kudu::Slice Class Reference

A wrapper around externally allocated data. More...

#include <slice.h>

Classes
struct	Comparator
	Comparator struct, useful for ordered collections (like STL maps). More...

Public Member Functions
	Slice ()
	Create an empty slice.
	Slice (const uint8_t *d, size_t n)
	Slice (const char *d, size_t n)
	Slice (const std::string &s)
	Slice (const char *s)
const uint8_t *	data () const
uint8_t *	mutable_data ()
size_t	size () const
bool	empty () const
const uint8_t &	operator[] (size_t n) const
void	clear ()
	Change this slice to refer to an empty array.
void	remove_prefix (size_t n)
void	truncate (size_t n)
Status	check_size (size_t expected_size) const
std::string	ToString () const
std::string	ToDebugString (size_t max_len=0) const
int	compare (const Slice &b) const
bool	starts_with (const Slice &x) const
void	relocate (uint8_t *d)

Detailed Description

A wrapper around externally allocated data.

Slice is a simple structure containing a pointer into some external storage and a size. The user of a Slice must ensure that the slice is not used after the corresponding external storage has been deallocated.

Multiple threads can invoke const methods on a Slice without external synchronization, but if any of the threads may call a non-const method, all threads accessing the same Slice must use external synchronization.

Slices can be built around faststrings and StringPieces using constructors with implicit casts. Both StringPieces and faststrings depend on a great deal of gutil code.

Constructor & Destructor Documentation

Slice() [1/4]

kudu::Slice::Slice ( const uint8_t *  d, size_t  n  )

inline

Create a slice that refers to a uint8_t byte array.

Parameters

[in]	d	The input array.
[in]	n	Number of bytes in the array.

Slice() [2/4]

kudu::Slice::Slice ( const char *  d, size_t  n  )

inline

Create a slice that refers to a char byte array.

Parameters

[in]	d	The input array.
[in]	n	Number of bytes in the array.

Slice() [3/4]

kudu::Slice::Slice ( const std::string &  s )

inline

Create a slice that refers to the contents of the given string.

Parameters

[in]

s

The input string.

Slice() [4/4]

kudu::Slice::Slice ( const char *  s )

inline

Create a slice that refers to a C-string s[0,strlen(s)-1].

Parameters

[in]

s

The input C-string.

Member Function Documentation

check_size()

Status kudu::Slice::check_size

(

size_t

expected_size

)

const

Check that the slice has the expected size.

Parameters

[in]

expected_size

Returns

Status::Corruption() iff size() != expected_size

compare()

int kudu::Slice::compare ( const Slice &  b ) const

inline

Do a three-way comparison of the slice's data.

Parameters

[in]

b

The other slice to compare with.

Returns

Values are

• < 0 iff "*this" < "b"
• == 0 iff "*this" == "b"
• > 0 iff "*this" > "b"

data()

const uint8_t* kudu::Slice::data ( ) const

inline

Returns

A pointer to the beginning of the referenced data.

empty()

bool kudu::Slice::empty ( ) const

inline

Returns

true iff the length of the referenced data is zero.

mutable_data()

uint8_t* kudu::Slice::mutable_data ( )

inline

Returns

A mutable pointer to the beginning of the referenced data.

operator[]()

const uint8_t& kudu::Slice::operator[] ( size_t  n ) const

inline

Precondition

n < size()

Parameters

[in]

n

The index of the byte.

Returns

the n-th byte in the referenced data.

relocate()

void kudu::Slice::relocate ( uint8_t *  d )

inline

Relocate/copy the slice's data into a new location.

Parameters

[in]

d

The new location for the data. If it's the same location, then no relocation is done. It is assumed that the new location is large enough to fit the data.

remove_prefix()

void kudu::Slice::remove_prefix ( size_t  n )

inline

Drop the first "n" bytes from this slice.

Precondition

n <= size()

Note

Only the base and bounds of the slice are changed; the data is not modified.

Parameters

[in]

n

Number of bytes that should be dropped from the beginning.

size()

size_t kudu::Slice::size ( ) const

inline

Returns

The length (in bytes) of the referenced data.

starts_with()

bool kudu::Slice::starts_with ( const Slice &  x ) const

inline

Check whether the slice starts with the given prefix.

Parameters

[in]

x

The slice in question.

Returns

true iff "x" is a prefix of "*this"

ToDebugString()

std::string kudu::Slice::ToDebugString

(

size_t

max_len = 0

)

const

Get printable representation of the data in the slice.

Parameters

[in]

max_len

The maximum number of bytes to output in the printable format; 0 means no limit.

Returns

A string with printable representation of the data.

ToString()

std::string kudu::Slice::ToString

(

)

const

Returns

A string that contains a copy of the referenced data.

truncate()

void kudu::Slice::truncate ( size_t  n )

inline

Truncate the slice to the given number of bytes.

Precondition

n <= size()

Note

Only the base and bounds of the slice are changed; the data is not modified.

Parameters

[in]

n

The new size of the slice.

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

• include/kudu/util/slice.h