summaryrefslogtreecommitdiff
path: root/src/basic/hash-funcs.h
diff options
context:
space:
mode:
authorLennart Poettering <lennart@poettering.net>2016-01-08 01:10:45 +0100
committerLennart Poettering <lennart@poettering.net>2016-01-11 19:39:59 +0100
commit758dd67e8d40e65f695103bb03a77afaa087c5be (patch)
tree9d2b7bc2bd45ab3a32af54f3394ad6981eb85bcd /src/basic/hash-funcs.h
parente84750c905111675bdae8437257c764e13d776b5 (diff)
basic: split hash functions into their own header files
The hash operations are not really that specific to hashmaps, hence split them into a .c module of their own.
Diffstat (limited to 'src/basic/hash-funcs.h')
-rw-r--r--src/basic/hash-funcs.h67
1 files changed, 67 insertions, 0 deletions
diff --git a/src/basic/hash-funcs.h b/src/basic/hash-funcs.h
new file mode 100644
index 0000000000..c640eaf4d1
--- /dev/null
+++ b/src/basic/hash-funcs.h
@@ -0,0 +1,67 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010 Lennart Poettering
+ Copyright 2014 Michal Schmidt
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "macro.h"
+#include "siphash24.h"
+
+typedef void (*hash_func_t)(const void *p, struct siphash *state);
+typedef int (*compare_func_t)(const void *a, const void *b);
+
+struct hash_ops {
+ hash_func_t hash;
+ compare_func_t compare;
+};
+
+void string_hash_func(const void *p, struct siphash *state);
+int string_compare_func(const void *a, const void *b) _pure_;
+extern const struct hash_ops string_hash_ops;
+
+/* This will compare the passed pointers directly, and will not
+ * dereference them. This is hence not useful for strings or
+ * suchlike. */
+void trivial_hash_func(const void *p, struct siphash *state);
+int trivial_compare_func(const void *a, const void *b) _const_;
+extern const struct hash_ops trivial_hash_ops;
+
+/* 32bit values we can always just embed in the pointer itself, but
+ * in order to support 32bit archs we need store 64bit values
+ * indirectly, since they don't fit in a pointer. */
+void uint64_hash_func(const void *p, struct siphash *state);
+int uint64_compare_func(const void *a, const void *b) _pure_;
+extern const struct hash_ops uint64_hash_ops;
+
+/* On some archs dev_t is 32bit, and on others 64bit. And sometimes
+ * it's 64bit on 32bit archs, and sometimes 32bit on 64bit archs. Yuck! */
+#if SIZEOF_DEV_T != 8
+void devt_hash_func(const void *p, struct siphash *state) _pure_;
+int devt_compare_func(const void *a, const void *b) _pure_;
+extern const struct hash_ops devt_hash_ops = {
+ .hash = devt_hash_func,
+ .compare = devt_compare_func
+};
+#else
+#define devt_hash_func uint64_hash_func
+#define devt_compare_func uint64_compare_func
+#define devt_hash_ops uint64_hash_ops
+#endif