X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fbasic%2Fhash-funcs.h;fp=src%2Fbasic%2Fhash-funcs.h;h=b085054ee21ecb18af9dc0f23a64128511debc41;hb=f7e8917981217e60a6b6071c2a1ae6367890eea0;hp=0000000000000000000000000000000000000000;hpb=07de3e94bec7f426258007c4a790a78589d2fee3;p=elogind.git

diff --git a/src/basic/hash-funcs.h b/src/basic/hash-funcs.h
new file mode 100644
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--- /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 elogind.
+
+  Copyright 2010 Lennart Poettering
+  Copyright 2014 Michal Schmidt
+
+  elogind 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.
+
+  elogind 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 elogind; 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