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--- programming:cpp:json [2022/03/29 12:40]
odagawa created
+++ programming:cpp:json [2022/04/11 14:23] (current)
odagawa
@@ Line 1: / Line 1: @@
 =====JSON=====
-JSON は JavaScript Object Notation 記法のこと．
+JSON は JavaScript Object Notation 記法のこと．\\
 人間にも機械にもそれなりの可読性を持ったファイル形式である．
@@ Line 7: / Line 7: @@
   * [[https://github.com/kazuho/picojson|GitHub]] から picojson.h を持ってくる
-  * ヘッダオンリーライブラリなので適当なところに picojson.h
+  * ヘッダオンリーライブラリなので適当なところに picojson.h を置けば使える
+  * sample code
+<code>
+{
+  "connect_param_angle":{
+     "slope2_x" :0.06,
+     "slope_x" :0.02,
+     "intercept_x":0.05,
+     "slope2_y":0.06,
+     "slope_y":0.02,
+     "intercept_y":0.05,
+     "slope2_r" :0.06,
+     "slope_r" :0.02,
+     "intercept_r":0.05,
+     "slope2_l":0.01,
+     "slope_l":0.03,
+     "intercept_l":0.05
+  },
+  "connect_param_position":{
+     "slope2_x" :0,
+     "slope_x" :100,
+     "intercept_x":30,
+     "slope2_y" :0,
+     "slope_y":100,
+     "intercept_y":30,
+     "slope2_r" :0,
+     "slope_r" :10,
+     "intercept_r":20,
+     "slope2_l" :1,
+     "slope_l":2,
+     "intercept_l":20
+  }
+}
+</code>
+<code cpp TestPicojson.cpp>
+#include "picojson.h"
+#include <boost/filesystem.hpp>
+#include <fstream>
+namespace fs = boost::filesystem;
+void ReadJsonData(t2l_param &param, const std::string json_file_path) {
+  if ( !fs::exists(json_file_path) )
+    throw std::runtime_error("File : " + json_file_path + " not found");
+  std::ifstream ifs(json_file_path);
+  const std::string json((std::istreambuf_iterator<char >(ifs)), std::istreambuf_iterator<char >());
+  ifs.close();
+  picojson::value v;
+  const std::string err = picojson::parse(v, json);
+  if ( !err.empty() )
+    throw std::runtime_error("JSON parse error : " + err);
+  picojson::object &all = v.get<picojson::object >();
+  picojson::object &connect_param_angle = all["connect_param_angle"].get<picojson::object >();
+  picojson::object &connect_param_position = all["connect_param_position"].get<picojson::object >();
+  param.intercept_ax = connect_param_angle["intercept_x"].get<double>();
+  param.intercept_ay = connect_param_angle["intercept_y"].get<double>();
+  param.intercept_ar = connect_param_angle["intercept_r"].get<double>();
+  param.intercept_al = connect_param_angle["intercept_l"].get<double>();
+  param.slope_ax = connect_param_angle["slope_x"].get<double>();
+  param.slope_ay = connect_param_angle["slope_y"].get<double>();
+  param.slope_ar = connect_param_angle["slope_r"].get<double>();
+  param.slope_al = connect_param_angle["slope_l"].get<double>();
+  param.slope2_ax = connect_param_angle["slope2_x"].get<double>();
+  param.slope2_ay = connect_param_angle["slope2_y"].get<double>();
+  param.slope2_ar = connect_param_angle["slope2_r"].get<double>();
+  param.slope2_al = connect_param_angle["slope2_l"].get<double>();
+  param.intercept_px = connect_param_position["intercept_x"].get<double>();
+  param.intercept_py = connect_param_position["intercept_y"].get<double>();
+  param.intercept_pr = connect_param_position["intercept_r"].get<double>();
+  param.intercept_pl = connect_param_position["intercept_l"].get<double>();
+  param.slope_px = connect_param_position["slope_x"].get<double>();
+  param.slope_py = connect_param_position["slope_y"].get<double>();
+  param.slope_pr = connect_param_position["slope_r"].get<double>();
+  param.slope_pl = connect_param_position["slope_l"].get<double>();
+  param.slope2_px = connect_param_position["slope2_x"].get<double>();
+  param.slope2_py = connect_param_position["slope2_y"].get<double>();
+  param.slope2_pr = connect_param_position["slope2_r"].get<double>();
+  param.slope2_pl = connect_param_position["slope2_l"].get<double>();
+}
+</code>

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