stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader Class Reference

Class used to read constant B-tree database files. More...

#include <stx-cbtreedb.h>

Collaboration diagram for stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader:

Public Member Functions
	Reader (const key_compare &key_less=key_compare())
	Create new reader, which is initially set to closed state.
	Reader (const Reader &rd)
	Copy Constructor: increment reference counter on base object.
	~Reader ()
	Destructor: decrement reference counter on buffer and possibly deallocate it.
Reader &	operator= (const Reader &rd)
	Assignment Operator: increment reference counter on base object.
void	SetSignature (const char *newsignature)
	Change the database signature (first 8 bytes) from 'cbtreedb' to a custom string.
bool	Open (std::istream &file, std::string *errortext=NULL)
	Attempt to open a cbtreedb database file.
void	Close ()
	Close the opened database.
void	SetPageCache (PageCache *newpagecache)
	Change the currently used page cache object.
uint32_t	Size () const
	Returns the number of items in the loaded database.
const SignaturePage &	GetSignature () const
	Returns a const reference to the signature page of the currently loaded database.
bool	Exists (const key_type &key)
	Check if a key is in the constant database.
bool	Lookup (const key_type &key, void *outvalue, uint32_t maxsize)
	Find a key in the constant database.
bool	Lookup (const key_type &key, std::string &outvalue)
	Find a key in the constant database.
std::string	operator[] (const key_type &key)
	Find a key in the constant database.
uint32_t	GetIndex (uint32_t index, key_type &outkey)
	Returns only the key by index.
uint32_t	GetIndex (uint32_t index, key_type &outkey, void *outvalue, uint32_t maxsize)
	Return a key and associated value by index.
uint32_t	GetIndex (uint32_t index, key_type &outkey, std::string &outvalue)
	Return a key and associated value by index.
bool	Verify ()
	Verify all aspects of the loaded database.
bool	VerifyBTree ()
	Verify B-tree structure in the loaded database.
bool	VerifyBTreeChecksum ()
	Verify the SHA256 checksum of the B-tree pages in the loaded database.
bool	VerifyValueChecksum ()
	Verify the SHA256 checksum of value data area in the loaded database.
Protected Attributes
ReaderImpl *	m_impl
	pointer to implementation class.

Detailed Description

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>
class stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader

Class used to read constant B-tree database files.

This is a reference counted front-end to ReaderImpl.

Refer to Design Principles and Database Architecture and Example Usage on how to use this class.

Definition at line 2124 of file stx-cbtreedb.h.

Constructor & Destructor Documentation

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Reader ( const key_compare & key_less = key_compare() ) [inline]

Create new reader, which is initially set to closed state.

Definition at line 2133 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Reader ( const Reader & rd ) [inline]

Copy Constructor: increment reference counter on base object.

Definition at line 2140 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::~Reader ( ) [inline]

Destructor: decrement reference counter on buffer and possibly deallocate it.

Definition at line 2148 of file stx-cbtreedb.h.

Member Function Documentation

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

void stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Close ( ) [inline]

Close the opened database.

Definition at line 2197 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Exists ( const key_type & key ) [inline]

Check if a key is in the constant database.

Parameters:

key

key to lookup

Returns:: true if found.

Definition at line 2231 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

uint32_t stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::GetIndex	(	uint32_t	index,
		key_type &	outkey,
		std::string &	outvalue
	)			`[inline]`

Return a key and associated value by index.

Looks directly into the leaf pages.

Parameters:

	index	zero-based index of item to retrieve
	outkey	set to key of item
	outvalue	string to hold data of value

Returns:: size of associated value

Definition at line 2312 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

uint32_t stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::GetIndex	(	uint32_t	index,
		key_type &	outkey,
		void *	outvalue,
		uint32_t	maxsize
	)			`[inline]`

Return a key and associated value by index.

Looks directly into the leaf pages.

