ICU 65.1 65.1
Public Member Functions | Static Public Attributes
icu::StringPiece Class Reference

A string-like object that points to a sized piece of memory. More...

#include <stringpiece.h>

Inheritance diagram for icu::StringPiece:
icu::UMemory

Public Member Functions

 StringPiece ()
 Default constructor, creates an empty StringPiece.
 
 StringPiece (const char *str)
 Constructs from a NUL-terminated const char * pointer.
 
 StringPiece (const std::string &str)
 Constructs from a std::string.
 
template<typename T , typename = typename std::enable_if< std::is_same<decltype(T().data()), const char*>::value && std::is_same<decltype(T().size()), size_t>::value>::type>
 StringPiece (T str)
 Constructs from some other implementation of a string piece class, from any C++ record type that has these two methods:
 
 StringPiece (const char *offset, int32_t len)
 Constructs from a const char * pointer and a specified length.
 
 StringPiece (const StringPiece &x, int32_t pos)
 Substring of another StringPiece.
 
 StringPiece (const StringPiece &x, int32_t pos, int32_t len)
 Substring of another StringPiece.
 
const chardata () const
 Returns the string pointer.
 
int32_t size () const
 Returns the string length.
 
int32_t length () const
 Returns the string length.
 
UBool empty () const
 Returns whether the string is empty.
 
void clear ()
 Sets to an empty string.
 
void set (const char *xdata, int32_t len)
 Reset the stringpiece to refer to new data.
 
void set (const char *str)
 Reset the stringpiece to refer to new data.
 
void remove_prefix (int32_t n)
 Removes the first n string units.
 
void remove_suffix (int32_t n)
 Removes the last n string units.
 
StringPiece substr (int32_t pos, int32_t len=npos) const
 Returns a substring of this StringPiece.
 

Static Public Attributes

static const int32_t npos
 Maximum integer, used as a default value for substring methods.
 

Detailed Description

A string-like object that points to a sized piece of memory.

We provide non-explicit singleton constructors so users can pass in a "const char*" or a "string" wherever a "StringPiece" is expected.

Functions or methods may use StringPiece parameters to accept either a "const char*" or a "string" value that will be implicitly converted to a StringPiece.

Systematic usage of StringPiece is encouraged as it will reduce unnecessary conversions from "const char*" to "string" and back again.

Stable:
ICU 4.2

Definition at line 60 of file stringpiece.h.

Constructor & Destructor Documentation

◆ StringPiece() [1/7]

icu::StringPiece::StringPiece ( )
inline

Default constructor, creates an empty StringPiece.

Stable:
ICU 4.2

Definition at line 70 of file stringpiece.h.

◆ StringPiece() [2/7]

icu::StringPiece::StringPiece ( const char str)

Constructs from a NUL-terminated const char * pointer.

Parameters
stra NUL-terminated const char * pointer
Stable:
ICU 4.2

◆ StringPiece() [3/7]

icu::StringPiece::StringPiece ( const std::string &  str)
inline

Constructs from a std::string.

Stable:
ICU 4.2

Definition at line 81 of file stringpiece.h.

◆ StringPiece() [4/7]

template<typename T , typename = typename std::enable_if< std::is_same<decltype(T().data()), const char*>::value && std::is_same<decltype(T().size()), size_t>::value>::type>
icu::StringPiece::StringPiece ( T  str)
inline

Constructs from some other implementation of a string piece class, from any C++ record type that has these two methods:

const char* data();
size_t size();
};
"Smart pointer" base class; do not use directly: use LocalPointer etc.

The other string piece class will typically be std::string_view from C++17 or absl::string_view from Abseil.

Parameters
strthe other string piece
Draft:
This API may be changed in the future versions and was introduced in ICU 65

Definition at line 107 of file stringpiece.h.

◆ StringPiece() [5/7]

icu::StringPiece::StringPiece ( const char offset,
int32_t  len 
)
inline

Constructs from a const char * pointer and a specified length.

