Rearrange sources (#4997)

src/libxrpl/protocol/Book.cpp

@@ -0,0 +1,50 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <ripple/protocol/Book.h>
+
+namespace ripple {
+
+bool
+isConsistent(Book const& book)
+{
+    return isConsistent(book.in) && isConsistent(book.out) &&
+        book.in != book.out;
+}
+
+std::string
+to_string(Book const& book)
+{
+    return to_string(book.in) + "->" + to_string(book.out);
+}
+
+std::ostream&
+operator<<(std::ostream& os, Book const& x)
+{
+    os << to_string(x);
+    return os;
+}
+
+Book
+reversed(Book const& book)
+{
+    return Book(book.out, book.in);
+}
+
+}  // namespace ripple