From b122c0cec2b449a0dd126307729249c72a570328 Mon Sep 17 00:00:00 2001
From: "rtenneti@chromium.org"
 <rtenneti@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Wed, 23 Feb 2011 22:31:18 +0000
Subject: Added CHECKs to make sure histogram caller's don't create histogram
 that are larger 1G. Added CHECK's to catch bucket_count_ is not corrupted
 before accessing ranges_ vector.

BUG=73452
TEST=none. histogram unit tests are enough.

Review URL: http://codereview.chromium.org/6542034

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@75804 0039d316-1c4b-4281-b951-d872f2087c98
---
 base/metrics/histogram.cc | 8 ++++++--
 base/metrics/histogram.h  | 2 ++
 2 files changed, 8 insertions(+), 2 deletions(-)

(limited to 'base/metrics')

diff --git a/base/metrics/histogram.cc b/base/metrics/histogram.cc
index a308932..6ac92ed 100644
--- a/base/metrics/histogram.cc
+++ b/base/metrics/histogram.cc
@@ -23,6 +23,9 @@ namespace base {
 
 typedef Histogram::Count Count;
 
+// static
+const size_t Histogram::kBucketCount_MAX = 10000u;
+
 scoped_refptr<Histogram> Histogram::FactoryGet(const std::string& name,
     Sample minimum, Sample maximum, size_t bucket_count, Flags flags) {
   scoped_refptr<Histogram> histogram(NULL);
@@ -413,7 +416,7 @@ size_t Histogram::BucketIndex(Sample value) const {
 
   do {
     DCHECK_GE(over, under);
-    mid = (over + under)/2;
+    mid = under + (over - under)/2;
     if (mid == under)
       break;
     if (ranges(mid) <= value)
@@ -423,7 +426,7 @@ size_t Histogram::BucketIndex(Sample value) const {
   } while (true);
 
   DCHECK_LE(ranges(mid), value);
-  DCHECK_GT(ranges(mid+1), value);
+  CHECK_GT(ranges(mid+1), value);
   return mid;
 }
 
@@ -483,6 +486,7 @@ void Histogram::Initialize() {
     declared_max_ = kSampleType_MAX - 1;
   DCHECK_LE(declared_min_, declared_max_);
   DCHECK_GT(bucket_count_, 1u);
+  CHECK_LT(bucket_count_, kBucketCount_MAX);
   size_t maximal_bucket_count = declared_max_ - declared_min_ + 2;
   DCHECK_LE(bucket_count_, maximal_bucket_count);
   DCHECK_EQ(0, ranges_[0]);
diff --git a/base/metrics/histogram.h b/base/metrics/histogram.h
index 3bb3f030..2ec56e6 100644
--- a/base/metrics/histogram.h
+++ b/base/metrics/histogram.h
@@ -241,6 +241,8 @@ class Histogram : public base::RefCountedThreadSafe<Histogram> {
   typedef int Sample;  // Used for samples (and ranges of samples).
   typedef int Count;  // Used to count samples in a bucket.
   static const Sample kSampleType_MAX = INT_MAX;
+  // Initialize maximum number of buckets in histograms as 10,000.
+  static const size_t kBucketCount_MAX;
 
   typedef std::vector<Count> Counts;
   typedef std::vector<Sample> Ranges;
-- 
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