copy from an old project

include/json.hpp

@@ -0,0 +1,75 @@
+#ifndef JSON_HPP
+#define JSON_HPP
+
+#include <cstddef>
+#include <cstdint>
+
+#include <zephyr/data/json.h>
+
+#include <log.hpp>
+
+namespace JsonParser
+{
+void init();
+void add_text(uint8_t* buf, size_t size);
+int json_printer(const char* bytes, size_t len, void* data);
+
+class HandlerBase
+{
+public:
+    /* private but accessible from static functions */
+    HandlerBase* _next;
+
+    HandlerBase();
+    virtual bool handle(const char* buf, size_t size) = 0;
+};
+
+template <typename Struct, size_t DESC_SIZE, typename Fct>
+class Handler: public HandlerBase
+{
+    const Struct& _s;
+    const json_obj_descr* _da;
+    Fct _fct;
+    bool _allow_partial;
+
+    const int64_t _all_fields;
+
+public:
+    Handler(Struct default_s, const json_obj_descr (&da)[DESC_SIZE], Fct fct, bool allow_partial=false):
+            _s {default_s},
+            _da {da},
+            _fct {fct},
+            _allow_partial{allow_partial},
+            _all_fields {(1 << DESC_SIZE) - 1}
+    {
+    }
+
+    void print( const Struct& s) { json_obj_encode(_da, DESC_SIZE, &s, json_printer, NULL); }
+
+    bool handle(const char* buf, size_t size) override
+    {
+        Struct s{_s};
+        int64_t ret = json_obj_parse((char*)buf, size, _da, DESC_SIZE, &s);
+        if (ret <= 0)
+        {
+            return false;
+        }
+        if(ret != _all_fields && !_allow_partial)
+        {
+            return false;
+        }
+        if (!_fct(s, ret, _all_fields))
+        {
+            return false;
+        }
+
+        // info("received a valid json\n");
+        // print(s);
+        // info("\n");
+        return true;
+    }
+};
+
+} // namespace JsonParser
+
+#endif /* JSON_HPP */