整理代码

util/xpack/example/my_decoder.cpp

@@ -0,0 +1,70 @@
+#include <iostream>
+#include <string>
+#include "xpack/json.h"
+
+using namespace std;
+
+
+// assign value by name
+class AssignDecoder {
+public:
+    AssignDecoder(const std::vector<std::string>&vs, const unsigned char *src, unsigned char *dst) {
+        for (size_t i=0; i<vs.size(); ++i) {
+            fields.insert(vs[i]);
+        }
+        this->src = src;
+        this->dst = dst;
+    }
+
+    // decoder need implemetion decode function
+    template<class T>
+    bool decode(const char *key, T&val, const xpack::Extend *ext) {
+        (void)ext;
+        // set value by offset
+        if (fields.end() != fields.find(key)) {
+            unsigned int offset = (unsigned int)((unsigned char*)&val - dst);
+            val = *((T*)(src+offset));
+        }
+        return true;
+    }
+private:
+    std::set<std::string> fields;
+    const unsigned char *src;
+    unsigned char *dst;
+};
+
+// SetFields<T>(src, dst, "a,b") means dst.a = src.a; dst.b = src.b;
+template <class T>
+void SetFields(const T&src, T&dst, const std::string&fields) {
+    std::vector<std::string> vs;
+    xpack::Util::split(vs, fields, ',');
+    if (vs.size() == 0) {
+        return;
+    }
+
+    AssignDecoder de(vs, (unsigned char*)(&src), (unsigned char*)(&dst));
+    dst.__x_pack_decode(de, dst, NULL);
+}
+
+struct Data {
+    int a;
+    int b;
+    std::string c;
+    XPACK(O(a,b,c));
+};
+
+
+int main(int argc, char *argv[]) {
+    (void)argc;
+    (void)argv;
+
+    Data d1;
+    Data d2;
+    d1.a = 5;
+    d1.b = 10;
+    d1.c = "hello";
+    d2.b = 9;
+    SetFields<Data>(d1, d2, "a,c");
+    cout<<d2.a<<','<<d2.b<<','<<d2.c<<endl;
+    return 0;
+}