src/basic/hash-funcs.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include "macro.h"
   5 #include "siphash24.h"
   6
   7 typedef void (*hash_func_t)(const void *p, struct siphash *state);
   8 typedef int (*compare_func_t)(const void *a, const void *b);
   9
  10 struct hash_ops {
  11         hash_func_t hash;
  12         compare_func_t compare;
  13 };
  14
  15 void string_hash_func(const void *p, struct siphash *state);
  16 int string_compare_func(const void *a, const void *b) _pure_;
  17 extern const struct hash_ops string_hash_ops;
  18
  19 void path_hash_func(const void *p, struct siphash *state);
  20 int path_compare_func(const void *a, const void *b) _pure_;
  21 extern const struct hash_ops path_hash_ops;
  22
  23 /* This will compare the passed pointers directly, and will not dereference them. This is hence not useful for strings
  24  * or suchlike. */
  25 void trivial_hash_func(const void *p, struct siphash *state);
  26 int trivial_compare_func(const void *a, const void *b) _const_;
  27 extern const struct hash_ops trivial_hash_ops;
  28
  29 /* 32bit values we can always just embed in the pointer itself, but in order to support 32bit archs we need store 64bit
  30  * values indirectly, since they don't fit in a pointer. */
  31 void uint64_hash_func(const void *p, struct siphash *state);
  32 int uint64_compare_func(const void *a, const void *b) _pure_;
  33 extern const struct hash_ops uint64_hash_ops;
  34
  35 /* On some archs dev_t is 32bit, and on others 64bit. And sometimes it's 64bit on 32bit archs, and sometimes 32bit on
  36  * 64bit archs. Yuck! */
  37 #if SIZEOF_DEV_T != 8
  38 void devt_hash_func(const void *p, struct siphash *state) _pure_;
  39 int devt_compare_func(const void *a, const void *b) _pure_;
  40 extern const struct hash_ops devt_hash_ops;
  41 #else
  42 #define devt_hash_func uint64_hash_func
  43 #define devt_compare_func uint64_compare_func
  44 #define devt_hash_ops uint64_hash_ops
  45 #endif