juce::StringRef Class Reference

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

#include <juce_StringRef.h>

Collaboration diagram for juce::StringRef:

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

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

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

@tags{Core}

Constructor & Destructor Documentation

StringRef() [1/5]

juce::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!

StringRef() [2/5]

juce::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]

juce::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]

juce::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]

juce::StringRef::StringRef ( )

noexcept

Creates a StringRef pointer to an empty string.

Member Function Documentation

isEmpty()

bool juce::StringRef::isEmpty ( ) const

inlinenoexcept

Returns true if the string is empty.

References juce::String::isEmpty(), and juce::UnitTestCategories::text.

isNotEmpty()

bool juce::StringRef::isNotEmpty ( ) const

inlinenoexcept

Returns true if the string is not empty.

References juce::String::isEmpty(), and juce::UnitTestCategories::text.

Referenced by juce::ValueTreePropertyWithDefault::varArrayToDelimitedString().

length()

int juce::StringRef::length ( ) const

inlinenoexcept

Returns the number of characters in the string.

References juce::String::length(), and juce::UnitTestCategories::text.

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

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

inlinenoexcept

Returns a raw pointer to the underlying string data.

References juce::UnitTestCategories::text.

operator String::CharPointerType()

juce::StringRef::operator String::CharPointerType ( ) const

inlinenoexcept

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

References juce::UnitTestCategories::text.

operator!=() [1/2]

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

inlinenoexcept

Compares this StringRef with a String.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator!=() [2/2]

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

inlinenoexcept

Case-sensitive comparison of two StringRefs.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator<()

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

inlinenoexcept

Compares this StringRef with a String.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator<=()

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

inlinenoexcept

Compares this StringRef with a String.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator==() [1/2]

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

inlinenoexcept

Compares this StringRef with a String.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator==() [2/2]

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

inlinenoexcept

Case-sensitive comparison of two StringRefs.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator>()

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

inlinenoexcept

Compares this StringRef with a String.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator>=()

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

inlinenoexcept

Compares this StringRef with a String.

References juce::String::compare(), juce::gl::s, and juce::UnitTestCategories::text.

operator[]()

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

inlinenoexcept

Retrieves a character by index.

References juce::gl::index, and juce::UnitTestCategories::text.

Member Data Documentation

text

String::CharPointerType juce::StringRef::text

The text that is referenced.

Referenced by juce::Rectangle< int >::fromString(), and juce::operator+().

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The documentation for this class was generated from the following file:

• juce_StringRef.h