diff --git a/src/WireDecoder.cpp b/src/WireDecoder.cpp
new file mode 100644
index 0000000..138225e
--- /dev/null
+++ b/src/WireDecoder.cpp
@@ -0,0 +1,206 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2015. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "WireDecoder.h"
+
+#include <cassert>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+
+#include "llvm/MathExtras.h"
+#include "leb128.h"
+
+using namespace nt;
+
+static double ReadDouble(const char*& buf) {
+  // Fast but non-portable!
+  std::uint64_t val = (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  val <<= 8;
+  val |= (*reinterpret_cast<const unsigned char*>(buf)) & 0xff;
+  ++buf;
+  return llvm::BitsToDouble(val);
+}
+
+WireDecoder::WireDecoder(raw_istream& is, unsigned int proto_rev) : m_is(is) {
+  // Start with a 1K temporary buffer.  Use malloc instead of new so we can
+  // realloc.
+  m_allocated = 1024;
+  m_buf = static_cast<char*>(std::malloc(m_allocated));
+  m_proto_rev = proto_rev;
+  m_error = nullptr;
+}
+
+WireDecoder::~WireDecoder() { std::free(m_buf); }
+
+bool WireDecoder::ReadDouble(double* val) {
+  const char* buf;
+  if (!Read(&buf, 8)) return false;
+  *val = ::ReadDouble(buf);
+  return true;
+}
+
+void WireDecoder::Realloc(std::size_t len) {
+  // Double current buffer size until we have enough space.
+  if (m_allocated >= len) return;
+  std::size_t newlen = m_allocated * 2;
+  while (newlen < len) newlen *= 2;
+  m_buf = static_cast<char*>(std::realloc(m_buf, newlen));
+  m_allocated = newlen;
+}
+
+bool WireDecoder::ReadType(NT_Type* type) {
+  unsigned int itype;
+  if (!Read8(&itype)) return false;
+  // Convert from byte value to enum
+  switch (itype) {
+    case 0x00:
+      *type = NT_BOOLEAN;
+      break;
+    case 0x01:
+      *type = NT_DOUBLE;
+      break;
+    case 0x02:
+      *type = NT_STRING;
+      break;
+    case 0x03:
+      *type = NT_RAW;
+      break;
+    case 0x10:
+      *type = NT_BOOLEAN_ARRAY;
+      break;
+    case 0x11:
+      *type = NT_DOUBLE_ARRAY;
+      break;
+    case 0x12:
+      *type = NT_STRING_ARRAY;
+      break;
+    case 0x20:
+      *type = NT_RPC;
+      break;
+    default:
+      *type = NT_UNASSIGNED;
+      m_error = "unrecognized value type";
+      return false;
+  }
+  return true;
+}
+
+std::shared_ptr<Value> WireDecoder::ReadValue(NT_Type type) {
+  switch (type) {
+    case NT_BOOLEAN: {
+      unsigned int v;
+      if (!Read8(&v)) return nullptr;
+      return Value::MakeBoolean(v != 0);
+    }
+    case NT_DOUBLE: {
+      double v;
+      if (!ReadDouble(&v)) return nullptr;
+      return Value::MakeDouble(v);
+    }
+    case NT_STRING: {
+      std::string v;
+      if (!ReadString(&v)) return nullptr;
+      return Value::MakeString(std::move(v));
+    }
+    case NT_RAW: {
+      if (m_proto_rev < 0x0300u) {
+        m_error = "received raw value in protocol < 3.0";
+        return nullptr;
+      }
+      std::string v;
+      if (!ReadString(&v)) return nullptr;
+      return Value::MakeRaw(std::move(v));
+    }
+    case NT_RPC: {
+      if (m_proto_rev < 0x0300u) {
+        m_error = "received RPC value in protocol < 3.0";
+        return nullptr;
+      }
+      std::string v;
+      if (!ReadString(&v)) return nullptr;
+      return Value::MakeRpc(std::move(v));
+    }
+    case NT_BOOLEAN_ARRAY: {
+      // size
+      unsigned int size;
+      if (!Read8(&size)) return nullptr;
+
+      // array values
+      const char* buf;
+      if (!Read(&buf, size)) return nullptr;
+      std::vector<int> v(size);
+      for (unsigned int i = 0; i < size; ++i)
+        v[i] = buf[i] ? 1 : 0;
+      return Value::MakeBooleanArray(std::move(v));
+    }
+    case NT_DOUBLE_ARRAY: {
+      // size
+      unsigned int size;
+      if (!Read8(&size)) return nullptr;
+
+      // array values
+      const char* buf;
+      if (!Read(&buf, size * 8)) return nullptr;
+      std::vector<double> v(size);
+      for (unsigned int i = 0; i < size; ++i)
+        v[i] = ::ReadDouble(buf);
+      return Value::MakeDoubleArray(std::move(v));
+    }
+    case NT_STRING_ARRAY: {
+      // size
+      unsigned int size;
+      if (!Read8(&size)) return nullptr;
+
+      // array values
+      std::vector<std::string> v(size);
+      for (unsigned int i = 0; i < size; ++i) {
+        if (!ReadString(&v[i])) return nullptr;
+      }
+      return Value::MakeStringArray(std::move(v));
+    }
+    default:
+      m_error = "invalid type when trying to read value";
+      return nullptr;
+  }
+}
+
+bool WireDecoder::ReadString(std::string* str) {
+  size_t len;
+  if (m_proto_rev < 0x0300u) {
+    unsigned int v;
+    if (!Read16(&v)) return false;
+    len = v;
+  } else {
+    unsigned long v;
+    if (!ReadUleb128(&v)) return false;
+    len = v;
+  }
+  const char* buf;
+  if (!Read(&buf, len)) return false;
+  *str = llvm::StringRef(buf, len);
+  return true;
+}