QRegExp Class Reference

The QRegExp class provides pattern matching using regular expressions and wildcards. More...

#include <qregexp.h>

List of all member functions.

Public Members

QRegExp ()
QRegExp ( const char *, bool caseSensitive=TRUE, bool wildcard=FALSE )
QRegExp ( const QRegExp & )
~QRegExp ()
QRegExp& operator= ( const QRegExp & )
QRegExp& operator= ( const char * pattern )
bool operator== ( const QRegExp & ) const
bool operator!= ( const QRegExp & r ) const
bool isEmpty () const
bool isValid () const
bool caseSensitive () const
void setCaseSensitive ( bool )
bool wildcard () const
void setWildcard ( bool )
const char* pattern () const
int match ( const char * str, int index=0, int * len=0 ) const

Protected Members

void compile ()
char* matchstr ( ushort *, char *, char * ) const

Detailed Description

The QRegExp class provides pattern matching using regular expressions and wildcards.

QRegExp knows these regexp primitives:

c matches the character 'c'
. matches any character
^ matches start of input (except [^x] which matches NOT [x])
$ matches end of input
[] matches a set of characters, for example [a-z0-9_]
a* matches a sequence of zero or more a's
a+ matches a sequence of one or more a's
a? matches an optional a
\c escape code for matching special characters like \, [, *, +, . etc.
\b matches the BELL character (7)
\t matches the TAB character (9)
\n matches newline (10)
\r matches return (13)
\s matches white space (9,10,11,12,13,32)
\x12 matches the character 0x12 (18 decimal, 12 hexadecimal).
\022 matches the character 022 (18 decimal, 22 octal).

In wildcard mode, it only knows three primitives:

? matches any character
* matches any sequence of characters
[] matches a defined set of characters, e.g. [a-zA-Z0-9\.] matches upper and lower case ASCII letters, digits, and dot, and [^z] matches everything except lower-case z.

When writing regular expressions in C++ code, remember that the C++ preprocessor processes \ characters. So in order to match a "." character, you must write "\\." in C++ source, not "\.".

Examples: qmag/qmag.cpp

Member Function Documentation

QRegExp::QRegExp ()

Constructs an empty regular expression.

QRegExp::QRegExp ( const QRegExp & r )

Constructs a regular expression which is a copy of r.

See also: operator=(const and QRegExp&).

QRegExp::QRegExp ( const char * pattern, bool caseSensitive=TRUE, bool wildcard=FALSE )

Constructs a regular expression.

Arguments:

pattern is the regular expression pattern string.
caseSensitive specifies whether or not to use case sensitive matching.
wildcard specifies whether the pattern string should be used for wildcard matching (also called globbing expression), normally used for matching file names.

QRegExp::~QRegExp ()

Destroys the regular expression and cleans up its internal data.

bool QRegExp::caseSensitive () const

Returns TRUE if case sensitivity is enabled, otherwise FALSE. The default is TRUE.

void QRegExp::compile () `[protected]`

For internal use only.

bool QRegExp::isEmpty () const

Returns TRUE if the regexp is empty.

bool QRegExp::isValid () const

Returns TRUE if the regexp is valid, or FALSE if it is invalid.

The pattern "[a-z" is an example of an invalid pattern, since it lacks a closing bracket.

int QRegExp::match ( const char * str, int index=0, int * len=0 ) const

Attempts to match in str, starting from position index. Returns the position of the match, or -1 if there was no match.

If len is not a null pointer, the length of the match is stored in *len.

Example:

    QRegExp r("[0-9]*\.[0-9]+");                // matches floating point
    int len;
    r.match("pi = 3.1416", 0, &len);            // returns 5, len == 6

Examples: qmag/qmag.cpp

char * QRegExp::matchstr ( ushort * rxd, char * str, char * bol ) const `[protected]`

For internal use only.

bool QRegExp::operator!= ( const QRegExp & r ) const

Returns TRUE if this regexp is not equal to r.

QRegExp & QRegExp::operator= ( const QRegExp & r )

Copies the regexp r and returns a reference to this regexp. The case sensitivity and wildcard options are copied, as well.

QRegExp & QRegExp::operator= ( const char * pattern )

Sets the pattern string to pattern and returns a reference to this regexp. The case sensitivity or wildcard options do not change.

bool QRegExp::operator== ( const QRegExp & r ) const

Returns TRUE if this regexp is equal to r.

Two regexp objects are equal if they have equal pattern strings, case sensitivity options and wildcard options.

const char * QRegExp::pattern () const

Returns the pattern string of the regexp.

void QRegExp::setCaseSensitive ( bool enable )

Enables or disables case sensitive matching.

In case sensitive mode, "a.e" matches "axe" but not "Axe".

void QRegExp::setWildcard ( bool wildcard )

Sets the wildcard option for the regular expression. The default is FALSE.

Setting wildcard to TRUE makes it convenient to match filenames instead of plain text.

For example, "qr*.cpp" matches the string "qregexp.cpp" in wildcard mode, but not "qicpp" (which will be matched in normal mode).

bool QRegExp::wildcard () const

Returns TRUE if wildcard mode is on, otherwise FALSE.