msgpack[C++]使用筆記 和 msgpack/cPickle性能對比

python版本的msgpack非常好用，速度上比python內置的pickle和cpickle都要快一些，C++版本的使用比較麻煩，下面是本人學習時的一個example，解析python-msgpack dump的一個復雜字典。

1. #include <msgpack.hpp>
3. #include <fstream>
4. #include <iostream>
5. using namespace std;
7. template <class T>
8. void msgunpack(const char* binary_file, T& t, char* buff, uint32_t max){
9. msgpack::unpacked msg;
10. ifstream tf_file(binary_file,ios::in|ios::binary|ios::ate);
11. uint32_t size = tf_file.tellg();
12. tf_file.seekg(0, ios::beg);
13. tf_file.read(buff, size);
14. tf_file.close();
15. msgpack::unpack(&msg, buff, size);
16. msg.get().convert(&t);
17. }
20. typedef map<uint32_t, uint32_t> WordsMap;
21. typedef map<uint32_t, WordsMap> FieldsMap;
22. typedef map<uint64_t, FieldsMap> DocsMap;
24. int main(int argc, char** argv)
25. {
26. uint32_t MAX_BUFF = 1024*1024*100; //100MB
27. char* BUFF = new char[MAX_BUFF];
29. DocsMap docsMap;
30. msgpack::unpacked msg;
31. msgunpack("/data/wikidoc/tf_dict_for_nodes/1-1000", docsMap, BUFF, MAX_BUFF);
32. // msg.get().convert(&docsMap);
33. cout << docsMap.size() << endl;
34. delete[] BUFF;
35. }

參考： http://wiki.msgpack.org/pages/viewpage.action?pageId=1081387#QuickStartforC%2B%2B-ImplementationStatus

下面是本人自己封裝的一個msgpack接口頭文件mymsgpack.h

1. #ifndef MY_MSGPACK_H
3. #ifndef MY_MSGPACK_H
4. #define MY_MSGPACK_H
5. #include <fstream>
6. #include <msgpack.hpp>
7. using namespace std;
9. template <class T>
10. void load_from_file(const char* binary_file, T& t) {
11. ifstream binaryFstream(binary_file,ios::in|ios::binary|ios::ate);
12. uint32_t size = binaryFstream.tellg();
13. char* buff = new char[size];
14. binaryFstream.seekg(0, ios::beg);
15. binaryFstream.read(buff, size);
16. binaryFstream.close();
17. msgpack::unpacked msg;
18. msgpack::unpack(&msg, buff, size);
19. msg.get().convert(&t);
20. delete[] buff;
21. }
23. template <class T>
24. void load_from_str(const char* binary_str, int len, T& t) {
25. msgpack::unpacked msg;
26. msgpack::unpack(&msg, binary_str, len);
27. msg.get().convert(&t);
28. }
30. template <class T>
31. void dump_to_file(T& t, const char* dump_file) {
32. msgpack::sbuffer sbuf;
33. msgpack::pack(sbuf, t);
34. ofstream dumpFstream(dump_file, ios::out|ios::binary|ios::trunc);
35. dumpFstream.write(sbuf.data(), sbuf.size());
36. dumpFstream.close();
37. }
39. template <class T>
40. void dump_to_str(T& t, char** dump_str, int& len) { //外部釋放*dump_str
41. msgpack::sbuffer sbuf;
42. msgpack::pack(sbuf, t);
43. len = sbuf.size();
44. *dump_str = (char*)malloc(sbuf.size());
45. memcpy(*dump_str, sbuf.data(), sbuf.size());
46. }
48. #endif