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[PATCH v2 1/4] uuid: add hash_func and equal_func
From: |
Albert Esteve |
Subject: |
[PATCH v2 1/4] uuid: add hash_func and equal_func |
Date: |
Thu, 18 May 2023 14:02:55 +0200 |
Add hash and an equal function to uuid module.
Add a couple simple unit tests for new functions,
checking collisions for similar UUIDs in the case
of the hash function, and comparing generated UUIDs
for the equal function.
Signed-off-by: Albert Esteve <aesteve@redhat.com>
---
include/qemu/uuid.h | 4 ++++
tests/unit/test-uuid.c | 46 ++++++++++++++++++++++++++++++++++++++++++
util/uuid.c | 38 ++++++++++++++++++++++++++++++++++
3 files changed, 88 insertions(+)
diff --git a/include/qemu/uuid.h b/include/qemu/uuid.h
index dc40ee1fc9..136df682c9 100644
--- a/include/qemu/uuid.h
+++ b/include/qemu/uuid.h
@@ -96,4 +96,8 @@ int qemu_uuid_parse(const char *str, QemuUUID *uuid);
QemuUUID qemu_uuid_bswap(QemuUUID uuid);
+uint32_t qemu_uuid_hash(const void *uuid);
+
+int qemu_uuid_equal(const void *lhv, const void *rhv);
+
#endif
diff --git a/tests/unit/test-uuid.c b/tests/unit/test-uuid.c
index c111de5fc1..8c865869d5 100644
--- a/tests/unit/test-uuid.c
+++ b/tests/unit/test-uuid.c
@@ -171,6 +171,50 @@ static void test_uuid_unparse_strdup(void)
}
}
+static void test_uuid_hash(void)
+{
+ QemuUUID uuid;
+ int i;
+
+ for (i = 0; i < 100; i++) {
+ qemu_uuid_generate(&uuid);
+ /* Obtain the UUID hash */
+ uint32_t hash_a = qemu_uuid_hash(&uuid);
+ int data_idx = g_random_int_range(0, 15);
+ /* Change a single random byte of the UUID */
+ if (uuid.data[data_idx] < 0xFF) {
+ uuid.data[data_idx]++;
+ } else {
+ uuid.data[data_idx]--;
+ }
+ /* Obtain the UUID hash again */
+ uint32_t hash_b = qemu_uuid_hash(&uuid);
+ /*
+ * Both hashes shall be different (avoid collision)
+ * for any change in the UUID fields
+ */
+ g_assert_cmpint(hash_a, !=, hash_b);
+ }
+}
+
+static void test_uuid_equal(void)
+{
+ QemuUUID uuid_a, uuid_b, uuid_c;
+ int i;
+
+ for (i = 0; i < 100; i++) {
+ qemu_uuid_generate(&uuid_a);
+ qemu_uuid_generate(&uuid_b);
+ memcpy(&uuid_c, &uuid_a, sizeof(uuid_a));
+
+ g_assert(qemu_uuid_equal(&uuid_a, &uuid_a));
+ g_assert(qemu_uuid_equal(&uuid_b, &uuid_b));
+ g_assert(qemu_uuid_equal(&uuid_a, &uuid_c));
+ g_assert_false(qemu_uuid_equal(&uuid_a, &uuid_b));
+ g_assert_false(qemu_uuid_equal(NULL, NULL));
+ }
+}
+
int main(int argc, char **argv)
{
g_test_init(&argc, &argv, NULL);
@@ -179,6 +223,8 @@ int main(int argc, char **argv)
g_test_add_func("/uuid/parse", test_uuid_parse);
g_test_add_func("/uuid/unparse", test_uuid_unparse);
g_test_add_func("/uuid/unparse_strdup", test_uuid_unparse_strdup);
+ g_test_add_func("/uuid/hash", test_uuid_hash);
+ g_test_add_func("/uuid/equal", test_uuid_equal);
return g_test_run();
}
diff --git a/util/uuid.c b/util/uuid.c
index b1108dde78..efa9b0a0e4 100644
--- a/util/uuid.c
+++ b/util/uuid.c
@@ -16,6 +16,7 @@
#include "qemu/osdep.h"
#include "qemu/uuid.h"
#include "qemu/bswap.h"
+#include "qemu/xxhash.h"
void qemu_uuid_generate(QemuUUID *uuid)
{
@@ -116,3 +117,40 @@ QemuUUID qemu_uuid_bswap(QemuUUID uuid)
bswap16s(&uuid.fields.time_high_and_version);
return uuid;
}
+
+uint32_t qemu_uuid_hash(const void *uuid)
+{
+ QemuUUID *id = (QemuUUID *) uuid;
+ uint64_t ab = (id->fields.time_low) |
+ (((uint64_t) id->fields.time_mid) << 32) |
+ (((uint64_t) id->fields.time_high_and_version) << 48);
+ uint64_t cd = (id->fields.clock_seq_and_reserved) |
+ (id->fields.clock_seq_low << 8);
+ int i = 0, shift = 8;
+
+ for (; i < 6; i++) {
+ shift += 8;
+ cd |= ((uint64_t) id->fields.node[i]) << shift;
+ }
+
+ return qemu_xxhash4(ab, cd);
+}
+
+int qemu_uuid_equal(const void *lhv, const void *rhv)
+{
+ int i;
+ QemuUUID *lid = (QemuUUID *) lhv;
+ QemuUUID *rid = (QemuUUID *) rhv;
+ if (lid == NULL || rid == NULL) {
+ return 0;
+ }
+ if (lid == rid) {
+ return 1;
+ }
+ for (i = 0; i < 16; i++) {
+ if (lid->data[i] != rid->data[i]) {
+ return 0;
+ }
+ }
+ return 1;
+}
--
2.40.0
[PATCH v2 4/4] vhost-user: refactor send_resp code, Albert Esteve, 2023/05/18