Merge pull request #11827 from keszybz/pkgconfig-variables

[thirdparty/systemd.git] / src / basic / hash-funcs.c

diff --git a/src/basic/hash-funcs.c b/src/basic/hash-funcs.c
index d4affaffeef8eda32671db109986fa9de976a4e4..1be43d41a93ff7ae1a78e0df57ea52f9247285b7 100644 (file)
--- a/src/basic/hash-funcs.c
+++ b/src/basic/hash-funcs.c
@@ -1,83 +1,91 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+/* SPDX-License-Identifier: LGPL-2.1+ */
 
-/***
-  This file is part of systemd.
+#include <string.h>
 
-  Copyright 2010 Lennart Poettering
-  Copyright 2014 Michal Schmidt
+#include "hash-funcs.h"
+#include "path-util.h"
 
-  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.
+void string_hash_func(const char *p, struct siphash *state) {
+        siphash24_compress(p, strlen(p) + 1, state);
+}
 
-  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.
+DEFINE_HASH_OPS(string_hash_ops, char, string_hash_func, string_compare_func);
 
-  You should have received a copy of the GNU Lesser General Public License
-  along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
+void path_hash_func(const char *q, struct siphash *state) {
+        size_t n;
 
-#include "hash-funcs.h"
+        assert(q);
+        assert(state);
 
-void string_hash_func(const void *p, struct siphash *state) {
-        siphash24_compress(p, strlen(p) + 1, state);
+        /* Calculates a hash for a path in a way this duplicate inner slashes don't make a differences, and also
+         * whether there's a trailing slash or not. This fits well with the semantics of path_compare(), which does
+         * similar checks and also doesn't care for trailing slashes. Note that relative and absolute paths (i.e. those
+         * which begin in a slash or not) will hash differently though. */
+
+        n = strspn(q, "/");
+        if (n > 0) { /* Eat up initial slashes, and add one "/" to the hash for all of them */
+                siphash24_compress(q, 1, state);
+                q += n;
+        }
+
+        for (;;) {
+                /* Determine length of next component */
+                n = strcspn(q, "/");
+                if (n == 0) /* Reached the end? */
+                        break;
+
+                /* Add this component to the hash and skip over it */
+                siphash24_compress(q, n, state);
+                q += n;
+
+                /* How many slashes follow this component? */
+                n = strspn(q, "/");
+                if (q[n] == 0) /* Is this a trailing slash? If so, we are at the end, and don't care about the slashes anymore */
+                        break;
+
+                /* We are not add the end yet. Hash exactly one slash for all of the ones we just encountered. */
+                siphash24_compress(q, 1, state);
+                q += n;
+        }
 }
 
-int string_compare_func(const void *a, const void *b) {
-        return strcmp(a, b);
+int path_compare_func(const char *a, const char *b) {
+        return path_compare(a, b);
 }
 
-const struct hash_ops string_hash_ops = {
-        .hash = string_hash_func,
-        .compare = string_compare_func
-};
+DEFINE_HASH_OPS(path_hash_ops, char, path_hash_func, path_compare_func);
 
 void trivial_hash_func(const void *p, struct siphash *state) {
         siphash24_compress(&p, sizeof(p), state);
 }
 
 int trivial_compare_func(const void *a, const void *b) {
-        return a < b ? -1 : (a > b ? 1 : 0);
+        return CMP(a, b);
 }
 
 const struct hash_ops trivial_hash_ops = {
         .hash = trivial_hash_func,
-        .compare = trivial_compare_func
+        .compare = trivial_compare_func,
 };
 
-void uint64_hash_func(const void *p, struct siphash *state) {
+void uint64_hash_func(const uint64_t *p, struct siphash *state) {
         siphash24_compress(p, sizeof(uint64_t), state);
 }
 
-int uint64_compare_func(const void *_a, const void *_b) {
-        uint64_t a, b;
-        a = *(const uint64_t*) _a;
-        b = *(const uint64_t*) _b;
-        return a < b ? -1 : (a > b ? 1 : 0);
+int uint64_compare_func(const uint64_t *a, const uint64_t *b) {
+        return CMP(*a, *b);
 }
 
-const struct hash_ops uint64_hash_ops = {
-        .hash = uint64_hash_func,
-        .compare = uint64_compare_func
-};
+DEFINE_HASH_OPS(uint64_hash_ops, uint64_t, uint64_hash_func, uint64_compare_func);
 
 #if SIZEOF_DEV_T != 8
-void devt_hash_func(const void *p, struct siphash *state) {
+void devt_hash_func(const dev_t *p, struct siphash *state) {
         siphash24_compress(p, sizeof(dev_t), state);
 }
 
-int devt_compare_func(const void *_a, const void *_b) {
-        dev_t a, b;
-        a = *(const dev_t*) _a;
-        b = *(const dev_t*) _b;
-        return a < b ? -1 : (a > b ? 1 : 0);
+int devt_compare_func(const dev_t *a, const dev_t *b) {
+        return CMP(*a, *b);
 }
 
-const struct hash_ops devt_hash_ops = {
-        .hash = devt_hash_func,
-        .compare = devt_compare_func
-};
+DEFINE_HASH_OPS(devt_hash_ops, dev_t, devt_hash_func, devt_compare_func);
 #endif