- a find() function

src/JSON.cc

@@ -484,6 +484,48 @@ JSON::json_t JSON::type() const {
     return _type;
 }
 
+JSON::iterator JSON::find(const std::string& key) {
+    return find(key.c_str());
+}
+
+JSON::const_iterator JSON::find(const std::string& key) const {
+    return find(key.c_str());
+}
+
+JSON::iterator JSON::find(const char* key) {
+    if (_type != object) {
+        return end();
+    } else {
+        std::map<std::string, JSON>* o = static_cast<std::map<std::string, JSON>*>(_payload);
+        const std::map<std::string, JSON>::iterator i = o->find(key);
+        if (i != o->end()) {
+            JSON::iterator result;
+            result._object = this;
+            result._oi = new std::map<std::string, JSON>::iterator(i);
+            return result;
+        } else {
+            return end();
+        }
+    }
+}
+
+JSON::const_iterator JSON::find(const char* key) const {
+    if (_type != object) {
+        return end();
+    } else {
+        std::map<std::string, JSON>* o = static_cast<std::map<std::string, JSON>*>(_payload);
+        const std::map<std::string, JSON>::const_iterator i = o->find(key);
+        if (i != o->end()) {
+            JSON::const_iterator result;
+            result._object = this;
+            result._oi = new std::map<std::string, JSON>::const_iterator(i);
+            return result;
+        } else {
+            return end();
+        }
+    }
+}
+
 /// direct access to the underlying payload
 void* JSON::data() {
     return _payload;

src/JSON.h

@@ -22,6 +22,11 @@
 #endif
 
 class JSON {
+    // forward declaration to friend this class
+    public:
+        class iterator;
+        class const_iterator;
+
     private:
 #ifdef __cplusplus11
         /// mutex to guard payload
@@ -158,6 +163,12 @@ class JSON {
         /// return the type of the object
         json_t type() const;
 
+        /// find an element in an object (returns end() iterator otherwise)
+        iterator find(const std::string&);
+        const_iterator find(const std::string&) const;
+        iterator find(const char *);
+        const_iterator find(const char *) const;
+
         /// direct access to the underlying payload
         void* data();
         /// direct access to the underlying payload
@@ -170,13 +181,10 @@ class JSON {
         /// return the type as string
         std::string _typename() const;
 
-        // forward declaration to friend this class
-    public:
-        class const_iterator;
-
     public:
         /// an iterator
         class iterator {
+            friend class JSON;
             friend class JSON::const_iterator;
             public:
                 iterator();
@@ -207,6 +215,7 @@ class JSON {
 
         /// a const iterator
         class const_iterator {
+            friend class JSON;
             public:
                 const_iterator();
                 const_iterator(const JSON*);