1 files changed, 55 insertions, 0 deletions
diff --git a/lib/math/bigint/big_io.cpp b/lib/math/bigint/big_io.cpp
new file mode 100644
index 000000000..b561c218f
--- /dev/null
+++ b/lib/math/bigint/big_io.cpp
@@ -0,0 +1,55 @@
+/*
+* BigInt Input/Output
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/bigint.h>
+#include <iostream>
+
+namespace Botan {
+
+/*
+* Write the BigInt into a stream
+*/
+std::ostream& operator<<(std::ostream& stream, const BigInt& n)
+   {
+   BigInt::Base base = BigInt::Decimal;
+   if(stream.flags() & std::ios::hex)
+      base = BigInt::Hexadecimal;
+   else if(stream.flags() & std::ios::oct)
+      throw std::runtime_error("Octal output of BigInt not supported");
+
+   if(n == 0)
+      stream.write("0", 1);
+   else
+      {
+      if(n < 0)
+         stream.write("-", 1);
+      const std::vector<byte> buffer = BigInt::encode(n, base);
+      size_t skip = 0;
+      while(skip < buffer.size() && buffer[skip] == '0')
+         ++skip;
+      stream.write(reinterpret_cast<const char*>(&buffer[0]) + skip,
+                   buffer.size() - skip);
+      }
+   if(!stream.good())
+      throw Stream_IO_Error("BigInt output operator has failed");
+   return stream;
+   }
+
+/*
+* Read the BigInt from a stream
+*/
+std::istream& operator>>(std::istream& stream, BigInt& n)
+   {
+   std::string str;
+   std::getline(stream, str);
+   if(stream.bad() || (stream.fail() && !stream.eof()))
+      throw Stream_IO_Error("BigInt input operator has failed");
+   n = BigInt(str);
+   return stream;
+   }
+
+}