From: MFraters <menno.fraters@hotmail.com>
Date: Sun, 4 Mar 2018 02:25:43 +0000 (+0100)
Subject: add json parser for input files.
X-Git-Tag: v9.0.0-rc1~337^2~2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6be5221f8b3111e26c0e71217e994eb82cffb3fe;p=dealii.git

add json parser for input files.
---

diff --git a/include/deal.II/base/parameter_handler.h b/include/deal.II/base/parameter_handler.h
index 95668d351d..0635f28027 100644
--- a/include/deal.II/base/parameter_handler.h
+++ b/include/deal.II/base/parameter_handler.h
@@ -963,6 +963,15 @@ public:
    */
   virtual void parse_input_from_xml (std::istream &input);
 
+  /**
+   * Parse input from an JSON stream to populate known parameter fields. This
+   * could be from a file originally written by the print_parameters() function
+   * using the XML output style and then modified by hand as necessary, or from
+   * a file written using this method and then modified by the graphical
+   * parameter GUI (see the general documentation of this class).
+   */
+  virtual void parse_input_from_json (std::istream &input);
+
   /**
    * Clear all contents.
    */
diff --git a/source/base/parameter_handler.cc b/source/base/parameter_handler.cc
index 604e1d0f3f..0b392a4cd5 100644
--- a/source/base/parameter_handler.cc
+++ b/source/base/parameter_handler.cc
@@ -580,6 +580,21 @@ void ParameterHandler::parse_input_from_xml (std::istream &in)
 }
 
 
+void ParameterHandler::parse_input_from_json (std::istream &in)
+{
+  AssertThrow(in, ExcIO());
+
+  boost::property_tree::ptree node_tree;
+  // This boost function will raise an exception if this is not a valid JSON
+  // file.
+  read_json (in, node_tree);
+
+  // The xml function is reused to read in the xml into the paramter file.
+  // This means that only mangled files can be read.
+  read_xml_recursively (node_tree, "", path_separator, patterns, *entries);
+}
+
+
 
 void ParameterHandler::clear ()
 {