Add 'third_party/abseil_cpp/' from commit '768eb2ca2857342673fcd462792ce04b8bac3fa3' r/781

git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54beb5796cd408fbe15d2d2da09ff37adf
git-subtree-split: 768eb2ca2857342673fcd462792ce04b8bac3fa3

1 files changed, 40 insertions, 0 deletions

diff --git a/third_party/abseil_cpp/absl/strings/internal/pow10_helper.h b/third_party/abseil_cpp/absl/strings/internal/pow10_helper.h
new file mode 100644
index 000000000000..c37c2c3ffee5
--- /dev/null
+++ b/third_party/abseil_cpp/absl/strings/internal/pow10_helper.h
@@ -0,0 +1,40 @@
+//
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// This test helper library contains a table of powers of 10, to guarantee
+// precise values are computed across the full range of doubles. We can't rely
+// on the pow() function, because not all standard libraries ship a version
+// that is precise.
+#ifndef ABSL_STRINGS_INTERNAL_POW10_HELPER_H_
+#define ABSL_STRINGS_INTERNAL_POW10_HELPER_H_
+
+#include <vector>
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace strings_internal {
+
+// Computes the precise value of 10^exp. (I.e. the nearest representable
+// double to the exact value, rounding to nearest-even in the (single) case of
+// being exactly halfway between.)
+double Pow10(int exp);
+
+}  // namespace strings_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STRINGS_INTERNAL_POW10_HELPER_H_