You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
61 lines
2.8 KiB
61 lines
2.8 KiB
2 months ago
|
/*
|
||
|
|
* UCW Library -- Hyper-super-meta-alt-control-shift extra fast
|
||
|
|
* str_len() and hash_*() routines
|
||
|
|
*
|
||
|
|
* (c) 2002, Robert Spalek <robert@ucw.cz>
|
||
|
|
*
|
||
|
|
* This software may be freely distributed and used according to the terms
|
||
|
|
* of the GNU Lesser General Public License.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef _UCW_HASHFUNC_H
|
||
|
|
#define _UCW_HASHFUNC_H
|
||
|
|
|
||
|
|
#include <ucw/lib.h>
|
||
|
|
|
||
|
|
#ifdef CONFIG_UCW_CLEAN_ABI
|
||
|
|
#define hash_block ucw_hash_block
|
||
|
|
#define hash_block_aligned ucw_hash_block_aligned
|
||
|
|
#define hash_string ucw_hash_string
|
||
|
|
#define hash_string_aligned ucw_hash_string_aligned
|
||
|
|
#define hash_string_nocase ucw_hash_string_nocase
|
||
|
|
#define str_len ucw_str_len
|
||
|
|
#define str_len_aligned ucw_str_len_aligned
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*** === String hashes [[strhash]] ***/
|
||
|
|
|
||
|
|
/* The following functions need str to be aligned to sizeof(uint). */
|
||
|
|
uint str_len_aligned(const char *str) PURE; /** Get the string length (not a really useful hash function, but there is no better place for it). The string must be aligned to sizeof(uint). For unaligned see @str_len(). **/
|
||
|
|
uint hash_string_aligned(const char *str) PURE; /** Hash the string. The string must be aligned to sizeof(uint). For unaligned see @hash_string(). **/
|
||
|
|
uint hash_block_aligned(const byte *buf, uint len) PURE; /** Hash arbitrary data. They must be aligned to sizeof(uint). For unaligned see @hash_block(). **/
|
||
|
|
|
||
|
|
#ifdef CPU_ALLOW_UNALIGNED
|
||
|
|
#undef str_len
|
||
|
|
#undef hash_string
|
||
|
|
#undef hash_block
|
||
|
|
#define str_len(str) str_len_aligned(str)
|
||
|
|
#define hash_string(str) hash_string_aligned(str)
|
||
|
|
#define hash_block(str, len) hash_block_aligned(str, len)
|
||
|
|
#else
|
||
|
|
uint str_len(const char *str) PURE; /** Get the string length. If you know it is aligned to sizeof(uint), you can use faster @str_len_aligned(). **/
|
||
|
|
uint hash_string(const char *str) PURE; /** Hash the string. If it is aligned to sizeof(uint), you can use faster @hash_string_aligned(). **/
|
||
|
|
uint hash_block(const byte *buf, uint len) PURE; /** Hash arbitrary data. If they are aligned to sizeof(uint), use faster @hash_block_aligned(). **/
|
||
|
|
#endif
|
||
|
|
|
||
|
|
uint hash_string_nocase(const char *str) PURE; /** Hash the string in a case insensitive way. Works only with ASCII characters. **/
|
||
|
|
|
||
|
|
/*** === Integer hashes [[inthash]] ***/
|
||
|
|
|
||
|
|
/***
|
||
|
|
* We hash integers by multiplying by a reasonably large prime with
|
||
|
|
* few ones in its binary form (to give the compiler the possibility
|
||
|
|
* of using shifts and adds on architectures where multiplication
|
||
|
|
* instructions are slow).
|
||
|
|
*/
|
||
|
|
static inline uint CONST hash_u32(uint x) { return 0x01008041*x; } /** Hash a 32 bit unsigned integer. **/
|
||
|
|
static inline uint CONST hash_u64(u64 x) { return hash_u32((uint)x ^ (uint)(x >> 32)); } /** Hash a 64 bit unsigned integer. **/
|
||
|
|
static inline uint CONST hash_pointer(void *x) { return ((sizeof(x) <= 4) ? hash_u32((uint)(uintptr_t)x) : hash_u64((u64)(uintptr_t)x)); } /** Hash a pointer. **/
|
||
|
|
|
||
|
|
#endif
|