replace int with size_t in stream methods

Thus the read(...) and write(...) methods of all stream classes now have identical parameter lists.
This will bring these classes one step closer to a common interface.

src/serialize.h

@@ -68,7 +68,7 @@ inline const T* end_ptr(const std::vector<T,TAl>& v)
 /////////////////////////////////////////////////////////////////
 //
 // Templates for serializing to anything that looks like a stream,
-// i.e. anything that supports .read(char*, int) and .write(char*, int)
+// i.e. anything that supports .read(char*, size_t) and .write(char*, size_t)
 //
 
 enum
@@ -876,7 +876,7 @@ class CSizeComputer
 
     CSizeComputer(int nTypeIn, int nVersionIn) : nSize(0), nType(nTypeIn), nVersion(nVersionIn) {}
 
-    CSizeComputer& write(const char *psz, int nSize)
+    CSizeComputer& write(const char *psz, size_t nSize)
     {
         this->nSize += nSize;
         return *this;
@@ -1105,10 +1105,9 @@ class CDataStream
     void ReadVersion()           { *this >> nVersion; }
     void WriteVersion()          { *this << nVersion; }
 
-    CDataStream& read(char* pch, int nSize)
+    CDataStream& read(char* pch, size_t nSize)
     {
         // Read from the beginning of the buffer
-        assert(nSize >= 0);
         unsigned int nReadPosNext = nReadPos + nSize;
         if (nReadPosNext >= vch.size())
         {
@@ -1145,10 +1144,9 @@ class CDataStream
         return (*this);
     }
 
-    CDataStream& write(const char* pch, int nSize)
+    CDataStream& write(const char* pch, size_t nSize)
     {
         // Write to the end of the buffer
-        assert(nSize >= 0);
         vch.insert(vch.end(), pch, pch + nSize);
         return (*this);
     }