Added istream/ostream funcs/operators

cdunn2001 · cdunn2001 · commit 56a1d6cbf5cd · 2007-03-23T09:57:01.000Z
diff --git a/doc/jsoncpp.dox b/doc/jsoncpp.dox
@@ -65,6 +65,13 @@ root["indent"]["use_space"] = getCurrentIndentUseSpace();
 Json::StyledWriter writer;
 // Make a new JSON document for the configuration. Preserve original comments.
 std::string outputConfig = writer.write( root );
+
+// You can also use streams.  This will put the contents of any JSON
+// stream at a particular sub-value, if you'd like.
+std::cin >> root["subtree"];
+
+// And you can write to a stream, using the StyledWriter automatically.
+std::cout << root;
 \endcode
 
 \section _plinks Build instructions
diff --git a/include/json/reader.h b/include/json/reader.h
@@ -6,6 +6,7 @@
 # include <deque>
 # include <stack>
 # include <string>
+# include <istream>
 
 namespace Json {
 
@@ -47,6 +48,12 @@ namespace Json {
                   Value &root,
                   bool collectComments = true );
 
+      /// \brief Parse from input stream.
+      /// \see Json::operator>>(std::istream&, Json::Value&).
+      bool parse( std::istream&,
+                  Value &root,
+                  bool collectComments = true );
+
       /** \brief Returns a user friendly string that list errors in the parsed document.
        * \return Formatted error message with the list of errors with their location in 
        *         the parsed document. An empty string is returned if no error occurred
@@ -144,6 +151,31 @@ namespace Json {
       bool collectComments_;
    };
 
+   /** \brief Read from 'sin' into 'root'.
+
+    Always keep comments from the input JSON.
+
+    This can be used to read a file into a particular sub-object.
+    For example:
+    \code
+    Json::Value root;
+    cin >> root["dir"]["file"];
+    cout << root;
+    \endcode
+    Result:
+    \verbatim
+    {
+	"dir": {
+	    "file": {
+		// The input stream JSON would be nested here.
+	    }
+	}
+    }
+    \endverbatim
+    \throw std::exception on parse error.
+    \see Json::operator<<()
+   */
+   std::istream& operator>>( std::istream&, Value& );
 
 } // namespace Json
 
diff --git a/include/json/writer.h b/include/json/writer.h
@@ -4,6 +4,7 @@
 # include "value.h"
 # include <vector>
 # include <string>
+# include <ostream>
 
 namespace Json {
 
@@ -68,7 +69,7 @@ namespace Json {
    public: // overridden from Writer
       /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
        * \param root Value to serialize.
-       * \return String containing the JSON document that represent the root value.
+       * \return String containing the JSON document that represents the root value.
        */
       virtual std::string write( const Value &root );
 
@@ -102,6 +103,10 @@ namespace Json {
    std::string JSON_API valueToString( bool value );
    std::string JSON_API valueToQuotedString( const char *value );
 
+   /// \brief Output using the StyledWriter.
+   /// \see Json::operator>>()
+   std::ostream& operator<<( std::ostream&, const Value &root );
+
 } // namespace Json
 
 
diff --git a/src/lib_json/json_reader.cpp b/src/lib_json/json_reader.cpp
@@ -3,6 +3,8 @@
 #include <utility>
 #include <stdio.h>
 #include <assert.h>
+#include <istream>
+#include <stdexcept>
 
 #if _MSC_VER >= 1400 // VC++ 8.0
 #pragma warning( disable : 4996 )   // disable warning about strdup being deprecated.
@@ -52,6 +54,23 @@ Reader::parse( const std::string &document,
    return parse( begin, end, root, collectComments );
 }
 
+bool
+Reader::parse( std::istream& sin,
+               Value &root,
+               bool collectComments )
+{
+   //std::istream_iterator<char> begin(sin);
+   //std::istream_iterator<char> end;
+   // Those would allow streamed input from a file, if parse() were a
+   // template function.
+
+   // Since std::string is reference-counted, this at least does not
+   // create an extra copy.
+   std::string doc;
+   std::getline(sin, doc, (char)EOF);
+   return parse( doc, root, collectComments );
+}
+
 bool 
 Reader::parse( const char *beginDoc, const char *endDoc, 
                Value &root,
@@ -718,4 +737,14 @@ Reader::getFormatedErrorMessages() const
 }
 
 
+std::istream& operator>>( std::istream &sin, Value &root )
+{
+    Json::Reader reader;
+    bool ok = reader.parse(sin, root, true);
+    //JSON_ASSERT( ok );
+    if (!ok) throw std::runtime_error(reader.getFormatedErrorMessages());
+    return sin;
+}
+
+
 } // namespace Json
diff --git a/src/lib_json/json_writer.cpp b/src/lib_json/json_writer.cpp
@@ -2,6 +2,7 @@
 #include <utility>
 #include <assert.h>
 #include <stdio.h>
+#include <ostream>
 
 #if _MSC_VER >= 1400 // VC++ 8.0
 #pragma warning( disable : 4996 )   // disable warning about strdup being deprecated.
@@ -475,5 +476,12 @@ StyledWriter::normalizeEOL( const std::string &text )
    return normalized;
 }
 
+std::ostream& operator<<( std::ostream &sout, const Value &root )
+{
+   Json::StyledWriter writer;
+   sout << writer.write(root);
+   return sout;
+}
+
 
 } // namespace Json
