[JGIT PATCH 1/2] Fix the UnpackedObjectCache hash function to prevent overflow
From: Shawn O. Pearce <hidden>
Date: 2016-06-15 22:45:25
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 <redacted> --- .../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;
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1.6.0.2.463.g7f0eb