1// Copyright 2017 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// Output extension hooks for the Format library.
16// `internal::InvokeFlush` calls the appropriate flush function for the
17// specified output argument.
18// `BufferRawSink` is a simple output sink for a char buffer. Used by SnprintF.
19// `FILERawSink` is a std::FILE* based sink. Used by PrintF and FprintF.
20
21#ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
22#define ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
23
24#include <cstdio>
25#include <ostream>
26#include <string>
27
28#include "absl/base/port.h"
29#include "absl/strings/string_view.h"
30
31class Cord;
32
33namespace absl {
34namespace str_format_internal {
35
36// RawSink implementation that writes into a char* buffer.
37// It will not overflow the buffer, but will keep the total count of chars
38// that would have been written.
39class BufferRawSink {
40 public:
41 BufferRawSink(char* buffer, size_t size) : buffer_(buffer), size_(size) {}
42
43 size_t total_written() const { return total_written_; }
44 void Write(string_view v);
45
46 private:
47 char* buffer_;
48 size_t size_;
49 size_t total_written_ = 0;
50};
51
52// RawSink implementation that writes into a FILE*.
53// It keeps track of the total number of bytes written and any error encountered
54// during the writes.
55class FILERawSink {
56 public:
57 explicit FILERawSink(std::FILE* output) : output_(output) {}
58
59 void Write(string_view v);
60
61 size_t count() const { return count_; }
62 int error() const { return error_; }
63
64 private:
65 std::FILE* output_;
66 int error_ = 0;
67 size_t count_ = 0;
68};
69
70// Provide RawSink integration with common types from the STL.
71inline void AbslFormatFlush(std::string* out, string_view s) {
72 out->append(s.data(), s.size());
73}
74inline void AbslFormatFlush(std::ostream* out, string_view s) {
75 out->write(s.data(), s.size());
76}
77
78template <class AbslCord, typename = typename std::enable_if<
79 std::is_same<AbslCord, ::Cord>::value>::type>
80inline void AbslFormatFlush(AbslCord* out, string_view s) {
81 out->Append(s);
82}
83
84inline void AbslFormatFlush(FILERawSink* sink, string_view v) {
85 sink->Write(v);
86}
87
88inline void AbslFormatFlush(BufferRawSink* sink, string_view v) {
89 sink->Write(v);
90}
91
92template <typename T>
93auto InvokeFlush(T* out, string_view s)
94 -> decltype(str_format_internal::AbslFormatFlush(out, s)) {
95 str_format_internal::AbslFormatFlush(out, s);
96}
97
98} // namespace str_format_internal
99} // namespace absl
100
101#endif // ABSL_STRINGS_INTERNAL_STR_FORMAT_OUTPUT_H_
102