From: Jani Nikula Date: Fri, 24 Oct 2014 04:40:25 +0000 (+0300) Subject: Re: [PATCH v3 3/9] lib: Introduce macros for bit operations X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=56aa01210ad4f03f44c0cdd7afc84a81a3ce7ffd;p=notmuch-archives.git Re: [PATCH v3 3/9] lib: Introduce macros for bit operations --- diff --git a/d9/3335128452599d0c929387a3553f7bb1ae0bbb b/d9/3335128452599d0c929387a3553f7bb1ae0bbb new file mode 100644 index 000000000..a1bacda04 --- /dev/null +++ b/d9/3335128452599d0c929387a3553f7bb1ae0bbb @@ -0,0 +1,230 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id 1F600431FDD + for ; Thu, 23 Oct 2014 21:40:36 -0700 (PDT) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: -0.699 +X-Spam-Level: +X-Spam-Status: No, score=-0.699 tagged_above=-999 required=5 + tests=[HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id UnOZiGwkTIwR for ; + Thu, 23 Oct 2014 21:40:28 -0700 (PDT) +Received: from mail-la0-f48.google.com (mail-la0-f48.google.com + [209.85.215.48]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) + (No client certificate requested) + by olra.theworths.org (Postfix) with ESMTPS id 5F3DB431FDC + for ; Thu, 23 Oct 2014 21:40:28 -0700 (PDT) +Received: by mail-la0-f48.google.com with SMTP id gi9so1966483lab.21 + for ; Thu, 23 Oct 2014 21:40:25 -0700 (PDT) +X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=1e100.net; s=20130820; + h=x-gm-message-state:mime-version:in-reply-to:references:date + :message-id:subject:from:to:cc:content-type; + bh=BQi7AgBJzl1M8yMutnXjYAo46AeFFQdOPzxbhPuq1F0=; + b=NmDEHvd1y52ANM/FsSu5jU3WzmNWktvPShuTUY7NSFprTwmOTLfIl8tJ2a2IqDXg5v + kcRZ1Cpx91Frs/2oXChdYmp/EVWPzZy8Y9GuBA0oZmsV5x2rXfpNU49ygFsW3gPIEOaF + lEYdKaXuLQ55kMHCO0oQNZ3A08la/SleSEm0TvSEmk31F7SoCO/HVRDndrUioPMatlCZ + xuP07mUKIz61NyMtTaNpqI8o++GJnfICNVqED3CqojDuHiBCozxDS9B/N5N6/q/Igk/e + rb4yDGYDbtN/s4zG47pDgQBw42yabM4Qo+gVuylwikEyNq0EsS9uzs0nP5QmQ2QzHOVn + jCHg== +X-Gm-Message-State: + ALoCoQnJKFx4G4udFAZq9Ld8gli2h35wXO3mDfvpC9G7OOj+u+ycR9nXMc+uydlnb40MxoVtZ44m +MIME-Version: 1.0 +X-Received: by 10.152.7.7 with SMTP id f7mr1666883laa.57.1414125625506; Thu, + 23 Oct 2014 21:40:25 -0700 (PDT) +Received: by 10.25.145.7 with HTTP; Thu, 23 Oct 2014 21:40:25 -0700 (PDT) +Received: by 10.25.145.7 with HTTP; Thu, 23 Oct 2014 21:40:25 -0700 (PDT) +In-Reply-To: <1414067441-29054-4-git-send-email-aclements@csail.mit.edu> +References: <1414067441-29054-1-git-send-email-aclements@csail.mit.edu> + <1414067441-29054-4-git-send-email-aclements@csail.mit.edu> +Date: Fri, 24 Oct 2014 07:40:25 +0300 +Message-ID: + +Subject: Re: [PATCH v3 3/9] lib: Introduce macros for bit operations +From: Jani Nikula +To: Austin Clements +Content-Type: multipart/alternative; boundary=001a11c2870a939325050623c78e +Cc: Notmuch Mail +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Fri, 24 Oct 2014 04:40:36 -0000 + +--001a11c2870a939325050623c78e +Content-Type: text/plain; charset=UTF-8 + +On Oct 23, 2014 3:31 PM, "Austin Clements" wrote: +> +> 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))) + +bit should be in braces in the above, like valp. + +Jani. + +> + +> #define unused(x) x __attribute__ ((unused)) +> +> #ifdef __cplusplus +> -- +> 2.1.0 +> +> _______________________________________________ +> notmuch mailing list +> notmuch@notmuchmail.org +> http://notmuchmail.org/mailman/listinfo/notmuch + +--001a11c2870a939325050623c78e +Content-Type: text/html; charset=UTF-8 +Content-Transfer-Encoding: quoted-printable + +


