C++17 compatible lambda expressions to replace `bind2nd` (#559)

* Conditionally use a lambda rather than the older `bind2nd` style.

* Duplicate the if statements.

* Centralise the conditional compilation to an implementation of find_if_not.

* Refactoring of name and code placement after review.

* Use `FindIfNot` where appropriate.

* Remove whitespace.

filters.cpp

@@ -821,8 +821,8 @@ void StreamTransformationFilter::LastPut(const byte *inString, size_t length)
 			if (m_padding == PKCS_PADDING)
 			{
 				byte pad = space[s-1];
-				if (pad < 1 || pad > s || std::find_if(space+s-pad, space+s, std::bind2nd(std::not_equal_to<byte>(), pad)) != space+s)
+                                if (pad < 1 || pad > s || FindIfNot(space+s-pad, space+s, pad) != space+s)
-					throw InvalidCiphertext("StreamTransformationFilter: invalid PKCS #7 block padding found");
+                                    throw InvalidCiphertext("StreamTransformationFilter: invalid PKCS #7 block padding found");
 				length = s-pad;
 			}
 			else if (m_padding == W3C_PADDING)

ida.cpp

@@ -389,7 +389,7 @@ size_t PaddingRemover::Put2(const byte *begin, size_t length, int messageEnd, bo
 
 	if (m_possiblePadding)
 	{
-		size_t len = std::find_if(begin, end, std::bind2nd(std::not_equal_to<byte>(), byte(0))) - begin;
+		size_t len = FindIfNot(begin, end, byte(0)) - begin;
 		m_zeroCount += len;
 		begin += len;
 		if (begin == end)
@@ -402,7 +402,7 @@ size_t PaddingRemover::Put2(const byte *begin, size_t length, int messageEnd, bo
 		m_possiblePadding = false;
 	}
 
-	const byte *x = std::find_if(RevIt(end), RevIt(begin), std::bind2nd(std::not_equal_to<byte>(), byte(0))).base();
+	const byte *x = FindIfNot(RevIt(end), RevIt(begin), byte(0)).base();
 	if (x != begin && *(x-1) == 1)
 	{
 		AttachedTransformation()->Put(begin, x-begin-1);

misc.h

@@ -2521,6 +2521,19 @@ inline T SafeLeftShift(T value)
 	return SafeShifter<(bits>=(8*sizeof(T)))>::LeftShift(value, bits);
 }
 
+/// \brief Return the first position where a value in the range does not
+/// equal the value passed in.
+template<typename InputIt, typename T>
+inline InputIt FindIfNot(InputIt first, InputIt last, const T &value) {
+#ifdef CRYPTOPP_CXX11_LAMBDA
+    return std::find_if(first, last, [&value](const T &o) {
+        return value!=o;
+    });
+#else
+    return std::find_if(first, last, std::bind2nd(std::not_equal_to<T>(), value));
+#endif
+}
+
 // ************** use one buffer for multiple data members ***************
 
 #define CRYPTOPP_BLOCK_1(n, t, s) t* m_##n() {return (t *)(void *)(m_aggregate+0);}     size_t SS1() {return       sizeof(t)*(s);} size_t m_##n##Size() {return (s);}

oaep.cpp

@@ -82,7 +82,7 @@ DecodingResult OAEP_Base::Unpad(const byte *oaepBlock, size_t oaepBlockLen, byte
 	// DB = pHash' || 00 ... || 01 || M
 	byte *M = std::find(maskedDB+hLen, maskedDB+dbLen, 0x01);
 	invalid = (M == maskedDB+dbLen) || invalid;
-	invalid = (std::find_if(maskedDB+hLen, M, std::bind2nd(std::not_equal_to<byte>(), byte(0))) != M) || invalid;
+	invalid = (FindIfNot(maskedDB+hLen, M, byte(0)) != M) || invalid;
 	invalid = !pHash->VerifyDigest(maskedDB, encodingParameters.begin(), encodingParameters.size()) || invalid;
 
 	if (invalid)

pssr.cpp

@@ -127,7 +127,7 @@ DecodingResult PSSR_MEM_Base::RecoverMessageFromRepresentative(
 
 	// extract salt and recoverableMessage from DB = 00 ... || 01 || M || salt
 	byte *salt = representative + representativeByteLength - u - digestSize - saltSize;
-	byte *M = std::find_if(representative, salt-1, std::bind2nd(std::not_equal_to<byte>(), byte(0)));
+	byte *M = FindIfNot(representative, salt-1, byte(0));
 	recoverableMessageLength = salt-M-1;
 	if (*M == 0x01 &&
 	   (size_t)(M - representative - (representativeBitLength % 8 != 0)) >= MinPadLen(digestSize) &&

zdeflate.cpp

@@ -676,11 +676,11 @@ void Deflator::EncodeBlock(bool eof, unsigned int blockType)
 			m_literalCounts[256] = 1;
 			HuffmanEncoder::GenerateCodeLengths(literalCodeLengths, 15, m_literalCounts, 286);
 			m_dynamicLiteralEncoder.Initialize(literalCodeLengths, 286);
-			unsigned int hlit = (unsigned int)(std::find_if(RevIt(literalCodeLengths.end()), RevIt(literalCodeLengths.begin()+257), std::bind2nd(std::not_equal_to<unsigned int>(), 0)).base() - (literalCodeLengths.begin()+257));
+			unsigned int hlit = (unsigned int)(FindIfNot(RevIt(literalCodeLengths.end()), RevIt(literalCodeLengths.begin()+257), 0).base() - (literalCodeLengths.begin()+257));
 
 			HuffmanEncoder::GenerateCodeLengths(distanceCodeLengths, 15, m_distanceCounts, 30);
 			m_dynamicDistanceEncoder.Initialize(distanceCodeLengths, 30);
-			unsigned int hdist = (unsigned int)(std::find_if(RevIt(distanceCodeLengths.end()), RevIt(distanceCodeLengths.begin()+1), std::bind2nd(std::not_equal_to<unsigned int>(), 0)).base() - (distanceCodeLengths.begin()+1));
+			unsigned int hdist = (unsigned int)(FindIfNot(RevIt(distanceCodeLengths.end()), RevIt(distanceCodeLengths.begin()+1), 0).base() - (distanceCodeLengths.begin()+1));
 
 			SecBlockWithHint<unsigned int, 286+30> combinedLengths(hlit+257+hdist+1);
 			memcpy(combinedLengths, literalCodeLengths, (hlit+257)*sizeof(unsigned int));