Hash set implementation. More...

#include "cpl_port.h"

Typedefs
typedef struct _CPLHashSet	CPLHashSet
	Opaque type for a hash set.

typedef unsigned long(*	CPLHashSetHashFunc) (const void *elt)
	CPLHashSetHashFunc.

typedef int(*	CPLHashSetEqualFunc) (const void elt1, const void elt2)
	CPLHashSetEqualFunc.

typedef void(*	CPLHashSetFreeEltFunc) (void *elt)
	CPLHashSetFreeEltFunc.

typedef int(*	CPLHashSetIterEltFunc) (void elt, void user_data)
	CPLHashSetIterEltFunc.

Functions
CPLHashSet *	CPLHashSetNew (CPLHashSetHashFunc fnHashFunc, CPLHashSetEqualFunc fnEqualFunc, CPLHashSetFreeEltFunc fnFreeEltFunc)
	Creates a new hash set. More...

void	CPLHashSetDestroy (CPLHashSet *set)
	Destroys an allocated hash set. More...

void	CPLHashSetClear (CPLHashSet *set)
	Clear all elements from a hash set. More...

int	CPLHashSetSize (const CPLHashSet *set)
	Returns the number of elements inserted in the hash set. More...

void	CPLHashSetForeach (CPLHashSet set, CPLHashSetIterEltFunc fnIterFunc, void user_data)
	Walk through the hash set and runs the provided function on all the elements. More...

int	CPLHashSetInsert (CPLHashSet set, void elt)
	Inserts an element into a hash set. More...

void *	CPLHashSetLookup (CPLHashSet set, const void elt)
	Returns the element found in the hash set corresponding to the element to look up The element must not be modified. More...

int	CPLHashSetRemove (CPLHashSet set, const void elt)
	Removes an element from a hash set. More...

int	CPLHashSetRemoveDeferRehash (CPLHashSet set, const void elt)
	Removes an element from a hash set. More...

unsigned long	CPLHashSetHashPointer (const void *elt)
	Hash function for an arbitrary pointer. More...

int	CPLHashSetEqualPointer (const void elt1, const void elt2)
	Equality function for arbitrary pointers. More...

unsigned long	CPLHashSetHashStr (const void *pszStr)
	Hash function for a zero-terminated string. More...

int	CPLHashSetEqualStr (const void pszStr1, const void pszStr2)
	Equality function for strings. More...

Detailed Description

Hash set implementation.

An hash set is a data structure that holds elements that are unique according to a comparison function. Operations on the hash set, such as insertion, removal or lookup, are supposed to be fast if an efficient "hash" function is provided.

Function Documentation

◆ CPLHashSetClear()

void CPLHashSetClear ( CPLHashSet * set )

Clear all elements from a hash set.

This function also frees the elements if a free function was provided at the creation of the hash set.

Parameters

set	the hash set

Since: GDAL 2.1

◆ CPLHashSetDestroy()

void CPLHashSetDestroy ( CPLHashSet * set )

Destroys an allocated hash set.

This function also frees the elements if a free function was provided at the creation of the hash set.

Parameters

set	the hash set

◆ CPLHashSetEqualPointer()

int CPLHashSetEqualPointer	(	const void *	elt1,
		const void *	elt2
	)

Equality function for arbitrary pointers.

Parameters

elt1	the first arbitrary pointer to compare
elt2	the second arbitrary pointer to compare

Returns: TRUE if the pointers are equal

◆ CPLHashSetEqualStr()

int CPLHashSetEqualStr	(	const void *	elt1,
		const void *	elt2
	)

Equality function for strings.

Parameters

elt1	the first string to compare. May be NULL.
elt2	the second string to compare. May be NULL.

Returns: TRUE if the strings are equal

◆ CPLHashSetForeach()

void CPLHashSetForeach	(	CPLHashSet *	set,
		CPLHashSetIterEltFunc	fnIterFunc,
		void *	user_data
	)

Walk through the hash set and runs the provided function on all the elements.

