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// Copyright 2017 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.
//
// Output extension hooks for the Format library.
// `internal::InvokeFlush` calls the appropriate flush function for the
// specified output argument.
// `BufferRawSink` is a simple output sink for a char buffer. Used by SnprintF.
// `FILERawSink` is a std::FILE* based sink. Used by PrintF and FprintF.
#ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
#define ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
#include <cstdio>
#include <ostream>
#include <string>
#include "absl/base/port.h"
#include "absl/strings/string_view.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
class Cord;
namespace str_format_internal {
// RawSink implementation that writes into a char* buffer.
// It will not overflow the buffer, but will keep the total count of chars
// that would have been written.
class BufferRawSink {
public:
BufferRawSink(char* buffer, size_t size) : buffer_(buffer), size_(size) {}
size_t total_written() const { return total_written_; }
void Write(string_view v);
private:
char* buffer_;
size_t size_;
size_t total_written_ = 0;
};
// RawSink implementation that writes into a FILE*.
// It keeps track of the total number of bytes written and any error encountered
// during the writes.
class FILERawSink {
public:
explicit FILERawSink(std::FILE* output) : output_(output) {}
void Write(string_view v);
size_t count() const { return count_; }
int error() const { return error_; }
private:
std::FILE* output_;
int error_ = 0;
size_t count_ = 0;
};
// Provide RawSink integration with common types from the STL.
inline void AbslFormatFlush(std::string* out, string_view s) {
out->append(s.data(), s.size());
}
inline void AbslFormatFlush(std::ostream* out, string_view s) {
out->write(s.data(), s.size());
}
template <class AbslCord, typename = typename std::enable_if<
std::is_same<AbslCord, absl::Cord>::value>::type>
inline void AbslFormatFlush(AbslCord* out, string_view s) {
out->Append(s);
}
inline void AbslFormatFlush(FILERawSink* sink, string_view v) {
sink->Write(v);
}
inline void AbslFormatFlush(BufferRawSink* sink, string_view v) {
sink->Write(v);
}
// This is a SFINAE to get a better compiler error message when the type
// is not supported.
template <typename T>
auto InvokeFlush(T* out, string_view s) -> decltype(AbslFormatFlush(out, s)) {
AbslFormatFlush(out, s);
}
} // namespace str_format_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
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