GCC Code Coverage Report

Directory: gridformat/
File: gridformat/common/istream_helper.hpp
Date: 2024-11-20 14:41:59
Exec Total Coverage
Lines: 87 94 92.6%
Functions: 14 14 100.0%
Branches: 35 70 50.0%
Line Branch Exec Source
1 // SPDX-FileCopyrightText: 2022-2023 Dennis Gläser <dennis.glaeser@iws.uni-stuttgart.de>
2 // SPDX-License-Identifier: MIT
3 /*!
4 * \file
5 * \ingroup Common
6 * \brief Helper for parsing data from input streams.
7 */
8 #ifndef GRIDFORMAT_COMMON_ISTREAM_HELPER_HPP_
9 #define GRIDFORMAT_COMMON_ISTREAM_HELPER_HPP_
10
11 #include <cmath>
12 #include <string>
13 #include <istream>
14 #include <optional>
15 #include <utility>
16 #include <concepts>
17 #include <iterator>
18 #include <limits>
19
20 #include <gridformat/common/exceptions.hpp>
21
22 namespace GridFormat {
23
24 /*!
25 * \ingroup Common
26 * \brief Helper for parsing data from input streams.
27 */
28 class InputStreamHelper {
29 public:
30 static constexpr std::size_t default_chunk_size = 5000;
31
32
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 105069 explicit InputStreamHelper(std::istream& s, std::string whitespace_chars = " \n\t")
33 35023 : _stream{s}
34 35023 , _whitespace_chars{std::move(whitespace_chars)}
35 35023 {}
36
37 //! Read a chunk of characters from the stream into the given buffer
38 1567415 void read_chunk_to(std::string& buffer, const std::size_t chunk_size = default_chunk_size) {
39
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 1567415 if (is_end_of_file())
40 ✗ throw IOError("End of file already reached");
41 1567415 buffer.resize(chunk_size);
42 1567415 _stream.read(buffer.data(), chunk_size);
43 1567415 _stream.clear();
44 1567415 buffer.resize(_stream.gcount());
45 1567415 }
46
47 //! Read a chunk of characters from the stream
48 1024164 std::string read_chunk(const std::size_t chunk_size = default_chunk_size) {
49
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 1024164 std::string tmp(chunk_size, ' ');
50
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 1024164 read_chunk_to(tmp, chunk_size);
51 1024164 return tmp;
52 ✗ }
53
54 //! Move the position forward until any of the given characters is found or EOF is reached
55 541888 bool shift_until_any_of(const std::string& chars, std::optional<std::size_t> max_chars = {}) {
56 541888 std::string tmp_buffer;
57 541888 std::size_t char_count = 0;
58 541888 const auto max_num_chars = max_chars.value_or(std::numeric_limits<std::size_t>::max());
59
60
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 554008 while (char_count < max_num_chars) {
61
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 541663 read_chunk_to(tmp_buffer, std::min(default_chunk_size, max_num_chars - char_count));
62 541663 const auto str_pos = tmp_buffer.find_first_of(chars);
63
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 541663 if (str_pos != std::string::npos) {
64 529117 const auto delta_pos = tmp_buffer.size() - str_pos;
65
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 529117 shift_by(-delta_pos);
66 529117 return true;
67 }
68
69
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 12546 if (is_end_of_file())
70 426 return false;
71
72 12120 char_count += tmp_buffer.size();
73 }
74
75 12345 return false;
76 541888 }
77
78 //! Read characters from the stream until any of the given characters is found or EOF is reached
79 325917 std::string read_until_any_of(const std::string& chars, std::optional<std::size_t> max_chars = {}) {
80 325917 const auto p0 = position();
81 325917 shift_until_any_of(chars, max_chars);
82 325917 const auto p1 = position();
83 325917 seek_position(p0);
84 325917 return read_chunk(p1 - p0);
85 }
86
87 //! Move the position forward until a character that is none of the given ones is found or EOF is reached
88 204429 bool shift_until_not_any_of(const std::string& chars) {
89 204429 std::string tmp_buffer;
90 while (true) {
91
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 204429 tmp_buffer = read_chunk();
92 204429 const auto pos = tmp_buffer.find_first_not_of(chars);
93
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 204429 if (pos != std::string::npos) {
94 204429 const auto delta_pos = tmp_buffer.size() - pos;
95
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 204429 shift_by(-delta_pos);
96 204429 return true;
97 }
98
99 ✗ if (is_end_of_file())
100 ✗ return false;
101 ✗ }
102 204429 }
103
104 //! Read from the stream until a character not matching any of the given characters is found or EOF is reached
105 10546 std::string read_until_not_any_of(const std::string& chars) {
106 10546 const auto p0 = position();
107 10546 shift_until_not_any_of(chars);
108 10546 const auto p1 = position();
109 10546 seek_position(p0);
110 10546 return read_chunk(p1 - p0);
111 }
112
113 //! Move the position until the given string is found or EOF is reached
114 1085 bool shift_until_substr(const std::string& substr) {
115 1085 const std::streamsize delta = -substr.size();
116 1085 const auto chunk_size = std::max(substr.size()*10, default_chunk_size);
117 1085 std::string chunk;
118 while (true) {
119
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 1588 const auto cur_pos = position();
120
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 1588 read_chunk_to(chunk, chunk_size);
121 1588 const auto substr_pos = chunk.find(substr);
122
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 1588 if (substr_pos != std::string::npos) {
123
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 1085 seek_position(cur_pos + substr_pos);
124 1085 return true;
125 }
126
127
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 503 if (is_end_of_file())
128 ✗ return false;
129
130 // shift back a bit in case the substr lies at chunk boundaries
131
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 503 shift_by(delta);
132 503 }
133 1085 }
134
135 //! Skip characters considered whitespace
136 15227 void shift_whitespace() {
137 15227 shift_until_not_any_of(_whitespace_chars);
138 15227 }
139
140 //! Skip characters until a whitespace is found
141 void shift_until_whitespace() {
142 shift_until_any_of(_whitespace_chars);
143 }
144
145 //! Jump forward in the stream by n characters
146 1060931 void shift_by(std::streamsize n) {
147 1060931 seek_position(position() + n);
148 1060931 }
149
150 //! Return the current position in the stream
151 2093130 std::streamsize position() {
152 2093130 _stream.clear();
153
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 2093130 return _stream.tellg();
154 }
155
156 //! Jump the the requested position
157 1857542 void seek_position(std::streamsize pos) {
158 1857542 _stream.clear();
159
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 1857542 _stream.seekg(pos);
160
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 1857542 if (_stream.fail())
161 ✗ throw SizeError("Given position is beyond EOF");
162 1857542 }
163
164 //! Return true if no more characters can be read from the stream
165 1650808 bool is_end_of_file() {
166 1650808 _stream.peek();
167 1650808 const bool end = _stream.eof();
168 1650808 _stream.clear();
169 1650808 return end;
170 }
171
172 1166 operator std::istream&() {
173 1166 return _stream;
174 }
175
176 private:
177 std::istream& _stream;
178 std::string _whitespace_chars;
179 };
180
181 } // end namespace GridFormat
182
183 #endif // GRIDFORMAT_COMMON_ISTREAM_HELPER_HPP_
184