On 09/18/12 21:55, Eric Blake wrote:
Commit 0fc89098 used functions only available on glibc, completely
botched 32-bit environments, and risked SIGBUS due to unaligned
memory access on platforms that aren't as forgiving as x86_64.
* bootstrap.conf (gnulib_modules): Import ffsl.
* src/util/bitmap.c (includes): Use <strings.h> for ffsl.
(virBitmapNewData, virBitmapToData): Avoid 64-bit assumptions and
non-portable functions.
---
I wish I could push this under the build-breaker rule, but it is
not quite trivial enough.
Indeed. Bit magic never was trivial :).
bootstrap.conf | 1 +
src/util/bitmap.c | 38 +++++++++++++++++++++++++++-----------
2 files changed, 28 insertions(+), 11 deletions(-)
diff --git a/src/util/bitmap.c b/src/util/bitmap.c
index 51e567a..4bade6c 100644
--- a/src/util/bitmap.c
+++ b/src/util/bitmap.c
@@ -418,15 +419,23 @@ virBitmapPtr virBitmapNewCopy(virBitmapPtr src)
virBitmapPtr virBitmapNewData(void *data, int len)
{
virBitmapPtr bitmap;
- int i;
+ int i, j;
+ unsigned long *p;
+ unsigned char *bytes = data;
bitmap = virBitmapNew(len * CHAR_BIT);
if (!bitmap)
return NULL;
- memcpy(bitmap->map, data, len);
- for (i = 0; i < bitmap->map_len; i++)
- bitmap->map[i] = le64toh(bitmap->map[i]);
+ /* le64toh is not provided by gnulib, so we do the conversion by hand */
+ p = bitmap->map;
+ for (i = j = 0; i < len; i++, j++) {
+ if (j == sizeof(*p)) {
Incrementing a variable is probably better than calculating modulo.
+ j = 0;
+ p++;
+ }
+ *p |= bytes[i] << (j * CHAR_BIT);
+ }
return bitmap;
}
ACK. If there isn't a bug in my "brain simulation unit" then this should
work as intended.
Peter
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