glibmm: Glib::MatchInfo Class Reference

MatchInfo - MatchInfo is used to retrieve information about the regular expression match which created it. More...

#include <glibmm/regex.h>

Public Member Functions

 MatchInfo ()
 Default constructor. More...

 
 MatchInfo (GMatchInfo* castitem, bool take_ownership=true)
 C object constructor. More...

 
 MatchInfo (const MatchInfo& other)=delete
 
MatchInfooperator= (const MatchInfo& other)=delete
 
 MatchInfo (MatchInfo&& other) noexcept
 
MatchInfooperator= (MatchInfo&& other) noexcept
 
virtual ~MatchInfo ()
 Destructor. More...

 
GMatchInfo* gobj ()
 Provides access to the underlying C object. More...

 
const GMatchInfo* gobj () const
 Provides access to the underlying C object. More...

 
Glib::RefPtr< Regexget_regex ()
 Returns Regex object used in match_info. More...

 
Glib::RefPtr< const Regexget_regex () const
 Returns Regex object used in match_info. More...

 
Glib::ustring get_string () const
 Returns the string searched with match_info. More...

 
bool matches () const
 Returns whether the previous match operation succeeded. More...

 
bool next ()
 Scans for the next match using the same parameters of the previous call to g_regex_match_full() or g_regex_match() that returned match_info. More...

 
int get_match_count () const
 Retrieves the number of matched substrings (including substring 0, that is the whole matched text), so 1 is returned if the pattern has no substrings in it and 0 is returned if the match failed. More...

 
bool is_partial_match () const
 Usually if the string passed to g_regex_match*() matches as far as it goes, but is too short to match the entire pattern, false is returned. More...

 
Glib::ustring expand_references (Glib::UStringView string_to_expand)
 Returns a new string containing the text in string_to_expand with references and escape sequences expanded. More...

 
Glib::ustring fetch (int match_num)
 Retrieves the text matching the match_num'th capturing parentheses. More...

 
bool fetch_pos (int match_num, int& start_pos, int& end_pos)
 Retrieves the position in bytes of the match_num'th capturing parentheses. More...

 
Glib::ustring fetch_named (Glib::UStringView name)
 Retrieves the text matching the capturing parentheses named name. More...

 
bool fetch_named_pos (Glib::UStringView name, int& start_pos, int& end_pos)
 Retrieves the position in bytes of the capturing parentheses named name. More...

 
std::vector< Glib::ustringfetch_all ()
 Bundles up pointers to each of the matching substrings from a match and stores them in an array of gchar pointers. More...

 

Protected Member Functions

void set_gobject (GMatchInfo* castitem, bool take_ownership=true)
 

Protected Attributes

GMatchInfo* gobject_
 
bool take_ownership_
 

Detailed Description

MatchInfo - MatchInfo is used to retrieve information about the regular expression match which created it.

Since glibmm 2.28:

Constructor & Destructor Documentation

Glib::MatchInfo::MatchInfo ( )

Default constructor.

Glib::MatchInfo::MatchInfo ( GMatchInfo *  castitem,
bool  take_ownership = true 
)
explicit

C object constructor.

Parameters
castitemThe C object.
take_ownershipWhether to destroy the C object with the wrapper or not.
Glib::MatchInfo::MatchInfo ( const MatchInfo other)
delete
Glib::MatchInfo::MatchInfo ( MatchInfo&&  other)
noexcept
virtual Glib::MatchInfo::~MatchInfo ( )
virtual

Destructor.

Member Function Documentation

Glib::ustring Glib::MatchInfo::expand_references ( Glib::UStringView  string_to_expand)

Returns a new string containing the text in string_to_expand with references and escape sequences expanded.

References refer to the last match done with string against regex and have the same syntax used by g_regex_replace().

The string_to_expand must be UTF-8 encoded even if Glib::Regex::CompileFlags::RAW was passed to g_regex_new().

The backreferences are extracted from the string passed to the match function, so you cannot call this function after freeing the string.

match_info may be nullptr in which case string_to_expand must not contain references. For instance "foo\\n" does not refer to an actual pattern and '\n' merely will be replaced with \n character, while to expand "\\0" (whole match) one needs the result of a match. Use g_regex_check_replacement() to find out whether string_to_expand contains references.