Parameters:

	index	zero-based index of item to retrieve
	outkey	set to key of item
	outvalue	buffer to hold data of value
	maxsize	maximum size of buffer

Returns:: size of associated value

Definition at line 2298 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

uint32_t stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::GetIndex	(	uint32_t	index,
		key_type &	outkey
	)			`[inline]`

Returns only the key by index.

Looks directly into the leaf pages.

Parameters:

	index	zero-based index of item to retrieve
	outkey	set to key of item

Returns:: size of key's data

Definition at line 2283 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

const SignaturePage& stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::GetSignature ( ) const [inline]

Returns a const reference to the signature page of the currently loaded database.

Definition at line 2220 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Lookup	(	const key_type &	key,
		std::string &	outvalue
	)			`[inline]`

Find a key in the constant database.

If found the coresponding value is copied into the output string buffer.

Parameters:

	key	key to lookup
	outvalue	string filled with the associated value if the key is found

Returns:: true if found.

Definition at line 2258 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Lookup	(	const key_type &	key,
		void *	outvalue,
		uint32_t	maxsize
	)			`[inline]`

Find a key in the constant database.

If found the corresponding value is copied into the output buffer.

Parameters:

	key	key to lookup
	outvalue	buffer filled with the associated value if the key is found
	maxsize	maximum size of buffer

Returns:: true if found.

Definition at line 2245 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Open	(	std::istream &	file,
		std::string *	errortext = `NULL`
	)			`[inline]`

Attempt to open a cbtreedb database file.

Reads and verifies the signature and initializes the reader. Note that this function does not through an exception if the file could not be loaded! The istream object must exist as long as the Reader is used.

Parameters:

	file	database file input stream to attach.
	errortext	in case of error, set to an informative text.

Returns:: true if loaded and verified correctly.

Definition at line 2189 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

Reader& stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::operator= ( const Reader & rd ) [inline]

Assignment Operator: increment reference counter on base object.

Definition at line 2155 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

std::string stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::operator[] ( const key_type & key ) [inline]

Find a key in the constant database.

If found the corresponding value is copied into the output string buffer. If the key does not exist, an empty string is returned.

Parameters:

key

key to lookup

Returns:: string containing the value

Definition at line 2271 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

void stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::SetPageCache ( PageCache * newpagecache ) [inline]

Change the currently used page cache object.

Definition at line 2203 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

void stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::SetSignature ( const char * newsignature ) [inline]

Change the database signature (first 8 bytes) from 'cbtreedb' to a custom string.

The signature is always 8 bytes long. Longer strings are truncated, shorter ones padded with nulls.

Definition at line 2174 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

uint32_t stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Size ( ) const [inline]

Returns the number of items in the loaded database.

Definition at line 2211 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::Verify ( ) [inline]

Verify all aspects of the loaded database.

Returns:: true if database is ok.

Definition at line 2322 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::VerifyBTree ( ) [inline]

Verify B-tree structure in the loaded database.

Returns:: true if database is ok.

Definition at line 2332 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::VerifyBTreeChecksum ( ) [inline]

Verify the SHA256 checksum of the B-tree pages in the loaded database.

Returns:: true if database is ok.

Definition at line 2343 of file stx-cbtreedb.h.

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

bool stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::VerifyValueChecksum ( ) [inline]

Verify the SHA256 checksum of value data area in the loaded database.

Returns:: true if database is ok.

Definition at line 2354 of file stx-cbtreedb.h.

Member Data Documentation

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>

ReaderImpl* stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader::m_impl [protected]

pointer to implementation class.

Definition at line 2129 of file stx-cbtreedb.h.

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

include/stx-cbtreedb.h

stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader Class Reference

Public Member Functions

Protected Attributes

Detailed Description

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0> class stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<typename _Key = uint32_t, typename _Compare = std::less<_Key>, unsigned int _BTreePageSize = 1024, uint32_t _AppVersionId = 0>
class stx::CBTreeDB< _Key, _Compare, _BTreePageSize, _AppVersionId >::Reader