simplehash: Add support for resetting a hashtable's contents.

A hashtable reset just reset the hashtable entries, but does not free
memory.

Author: Andres Freund
Discussion: https://postgr.es/m/20190114180423.ywhdg2iagzvh43we@alap3.anarazel.de
Bug: #15592 #15486
Backpatch: 11, this is a prerequisite for other fixes
This commit is contained in:
Andres Freund 2019-02-09 00:35:57 -08:00
parent 5567d12ce0
commit 3b632a58e7

View File

@ -72,6 +72,7 @@
/* function declarations */
#define SH_CREATE SH_MAKE_NAME(create)
#define SH_DESTROY SH_MAKE_NAME(destroy)
#define SH_RESET SH_MAKE_NAME(reset)
#define SH_INSERT SH_MAKE_NAME(insert)
#define SH_DELETE SH_MAKE_NAME(delete)
#define SH_LOOKUP SH_MAKE_NAME(lookup)
@ -140,6 +141,7 @@ typedef struct SH_ITERATOR
SH_SCOPE SH_TYPE *SH_CREATE(MemoryContext ctx, uint32 nelements,
void *private_data);
SH_SCOPE void SH_DESTROY(SH_TYPE * tb);
SH_SCOPE void SH_RESET(SH_TYPE * tb);
SH_SCOPE void SH_GROW(SH_TYPE * tb, uint32 newsize);
SH_SCOPE SH_ELEMENT_TYPE *SH_INSERT(SH_TYPE * tb, SH_KEY_TYPE key, bool *found);
SH_SCOPE SH_ELEMENT_TYPE *SH_LOOKUP(SH_TYPE * tb, SH_KEY_TYPE key);
@ -368,6 +370,14 @@ SH_DESTROY(SH_TYPE * tb)
pfree(tb);
}
/* reset the contents of a previously created hash table */
SH_SCOPE void
SH_RESET(SH_TYPE * tb)
{
memset(tb->data, 0, sizeof(SH_ELEMENT_TYPE) * tb->size);
tb->members = 0;
}
/*
* Grow a hash table to at least `newsize` buckets.
*
@ -959,6 +969,7 @@ SH_STAT(SH_TYPE * tb)
/* external function names */
#undef SH_CREATE
#undef SH_DESTROY
#undef SH_RESET
#undef SH_INSERT
#undef SH_DELETE
#undef SH_LOOKUP