From: Austin Clements <aclements@csail.mit.edu>
To: notmuch@notmuchmail.org
Cc: Austin Clements <aclements@csail.mit.edu>
Subject: [PATCH v2 06/12] lib: Introduce macros for bit operations
Date: Mon, 6 Oct 2014 17:17:12 -0600 [thread overview]
Message-ID: <1412637438-4821-7-git-send-email-aclements@csail.mit.edu> (raw)
In-Reply-To: <1412637438-4821-1-git-send-email-aclements@csail.mit.edu>
These macros help clarify basic bit-twiddling code and are written to
be robust against C undefined behavior of shift operators.
---
lib/message.cc | 6 +++---
lib/notmuch-private.h | 11 +++++++++++
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/lib/message.cc b/lib/message.cc
index 38bc929..55d2ff6 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -869,7 +869,7 @@ notmuch_bool_t
notmuch_message_get_flag (notmuch_message_t *message,
notmuch_message_flag_t flag)
{
- return message->flags & (1 << flag);
+ return NOTMUCH_TEST_BIT (message->flags, flag);
}
void
@@ -877,9 +877,9 @@ notmuch_message_set_flag (notmuch_message_t *message,
notmuch_message_flag_t flag, notmuch_bool_t enable)
{
if (enable)
- message->flags |= (1 << flag);
+ NOTMUCH_SET_BIT (&message->flags, flag);
else
- message->flags &= ~(1 << flag);
+ NOTMUCH_CLEAR_BIT (&message->flags, flag);
}
time_t
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 36cc12b..7250291 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -63,6 +63,17 @@ NOTMUCH_BEGIN_DECLS
#define STRNCMP_LITERAL(var, literal) \
strncmp ((var), (literal), sizeof (literal) - 1)
+/* Robust bit test/set/reset macros */
+#define NOTMUCH_TEST_BIT(val, bit) \
+ ((bit < 0 || bit >= CHAR_BIT * sizeof (unsigned long long)) ? 0 \
+ : !!((val) & (1ull << bit)))
+#define NOTMUCH_SET_BIT(valp, bit) \
+ ((bit < 0 || bit >= CHAR_BIT * sizeof (unsigned long long)) ? *(valp) \
+ : (*(valp) |= (1ull << bit)))
+#define NOTMUCH_CLEAR_BIT(valp, bit) \
+ ((bit < 0 || bit >= CHAR_BIT * sizeof (unsigned long long)) ? *(valp) \
+ : (*(valp) &= ~(1ull << bit)))
+
#define unused(x) x __attribute__ ((unused))
#ifdef __cplusplus
--
2.1.0
next prev parent reply other threads:[~2014-10-06 23:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-06 23:17 [PATCH 00/12] Add ghost messages and fix thread linking Austin Clements
2014-10-06 23:17 ` [PATCH v2 01/12] lib: Move message ID compression to _notmuch_message_create_for_message_id Austin Clements
2014-10-06 23:17 ` [PATCH v2 02/12] lib: Refactor _notmuch_database_link_message Austin Clements
2014-10-06 23:17 ` [PATCH v2 03/12] lib: Handle empty date value Austin Clements
2014-10-11 5:12 ` David Bremner
2014-10-06 23:17 ` [PATCH v2 04/12] lib: Add a ghost messages database feature Austin Clements
2014-10-06 23:17 ` [PATCH v2 05/12] lib: Update database schema doc for ghost messages Austin Clements
2014-10-06 23:17 ` Austin Clements [this message]
2014-10-06 23:17 ` [PATCH v2 07/12] lib: Internal support for querying and creating " Austin Clements
2014-10-21 23:05 ` Mark Walters
2014-10-22 1:33 ` Austin Clements
2014-10-06 23:17 ` [PATCH v2 08/12] lib: Implement ghost-based thread linking Austin Clements
2014-10-21 23:10 ` Mark Walters
2014-10-22 1:49 ` Austin Clements
2014-10-06 23:17 ` [PATCH v2 09/12] lib: Implement upgrade to ghost messages feature Austin Clements
2014-10-06 23:17 ` [PATCH v2 10/12] lib: Enable " Austin Clements
2014-10-06 23:17 ` [PATCH v2 11/12] test: Test upgrade to " Austin Clements
2014-10-06 23:17 ` [PATCH v2 12/12] lib: Remove unnecessary thread linking steps when using ghost messages Austin Clements
2014-10-21 23:17 ` Mark Walters
2014-10-22 1:51 ` Austin Clements
2014-10-21 23:32 ` [PATCH 00/12] Add ghost messages and fix thread linking Mark Walters
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