StringHash Class Reference

Represents a string hash function. More...

#include <stringhash.h>

Collaboration diagram for StringHash:

[legend]

List of all members.

Public Member Functions
	StringHash ()
	Constructor.
virtual	~StringHash ()
unsigned	hash (const char *s)
	Hashes a string value.
unsigned	hash (const char *s, unsigned start_offset, unsigned end_offset)
	Hashes a string value.
Private Member Functions
unsigned	h (const char *s)
	Internal hash function.
unsigned	h (const char *s, unsigned start_offset, unsigned end_offset)
	Internal hash function, to hash a substring of the passed string.
Private Attributes
int	base
	The hash base.
vector< TagInfo * > *	matches
	Hashed values.
unsigned	free_index
	The next available free index position.

---

Detailed Description

Represents a string hash function.

Implements a simple yet efficient string hash function.

Author:

Michael Schmidt

Gunnar Jehl

Version:

2.1

License:

Software License Agreement (BSD License)

Definition at line 94 of file stringhash.h.

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Constructor & Destructor Documentation

StringHash::StringHash

(

)

Constructor.

Constructor - creating object.

Definition at line 39 of file stringhash.cpp.

References hash().

StringHash::~StringHash

(

)

[virtual]

Destructor.

Definition at line 44 of file stringhash.cpp.

References base, and matches.

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Member Function Documentation

unsigned StringHash::h	(	const char *	s,
		unsigned	start_offset,
		unsigned	end_offset
	)			[private]

Internal hash function, to hash a substring of the passed string.

The hash function sums up the substring character values and divides the result through the specified base.

Parameters:

[in]	s	The string to be hashed.
[in]	start_offset	The start offset position inside the string.
[in]	end_offset	The end offsetposition inside the string.

Return values:

unsigned

The hash value.

Definition at line 108 of file stringhash.cpp.

References base.

unsigned StringHash::h

(

const char *

s

)

[private]

Internal hash function.

The hash function sums up the character values and divides the result through the specified base.

Parameters:

[in]

s

The string to be hashed.

Return values:

unsigned

The hash value.

Definition at line 97 of file stringhash.cpp.

References base.

Referenced by hash().

unsigned StringHash::hash	(	const char *	s,
		unsigned	start_offset,
		unsigned	end_offset
	)

Hashes a string value.

Hashes a substring of the passed string value.

Parameters:

[in]	s	The string to be hashed.
[in]	start_offset	The start offset position inside the string.
[in]	end_offset	The end offsetposition inside the string.

Return values:

unsigned

The hash value.

Definition at line 73 of file stringhash.cpp.

References free_index, h(), and matches.

unsigned StringHash::hash

(

const char *

s

)

Hashes a string value.

Hashes a complete string value, i.e. computes the hash value of the string.

Parameters:

[in]

s

The string to be hashed.

Return values:

unsigned

The hash value.

Definition at line 54 of file stringhash.cpp.

References free_index, h(), and matches.

Referenced by TagMap::insertTag(), TagMap::insertTagWithOffset(), and StringHash().

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Member Data Documentation

int StringHash::base [private]

The hash base.

The hash base, initialized with valur HASH_BASE (which should always be set to a prime number).

Definition at line 151 of file stringhash.h.

Referenced by h(), and ~StringHash().

unsigned StringHash::free_index [private]

The next available free index position.

The next available free index position in member matches.

Definition at line 164 of file stringhash.h.

Referenced by hash().

vector< TagInfo * > * StringHash::matches [private]

Hashed values.

The buckets containing previous matches computed by the hash function.

Definition at line 158 of file stringhash.h.

Referenced by hash(), and ~StringHash().