dconfig.h

00001 /**
00002 * @file dconfig.h
00003 *
00004 * @author hillkim7@gmail.com
00005 * @brief The key and value pairs config wrapper class for managing app setting.
00006 * Most of programs need to hold application specific setting.
00007 * The dconfig class can provide functionality for that.
00008 */
00009 
00010 #pragma once
00011 
00012 #include <string>
00013 #include <map>
00014 #include <stdlib.h>
00015 
00016 /**  Example:
00017  * @code
00018  *
00019  * #include <stdio.h>
00020  * #include "dconfig.h"
00021  *
00022  * class MyConfig : public DConfig
00023  * {
00024  * public:
00025  *  virtual void reset_default(void)
00026  *  {
00027  *      (*this)["tz"] = "9";
00028  *      (*this)["name"] = "my_app";
00029  *  }
00030  * };
00031  *
00032  * int main(int argc, char* argv[])
00033  * {
00034  *  MyConfig mycfg;
00035  *  std::string serialized_data;
00036  *
00037  *  // setup initial key & value
00038  *  mycfg.reset_default();
00039  *
00040  *  printf("name=%s\r\n", mycfg.lookup_as_cstr("name", ""));
00041  *  printf("tz=%d\r\n", mycfg.lookup_as_int("tz", 0));
00042  *  return 0;
00043  * }
00044 
00045  */
00046 
00047 typedef bool (*DConfigOutput_t) (void *user_data, char c);
00048 
00049 class DConfig : public std::map<std::string, std::string>
00050 {
00051 public:
00052     DConfig(char kv_delimiter='=', char item_delimiter='\n')
00053         : kv_delimiter_(kv_delimiter)
00054         , item_delimiter_(item_delimiter)
00055     {
00056     }
00057     
00058     /** lookup value by key and return value as int if a key exists. */
00059     int lookup_as_int(const std::string &key_name, int default_value) const;
00060 
00061     /** lookup value by key and return value as C string if a key exists. */
00062     const char *lookup_as_cstr(const std::string &key_name, const char *default_value) const;
00063 
00064     /** lookup value by key */
00065     bool lookup(const std::string &key_name, std::string &value) const;
00066 
00067     /** lookup value by key and return value as C string if a key exists. */
00068     std::string lookup(const std::string &key_name) const;
00069 
00070     /** replace value of existing value matching key. */
00071     bool value_replace(const std::string &key_name, std::string value);
00072 
00073     /** replace value of existing value matching key. */
00074     bool value_replace(const std::string &key_name, int value);
00075 
00076     /** load key & value pairs from memory.
00077      * The delimiters are same as them used in the load_from().
00078      */
00079     bool load_from(const char *ptr, size_t ptr_len);
00080 
00081     /** save all key & value pairs by calling callback function.
00082     */
00083     bool save_to(DConfigOutput_t func, void *user_data) const;
00084 
00085 
00086     /** print all item into the stdout */
00087     void print_all(void) const;
00088 
00089     /** estimate number of bytes for saving */
00090     size_t estimate_save(void) const;
00091 
00092     /** check if a key exists. */
00093     bool has_key(const std::string &key_name) const
00094     {
00095         return this->find(key_name) != this->end();
00096     }
00097 
00098     /** virtual function for default setting. */
00099     virtual void reset_default(void)
00100     {
00101     }
00102 
00103 protected:
00104     /// kv_delimiter delimiter char between key and value.
00105     char kv_delimiter_;
00106     /// item_delimiter delimiter char between items.
00107     char item_delimiter_;
00108 };
00109 
00110