boost_1_45_0/libs/regex/doc/regex_match.qbk

[/ 
  Copyright 2006-2007 John Maddock.
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or copy at
  http://www.boost.org/LICENSE_1_0.txt).
]


[section:regex_match regex_match]

   #include <boost/regex.hpp> 

The algorithm [regex_match] determines whether a given regular expression 
matches [*all] of a given character sequence denoted by a pair of 
bidirectional-iterators, the algorithm is defined as follows, 
the main use of this function is data input validation.

[important Note that the result is true only if the expression matches the 
*whole* of the input sequence.  If you want to search for an 
expression somewhere within the sequence then use [regex_search].  If you 
want to match a prefix of the character string then use [regex_search] 
with the flag match_continuous set.]

   template <class BidirectionalIterator, class Allocator, class charT, class traits>
   bool regex_match(BidirectionalIterator first, BidirectionalIterator last,
                    match_results<BidirectionalIterator, Allocator>& m,
                    const basic_regex <charT, traits>& e,
                    match_flag_type flags = match_default); 

   template <class BidirectionalIterator, class charT, class traits>
   bool regex_match(BidirectionalIterator first, BidirectionalIterator last,
                    const basic_regex <charT, traits>& e,
                    match_flag_type flags = match_default); 

   template <class charT, class Allocator, class traits>
   bool regex_match(const charT* str, match_results<const charT*, Allocator>& m,
                    const basic_regex <charT, traits>& e,
                    match_flag_type flags = match_default); 

   template <class ST, class SA, class Allocator, class charT, class traits>
   bool regex_match(const basic_string<charT, ST, SA>& s,
                    match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m, 
                    const basic_regex <charT, traits>& e, 
                    match_flag_type flags = match_default); 

   template <class charT, class traits>
   bool regex_match(const charT* str,
                    const basic_regex <charT, traits>& e,
                    match_flag_type flags = match_default); 
  
   template <class ST, class SA, class charT, class traits>
   bool regex_match(const basic_string<charT, ST, SA>& s,
                    const basic_regex <charT, traits>& e,
                    match_flag_type flags = match_default);

[h4 Description]

   template <class BidirectionalIterator, class Allocator, class charT, class traits>
   bool regex_match(BidirectionalIterator first, BidirectionalIterator last,
                    match_results<BidirectionalIterator, Allocator>& m,
                    const basic_regex <charT, traits>& e,
                    match_flag_type flags = match_default);

[*Requires]: Type BidirectionalIterator meets the requirements of a 
Bidirectional Iterator (24.1.4).

[*Effects]: Determines whether there is an exact match between the regular expression /e/, 
and all of the character sequence \[first, last), parameter /flags/ 
(see [match_flag_type]) is used to 
control how the expression is matched against the character sequence. 
Returns true if such a match exists, false otherwise.

[*Throws]: `std::runtime_error` if the complexity of matching the expression 
against an N character string begins to exceed O(N[super 2]), or if the 
program runs out of stack space while matching the expression (if Boost.Regex is 
configured in recursive mode), or if the matcher exhausts its permitted 
memory allocation (if Boost.Regex is configured in non-recursive mode).

[*Postconditions]: If the function returns false, then the effect on 
parameter /m/ is undefined, otherwise the effects on parameter /m/ are 
given in the table:

[table
[[Element][Value]]
[[`m.size()`][`e.mark_count()`]]
[[`m.empty()`][`false`]]
[[`m.prefix().first`][`first`]]
[[`m.prefix().last`][`first`]]
[[`m.prefix().matched`][`false`]]
[[`m.suffix().first`][`last`]]
[[`m.suffix().last`][`last`]]
[[`m.suffix().matched`][`false`]]
[[`m[0].first`][`first`]]
[[`m[0].second`][`last`]]
[[`m[0].matched`][true if a full match was found, and false if it was a 
partial match (found as a result of the match_partial flag being set).]]
[[`m[n].first`][For all integers `n < m.size()`, the start of the sequence that 
   matched sub-expression /n/. Alternatively, if sub-expression /n/ did not 
   participate in the match, then `last`.]]
[[`m[n].second`][For all integers `n < m.size()`, the end of the sequence that 
      matched sub-expression /n/. Alternatively, if sub-expression /n/ did not 
      participate in the match, then `last`.]]
[[`m[n].matched`][For all integers `n < m.size()`, true if sub-expression /n/ 
      participated in the match, false otherwise.]]
]
 

   template <class BidirectionalIterator, class charT, class traits>
   bool regex_match(BidirectionalIterator first, BidirectionalIterator last,
                  const basic_regex <charT, traits>& e,
                  match_flag_type flags = match_default);

[*Effects]: Behaves "as if" by constructing an instance of 
`match_results<BidirectionalIterator> what`, and then returning the result of 
`regex_match(first, last, what, e, flags)`.

   template <class charT, class Allocator, class traits>
   bool regex_match(const charT* str, match_results<const charT*, Allocator>& m,
                  const basic_regex <charT, traits>& e,
                  match_flag_type flags = match_default);

[*Effects]: Returns the result of `regex_match(str, str + char_traits<charT>::length(str), m, e, flags)`.

   template <class ST, class SA, class Allocator,
            class charT, class traits>
   bool regex_match(const basic_string<charT, ST, SA>& s,
                  match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m, 
                  const basic_regex <charT, traits>& e, 
                  match_flag_type flags = match_default);

[*Effects]: Returns the result of `regex_match(s.begin(), s.end(), m, e, flags)`.

   template <class charT, class traits>
   bool regex_match(const charT* str,
                  const basic_regex <charT, traits>& e,
                  match_flag_type flags = match_default);

[*Effects]: Returns the result of `regex_match(str, str + char_traits<charT>::length(str), e, flags)`.

   template <class ST, class SA, class charT, class traits>
   bool regex_match(const basic_string<charT, ST, SA>& s,
                  const basic_regex <charT, traits>& e,
                  match_flag_type flags = match_default);

[*Effects]: Returns the result of `regex_match(s.begin(), s.end(), e, flags)`.

[h4 Examples]

The following example processes an ftp response:

   #include <stdlib.h> 
   #include <boost/regex.hpp> 
   #include <string> 
   #include <iostream> 

   using namespace boost; 

   regex expression("([0-9]+)(\\-| |$)(.*)"); 

   // process_ftp: 
   // on success returns the ftp response code, and fills 
   // msg with the ftp response message. 
   int process_ftp(const char* response, std::string* msg) 
   { 
      cmatch what; 
      if(regex_match(response, what, expression)) 
      { 
         // what[0] contains the whole string 
         // what[1] contains the response code 
         // what[2] contains the separator character 
         // what[3] contains the text message. 
         if(msg) 
            msg->assign(what[3].first, what[3].second); 
         return std::atoi(what[1].first); 
      } 
      // failure did not match 
      if(msg) 
         msg->erase(); 
      return -1; 
   }
      

[endsect]