bsl::String_Imp< CHAR_TYPE, SIZE_TYPE > Class Template Reference [Component bslstl_string]

#include <bslstl_string.h>

List of all members.

Public Types
enum	ShortBufferConstraints {   SHORT_BUFFER_MIN_BYTES = 20, SHORT_BUFFER_NEED_BYTES, SHORT_BUFFER_BYTES, SHORT_BUFFER_LENGTH = SHORT_BUFFER_BYTES / sizeof(CHAR_TYPE),   SHORT_BUFFER_CAPACITY = SHORT_BUFFER_LENGTH - 1 }
enum	ConfigurableParameters { BASIC_STRING_DEALLOCATE_IN_CLEAR = false, BASIC_STRING_HONOR_SHRINK_REQUEST = false }
Public Member Functions
	BSLMF_ASSERT (SHORT_BUFFER_BYTES >=sizeof(CHAR_TYPE *))
	BSLMF_NESTED_TRAIT_DECLARATION (String_Imp, BloombergLP::bslmf::IsBitwiseMoveable)
	String_Imp ()
	String_Imp (SIZE_TYPE length, SIZE_TYPE capacity)
	String_Imp (const String_Imp &original)
	~String_Imp ()
String_Imp &	operator= (const String_Imp &rhs)
void	swap (String_Imp &other)
void	resetFields ()
CHAR_TYPE *	dataPtr ()
bool	isShortString () const
const CHAR_TYPE *	dataPtr () const
Static Public Member Functions
static SIZE_TYPE	computeNewCapacity (SIZE_TYPE newLength, SIZE_TYPE oldCapacity, SIZE_TYPE maxSize)
Public Attributes
union {
BloombergLP::bsls::AlignedBuffer < SHORT_BUFFER_BYTES, BloombergLP::bsls::AlignmentFromType < CHAR_TYPE >::VALUE >   d_short
CHAR_TYPE *   bsl::String_Imp::d_start_p
};
SIZE_TYPE	d_length
SIZE_TYPE	d_capacity

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Detailed Description

template<class CHAR_TYPE, class SIZE_TYPE>
class bsl::String_Imp< CHAR_TYPE, SIZE_TYPE >

This component private class describes the basic data layout for a string class and provides methods to help encapsulate internal string implementation details. It is parameterized by CHAR_TYPE and SIZE_TYPE only, and implements the portion of basic_string that does not need to know about its (template parameter) types CHAR_TRAITS or ALLOCATOR. It contains the following data fields: pointer to string, short string buffer, length, and capacity. The purpose of the short string buffer is to implement a "short string optimization" such that strings with lengths shorter than a certain number of characters are stored directly inside the string object (inside the short string buffer), and thereby avoid memory allocations/deallocations.

See Component bslstl_string

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Member Enumeration Documentation

template<class CHAR_TYPE, class SIZE_TYPE>

enum bsl::String_Imp::ShortBufferConstraints

This enum contains values necessary to calculate the size of the short string buffer. The starting value is SHORT_BUFFER_MIN_BYTES, which defines the minimal number of bytes (or char values) that the short string buffer should be able to contain. Then this value is aligned to a word boundary. Then we make sure that it fits at least one CHAR_TYPE character (because the default state of the string object requires that the first character is initialized with a NULL-terminator). The final output of this enum used by String_Imp is the SHORT_BUFFER_CAPACITY value. It defines the capacity of the short string buffer and also the capacity of the default-constructed empty string object.

Enumerator:

SHORT_BUFFER_MIN_BYTES	minimum required size of the short string buffer in bytes
SHORT_BUFFER_NEED_BYTES	round it to a word boundary
SHORT_BUFFER_BYTES	in case CHAR_TYPE is very large
SHORT_BUFFER_LENGTH
SHORT_BUFFER_CAPACITY	short string buffer capacity (not including the null-terminator)

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Member Data Documentation

template<class CHAR_TYPE, class SIZE_TYPE>

BloombergLP::bsls::AlignedBuffer< SHORT_BUFFER_BYTES, BloombergLP::bsls::AlignmentFromType<CHAR_TYPE>::VALUE> bsl::String_Imp< CHAR_TYPE, SIZE_TYPE >::d_short

short string buffer

Referenced by bsl::String_Imp< CHAR_TYPE, SIZE_TYPE >::dataPtr().

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

• bslstl_string.h