git.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Shawn O. Pearce" <spearce@spearce.org>
To: Robin Rosenberg <robin.rosenberg@dewire.com>
Cc: Matthias Sohn <matthias.sohn@sap.com>, git@vger.kernel.org
Subject: [JGIT PATCH] Fix more computation of integer average overflows
Date: Mon, 27 Apr 2009 16:14:30 -0700	[thread overview]
Message-ID: <1240874070-10562-1-git-send-email-spearce@spearce.org> (raw)

In 1d99aaab8e364c6ad722437e43c77fd54e13b071 Matthias Sohn pointed
out that (low+high)/2 can overflow, so (low+high)>>>1 is a better
choice when the result will be used as an array index.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---

 I guess we need this too then, eh?

 .../src/org/spearce/jgit/lib/PackIndexV1.java      |    2 +-
 .../src/org/spearce/jgit/lib/PackIndexV2.java      |    6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV1.java b/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV1.java
index fdaa094..0ad29e1 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV1.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV1.java
@@ -129,7 +129,7 @@ long findOffset(final AnyObjectId objId) {
 		int high = data.length / (4 + Constants.OBJECT_ID_LENGTH);
 		int low = 0;
 		do {
-			final int mid = (low + high) / 2;
+			final int mid = (low + high) >>> 1;
 			final int pos = ((4 + Constants.OBJECT_ID_LENGTH) * mid) + 4;
 			final int cmp = objId.compareTo(data, pos);
 			if (cmp < 0)
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV2.java b/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV2.java
index eb56ed9..b539547 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV2.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/PackIndexV2.java
@@ -108,7 +108,7 @@ PackIndexV2(final InputStream fd) throws IOException {
 
 			final int intNameLen = (int) nameLen;
 			final byte[] raw = new byte[intNameLen];
-			final int[] bin = new int[intNameLen >> 2];
+			final int[] bin = new int[intNameLen >>> 2];
 			NB.readFully(fd, raw, 0, raw.length);
 			for (int i = 0; i < bin.length; i++)
 				bin[i] = NB.decodeInt32(raw, i << 2);
@@ -212,12 +212,12 @@ boolean hasCRC32Support() {
 
 	private int binarySearchLevelTwo(final AnyObjectId objId, final int levelOne) {
 		final int[] data = names[levelOne];
-		int high = offset32[levelOne].length >> 2;
+		int high = offset32[levelOne].length >>> 2;
 		if (high == 0)
 			return -1;
 		int low = 0;
 		do {
-			final int mid = (low + high) >> 1;
+			final int mid = (low + high) >>> 1;
 			final int mid4 = mid << 2;
 			final int cmp;
 
-- 
1.6.3.rc1.205.g37f8

                 reply	other threads:[~2009-04-27 23:14 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1240874070-10562-1-git-send-email-spearce@spearce.org \
    --to=spearce@spearce.org \
    --cc=git@vger.kernel.org \
    --cc=matthias.sohn@sap.com \
    --cc=robin.rosenberg@dewire.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).