Abseil Common Libraries (C++) (grcp 依赖)
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97 lines
2.8 KiB
97 lines
2.8 KiB
// Copyright 2017 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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// |
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// Output extension hooks for the Format library. |
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// `internal::InvokeFlush` calls the appropriate flush function for the |
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// specified output argument. |
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// `BufferRawSink` is a simple output sink for a char buffer. Used by SnprintF. |
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// `FILERawSink` is a std::FILE* based sink. Used by PrintF and FprintF. |
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#ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_ |
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#define ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_ |
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#include <cstdio> |
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#include <ios> |
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#include <ostream> |
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#include <string> |
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#include "absl/base/port.h" |
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#include "absl/strings/string_view.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace str_format_internal { |
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// RawSink implementation that writes into a char* buffer. |
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// It will not overflow the buffer, but will keep the total count of chars |
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// that would have been written. |
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class BufferRawSink { |
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public: |
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BufferRawSink(char* buffer, size_t size) : buffer_(buffer), size_(size) {} |
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size_t total_written() const { return total_written_; } |
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void Write(string_view v); |
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private: |
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char* buffer_; |
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size_t size_; |
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size_t total_written_ = 0; |
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}; |
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// RawSink implementation that writes into a FILE*. |
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// It keeps track of the total number of bytes written and any error encountered |
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// during the writes. |
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class FILERawSink { |
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public: |
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explicit FILERawSink(std::FILE* output) : output_(output) {} |
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void Write(string_view v); |
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size_t count() const { return count_; } |
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int error() const { return error_; } |
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private: |
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std::FILE* output_; |
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int error_ = 0; |
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size_t count_ = 0; |
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}; |
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// Provide RawSink integration with common types from the STL. |
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inline void AbslFormatFlush(std::string* out, string_view s) { |
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out->append(s.data(), s.size()); |
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} |
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inline void AbslFormatFlush(std::ostream* out, string_view s) { |
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out->write(s.data(), static_cast<std::streamsize>(s.size())); |
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} |
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inline void AbslFormatFlush(FILERawSink* sink, string_view v) { |
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sink->Write(v); |
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} |
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inline void AbslFormatFlush(BufferRawSink* sink, string_view v) { |
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sink->Write(v); |
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} |
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// This is a SFINAE to get a better compiler error message when the type |
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// is not supported. |
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template <typename T> |
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auto InvokeFlush(T* out, string_view s) -> decltype(AbslFormatFlush(out, s)) { |
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AbslFormatFlush(out, s); |
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} |
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} // namespace str_format_internal |
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ABSL_NAMESPACE_END |
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} // namespace absl |
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#endif // ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
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