BIP155 (addrv2)

Tor v3 + i2p

src/streams.h

@@ -77,6 +77,8 @@ public:
 
     int GetVersion() const { return nVersion; }
     int GetType() const { return nType; }
+    size_t size() const { return stream->size(); }
+    void ignore(size_t size) { return stream->ignore(size); }
 };
 
 template<typename S>
@@ -85,6 +87,70 @@ OverrideStream<S> WithVersion(S* s, int nVersion)
     return OverrideStream<S>(s, s->GetType(), nVersion);
 }
 
+/* Minimal stream for overwriting and/or appending to an existing byte vector
+ *
+ * The referenced vector will grow as necessary
+ */
+class CVectorWriter
+{
+ public:
+
+/*
+ * @param[in]  nTypeIn Serialization Type
+ * @param[in]  nVersionIn Serialization Version (including any flags)
+ * @param[in]  vchDataIn  Referenced byte vector to overwrite/append
+ * @param[in]  nPosIn Starting position. Vector index where writes should start. The vector will initially
+ *                    grow as necessary to max(nPosIn, vec.size()). So to append, use vec.size().
+*/
+    CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn) : nType(nTypeIn), nVersion(nVersionIn), vchData(vchDataIn), nPos(nPosIn)
+    {
+        if(nPos > vchData.size())
+            vchData.resize(nPos);
+    }
+/*
+ * (other params same as above)
+ * @param[in]  args  A list of items to serialize starting at nPosIn.
+*/
+    template <typename... Args>
+    CVectorWriter(int nTypeIn, int nVersionIn, std::vector<unsigned char>& vchDataIn, size_t nPosIn, Args&&... args) : CVectorWriter(nTypeIn, nVersionIn, vchDataIn, nPosIn)
+    {
+        ::SerializeMany(*this, std::forward<Args>(args)...);
+    }
+    void write(const char* pch, size_t nSize)
+    {
+        assert(nPos <= vchData.size());
+        size_t nOverwrite = std::min(nSize, vchData.size() - nPos);
+        if (nOverwrite) {
+            memcpy(vchData.data() + nPos, reinterpret_cast<const unsigned char*>(pch), nOverwrite);
+        }
+        if (nOverwrite < nSize) {
+            vchData.insert(vchData.end(), reinterpret_cast<const unsigned char*>(pch) + nOverwrite, reinterpret_cast<const unsigned char*>(pch) + nSize);
+        }
+        nPos += nSize;
+    }
+    template<typename T>
+    CVectorWriter& operator<<(const T& obj)
+    {
+        // Serialize to this stream
+        ::Serialize(*this, obj);
+        return (*this);
+    }
+    int GetVersion() const
+    {
+        return nVersion;
+    }
+    int GetType() const
+    {
+        return nType;
+    }
+private:
+    const int nType;
+    const int nVersion;
+    std::vector<unsigned char>& vchData;
+    size_t nPos;
+};
+
+
 /** Double ended buffer combining vector and stream-like interfaces.
  *
  * >> and << read and write unformatted data using the above serialization templates.
@@ -355,7 +421,7 @@ public:
     }
 
     template<typename T>
-    CBaseDataStream& operator>>(T& obj)
+    CBaseDataStream& operator>>(T&& obj)
     {
         // Unserialize from this stream
         ::Unserialize(*this, obj);
@@ -547,19 +613,20 @@ protected:
             readNow = nAvail;
         if (readNow == 0)
             return false;
-        size_t read = fread((void*)&vchBuf[pos], 1, readNow, src);
-        if (read == 0) {
+        size_t nBytes = fread((void*)&vchBuf[pos], 1, readNow, src);
+        if (nBytes == 0) {
             throw std::ios_base::failure(feof(src) ? "CBufferedFile::Fill: end of file" : "CBufferedFile::Fill: fread failed");
-        } else {
-            nSrcPos += read;
-            return true;
         }
+        nSrcPos += nBytes;
+            return true;
     }
 
 public:
     CBufferedFile(FILE *fileIn, uint64_t nBufSize, uint64_t nRewindIn, int nTypeIn, int nVersionIn) :
         nType(nTypeIn), nVersion(nVersionIn), nSrcPos(0), nReadPos(0), nReadLimit((uint64_t)(-1)), nRewind(nRewindIn), vchBuf(nBufSize, 0)
     {
+        if (nRewindIn >= nBufSize)
+            throw std::ios_base::failure("Rewind limit must be less than buffer size");
         src = fileIn;
     }
 
@@ -594,8 +661,6 @@ public:
 
         if (nSize + nReadPos > nReadLimit)
             throw std::ios_base::failure("Read attempted past buffer limit");
-        if (nSize + nRewind > vchBuf.size())
-            throw std::ios_base::failure("Read larger than buffer size");
         while (nSize > 0) {
             if (nReadPos == nSrcPos)
                 Fill();
@@ -619,16 +684,19 @@ public:
 
     // rewind to a given reading position
     bool SetPos(uint64_t nPos) {
-        nReadPos = nPos;
-        if (nReadPos + nRewind < nSrcPos) {
-            nReadPos = nSrcPos - nRewind;
+        size_t bufsize = vchBuf.size();
+        if (nPos + bufsize < nSrcPos) {
+            // rewinding too far, rewind as far as possible
+            nReadPos = nSrcPos - bufsize;
             return false;
-        } else if (nReadPos > nSrcPos) {
+        }
+        if (nPos > nSrcPos) {
+            // can't go this far forward, go as far as possible
             nReadPos = nSrcPos;
             return false;
-        } else {
-            return true;
         }
+        nReadPos = nPos;
+        return true;
     }
 
     bool Seek(uint64_t nPos) {