Since glibmm 2.14:
Parameters
string_to_expandThe string to expand.
Returns
The expanded string, or nullptr if an error occurred.
Exceptions
Glib::RegexError
Glib::ustring Glib::MatchInfo::fetch ( int  match_num)

Retrieves the text matching the match_num'th capturing parentheses.

0 is the full text of the match, 1 is the first paren set, 2 the second, and so on.

If match_num is a valid sub pattern but it didn't match anything (e.g. sub pattern 1, matching "b" against "(a)?b") then an empty string is returned.

If the match was obtained using the DFA algorithm, that is using g_regex_match_all() or g_regex_match_all_full(), the retrieved string is not that of a set of parentheses but that of a matched substring. Substrings are matched in reverse order of length, so 0 is the longest match.

The string is fetched from the string passed to the match function, so you cannot call this function after freeing the string.

Since glibmm 2.14:
Parameters
match_numNumber of the sub expression.
Returns
The matched substring, or nullptr if an error occurred. You have to free the string yourself.
std::vector<Glib::ustring> Glib::MatchInfo::fetch_all ( )

Bundles up pointers to each of the matching substrings from a match and stores them in an array of gchar pointers.

The first element in the returned array is the match number 0, i.e. the entire matched text.

If a sub pattern didn't match anything (e.g. sub pattern 1, matching "b" against "(a)?b") then an empty string is inserted.

If the last match was obtained using the DFA algorithm, that is using g_regex_match_all() or g_regex_match_all_full(), the retrieved strings are not that matched by sets of parentheses but that of the matched substring. Substrings are matched in reverse order of length, so the first one is the longest match.

The strings are fetched from the string passed to the match function, so you cannot call this function after freeing the string.

Since glibmm 2.14:
Returns
A nullptr-terminated array of gchar * pointers. If the previous match failed nullptr is returned.
Glib::ustring Glib::MatchInfo::fetch_named ( Glib::UStringView  name)

Retrieves the text matching the capturing parentheses named name.

If name is a valid sub pattern name but it didn't match anything (e.g. sub pattern "X", matching "b" against "(?P<X>a)?b") then an empty string is returned.

The string is fetched from the string passed to the match function, so you cannot call this function after freeing the string.

Since glibmm 2.14:
Parameters
nameName of the subexpression.
Returns
The matched substring, or nullptr if an error occurred. You have to free the string yourself.
bool Glib::MatchInfo::fetch_named_pos ( Glib::UStringView  name,
int &  start_pos,
int &  end_pos 
)

Retrieves the position in bytes of the capturing parentheses named name.

If name is a valid sub pattern name but it didn't match anything (e.g. sub pattern "X", matching "b" against "(?P<X>a)?b") then start_pos and end_pos are set to -1 and true is returned.

Since glibmm 2.14:
Parameters
nameName of the subexpression.
start_posPointer to location where to store the start position, or nullptr.
end_posPointer to location where to store the end position, or nullptr.
Returns
true if the position was fetched, false otherwise. If the position cannot be fetched, start_pos and end_pos are left unchanged.
bool Glib::MatchInfo::fetch_pos ( int  match_num,
int &  start_pos,
int &  end_pos 
)

Retrieves the position in bytes of the match_num'th capturing parentheses.

0 is the full text of the match, 1 is the first paren set, 2 the second, and so on.

If match_num is a valid sub pattern but it didn't match anything (e.g. sub pattern 1, matching "b" against "(a)?b") then start_pos and end_pos are set to -1 and true is returned.

If the match was obtained using the DFA algorithm, that is using g_regex_match_all() or g_regex_match_all_full(), the retrieved position is not that of a set of parentheses but that of a matched substring. Substrings are matched in reverse order of length, so 0 is the longest match.

Since glibmm 2.14:
Parameters
match_numNumber of the sub expression.
start_posPointer to location where to store the start position, or nullptr.
end_posPointer to location where to store the end position, or nullptr.
Returns
true if the position was fetched, false otherwise. If the position cannot be fetched, start_pos and end_pos are left unchanged.
int Glib::MatchInfo::get_match_count ( ) const

Retrieves the number of matched substrings (including substring 0, that is the whole matched text), so 1 is returned if the pattern has no substrings in it and 0 is returned if the match failed.

