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| author | andreas_kupries <andreas_kupries@noemail.net> | 2006-09-12 22:05:01 (GMT) |
|---|---|---|
| committer | andreas_kupries <andreas_kupries@noemail.net> | 2006-09-12 22:05:01 (GMT) |
| commit | eec4984942e8b2184afd27fa1f2338974438420d (patch) | |
| tree | 6de91b9fbb165378373cabb64e14af69d10297a3 /unix/tclUnixCompat.c | |
| parent | 3dfcdd63553887015f76aaf694485badbb28cfbf (diff) | |
| download | tcl-eec4984942e8b2184afd27fa1f2338974438420d.zip tcl-eec4984942e8b2184afd27fa1f2338974438420d.tar.gz tcl-eec4984942e8b2184afd27fa1f2338974438420d.tar.bz2 | |
* 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.
FossilOrigin-Name: 2b856a9c1f8fa386dbf2b5af65790c02ff2e7180
Diffstat (limited to 'unix/tclUnixCompat.c')
| -rw-r--r-- | unix/tclUnixCompat.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/unix/tclUnixCompat.c b/unix/tclUnixCompat.c index 84684b5..7e419cf 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 1.1.2.9 2006/09/11 16:07:45 das Exp $ + * RCS: @(#) $Id: tclUnixCompat.c,v 1.1.2.10 2006/09/12 22:05:03 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))); \ } /* |