This function is provided the user_data argument of CPLHashSetForeach. It must return TRUE to go on the walk through the hash set, or FALSE to make it stop.

Note : the structure of the hash set must NOT be modified during the walk.

Parameters

set	the hash set.
fnIterFunc	the function called on each element.
user_data	the user data provided to the function.

◆ CPLHashSetHashPointer()

unsigned long CPLHashSetHashPointer ( const void * elt )

Hash function for an arbitrary pointer.

Parameters

elt	the arbitrary pointer to hash

Returns: the hash value of the pointer

◆ CPLHashSetHashStr()

unsigned long CPLHashSetHashStr ( const void * elt )

Hash function for a zero-terminated string.

Parameters

elt	the string to hash. May be NULL.

Returns: the hash value of the string

◆ CPLHashSetInsert()

int CPLHashSetInsert	(	CPLHashSet *	set,
		void *	elt
	)

Inserts an element into a hash set.

If the element was already inserted in the hash set, the previous element is replaced by the new element. If a free function was provided, it is used to free the previously inserted element

Parameters

set	the hash set
elt	the new element to insert in the hash set

Returns: TRUE if the element was not already in the hash set

◆ CPLHashSetLookup()

void * CPLHashSetLookup	(	CPLHashSet *	set,
		const void *	elt
	)

Returns the element found in the hash set corresponding to the element to look up The element must not be modified.

Parameters

set	the hash set
elt	the element to look up in the hash set

Returns: the element found in the hash set or NULL

◆ CPLHashSetNew()

CPLHashSet * CPLHashSetNew	(	CPLHashSetHashFunc	fnHashFunc,
		CPLHashSetEqualFunc	fnEqualFunc,
		CPLHashSetFreeEltFunc	fnFreeEltFunc
	)

Creates a new hash set.

The hash function must return a hash value for the elements to insert. If fnHashFunc is NULL, CPLHashSetHashPointer will be used.

The equal function must return if two elements are equal. If fnEqualFunc is NULL, CPLHashSetEqualPointer will be used.

The free function is used to free elements inserted in the hash set, when the hash set is destroyed, when elements are removed or replaced. If fnFreeEltFunc is NULL, elements inserted into the hash set will not be freed.

Parameters

fnHashFunc	hash function. May be NULL.
fnEqualFunc	equal function. May be NULL.
fnFreeEltFunc	element free function. May be NULL.

Returns: a new hash set

◆ CPLHashSetRemove()

int CPLHashSetRemove	(	CPLHashSet *	set,
		const void *	elt
	)

Removes an element from a hash set.

Parameters

set	the hash set
elt	the new element to remove from the hash set

Returns: TRUE if the element was in the hash set

◆ CPLHashSetRemoveDeferRehash()

int CPLHashSetRemoveDeferRehash	(	CPLHashSet *	set,
		const void *	elt
	)

Removes an element from a hash set.

This will defer potential rehashing of the set to later calls to CPLHashSetInsert() or CPLHashSetRemove().

Parameters

set	the hash set
elt	the new element to remove from the hash set

Returns: TRUE if the element was in the hash set

Since: GDAL 2.1

◆ CPLHashSetSize()

int CPLHashSetSize ( const CPLHashSet * set )

Returns the number of elements inserted in the hash set.

Note: this is not the internal size of the hash set

Parameters

set	the hash set

Returns: the number of elements in the hash set

Typedefs

Functions

Detailed Description

Function Documentation

◆ CPLHashSetClear()

◆ CPLHashSetDestroy()

◆ CPLHashSetEqualPointer()

◆ CPLHashSetEqualStr()

◆ CPLHashSetForeach()

◆ CPLHashSetHashPointer()

◆ CPLHashSetHashStr()

◆ CPLHashSetInsert()

◆ CPLHashSetLookup()

◆ CPLHashSetNew()

◆ CPLHashSetRemove()

◆ CPLHashSetRemoveDeferRehash()

◆ CPLHashSetSize()