encodeLongType(R)(auto ref R sink, ubyte majorType, ulong length)
 
 	majorType <<= 5;
 	if (length < 24) {
-		put(sink, cast(ubyte)(majorType | length));
+		putChecked(sink, cast(ubyte)(majorType | length));
 		return 1;
 	} else if (length <= ubyte.max) {
-		put(sink, cast(ubyte)(majorType | 24));
-		put(sink, cast(ubyte)length);
+		putChecked(sink, cast(ubyte)(majorType | 24));
+		putChecked(sink, cast(ubyte)length);
 		return 2;
 	} else if (length <= ushort.max) {
-		put(sink, cast(ubyte)(majorType | 25));
-		put(sink, nativeToBigEndian!ushort(cast(ushort)length)[]);
+		putChecked(sink, cast(ubyte)(majorType | 25));
+		putChecked(sink, nativeToBigEndian!ushort(cast(ushort)length)[]);
 		return 3;
 	} else if (length <= uint.max) {
-		put(sink, cast(ubyte)(majorType | 26));
-		put(sink, nativeToBigEndian!uint(cast(uint)length)[]);
+		putChecked(sink, cast(ubyte)(majorType | 26));
+		putChecked(sink, nativeToBigEndian!uint(cast(uint)length)[]);
 		return 5;
 	} else { // if (length <= ulong.max)
-		put(sink, cast(ubyte)(majorType | 27));
-		put(sink, nativeToBigEndian!ulong(cast(ulong)length)[]);
+		putChecked(sink, cast(ubyte)(majorType | 27));
+		putChecked(sink, nativeToBigEndian!ulong(cast(ulong)length)[]);
 		return 9;
 	}
 }
@@ -689,17 +701,17 @@ size_t encodeCborFloat(R, E)(auto ref R sink, E value)
 
 		__FloatRep flt;
 		flt.f = value;
-		put(sink, cast(ubyte)(majorType | 26));
-		put(sink, nativeToBigEndian!uint(flt.u)[]);
+		putChecked(sink, cast(ubyte)(majorType | 26));
+		putChecked(sink, nativeToBigEndian!uint(flt.u)[]);
 		return 5;
 	}
 	else static if (is(E == double) || is(E == real))
 	{
 
 		__DoubleRep dbl;
 		dbl.d = cast(double)value;
-		put(sink, cast(ubyte)(majorType | 27));
-		put(sink, nativeToBigEndian!ulong(dbl.u)[]);
+		putChecked(sink, cast(ubyte)(majorType | 27));
+		putChecked(sink, nativeToBigEndian!ulong(dbl.u)[]);
 		return 9;
 	}
 }
@@ -709,17 +721,18 @@ size_t encodeCborBool(R, E)(auto ref R sink, E value)
 	if(isOutputRange!(R, ubyte) && isBoolean!E)
 {
 	if (value)
-		put(sink, cast(ubyte)0xf5);
+		putChecked(sink, cast(ubyte)0xf5);
 	else
-		put(sink, cast(ubyte)0xf4);
+		putChecked(sink, cast(ubyte)0xf4);
 	return 1;
 }
 
 /// Encodes null.
 size_t encodeCborNull(R, E)(auto ref R sink, E value)
 	if(isOutputRange!(R, ubyte) && is(E == typeof(null)))
 {
-	put(sink, cast(ubyte)0xf6);
+
+	putChecked(sink, cast(ubyte)0xf6);
 	return 1;
 }
 
@@ -729,7 +742,7 @@ size_t encodeCborRaw(R, E)(auto ref R sink, E value)
 {
 	auto size = encodeLongType(sink, 2, value.length);
 	size += value.length;
-	put(sink, value);
+	putChecked(sink, value);
 	return size;
 }
 
@@ -739,7 +752,7 @@ size_t encodeCborString(R, E)(auto ref R sink, E value)
 {
 	auto size = encodeLongType(sink, 3, value.length);
 	size += value.length;
-	put(sink, cast(ubyte[])value);
+	putChecked(sink, cast(ubyte[])value);
 	return size;
 }
 
@@ -1008,6 +1021,25 @@ T decodeCborSingleDup(T, R)(auto ref R input)
 //		HH   HH EEEEEEE LLLLLLL PP      EEEEEEE RR   RR  SSSSS  
 //------------------------------------------------------------------------------
 
+private void putChecked(R, E)(ref R sink, const auto ref E e)
+{
+	import std.range : put, hasLength;
+	version(Cbor_Debug)
+	static if (hasLength!R)
+	{
+		size_t elemSize;
+
+		static if (hasLength!E)
+			elemSize = e.length * ElementType!E.sizeof;
+		else
+			elemSize = E.sizeof;
+
+		assert(sink.length >= elemSize,
+			format("Provided sink length is to small. Sink.$ %s < Data.$ %s", sink.length, elemSize));
+	}
+	put(sink, e);
+}
+
 private T readInteger(T, R)(auto ref R input)
 {
 	return readN!(T.sizeof, T, R)(input);
@@ -1120,7 +1152,7 @@ private template isEncodedField(T)
 	enum isEncodedField = __traits(compiles, { encodeCbor((ubyte[]).init, T.init); });
 }
 
-private template numEncodableMembers(alias T)
+template numEncodableMembers(alias T)
 {
 	enum numEncodableMembers = numEncodableMembersImpl!(T.tupleof);
 }