Fix a bug in range_map-inl.h and add a unittest to expose the exisiting bug.

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@683 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/range_map-inl.h

@@ -184,7 +184,7 @@ bool RangeMap<AddressType, EntryType>::RetrieveRangeAtIndex(
 
   *entry = iterator->second.entry();
   if (entry_base)
-    *entry_base = iterator->first;
+    *entry_base = iterator->second.base();
   if (entry_size)
     *entry_size = iterator->first - iterator->second.base() + 1;
 

src/processor/range_map_unittest.cc

@@ -325,6 +325,43 @@ static bool RetrieveIndexTest(TestMap *range_map, int set) {
   return true;
 }
 
+// Additional RetriveAtIndex test to expose the bug in RetrieveRangeAtIndex().
+// Bug info: RetrieveRangeAtIndex() previously retrieves the high address of
+// entry, however, it is supposed to retrieve the base address of entry as
+// stated in the comment in range_map.h.
+static bool RetriveAtIndexTest2() {
+  scoped_ptr<TestMap> range_map(new TestMap());
+
+  // Store ranges with base address = 2 * object_id:
+  const int range_size = 2;
+  for (int object_id = 0; object_id < 100; ++object_id) {
+    linked_ptr<CountedObject> object(new CountedObject(object_id));
+    int base_address = 2 * object_id;
+    range_map->StoreRange(base_address, range_size, object);
+  }
+
+  linked_ptr<CountedObject> object;
+  int object_count = range_map->GetCount();
+  for (int object_index = 0; object_index < object_count; ++object_index) {
+    AddressType base;
+    if (!range_map->RetrieveRangeAtIndex(object_index, &object, &base, NULL)) {
+      fprintf(stderr, "FAILED: RetrieveAtIndexTest2 index %d, "
+              "expected success, observed failure\n", object_index);
+      return false;
+    }
+
+    int expected_base = 2 * object->id();
+    if (base != expected_base) {
+      fprintf(stderr, "FAILED: RetriveAtIndexTest2 index %d, "
+              "expected base %d, observed base %d",
+              object_index, expected_base, base);
+      return false;
+    }
+  }
+
+  return true;
+}
+
 
 // RunTests runs a series of test sets.
 static bool RunTests() {
@@ -497,6 +534,11 @@ static bool RunTests() {
     }
   }
 
+  if (!RetriveAtIndexTest2()) {
+    fprintf(stderr, "FAILED: did not pass RetrieveAtIndexTest2()\n");
+    return false;
+  }
+
   return true;
 }