- Qt 5.15
- Qt Core
- C++ Classes
- QByteArrayMatcher
- Qt 5.15.19 Reference Documentation

# QByteArrayMatcher Class

The QByteArrayMatcher class holds a sequence of bytes that can be quickly matched in a byte array. More...

Header: | #include <QByteArrayMatcher>
qmake: | QT += core

- List of all members, including inherited members

## Public Functions

| QByteArrayMatcher(const QByteArrayMatcher &other)
| QByteArrayMatcher(const char *pattern, int length)
| QByteArrayMatcher(const QByteArray &pattern)
| QByteArrayMatcher()
QByteArrayMatcher & | operator=(const QByteArrayMatcher &other)
| ~QByteArrayMatcher()
int | indexIn(const QByteArray &ba, int from = 0) const
int | indexIn(const char *str, int len, int from = 0) const
QByteArray | pattern() const
void | setPattern(const QByteArray &pattern)

## Detailed Description

This class is useful when you have a sequence of bytes that you want to repeatedly match against some byte arrays (perhaps in a loop), or when you want to search for the same sequence of bytes multiple times in the same byte array. Using a matcher object and indexIn() is faster than matching a plain QByteArray with QByteArray::indexOf() if repeated matching takes place. This class offers no benefit if you are doing one-off byte array matches.

Create the QByteArrayMatcher with the QByteArray you want to search for. Then call indexIn() on the QByteArray that you want to search.

See also QByteArray and QStringMatcher.

## Member Function Documentation

### QByteArrayMatcher::QByteArrayMatcher(const QByteArrayMatcher &other)

Copies the other byte array matcher to this byte array matcher.

### QByteArrayMatcher::QByteArrayMatcher(const char *pattern, int length)

Constructs a byte array matcher from pattern. pattern has the given length. pattern must remain in scope, but the destructor does not delete pattern.

### QByteArrayMatcher::QByteArrayMatcher(const QByteArray &pattern)

Constructs a byte array matcher that will search for pattern. Call indexIn() to perform a search.

### QByteArrayMatcher::QByteArrayMatcher()

Constructs an empty byte array matcher that won't match anything. Call setPattern() to give it a pattern to match.

### QByteArrayMatcher &QByteArrayMatcher::operator=(const QByteArrayMatcher &other)

Assigns the other byte array matcher to this byte array matcher.

### QByteArrayMatcher::~QByteArrayMatcher()

Destroys the byte array matcher.

### int QByteArrayMatcher::indexIn(const QByteArray &ba, int from = 0) const

Searches the byte array ba, from byte position from (default 0, i.e. from the first byte), for the byte array pattern() that was set in the constructor or in the most recent call to setPattern(). Returns the position where the pattern() matched in ba, or -1 if no match was found.

### int QByteArrayMatcher::indexIn(const char *str, int len, int from = 0) const

Searches the char string str, which has length len, from byte position from (default 0, i.e. from the first byte), for the byte array pattern() that was set in the constructor or in the most recent call to setPattern(). Returns the position where the pattern() matched in str, or -1 if no match was found.

### QByteArray QByteArrayMatcher::pattern() const

Returns the byte array pattern that this byte array matcher will search for.

See also setPattern().

### void QByteArrayMatcher::setPattern(const QByteArray &pattern)

Sets the byte array that this byte array matcher will search for to pattern.

See also pattern() and indexIn().