donner::RcString Class Reference

A reference counted string, that is copy-on-write and implements the small-string optimization. More...

#include "donner/base/RcString.h"

Public Types
using	iterator = std::string_view::iterator
	String iterator.
using	const_iterator = std::string_view::const_iterator
	Const string iterator.

Public Member Functions
constexpr	RcString ()=default
	Create an empty string.
	~RcString ()=default
	Destructor.
	RcString (std::string_view data)
	Constructs a new RcString object by copying an existing string.
	RcString (const char *data, size_t len=npos)
	Constructs a new RcString object from a C-style string and optional length.
constexpr	RcString (const RcString &other)
	Copy constructor.
constexpr	RcString (RcString &&other) noexcept
	Move constructor.
RcString &	operator= (const RcString &other)
	Copy assignment operator.
RcString &	operator= (RcString &&other) noexcept
	Move assignment operator.
RcString &	operator= (const char *data)
	Assignment operator from a C-style string.
RcString &	operator= (std::string_view data)
	Assignment operator from a std::string_view.
	operator std::string_view () const
	Cast operator to std::string_view.
const char *	data () const
bool	empty () const
size_t	size () const
std::string	str () const
constexpr const_iterator	begin () const noexcept
	Begin iterator.
constexpr const_iterator	end () const noexcept
	End iterator.
constexpr const_iterator	cbegin () const noexcept
	Begin iterator.
constexpr const_iterator	cend () const noexcept
	End iterator.
bool	equalsLowercase (std::string_view lowercaseOther) const
	Returns true if the string equals another all-lowercase string, with a case insensitive comparison.
bool	equalsIgnoreCase (std::string_view other) const
	Returns true if the string equals another string with a case-insensitive comparison.
RcString	substr (size_t pos, size_t len=npos) const
	Returns a substring of the string, returning a reference to the original string's data.
void	dedup ()
	Deduplicates the string, updating its underlying storage to ensure that it has a unique reference to the underlying contents.

Static Public Member Functions
static RcString	fromVector (std::vector< char > &&data)
	Constructs an RcString by consuming an existing vector.

Static Public Attributes
static constexpr size_t	npos = std::string_view::npos
	Sentinel value for the maximum value of size_t, used to indicate when the size is not known.

Friends
constexpr friend auto	operator<=> (const RcString &lhs, const RcString &rhs)
	Spaceship equality operator to another RcString.
constexpr friend auto	operator<=> (const RcString &lhs, const char *rhs)
	Spaceship equality operator to a C-style string.
constexpr friend auto	operator<=> (const RcString &lhs, std::string_view rhs)
	Spaceship equality operator to a std::string_view.
constexpr friend auto	operator<=> (const char *lhs, const RcString &rhs)
	Spaceship equality operator to another RcString.
constexpr friend auto	operator<=> (std::string_view lhs, const RcString &rhs)
	Spaceship equality operator to a C-style string.
constexpr friend bool	operator== (const RcString &lhs, const RcString &rhs)
	Equality operator to another RcString.
constexpr friend bool	operator== (const RcString &lhs, const char *rhs)
	Equality operator to a C-style string.
constexpr friend bool	operator== (const RcString &lhs, std::string_view rhs)
	Equality operator to a std::string_view.
constexpr friend bool	operator== (const char *lhs, const RcString &rhs)
	Reversed equality operator to another RcString.
constexpr friend bool	operator== (std::string_view lhs, const RcString &rhs)
	Reversed equality operator to a C-style string.
std::ostream &	operator<< (std::ostream &os, const RcString &self)
	Ostream output operator.
std::string	operator+ (const RcString &lhs, const RcString &rhs)
	Concatenation operator with another RcString.
std::string	operator+ (const RcString &lhs, const char *rhs)
	Concatenation operator with a C-style string.
std::string	operator+ (const RcString &lhs, std::string_view rhs)
	Concatenation operator with a std::string_view.
std::string	operator+ (std::string_view lhs, const RcString &rhs)
	Reversed concatenation operator with a C-style string.
std::string	operator+ (const char *lhs, const RcString &rhs)
	Reversed concatenation operator with a std::string_view.

Detailed Description

A reference counted string, that is copy-on-write and implements the small-string optimization.

Implements a short-string optimization similar to the libc++ std::string class, see https://joellaity.com/2020/01/31/string.html for details.

USAGE NOTES:

• This class is not thread-safe, and should not be shared between threads without synchronization.
• data() is not guaranteed to remain stable across references, and should not be stored longer than the original RcString which created it.

Constructor & Destructor Documentation

RcString() [1/2]

donner::RcString::RcString ( std::string_view data )

inlineexplicit

Constructs a new RcString object by copying an existing string.

Parameters

data	Input string to copy.

RcString() [2/2]

donner::RcString::RcString ( const char * data, size_t len = npos )

inline

Constructs a new RcString object from a C-style string and optional length.

Parameters

data	C-style string.
len	Length of the string, or npos to automatically measure, which requires that data is null-terminated.

Member Function Documentation

data()

const char * donner::RcString::data ( ) const

inline

Returns

a pointer to the string data.

dedup()

void donner::RcString::dedup ( )

inline

Deduplicates the string, updating its underlying storage to ensure that it has a unique reference to the underlying contents.

This can be used to reduce memory usage whe taking a substring.

Has no effect if the string is short due to the short-string optimization.

empty()

bool donner::RcString::empty ( ) const

inline

Returns

if the string is empty.

equalsIgnoreCase()

bool donner::RcString::equalsIgnoreCase ( std::string_view other ) const

inline

Returns true if the string equals another string with a case-insensitive comparison.

Parameters

other

string to compare to.

Returns

true If the strings are equal (case insensitive).

equalsLowercase()

bool donner::RcString::equalsLowercase ( std::string_view lowercaseOther ) const

inline

Returns true if the string equals another all-lowercase string, with a case insensitive comparison.

Example:

RcString("EXAMPLe").equalsLowercase("example"); // true

Parameters

lowercaseOther

string to compare to, must be lowercase.

Returns

true If the strings are equal (case insensitive).

fromVector()

static RcString donner::RcString::fromVector ( std::vector< char > && data )

inlinestatic

Constructs an RcString by consuming an existing vector.

Parameters

data	Input data to consume, moved into the RcString storage.

Returns

RcString using the input data.

size()

size_t donner::RcString::size ( ) const

inline

Returns

the length of the string.

str()

std::string donner::RcString::str ( ) const

inline

Returns

the string as a std::string.

substr()

RcString donner::RcString::substr ( size_t pos, size_t len = npos ) const

inline

Returns a substring of the string, returning a reference to the original string's data.

Note that due to the short-string optimization, this may not always reference the original data and may contain a copy if the string is below the short-string threshold.

Parameters

pos	The position to start the substring.
len	The length of the substring, or RcString::npos to return the whole string.

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

• donner/base/RcString.h