[JGIT PATCH 1/2] Fix the UnpackedObjectCache hash function to prevent overflow
- From
Shawn O. Pearce <spearce@spearce.org>
- Date
- Sep 30, 2008, 07:47 UTC
- Message-ID
- <1222760871-58768-1-git-send-email-spearce@spearce.org>
Sometimes we got negative array indexes inside of the cache due to WindowedFile.hash having a negative value assigned by the JVM. We now use only the lower 8 bits as the cache is fixed to at most 256 entries.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org> --- .../org/spearce/jgit/lib/UnpackedObjectCache.java | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java b/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java index 03cf674..ee6a680 100644 --- a/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java +++ b/org.spearce.jgit/src/org/spearce/jgit/lib/UnpackedObjectCache.java @@ -48,9 +48,9 @@ private static int hash(final WindowedFile pack, final long position) { int h = pack.hash + (int) position; - h += h >> 16; - h += h >> 8; - return h % CACHE_SZ; + h += h >>> 16; + h += h >>> 8; + return h & (CACHE_SZ - 1); } private static int maxByteCount;
-- 1.6.0.2.463.g7f0eb