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From: Kiran Rangoon <kiranrangoon0@gmail.com>
To: util-linux@vger.kernel.org
Cc: thomas@t-8ch.de, Kiran Rangoon <kiranrangoon0@gmail.com>
Subject: [PATCH v4 1/4] libuuid: simplify gregorian-to-unix offset calculation
Date: Tue, 23 Dec 2025 13:00:52 -0500	[thread overview]
Message-ID: <20251223180055.2396-2-kiranrangoon0@gmail.com> (raw)
In-Reply-To: <20251223180055.2396-1-kiranrangoon0@gmail.com>

Replace complex bit-shift offset calculation with a simple constant
definition for better readability and maintainability.

Signed-off-by: Kiran Rangoon <kiranrangoon0@gmail.com>
---
 libuuid/src/uuid_time.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libuuid/src/uuid_time.c b/libuuid/src/uuid_time.c
index c7516152b..e2b991d74 100644
--- a/libuuid/src/uuid_time.c
+++ b/libuuid/src/uuid_time.c
@@ -62,7 +62,8 @@ time_t __uuid_time(const uuid_t uu, struct timeval *ret_tv);
 
 static uint64_t gregorian_to_unix(uint64_t ts)
 {
-	return ts - ((((uint64_t) 0x01B21DD2) << 32) + 0x13814000);
+	const uint64_t offset = 0x01B21DD213814000ULL;
+	return ts - offset;
 }
 
 static void uuid_time_v1(const struct uuid *uuid, struct timeval *tv)
-- 
2.47.3


  reply	other threads:[~2025-12-23 18:01 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-13 20:04 [PATCH] libuuid: Fix pre-1970 UUID v1 timestamp wraparound Kiran Rangoon
2025-12-13 23:36 ` Thomas Weißschuh 
2025-12-14  1:01 ` [PATCH v2] " Kiran Rangoon
2025-12-16 13:08   ` Thomas Weißschuh
2025-12-16 20:40     ` Kiran
2025-12-16 23:21       ` Thomas Weißschuh
2025-12-17 20:42         ` [PATCH v3 1/2] libuuid: Refactor UUID time conversion for pre-epoch dates Kiran Rangoon
2025-12-17 20:59         ` Kiran Rangoon
2025-12-18 21:31         ` Kiran Rangoon
2025-12-19 11:40           ` Thomas Weißschuh
2025-12-23 18:00             ` [PATCH v4 0/4] libuuid: Fix pre-1970 UUID timestamp overflow Kiran Rangoon
2025-12-23 18:00               ` Kiran Rangoon [this message]
2025-12-23 18:00               ` [PATCH v4 2/4] libuuid: refactor gregorian_to_unix to populate timeval directly Kiran Rangoon
2025-12-23 18:03               ` [PATCH v4 1/4] libuuid: simplify gregorian-to-unix offset calculation Kiran Rangoon
2025-12-23 18:22               ` [PATCH v4 0/4] libuuid: Fix pre-1970 UUID timestamp overflow Thomas Weißschuh 
2025-12-28  8:47               ` Thomas Weißschuh
2025-12-23 18:04             ` [PATCH v4 3/4] libuuid: fix timestamp overflow for pre-1970 dates Kiran Rangoon
2025-12-23 18:05             ` [PATCH v4 4/4] tests: correct UUID timestamp test expectations Kiran Rangoon
2025-12-17 11:01   ` [PATCH v2] libuuid: Fix pre-1970 UUID v1 timestamp wraparound Karel Zak

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