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Commit 8c0d7bafad36434cb08ac2c78e69ae72c194ca20 introduced dshash with hash and compare functions like DynaHash's, and also variants that take a user data pointer instead of size. Simplify the interface by merging them into a single pair of function pointer types that take both size and a user data pointer. Since it is anticipated that memcmp and tag_hash behavior will be a common requirement, provide wrapper functions dshash_memcmp and dshash_memhash that conform to the new function types. Author: Thomas Munro Reviewed-By: Andres Freund Discussion: https://postgr.es/m/20170823054644.efuzftxjpfi6wwqs%40alap3.anarazel.de
This directory contains a general purpose data structures, for use anywhere in the backend: binaryheap.c - a binary heap hyperloglog.c - a streaming cardinality estimator pairingheap.c - a pairing heap rbtree.c - a red-black tree ilist.c - single and double-linked lists. stringinfo.c - an extensible string type Aside from the inherent characteristics of the data structures, there are a few practical differences between the binary heap and the pairing heap. The binary heap is fully allocated at creation, and cannot be expanded beyond the allocated size. The pairing heap on the other hand has no inherent maximum size, but the caller needs to allocate each element being stored in the heap, while the binary heap works with plain Datums or pointers. The linked-lists in ilist.c can be embedded directly into other structs, as opposed to the List interface in nodes/pg_list.h.