Specify ECDSA constant sizes as constants

src/pubkey.h

@@ -1,5 +1,6 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
+// Copyright (c) 2017 The Zcash developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -15,10 +16,12 @@
 
 /**
  * secp256k1:
- * const unsigned int PRIVATE_KEY_SIZE = 279;
- * const unsigned int PUBLIC_KEY_SIZE  = 65;
- * const unsigned int SIGNATURE_SIZE   = 72;
- *
+ */
+const unsigned int PUBLIC_KEY_SIZE             = 65;
+const unsigned int COMPRESSED_PUBLIC_KEY_SIZE  = 33;
+const unsigned int SIGNATURE_SIZE              = 72;
+const unsigned int COMPACT_SIGNATURE_SIZE      = 65;
+/**
  * see www.keylength.com
  * script supports up to 75 for single byte push
  */
@@ -44,15 +47,15 @@ private:
      * Just store the serialized data.
      * Its length can very cheaply be computed from the first byte.
      */
-    unsigned char vch[65];
+    unsigned char vch[PUBLIC_KEY_SIZE];
 
     //! Compute the length of a pubkey with a given first byte.
     unsigned int static GetLen(unsigned char chHeader)
     {
         if (chHeader == 2 || chHeader == 3)
-            return 33;
+            return COMPRESSED_PUBLIC_KEY_SIZE;
         if (chHeader == 4 || chHeader == 6 || chHeader == 7)
-            return 65;
+            return PUBLIC_KEY_SIZE;
         return 0;
     }
 
@@ -127,7 +130,7 @@ public:
     void Unserialize(Stream& s)
     {
         unsigned int len = ::ReadCompactSize(s);
-        if (len <= 65) {
+        if (len <= PUBLIC_KEY_SIZE) {
             s.read((char*)vch, len);
         } else {
             // invalid pubkey, skip available data
@@ -166,7 +169,7 @@ public:
     //! Check whether this is a compressed public key.
     bool IsCompressed() const
     {
-        return size() == 33;
+        return size() == COMPRESSED_PUBLIC_KEY_SIZE;
     }
 
     /**