1 files changed, 62 insertions, 0 deletions
diff --git a/src/common/varint.h b/src/common/varint.h
new file mode 100644
index 000000000..e62470fdf
--- /dev/null
+++ b/src/common/varint.h
@@ -0,0 +1,62 @@
+// Copyright (c) 2012-2013 The Cryptonote developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#pragma once
+
+#include <limits>
+#include <type_traits>
+#include <utility>
+#include <sstream>
+#include <string>
+
+namespace tools {
+
+    template<typename OutputIt, typename T>
+    typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value, void>::type
+    write_varint(OutputIt &&dest, T i) {
+        while (i >= 0x80) {
+            *dest++ = (static_cast<char>(i) & 0x7f) | 0x80;
+            i >>= 7;
+        }
+        *dest++ = static_cast<char>(i);
+    }
+
+    template<typename t_type>
+    std::string get_varint_data(const t_type& v)
+    {
+      std::stringstream ss;
+      write_varint(std::ostreambuf_iterator<char>(ss), v);
+      return ss.str();
+    }
+
+    template<int bits, typename InputIt, typename T>
+    typename std::enable_if<std::is_integral<T>::value && std::is_unsigned<T>::value && 0 <= bits && bits <= std::numeric_limits<T>::digits, int>::type
+    read_varint(InputIt &&first, InputIt &&last, T &i) {
+        int read = 0;
+        i = 0;
+        for (int shift = 0;; shift += 7) {
+            if (first == last) {
+                return read; // End of input.
+            }
+            unsigned char byte = *first++;
+            ++read;
+            if (shift + 7 >= bits && byte >= 1 << (bits - shift)) {
+                return -1; // Overflow.
+            }
+            if (byte == 0 && shift != 0) {
+                return -2; // Non-canonical representation.
+            }
+            i |= static_cast<T>(byte & 0x7f) << shift;
+            if ((byte & 0x80) == 0) {
+                break;
+            }
+        }
+        return read;
+    }
+
+    template<typename InputIt, typename T>
+    int read_varint(InputIt &&first, InputIt &&last, T &i) {
+        return read_varint<std::numeric_limits<T>::digits, InputIt, T>(std::move(first), std::move(last), i);
+    }
+}