Add missing BLAKE2 constructors

BLAKE2b and BLAKE2s are both missing a constructor that takes only the digest size. Also see https://groups.google.com/d/msg/cryptopp-users/QCFGYw8q3Yo/vpBCqz-vBgAJ

blake2.cpp

@@ -343,6 +343,26 @@ BLAKE2b::BLAKE2b(bool treeMode, unsigned int digestSize)
         (Name::TreeMode(), treeMode));
 }
 
+BLAKE2s::BLAKE2s(unsigned int digestSize)
+    : m_digestSize(digestSize), m_keyLength(0), m_treeMode(false)
+{
+    CRYPTOPP_ASSERT(digestSize <= DIGESTSIZE);
+
+    UncheckedSetKey(NULLPTR, 0, MakeParameters
+        (Name::DigestSize(), (int)digestSize)
+        (Name::TreeMode(), false));
+}
+
+BLAKE2b::BLAKE2b(unsigned int digestSize)
+    : m_digestSize(digestSize), m_keyLength(0), m_treeMode(false)
+{
+    CRYPTOPP_ASSERT(digestSize <= DIGESTSIZE);
+
+    UncheckedSetKey(NULLPTR, 0, MakeParameters
+        (Name::DigestSize(), (int)digestSize)
+        (Name::TreeMode(), false));
+}
+
 BLAKE2s::BLAKE2s(const byte *key, size_t keyLength, const byte* salt, size_t saltLength,
     const byte* personalization, size_t personalizationLength, bool treeMode, unsigned int digestSize)
     : m_digestSize(digestSize), m_keyLength(static_cast<unsigned int>(keyLength)), m_treeMode(treeMode)

blake2.h

@@ -256,8 +256,15 @@ class BLAKE2s : public SimpleKeyingInterfaceImpl<MessageAuthenticationCode, BLAK
     /// \brief Construct a BLAKE2s hash
     /// \param digestSize the digest size, in bytes
     /// \param treeMode flag indicating tree mode
+    /// \since Crypto++ 5.6.4
     BLAKE2s(bool treeMode=false, unsigned int digestSize = DIGESTSIZE);
 
+    /// \brief Construct a BLAKE2s hash
+    /// \param digestSize the digest size, in bytes
+    /// \details treeMode flag is set to false
+    /// \since Crypto++ 8.2
+    BLAKE2s(unsigned int digestSize);
+
     /// \brief Construct a BLAKE2s hash
     /// \param key a byte array used to key the cipher
     /// \param keyLength the size of the byte array
@@ -267,6 +274,7 @@ class BLAKE2s : public SimpleKeyingInterfaceImpl<MessageAuthenticationCode, BLAK
     /// \param personalizationLength the size of the byte array
     /// \param treeMode flag indicating tree mode
     /// \param digestSize the digest size, in bytes
+    /// \since Crypto++ 5.6.4
     BLAKE2s(const byte *key, size_t keyLength, const byte* salt = NULLPTR, size_t saltLength = 0,
         const byte* personalization = NULLPTR, size_t personalizationLength = 0,
         bool treeMode=false, unsigned int digestSize = DIGESTSIZE);
@@ -355,8 +363,15 @@ class BLAKE2b : public SimpleKeyingInterfaceImpl<MessageAuthenticationCode, BLAK
     /// \brief Construct a BLAKE2b hash
     /// \param digestSize the digest size, in bytes
     /// \param treeMode flag indicating tree mode
+    /// \since Crypto++ 5.6.4
     BLAKE2b(bool treeMode=false, unsigned int digestSize = DIGESTSIZE);
 
+    /// \brief Construct a BLAKE2s hash
+    /// \param digestSize the digest size, in bytes
+    /// \details treeMode flag is set to false
+    /// \since Crypto++ 8.2
+    BLAKE2b(unsigned int digestSize);
+
     /// \brief Construct a BLAKE2b hash
     /// \param key a byte array used to key the cipher
     /// \param keyLength the size of the byte array
@@ -366,6 +381,7 @@ class BLAKE2b : public SimpleKeyingInterfaceImpl<MessageAuthenticationCode, BLAK
     /// \param personalizationLength the size of the byte array
     /// \param treeMode flag indicating tree mode
     /// \param digestSize the digest size, in bytes
+    /// \since Crypto++ 5.6.4
     BLAKE2b(const byte *key, size_t keyLength, const byte* salt = NULLPTR, size_t saltLength = 0,
         const byte* personalization = NULLPTR, size_t personalizationLength = 0,
         bool treeMode=false, unsigned int digestSize = DIGESTSIZE);