params.h

这是一个著名的应用层组播中间件的源码

//Copyright (c) 2004, Charles Killian, Adolfo Rodriguez, Dejan Kostic, Sooraj Bhat, and Amin Vahdat
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in
//     the documentation and/or other materials provided with the
//     distribution.
//   * Neither the names of Duke University nor The University of
//     California, San Diego, nor the names of its contributors
//     may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
//AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
//IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
//FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
//DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
//SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
//CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
//OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
//USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef params_h
#define params_h

#include <stdio.h>

//For internal use from within params.  See params below.
class param {
  char* key;
  char* strvalue;
  int* intvalue;
  double* doublevalue;

  public:
    param(char* key, char* value) { this->key = key; this->strvalue = value; intvalue=NULL; doublevalue=NULL; }
    param() { key=NULL; strvalue=NULL; intvalue=NULL; doublevalue=NULL; }
    ~param() { }
    char* getkey() {return key;}
    char* set(char* value) { char* old = strvalue; strvalue=value; delete intvalue; intvalue=NULL; 
                            delete doublevalue; doublevalue=NULL; return old;}
    int getint();
    double getdouble();
    char* getstr() { return strvalue; }
    int print(FILE* ostream);
};

class params {
  public:
    bool isset(char* key); //returns true if the parameter is set.
    int getint(char* key); //returns the value of the parameter as an int.
    double getdouble(char* key); //returns the value of the parameter as a double.
    char* getstr(char* key); //returns the value of the parameter as a string.
    
    char* set(char* key, char* value); //returns the old value of the param.

    /** 
     * Loads the parameters as though from the command line.  Follows this method:
     * 1 - Ignores argv[0], as this is the program executable
     * 2 - If no option file is specified, defaults are read in from params.default
     * 3 - If argv[1] is a file -- parameters are read in from it
     * 4 - Remaining arguments are read and parsed as command-line [potentially] overriding values.
     * 5 - Returns the number of parameters set.
     */
    int loadparams(int argc, char** argv);

    /**
     * Files are read in as follows:
     * # is the comment delimiter.  Lines beginning with it are ignored.  
     *   The remainder of any line containing it, unless a quoted string are ignored.
     * parameters are set by parameter = value, or parameter = "value"  
     */
    int loadfile(char* filename);
    
    int print(FILE* ostream); // Prints the parameters to the FILE specified.
    
    params();
  
  private:  
    param* data;
    int max_data;
    int cur_data;

    param* find(char* key);
};

#endif