Home | History | Annotate | Download | only in libutil++
      1 /**
      2  * @file generic_spec.h
      3  * Container holding an item or a special "match all" item
      4  *
      5  * @remark Copyright 2003 OProfile authors
      6  * @remark Read the file COPYING
      7  *
      8  * @author John Levon
      9  * @author Philippe Elie
     10  */
     11 
     12 #ifndef GENERIC_SPEC_H
     13 #define GENERIC_SPEC_H
     14 
     15 #include <stdexcept>
     16 #include <string>
     17 #include <sstream>
     18 
     19 #include "string_manip.h"
     20 
     21 
     22 /**
     23  * used to hold something like { int cpu_nr, bool is_all };
     24  * to store a sub part of a samples filename see PP:3.21.
     25  */
     26 template <class T>
     27 class generic_spec
     28 {
     29 public:
     30 	/**
     31 	 * build a default spec which match anything
     32 	 */
     33 	generic_spec();
     34 
     35 	/// build a spec from a string, valid argument are "all"
     36 	/// or a string convertible to T through istringtream(str) >> data
     37 	/// conversion is strict, no space are allowed at begin or end of str
     38 	void set(std::string const &);
     39 
     40 	/// return true if a specific value is held by this container
     41 	bool is_set() const {
     42 		return !is_all;
     43 	}
     44 
     45 	/// return the specific value (only if is_set() == true)
     46 	T const value() const {
     47 		if (!is_all)
     48 			return data;
     49 		throw std::out_of_range("generic_spec holds no value");
     50 	}
     51 
     52 	/// return true if rhs match this spec. Sub part of PP:3.24
     53 	bool match(T const & rhs) const {
     54 		return rhs == data;
     55 	}
     56 
     57 	/// return true if rhs match this spec. Sub part of PP:3.24
     58 	bool match(generic_spec<T> const & rhs) const {
     59 		return is_all || rhs.is_all || rhs.data == data;
     60 	}
     61 
     62 private:
     63 	T data;
     64 	bool is_all;
     65 };
     66 
     67 
     68 template <class T>
     69 generic_spec<T>::generic_spec()
     70 	:
     71 	data(T()),
     72 	is_all(true)
     73 {
     74 }
     75 
     76 
     77 template <class T>
     78 void generic_spec<T>::set(std::string const & str)
     79 {
     80 	if (str == "all") {
     81 		is_all = true;
     82 		return;
     83 	}
     84 
     85 	is_all = false;
     86 	data = op_lexical_cast<T>(str);
     87 }
     88 
     89 
     90 /// We don't use generic_spec<string>, since it's probably an error to try
     91 /// to use generic_spec<string> we specialize but don't define it to get a
     92 /// link error (using generic_spec<string> is problematic because g.set("all")
     93 /// is ambiguous)
     94 template <>
     95 void generic_spec<std::string>::set(std::string const & str);
     96 
     97 #endif /* !GENERIC_SPEC_H */
     98