UTF-8 encoding library to support Rust Punycode decoding.

PiperOrigin-RevId: 641983507
Change-Id: Iad7933884aef6bfd90d159c049a1d698d19456c6

1 files changed, 47 insertions, 0 deletions

diff --git a/absl/debugging/internal/utf8_for_code_point.h b/absl/debugging/internal/utf8_for_code_point.h
new file mode 100644
index 00000000..f23cde6d
--- /dev/null
+++ b/absl/debugging/internal/utf8_for_code_point.h
@@ -0,0 +1,47 @@
+// Copyright 2024 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.
+
+#ifndef ABSL_DEBUGGING_INTERNAL_UTF8_FOR_CODE_POINT_H_
+#define ABSL_DEBUGGING_INTERNAL_UTF8_FOR_CODE_POINT_H_
+
+#include <cstdint>
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace debugging_internal {
+
+struct Utf8ForCodePoint {
+  // Converts a Unicode code point to the corresponding UTF-8 byte sequence.
+  // Async-signal-safe to support use in symbolizing stack traces from a signal
+  // handler.
+  explicit Utf8ForCodePoint(uint64_t code_point);
+
+  // Returns true if the constructor's code_point argument was valid.
+  bool ok() const { return length != 0; }
+
+  // If code_point was in range, then 1 <= length <= 4, and the UTF-8 encoding
+  // is found in bytes[0 .. (length - 1)].  If code_point was invalid, then
+  // length == 0.  In either case, the contents of bytes[length .. 3] are
+  // unspecified.
+  char bytes[4] = {};
+  uint32_t length = 0;
+};
+
+}  // namespace debugging_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_DEBUGGING_INTERNAL_UTF8_FOR_CODE_POINT_H_