+On Oct 23, 2014 3:31 PM, "Austin Clements" <aclements@csail.mit.edu> wrote:
+>
+> These macros help clarify basic bit-twiddling code and are written to<= +br> +> be robust against C undefined behavior of shift operators.
+> ---
+> =C2=A0lib/message.cc=C2=A0 =C2=A0 =C2=A0 =C2=A0 |=C2=A0 6 +++---
+> =C2=A0lib/notmuch-private.h | 11 +++++++++++
+> =C2=A02 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
+> =C2=A0notmuch_message_get_flag (notmuch_message_t *message,
+> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = +=C2=A0 =C2=A0 =C2=A0 notmuch_message_flag_t flag)
+> =C2=A0{
+> -=C2=A0 =C2=A0 return message->flags & (1 << flag);
+> +=C2=A0 =C2=A0 return NOTMUCH_TEST_BIT (message->flags, flag);
+> =C2=A0}
+>
+> =C2=A0void
+> @@ -877,9 +877,9 @@ notmuch_message_set_flag (notmuch_message_t *messa= +ge,
+> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = +=C2=A0 =C2=A0 =C2=A0 notmuch_message_flag_t flag, notmuch_bool_t enable) +> =C2=A0{
+> =C2=A0 =C2=A0 =C2=A0if (enable)
+> -=C2=A0 =C2=A0 =C2=A0 =C2=A0message->flags |=3D (1 << flag);<= +br> +> +=C2=A0 =C2=A0 =C2=A0 =C2=A0NOTMUCH_SET_BIT (&message->flags, f= +lag);
+> =C2=A0 =C2=A0 =C2=A0else
+> -=C2=A0 =C2=A0 =C2=A0 =C2=A0message->flags &=3D ~(1 << fl= +ag);
+> +=C2=A0 =C2=A0 =C2=A0 =C2=A0NOTMUCH_CLEAR_BIT (&message->flags,= + flag);
+> =C2=A0}
+>
+> =C2=A0time_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
+> =C2=A0#define STRNCMP_LITERAL(var, literal) \
+> =C2=A0 =C2=A0 =C2=A0strncmp ((var), (literal), sizeof (literal) - 1) +>
+> +/* Robust bit test/set/reset macros */
+> +#define NOTMUCH_TEST_BIT(val, bit) \
+> +=C2=A0 =C2=A0 ((bit < 0 || bit >=3D CHAR_BIT * sizeof (unsigned= + long long)) ? 0=C2=A0 =C2=A0 \
+> +=C2=A0 =C2=A0 =C2=A0: !!((val) & (1ull << bit)))
+> +#define NOTMUCH_SET_BIT(valp, bit) \
+> +=C2=A0 =C2=A0 ((bit < 0 || bit >=3D CHAR_BIT * sizeof (unsigned= + long long)) ? *(valp) \
+> +=C2=A0 =C2=A0 =C2=A0: (*(valp) |=3D (1ull << bit)))
+> +#define NOTMUCH_CLEAR_BIT(valp,=C2=A0 bit) \
+> +=C2=A0 =C2=A0 ((bit < 0 || bit >=3D CHAR_BIT * sizeof (unsigned= + long long)) ? *(valp) \
+> +=C2=A0 =C2=A0 =C2=A0: (*(valp) &=3D ~(1ull << bit)))

+

bit should be in braces in the above, like valp.

+

Jani.

+

> +
+> =C2=A0#define unused(x) x __attribute__ ((unused))
+>
+> =C2=A0#ifdef __cplusplus
+> --
+> 2.1.0
+>
+> _______________________________________________
+> notmuch mailing list
+> notmuch@notmuchmail.org= +
+> http://not= +muchmail.org/mailman/listinfo/notmuch
+

+ +--001a11c2870a939325050623c78e--