append_truncated.h (1623B)
1 // Copyright 2022 The Abseil Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef ABSL_LOG_INTERNAL_APPEND_TRUNCATED_H_ 16 #define ABSL_LOG_INTERNAL_APPEND_TRUNCATED_H_ 17 18 #include <cstddef> 19 #include <cstring> 20 21 #include "absl/base/config.h" 22 #include "absl/strings/string_view.h" 23 #include "absl/types/span.h" 24 25 namespace absl { 26 ABSL_NAMESPACE_BEGIN 27 namespace log_internal { 28 // Copies into `dst` as many bytes of `src` as will fit, then truncates the 29 // copied bytes from the front of `dst` and returns the number of bytes written. 30 inline size_t AppendTruncated(absl::string_view src, absl::Span<char> &dst) { 31 if (src.size() > dst.size()) src = src.substr(0, dst.size()); 32 memcpy(dst.data(), src.data(), src.size()); 33 dst.remove_prefix(src.size()); 34 return src.size(); 35 } 36 // Likewise, but `n` copies of `c`. 37 inline size_t AppendTruncated(char c, size_t n, absl::Span<char> &dst) { 38 if (n > dst.size()) n = dst.size(); 39 memset(dst.data(), c, n); 40 dst.remove_prefix(n); 41 return n; 42 } 43 } // namespace log_internal 44 ABSL_NAMESPACE_END 45 } // namespace absl 46 47 #endif // ABSL_LOG_INTERNAL_APPEND_TRUNCATED_H_