If the last match was obtained using the DFA algorithm, that is using g_regex_match_all() or g_regex_match_all_full(), the retrieved count is not that of the number of capturing parentheses but that of the number of matched substrings.

Since glibmm 2.14:
Returns
Number of matched substrings, or -1 if an error occurred.
Glib::RefPtr<Regex> Glib::MatchInfo::get_regex ( )

Returns Regex object used in match_info.

It belongs to Glib and must not be freed. Use g_regex_ref() if you need to keep it after you free match_info object.

Since glibmm 2.14:
Returns
Regex object used in match_info.
Glib::RefPtr<const Regex> Glib::MatchInfo::get_regex ( ) const

Returns Regex object used in match_info.

It belongs to Glib and must not be freed. Use g_regex_ref() if you need to keep it after you free match_info object.

Since glibmm 2.14:
Returns
Regex object used in match_info.
Glib::ustring Glib::MatchInfo::get_string ( ) const

Returns the string searched with match_info.

This is the string passed to g_regex_match() or g_regex_replace() so you may not free it before calling this function.

Since glibmm 2.14:
Returns
The string searched with match_info.
GMatchInfo* Glib::MatchInfo::gobj ( )
inline

Provides access to the underlying C object.

const GMatchInfo* Glib::MatchInfo::gobj ( ) const
inline

Provides access to the underlying C object.

bool Glib::MatchInfo::is_partial_match ( ) const

Usually if the string passed to g_regex_match*() matches as far as it goes, but is too short to match the entire pattern, false is returned.

There are circumstances where it might be helpful to distinguish this case from other cases in which there is no match.

Consider, for example, an application where a human is required to type in data for a field with specific formatting requirements. An example might be a date in the form ddmmmyy, defined by the pattern "^\\d?\\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\\d\\d$". If the application sees the user’s keystrokes one by one, and can check that what has been typed so far is potentially valid, it is able to raise an error as soon as a mistake is made.

GRegex supports the concept of partial matching by means of the Glib::Regex::MatchFlags::PARTIAL_SOFT and Glib::Regex::MatchFlags::PARTIAL_HARD flags. When they are used, the return code for g_regex_match() or g_regex_match_full() is, as usual, true for a complete match, false otherwise. But, when these functions return false, you can check if the match was partial calling g_match_info_is_partial_match().

The difference between Glib::Regex::MatchFlags::PARTIAL_SOFT and Glib::Regex::MatchFlags::PARTIAL_HARD is that when a partial match is encountered with Glib::Regex::MatchFlags::PARTIAL_SOFT, matching continues to search for a possible complete match, while with Glib::Regex::MatchFlags::PARTIAL_HARD matching stops at the partial match. When both Glib::Regex::MatchFlags::PARTIAL_SOFT and Glib::Regex::MatchFlags::PARTIAL_HARD are set, the latter takes precedence.

There were formerly some restrictions on the pattern for partial matching. The restrictions no longer apply.

See pcrepartial(3) for more information on partial matching.

Since glibmm 2.14:
Returns
true if the match was partial, false otherwise.
bool Glib::MatchInfo::matches ( ) const

Returns whether the previous match operation succeeded.

Since glibmm 2.14:
Returns
true if the previous match operation succeeded, false otherwise.
bool Glib::MatchInfo::next ( )

Scans for the next match using the same parameters of the previous call to g_regex_match_full() or g_regex_match() that returned match_info.

The match is done on the string passed to the match function, so you cannot free it before calling this function.

Since glibmm 2.14:
Returns
true is the string matched, false otherwise.
Exceptions
Glib::RegexError
MatchInfo& Glib::MatchInfo::operator= ( const MatchInfo other)
delete
MatchInfo& Glib::MatchInfo::operator= ( MatchInfo&&  other)
noexcept
void Glib::MatchInfo::set_gobject ( GMatchInfo *  castitem,
bool  take_ownership = true 
)
protected

Member Data Documentation

GMatchInfo* Glib::MatchInfo::gobject_
protected
bool Glib::MatchInfo::take_ownership_
protected