From 0d1733cd6115eb7c1cb427a936de39f20ead4f23 Mon Sep 17 00:00:00 2001 From: andreas_kupries Date: Tue, 12 Sep 2006 21:59:53 +0000 Subject: * unix/tclUnixCompat.c (PadBuffer): Fixed bug in calculation of the increment needed to align the pointer, and added documentation explaining why the macro is implemented as it is. --- ChangeLog | 6 ++++++ unix/tclUnixCompat.c | 16 +++++++++++----- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/ChangeLog b/ChangeLog index ea21597..62ebf21 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2006-09-12 Andreas Kupries + + * unix/tclUnixCompat.c (PadBuffer): Fixed bug in calculation of + the increment needed to align the pointer, and added + documentation explaining why the macro is implemented as it is. + 2006-09-11 Pat Thoyts * win/rules.vc: Updated to install http, tcltest and msgcat as diff --git a/unix/tclUnixCompat.c b/unix/tclUnixCompat.c index 37d6d05..d9deb8a 100644 --- a/unix/tclUnixCompat.c +++ b/unix/tclUnixCompat.c @@ -6,7 +6,7 @@ * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclUnixCompat.c,v 1.7 2006/09/11 16:07:33 das Exp $ + * RCS: @(#) $Id: tclUnixCompat.c,v 1.8 2006/09/12 21:59:53 andreas_kupries Exp $ * */ @@ -19,12 +19,18 @@ /* * Used to pad structures at size'd boundaries + * + * This macro assumes that the pointer 'buffer' was created from an + * aligned pointer by adding the 'length'. If this 'length' was not a + * multiple of the 'size' the result is unaligned and PadBuffer + * corrects both the pointer, _and_ the 'length'. The latter means + * that future increments of 'buffer' by 'length' stay aligned. */ -#define PadBuffer(buffer, length, size) \ - if (((length) % (size))) { \ - (buffer) += ((length) % (size)); \ - (length) += ((length) % (size)); \ +#define PadBuffer(buffer, length, size) \ + if (((length) % (size))) { \ + (buffer) += ((size) - ((length) % (size))); \ + (length) += ((size) - ((length) % (size))); \ } /* -- cgit v0.12