From 0bb59462ed60f87eb18effdd06e74a750e274ca8 Mon Sep 17 00:00:00 2001 From: David Robillard Date: Fri, 10 Aug 2012 02:15:53 +0000 Subject: Minimal space overhead inline value hash table. Add ZixChunk. Add SSE 4.2 accelerated digest (with fallback) in zix/digest.h. Make library optionally header-only (define ZIX_INLINE). git-svn-id: http://svn.drobilla.net/zix/trunk@76 df6676b4-ccc9-40e5-b5d6-7c4628a128e3 --- zix/digest.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 zix/digest.c (limited to 'zix/digest.c') diff --git a/zix/digest.c b/zix/digest.c new file mode 100644 index 0000000..4e8e974 --- /dev/null +++ b/zix/digest.c @@ -0,0 +1,56 @@ +/* + Copyright 2012 David Robillard + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +#include "zix/digest.h" + +#ifdef __SSE4_2__ +# include +#endif + +ZIX_API uint32_t +zix_digest_start(void) +{ +#ifdef __SSE4_2__ + return 1; // CRC32 initial value +#else + return 5381; // DJB hash initial value +#endif +} + +ZIX_API uint32_t +zix_digest_add(uint32_t hash, const void* buf, const size_t len) +{ +#ifdef __SSE4_2__ + // SSE 4.2 CRC32 + for (size_t i = 0; i < (len / sizeof(uint32_t)); ++i) { + hash = _mm_crc32_u32(hash, *(uint32_t*)buf); + buf += sizeof(uint32_t); + } + if (len & sizeof(uint16_t)) { + hash = _mm_crc32_u16(hash, *(uint16_t*)buf); + buf += sizeof(uint16_t); + } + if (len & sizeof(uint8_t)) { + hash = _mm_crc32_u8(hash, *(uint8_t*)buf); + } +#else + // Classic DJB hash + for (size_t i = 0; i < len; ++i) { + hash = (hash << 5) + hash + ((const uint8_t*)buf)[i]; + } +#endif + return hash; +} -- cgit v1.2.1