Factor out the internal helper AppendTruncated, which is used and redefined in a couple places, plus several more that have yet to be released.

PiperOrigin-RevId: 486759835
Change-Id: Ib1b24f287f856ca38b691fbce7e747f0f5a34626

1 files changed, 40 insertions, 0 deletions

diff --git a/absl/log/internal/append_truncated.h b/absl/log/internal/append_truncated.h
new file mode 100644
index 00000000..096b7517
--- /dev/null
+++ b/absl/log/internal/append_truncated.h
@@ -0,0 +1,40 @@
+// Copyright 2022 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_LOG_INTERNAL_APPEND_TRUNCATED_H_
+#define ABSL_LOG_INTERNAL_APPEND_TRUNCATED_H_
+
+#include <cstddef>
+#include <cstring>
+
+#include "absl/base/config.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/span.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace log_internal {
+// Copies into `dst` as many bytes of `src` as will fit, then truncates the
+// copied bytes from the front of `dst` and returns the number of bytes written.
+inline size_t AppendTruncated(absl::string_view src, absl::Span<char> &dst) {
+  if (src.size() > dst.size()) src = src.substr(0, dst.size());
+  memcpy(dst.data(), src.data(), src.size());
+  dst.remove_prefix(src.size());
+  return src.size();
+}
+}  // namespace log_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_LOG_INTERNAL_APPEND_TRUNCATED_H_