StringRef Class Reference

A simple class for holding temporary references to a string literal or String. More...

Public Member Functions
	StringRef (const char *stringLiteral) noexcept
	Creates a StringRef from a raw string literal.
	StringRef (String::CharPointerType stringLiteral) noexcept
	Creates a StringRef from a raw char pointer.
	StringRef (const String &string) noexcept
	Creates a StringRef from a String.
	StringRef (const std::string &string)
	Creates a StringRef from a String.
	StringRef () noexcept
	Creates a StringRef pointer to an empty string.
	operator const String::CharPointerType::CharType * () const noexcept
	Returns a raw pointer to the underlying string data.
	operator String::CharPointerType () const noexcept
	Returns a pointer to the underlying string data as a char pointer object.
bool	isEmpty () const noexcept
	Returns true if the string is empty.
bool	isNotEmpty () const noexcept
	Returns true if the string is not empty.
int	length () const noexcept
	Returns the number of characters in the string.
juce_wchar	operator[] (int index) const noexcept
	Retrieves a character by index.
bool	operator== (const String &s) const noexcept
	Compares this StringRef with a String.
bool	operator!= (const String &s) const noexcept
	Compares this StringRef with a String.
bool	operator< (const String &s) const noexcept
	Compares this StringRef with a String.
bool	operator<= (const String &s) const noexcept
	Compares this StringRef with a String.
bool	operator> (const String &s) const noexcept
	Compares this StringRef with a String.
bool	operator>= (const String &s) const noexcept
	Compares this StringRef with a String.
bool	operator== (StringRef s) const noexcept
	Case-sensitive comparison of two StringRefs.
bool	operator!= (StringRef s) const noexcept
	Case-sensitive comparison of two StringRefs.

Public Attributes
String::CharPointerType	text
	The text that is referenced.

Detailed Description

A simple class for holding temporary references to a string literal or String.

Unlike a real String object, the StringRef does not allocate any memory or take ownership of the strings you give to it - it simply holds a reference to a string that has been allocated elsewhere. The main purpose of the class is to be used instead of a const String& as the type of function arguments where the caller may pass either a string literal or a String object. This means that when the called uses a string literal, there's no need for an temporary String object to be allocated, and this cuts down overheads substantially.

Because the class is simply a wrapper around a pointer, you should always pass it by value, not by reference.

void myStringFunction1 (const String&);
void myStringFunction2 (StringRef);
 
myStringFunction1 ("abc"); // Implicitly allocates a temporary String object.
myStringFunction2 ("abc"); // Much faster, as no local allocations are needed.

For examples of it in use, see the XmlElement or StringArray classes.

Bear in mind that there are still many cases where it's better to use an argument which is a const String&. For example if the function stores the string or needs to internally create a String from the argument, then it's better for the original argument to already be a String.

See also

String

Constructor & Destructor Documentation

StringRef() [1/5]

StringRef::StringRef ( const char * stringLiteral )

noexcept

Creates a StringRef from a raw string literal.

The StringRef object does NOT take ownership or copy this data, so you must ensure that the data does not change during the lifetime of the StringRef. Note that this pointer cannot be null!

Referenced by operator!=(), and operator==().

StringRef() [2/5]

StringRef::StringRef ( String::CharPointerType stringLiteral )

noexcept

Creates a StringRef from a raw char pointer.

The StringRef object does NOT take ownership or copy this data, so you must ensure that the data does not change during the lifetime of the StringRef.

StringRef() [3/5]

StringRef::StringRef ( const String & string )

noexcept

Creates a StringRef from a String.

The StringRef object does NOT take ownership or copy the data from the String, so you must ensure that the String is not modified or deleted during the lifetime of the StringRef.

StringRef() [4/5]

StringRef::StringRef

(

const std::string &

string

)

Creates a StringRef from a String.

The StringRef object does NOT take ownership or copy the data from the std::string, so you must ensure that the source string object is not modified or deleted during the lifetime of the StringRef.

StringRef() [5/5]

StringRef::StringRef ( )

noexcept

Creates a StringRef pointer to an empty string.

Member Function Documentation

operator const String::CharPointerType::CharType *()

StringRef::operator const String::CharPointerType::CharType * ( ) const

noexcept

Returns a raw pointer to the underlying string data.

References operator String::CharPointerType(), and text.

operator String::CharPointerType()

StringRef::operator String::CharPointerType ( ) const

noexcept

Returns a pointer to the underlying string data as a char pointer object.

References text.

Referenced by operator const String::CharPointerType::CharType *().

isEmpty()

bool StringRef::isEmpty ( ) const

noexcept

Returns true if the string is empty.

References text.

isNotEmpty()

bool StringRef::isNotEmpty ( ) const

noexcept

Returns true if the string is not empty.

References text.

length()

int StringRef::length ( ) const

noexcept

Returns the number of characters in the string.

References text.

operator[]()

juce_wchar StringRef::operator[] ( int index ) const

noexcept

Retrieves a character by index.

References text.

operator==() [1/2]

bool StringRef::operator== ( const String & s ) const

noexcept

Compares this StringRef with a String.

References text.

operator!=() [1/2]

bool StringRef::operator!= ( const String & s ) const

noexcept

Compares this StringRef with a String.

References text.

operator<()

bool StringRef::operator< ( const String & s ) const

noexcept

Compares this StringRef with a String.

References text.

operator<=()

bool StringRef::operator<= ( const String & s ) const

noexcept

Compares this StringRef with a String.

References text.

operator>()

bool StringRef::operator> ( const String & s ) const

noexcept

Compares this StringRef with a String.

References text.

operator>=()

bool StringRef::operator>= ( const String & s ) const

noexcept

Compares this StringRef with a String.

References text.

operator==() [2/2]

bool StringRef::operator== ( StringRef s ) const

noexcept

Case-sensitive comparison of two StringRefs.

References StringRef(), and text.

operator!=() [2/2]

bool StringRef::operator!= ( StringRef s ) const

noexcept

Case-sensitive comparison of two StringRefs.

References StringRef(), and text.

Member Data Documentation

text

String::CharPointerType StringRef::text

The text that is referenced.

Referenced by Rectangle< ValueType >::fromString(), isEmpty(), isNotEmpty(), length(), operator const String::CharPointerType::CharType *(), operator String::CharPointerType(), operator!=(), operator!=(), operator+(), operator+(), operator+(), operator+(), operator<(), operator<=(), operator==(), operator==(), operator>(), operator>=(), and operator[]().