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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 * Parameters for creating a File object.
60 * This class (mostly) replaces the ability to return a File object from a
61 * function (since File is not copyable): returning a FileInitializer instead
62 * allows the caller to construct the File object.
65 * \ingroup module_utility
71 * Creates the initializer with given parameters.
73 * The passed strings must remain valid until the initializer is used
74 * to construct a File object.
76 FileInitializer(const char *filename, const char *mode)
77 : filename_(filename), mode_(mode)
82 const char *filename_;
86 * Needed to allow access to the parameters without otherwise
87 * unnecessary accessors.
95 * This class provides basic file I/O functionality and uses exceptions
96 * (FileIOError) for error reporting.
99 * \ingroup module_utility
105 * Opens a file and returns a `FILE` handle.
107 * \param[in] filename Path of the file to open.
108 * \param[in] mode Mode to open the file in (for fopen()).
109 * \throws FileIOError on any I/O error.
111 * Instead of returning `NULL` on errors, throws an exception with
112 * additional details (including the file name and `errno`).
114 static FILE *openRawHandle(const char *filename, const char *mode);
115 //! \copydoc openRawHandle(const char *, const char *)
116 static FILE *openRawHandle(const std::string &filename, const char *mode);
118 * Creates a file object and opens a file.
120 * \param[in] filename Path of the file to open.
121 * \param[in] mode Mode to open the file in (for fopen()).
122 * \throws std::bad_alloc if out of memory.
123 * \throws FileIOError on any I/O error.
125 * \see open(const char *, const char *)
127 File(const char *filename, const char *mode);
128 //! \copydoc File(const char *, const char *)
129 File(const std::string &filename, const char *mode);
131 * Creates a file object and opens a file.
133 * \param[in] initializer Parameters to open the file.
134 * \throws std::bad_alloc if out of memory.
135 * \throws FileIOError on any I/O error.
137 File(const FileInitializer &initializer);
139 * Destroys the file object.
141 * If the file is still open, it is closed.
142 * Any error conditions will be ignored.
149 * \param[in] filename Path of the file to open.
150 * \param[in] mode Mode to open the file in (for fopen()).
151 * \throws FileIOError on any I/O error.
153 * The file object must not be open.
155 void open(const char *filename, const char *mode);
156 //! \copydoc open(const char *, const char *)
157 void open(const std::string &filename, const char *mode);
159 * Closes the file object.
161 * \throws FileIOError on any I/O error.
163 * The file must be open.
168 * Returns whether the file is an interactive terminal.
170 * Only works on Unix, otherwise always returns true.
171 * It only makes sense to call this for File::standardInput() and
174 * Thie file must be open.
177 bool isInteractive() const;
179 * Returns a file handle for interfacing with C functions.
181 * The file must be open.
187 * Reads given number of bytes from the file.
189 * \param[out] buffer Pointer to buffer that receives the bytes.
190 * \param[in] bytes Number of bytes to read.
191 * \throws FileIOError on any I/O error.
193 * The file must be open.
195 void readBytes(void *buffer, size_t bytes);
197 * Reads a single line from the file.
199 * \param[out] line String to receive the line.
200 * \returns false if nothing was read because the file ended.
201 * \throws std::bad_alloc if out of memory.
202 * \throws FileIOError on any I/O error.
204 * On error or when false is returned, \p line will be empty.
205 * Trailing space will be removed from the line.
206 * To loop over all lines in the file, use:
209 while (file.readLine(&line))
215 bool readLine(std::string *line);
217 * Reads a single line from the file.
219 * \param[out] line String to receive the line.
220 * \returns false if nothing was read because the file ended.
221 * \throws std::bad_alloc if out of memory.
222 * \throws FileIOError on any I/O error.
224 * On error or when false is returned, \p line will be empty.
225 * Works as readLine(), except that terminating newline will be present
226 * in \p line if it was present in the file.
230 bool readLineWithTrailingSpace(std::string *line);
233 * Writes a string to the file.
235 * \param[in] str String to write.
236 * \throws FileIOError on any I/O error.
238 * The file must be open.
240 void writeString(const char *str);
241 //! \copydoc writeString(const char *)
242 void writeString(const std::string &str) { writeString(str.c_str()); }
244 * Writes a line to the file.
246 * \param[in] line Line to write.
247 * \throws FileIOError on any I/O error.
249 * If \p line does not end in a newline, one newline is appended.
250 * Otherwise, works as writeString().
252 * The file must be open.
254 void writeLine(const char *line);
255 //! \copydoc writeLine(const char *)
256 void writeLine(const std::string &line) { writeLine(line.c_str()); }
258 * Writes a newline to the file.
260 * \throws FileIOError on any I/O error.
265 * Checks whether a file exists and is a regular file.
267 * \param[in] filename Path to the file to check.
268 * \returns true if \p filename exists and is accessible.
272 static bool exists(const char *filename);
273 //! \copydoc exists(const char *)
274 static bool exists(const std::string &filename);
277 * Returns a File object for accessing stdin.
279 * \throws std::bad_alloc if out of memory (only on first call).
281 static File &standardInput();
283 * Returns a File object for accessing stdout.
285 * \throws std::bad_alloc if out of memory (only on first call).
287 static File &standardOutput();
289 * Returns a File object for accessing stderr.
291 * \throws std::bad_alloc if out of memory (only on first call).
293 static File &standardError();
296 * Reads contents of a file to a std::string.
298 * \param[in] filename Name of the file to read.
299 * \returns The contents of \p filename.
300 * \throws std::bad_alloc if out of memory.
301 * \throws FileIOError on any I/O error.
303 static std::string readToString(const char *filename);
304 //! \copydoc readToString(const char *)
305 static std::string readToString(const std::string &filename);
307 * Convenience method for writing a file from a string in a single call.
309 * \param[in] filename Name of the file to read.
310 * \param[in] text String to write to \p filename.
311 * \throws FileIOError on any I/O error.
313 * If \p filename exists, it is overwritten.
315 static void writeFileFromString(const std::string &filename,
316 const std::string &text);
320 * Initialize file object from an existing file handle.
322 * \param[in] fp %File handle to use (may be NULL).
323 * \param[in] bClose Whether this object should close its file handle.
324 * \throws std::bad_alloc if out of memory.
326 * Used internally to implement standardOutput() and standardError().
328 File(FILE *fp, bool bClose);
332 PrivateImplPointer<Impl> impl_;