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39 * \author Teemu Murtola <teemu.murtola@gmail.com>
41 * \ingroup module_utility
43 #ifndef GMX_UTILITY_FILE_H
44 #define GMX_UTILITY_FILE_H
50 #include "gromacs/utility/classhelpers.h"
58 * This class provides basic file I/O functionality and uses exceptions
59 * (FileIOError) for error reporting.
62 * \ingroup module_utility
68 * Opens a file and returns a `FILE` handle.
70 * \param[in] filename Path of the file to open.
71 * \param[in] mode Mode to open the file in (for fopen()).
72 * \throws FileIOError on any I/O error.
74 * Instead of returning `NULL` on errors, throws an exception with
75 * additional details (including the file name and `errno`).
77 static FILE *openRawHandle(const char *filename, const char *mode);
78 //! \copydoc openRawHandle(const char *, const char *)
79 static FILE *openRawHandle(const std::string &filename, const char *mode);
81 * Creates a file object and opens a file.
83 * \param[in] filename Path of the file to open.
84 * \param[in] mode Mode to open the file in (for fopen()).
85 * \throws std::bad_alloc if out of memory.
86 * \throws FileIOError on any I/O error.
88 * \see open(const char *, const char *)
90 File(const char *filename, const char *mode);
91 //! \copydoc File(const char *, const char *)
92 File(const std::string &filename, const char *mode);
94 * Destroys the file object.
96 * If the file is still open, it is closed.
97 * Any error conditions will be ignored.
104 * \param[in] filename Path of the file to open.
105 * \param[in] mode Mode to open the file in (for fopen()).
106 * \throws FileIOError on any I/O error.
108 * The file object must not be open.
110 void open(const char *filename, const char *mode);
111 //! \copydoc open(const char *, const char *)
112 void open(const std::string &filename, const char *mode);
114 * Closes the file object.
116 * \throws FileIOError on any I/O error.
118 * The file must be open.
123 * Returns whether the file is an interactive terminal.
125 * Only works on Unix, otherwise always returns true.
126 * It only makes sense to call this for File::standardInput() and
129 * Thie file must be open.
132 bool isInteractive() const;
134 * Returns a file handle for interfacing with C functions.
136 * The file must be open.
142 * Reads given number of bytes from the file.
144 * \param[out] buffer Pointer to buffer that receives the bytes.
145 * \param[in] bytes Number of bytes to read.
146 * \throws FileIOError on any I/O error.
148 * The file must be open.
150 void readBytes(void *buffer, size_t bytes);
152 * Reads a single line from the file.
154 * \param[out] line String to receive the line.
155 * \returns false if nothing was read because the file ended.
156 * \throws std::bad_alloc if out of memory.
157 * \throws FileIOError on any I/O error.
159 * On error or when false is returned, \p line will be empty.
160 * Trailing space will be removed from the line.
161 * To loop over all lines in the file, use:
164 while (file.readLine(&line))
170 bool readLine(std::string *line);
172 * Reads a single line from the file.
174 * \param[out] line String to receive the line.
175 * \returns false if nothing was read because the file ended.
176 * \throws std::bad_alloc if out of memory.
177 * \throws FileIOError on any I/O error.
179 * On error or when false is returned, \p line will be empty.
180 * Works as readLine(), except that terminating newline will be present
181 * in \p line if it was present in the file.
185 bool readLineWithTrailingSpace(std::string *line);
188 * Writes a string to the file.
190 * \param[in] str String to write.
191 * \throws FileIOError on any I/O error.
193 * The file must be open.
195 void writeString(const char *str);
196 //! \copydoc writeString(const char *)
197 void writeString(const std::string &str) { writeString(str.c_str()); }
199 * Writes a line to the file.
201 * \param[in] line Line to write.
202 * \throws FileIOError on any I/O error.
204 * If \p line does not end in a newline, one newline is appended.
205 * Otherwise, works as writeString().
207 * The file must be open.
209 void writeLine(const char *line);
210 //! \copydoc writeLine(const char *)
211 void writeLine(const std::string &line) { writeLine(line.c_str()); }
213 * Writes a newline to the file.
215 * \throws FileIOError on any I/O error.
220 * Checks whether a file exists and is a regular file.
222 * \param[in] filename Path to the file to check.
223 * \returns true if \p filename exists and is accessible.
227 static bool exists(const char *filename);
228 //! \copydoc exists(const char *)
229 static bool exists(const std::string &filename);
232 * Returns a File object for accessing stdin.
234 * \throws std::bad_alloc if out of memory (only on first call).
236 static File &standardInput();
238 * Returns a File object for accessing stdout.
240 * \throws std::bad_alloc if out of memory (only on first call).
242 static File &standardOutput();
244 * Returns a File object for accessing stderr.
246 * \throws std::bad_alloc if out of memory (only on first call).
248 static File &standardError();
251 * Reads contents of a file to a std::string.
253 * \param[in] filename Name of the file to read.
254 * \returns The contents of \p filename.
255 * \throws std::bad_alloc if out of memory.
256 * \throws FileIOError on any I/O error.
258 static std::string readToString(const char *filename);
259 //! \copydoc readToString(const char *)
260 static std::string readToString(const std::string &filename);
262 * Convenience method for writing a file from a string in a single call.
264 * \param[in] filename Name of the file to read.
265 * \param[in] text String to write to \p filename.
266 * \throws FileIOError on any I/O error.
268 * If \p filename exists, it is overwritten.
270 static void writeFileFromString(const std::string &filename,
271 const std::string &text);
275 * Initialize file object from an existing file handle.
277 * \param[in] fp %File handle to use (may be NULL).
278 * \param[in] bClose Whether this object should close its file handle.
279 * \throws std::bad_alloc if out of memory.
281 * Used internally to implement standardOutput() and standardError().
283 File(FILE *fp, bool bClose);
287 PrivateImplPointer<Impl> impl_;