Parameters
offseta const char * pointer (need not be terminated)
lenthe length of the string; must be non-negative
Stable:
ICU 4.2

Definition at line 116 of file stringpiece.h.

◆ StringPiece() [6/7]

icu::StringPiece::StringPiece ( const StringPiece x,
int32_t  pos 
)

Substring of another StringPiece.

Parameters
xthe other StringPiece
posstart position in x; must be non-negative and <= x.length().
Stable:
ICU 4.2

◆ StringPiece() [7/7]

icu::StringPiece::StringPiece ( const StringPiece x,
int32_t  pos,
int32_t  len 
)

Substring of another StringPiece.

Parameters
xthe other StringPiece
posstart position in x; must be non-negative and <= x.length().
lenlength of the substring; must be non-negative and will be pinned to at most x.length() - pos.
Stable:
ICU 4.2

Member Function Documentation

◆ clear()

void icu::StringPiece::clear ( )
inline

Sets to an empty string.

Stable:
ICU 4.2

Definition at line 168 of file stringpiece.h.

References NULL.

◆ data()

const char * icu::StringPiece::data ( ) const
inline

Returns the string pointer.

May be NULL if it is empty.

data() may return a pointer to a buffer with embedded NULs, and the returned buffer may or may not be null terminated. Therefore it is typically a mistake to pass data() to a routine that expects a NUL terminated string.

Returns
the string pointer
Stable:
ICU 4.2

Definition at line 144 of file stringpiece.h.

◆ empty()

UBool icu::StringPiece::empty ( ) const
inline

Returns whether the string is empty.

Returns
TRUE if the string is empty
Stable:
ICU 4.2

Definition at line 162 of file stringpiece.h.

◆ length()

int32_t icu::StringPiece::length ( ) const
inline

Returns the string length.

Same as size().

Returns
the string length
Stable:
ICU 4.2

Definition at line 156 of file stringpiece.h.

◆ remove_prefix()

void icu::StringPiece::remove_prefix ( int32_t  n)
inline

Removes the first n string units.

Parameters
nprefix length, must be non-negative and <=length()
Stable:
ICU 4.2

Definition at line 190 of file stringpiece.h.

◆ remove_suffix()

void icu::StringPiece::remove_suffix ( int32_t  n)
inline

Removes the last n string units.

Parameters
nsuffix length, must be non-negative and <=length()
Stable:
ICU 4.2

Definition at line 205 of file stringpiece.h.

◆ set() [1/2]

void icu::StringPiece::set ( const char str)

Reset the stringpiece to refer to new data.

Parameters
stra pointer to a NUL-terminated string.
Stable:
ICU 4.8

◆ set() [2/2]

void icu::StringPiece::set ( const char xdata,
int32_t  len 
)
inline

Reset the stringpiece to refer to new data.

Parameters
xdatapointer the new string data. Need not be nul terminated.
lenthe length of the new data
Stable:
ICU 4.8

Definition at line 176 of file stringpiece.h.

◆ size()

int32_t icu::StringPiece::size ( ) const
inline

Returns the string length.

Same as length().

Returns
the string length
Stable:
ICU 4.2

Definition at line 150 of file stringpiece.h.

◆ substr()

StringPiece icu::StringPiece::substr ( int32_t  pos,
int32_t  len = npos 
) const
inline

Returns a substring of this StringPiece.

Parameters
posstart position; must be non-negative and <= length().
lenlength of the substring; must be non-negative and will be pinned to at most length() - pos.
Returns
the substring StringPiece
Stable:
ICU 4.2

Definition at line 229 of file stringpiece.h.

Field Documentation

◆ npos

const int32_t icu::StringPiece::npos
static

Maximum integer, used as a default value for substring methods.

Stable:
ICU 4.2

Definition at line 219 of file stringpiece.h.


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