Class representing a regular expression. 更多...

#include <regex.h>

类
class	Private
	Private members of a regular expression 更多...

Public 类型
enum	Mode { Mode::RegEx, Mode::Wildcard }
	Matching algorithm 更多...

Public 成员函数
	Ex (const std::string &pattern, Mode mode=Mode::RegEx)
	Creates a regular expression object given the pattern as a string. 更多...

	~Ex ()
	Destroys the regular expression object. 更多...

bool	match (const std::string &str, Match &match, size_t pos=0) const
	Check if a given string matches this regular expression. 更多...

bool	isValid () const

Private 成员函数
	Ex (const Ex &)=delete

Ex &	operator= (const Ex &e)=delete

Private 属性
std::unique_ptr< Private >	p

详细描述

Class representing a regular expression.

It has a similar API as std::regex, but is much faster (and also somewhat more limited).

在文件 regex.h 第 48 行定义.

成员枚举类型说明

◆ Mode

enum reg::Ex::Mode

strong

Matching algorithm

枚举值
RegEx	full regular expression.
Wildcard	simple globbing pattern.

在文件 regex.h 第 52 行定义.

构造及析构函数说明

◆ Ex() [1/2]

reg::Ex::Ex	(	const std::string &	pattern,
		Mode	mode = `Mode::RegEx`
	)

Creates a regular expression object given the pattern as a string.

Two modes of matching are supported: RegEx and Wildcard

The following special characters are supported in Mode::RegEx mode.

c matches character c
. matches any character
^ matches the start of the input
$ matches the end of the input
\< matches the start of a word
\> matches the end of a word
[] matches a set of characters
x* matches a sequence of zero or more x's
x+ matches a sequence of one or more x's
x? matches an optional x
( matches the start of a capture range
) matches the ends a capture range
\c to escape a special character, such as +, [, *, (, etc.
\t matches a tab character
\n matches a newline character
\r matches a return character
\s matches any whitespace as defined by std::isspace()
\d matches any digit as defined by std::digit()
\a matches any alphabetical characters, same as [a-z_A-Z\x80-\xFF]
\w matches any alpha numercial character, same as [a-z_A-Z0-9\x80-\xFF]
\xHH matches a hexadecimal character, e.g. \xA0 matches character code 160.

A character range can be used to match a character that falls inside a range (or set of ranges). Within the opening [ and closing ] brackets of a character ranges the following is supported:

^ if at the start of the range, a character matches if it is not in the range, e.g. [^\d] matches any character not a digit
- when placed between 2 characters it defines a range from the first character to the second. any character that falls in the range will match, e.g. [0-9] matches the digit from 0 to 9.
\s, \d, \a, and \w as explained above.

注解: that special characters ., *, ?, $, +, [ do not have a special meaning in a character range. ^ only has a special meaning as the first character.; that capture ranges cannot be nested, and *, +, and ? do not work on capture ranges. e.g. (abd)? is not valid. If multiple capture ranges are specified then some character has to be in between them, e.g. this does not work (.*)(a.*), but this does (.*)a(.*).

In Wildcard mode * is used to match any sequence of zero or more characters. The character ? can be used to match an optional character. Character ranges are also supported, but other characters like $ and + are just treated as literal characters.

在文件 regex.cpp 第 662 行定义.

   : p(std::make_unique<Private>(mode==Mode::RegEx ? pattern : wildcard2regex(pattern)))
 {
   p->compile();
 #if ENABLE_DEBUG
   p->dump();
   assert(!p->error);
 #endif
 }

引用了 p.

◆ ~Ex()

reg::Ex::~Ex ( )

Destroys the regular expression object.

Frees resources.

在文件 regex.cpp 第 672 行定义.

673 {

674 }

◆ Ex() [2/2]

reg::Ex::Ex ( const Ex & )

privatedelete

成员函数说明

◆ isValid()

bool reg::Ex::isValid ( ) const

在文件 regex.cpp 第 711 行定义.

 {
   return !p->pattern.empty() && !p->error;
 }

引用了 p.

被这些函数引用 getFilterFromList() , 以及 patternMatch().

◆ match()

bool reg::Ex::match	(	const std::string &	str,
		Match &	match,
		size_t	pos = `0`
	)		const

Check if a given string matches this regular expression.

参数

str	The input string to match against.
match	The match object to hold the matching results.
pos	The position in the string at which to start the match.

返回: true iff a match is found. Details are stored in the match object.

在文件 regex.cpp 第 676 行定义.

 {
   bool found=false;
   if (p->data.size()==0 || p->error) return found;
   match.init(&str);
  
   PToken tok = p->data[0];
   if (tok.kind()==PToken::Kind::BeginOfLine) // only test match at the given position
   {
     found = p->matchAt(0,str,match,pos,0);
   }
   else
   {
     if (tok.kind()==PToken::Kind::Character) // search for the start character
     {
       size_t index = str.find(tok.asciiValue(),pos);
       if (index==std::string::npos)
       {
         DBG("Ex::match(str='%s',pos=%zu)=false (no start char '%c')\n",str.c_str(),pos,tok.asciiValue());
         return false;
       }
       DBG("pos=%zu str='%s' char='%c' index=%zu\n",index,str.c_str(),tok.asciiValue(),index);
       pos=index;
     }
     while (pos<str.length()) // search for a match starting at pos
     {
       found = p->matchAt(0,str,match,pos,0);
       if (found) break;
       pos++;
     }
   }
   DBG("Ex::match(str='%s',pos=%zu)=%d\n",str.c_str(),pos,found);
   return found;
 }