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Diffstat (limited to 'lib/python2.7/fileinput.py')
-rw-r--r-- | lib/python2.7/fileinput.py | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/lib/python2.7/fileinput.py b/lib/python2.7/fileinput.py new file mode 100644 index 0000000..b2e2f05 --- /dev/null +++ b/lib/python2.7/fileinput.py @@ -0,0 +1,405 @@ +"""Helper class to quickly write a loop over all standard input files. + +Typical use is: + + import fileinput + for line in fileinput.input(): + process(line) + +This iterates over the lines of all files listed in sys.argv[1:], +defaulting to sys.stdin if the list is empty. If a filename is '-' it +is also replaced by sys.stdin. To specify an alternative list of +filenames, pass it as the argument to input(). A single file name is +also allowed. + +Functions filename(), lineno() return the filename and cumulative line +number of the line that has just been read; filelineno() returns its +line number in the current file; isfirstline() returns true iff the +line just read is the first line of its file; isstdin() returns true +iff the line was read from sys.stdin. Function nextfile() closes the +current file so that the next iteration will read the first line from +the next file (if any); lines not read from the file will not count +towards the cumulative line count; the filename is not changed until +after the first line of the next file has been read. Function close() +closes the sequence. + +Before any lines have been read, filename() returns None and both line +numbers are zero; nextfile() has no effect. After all lines have been +read, filename() and the line number functions return the values +pertaining to the last line read; nextfile() has no effect. + +All files are opened in text mode by default, you can override this by +setting the mode parameter to input() or FileInput.__init__(). +If an I/O error occurs during opening or reading a file, the IOError +exception is raised. + +If sys.stdin is used more than once, the second and further use will +return no lines, except perhaps for interactive use, or if it has been +explicitly reset (e.g. using sys.stdin.seek(0)). + +Empty files are opened and immediately closed; the only time their +presence in the list of filenames is noticeable at all is when the +last file opened is empty. + +It is possible that the last line of a file doesn't end in a newline +character; otherwise lines are returned including the trailing +newline. + +Class FileInput is the implementation; its methods filename(), +lineno(), fileline(), isfirstline(), isstdin(), nextfile() and close() +correspond to the functions in the module. In addition it has a +readline() method which returns the next input line, and a +__getitem__() method which implements the sequence behavior. The +sequence must be accessed in strictly sequential order; sequence +access and readline() cannot be mixed. + +Optional in-place filtering: if the keyword argument inplace=1 is +passed to input() or to the FileInput constructor, the file is moved +to a backup file and standard output is directed to the input file. +This makes it possible to write a filter that rewrites its input file +in place. If the keyword argument backup=".<some extension>" is also +given, it specifies the extension for the backup file, and the backup +file remains around; by default, the extension is ".bak" and it is +deleted when the output file is closed. In-place filtering is +disabled when standard input is read. XXX The current implementation +does not work for MS-DOS 8+3 filesystems. + +XXX Possible additions: + +- optional getopt argument processing +- isatty() +- read(), read(size), even readlines() + +""" + +import sys, os + +__all__ = ["input","close","nextfile","filename","lineno","filelineno", + "isfirstline","isstdin","FileInput"] + +_state = None + +# No longer used +DEFAULT_BUFSIZE = 8*1024 + +def input(files=None, inplace=0, backup="", bufsize=0, + mode="r", openhook=None): + """Return an instance of the FileInput class, which can be iterated. + + The parameters are passed to the constructor of the FileInput class. + The returned instance, in addition to being an iterator, + keeps global state for the functions of this module,. + """ + global _state + if _state and _state._file: + raise RuntimeError, "input() already active" + _state = FileInput(files, inplace, backup, bufsize, mode, openhook) + return _state + +def close(): + """Close the sequence.""" + global _state + state = _state + _state = None + if state: + state.close() + +def nextfile(): + """ + Close the current file so that the next iteration will read the first + line from the next file (if any); lines not read from the file will + not count towards the cumulative line count. The filename is not + changed until after the first line of the next file has been read. + Before the first line has been read, this function has no effect; + it cannot be used to skip the first file. After the last line of the + last file has been read, this function has no effect. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.nextfile() + +def filename(): + """ + Return the name of the file currently being read. + Before the first line has been read, returns None. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.filename() + +def lineno(): + """ + Return the cumulative line number of the line that has just been read. + Before the first line has been read, returns 0. After the last line + of the last file has been read, returns the line number of that line. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.lineno() + +def filelineno(): + """ + Return the line number in the current file. Before the first line + has been read, returns 0. After the last line of the last file has + been read, returns the line number of that line within the file. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.filelineno() + +def fileno(): + """ + Return the file number of the current file. When no file is currently + opened, returns -1. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.fileno() + +def isfirstline(): + """ + Returns true the line just read is the first line of its file, + otherwise returns false. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.isfirstline() + +def isstdin(): + """ + Returns true if the last line was read from sys.stdin, + otherwise returns false. + """ + if not _state: + raise RuntimeError, "no active input()" + return _state.isstdin() + +class FileInput: + """FileInput([files[, inplace[, backup[, bufsize[, mode[, openhook]]]]]]) + + Class FileInput is the implementation of the module; its methods + filename(), lineno(), fileline(), isfirstline(), isstdin(), fileno(), + nextfile() and close() correspond to the functions of the same name + in the module. + In addition it has a readline() method which returns the next + input line, and a __getitem__() method which implements the + sequence behavior. The sequence must be accessed in strictly + sequential order; random access and readline() cannot be mixed. + """ + + def __init__(self, files=None, inplace=0, backup="", bufsize=0, + mode="r", openhook=None): + if isinstance(files, basestring): + files = (files,) + else: + if files is None: + files = sys.argv[1:] + if not files: + files = ('-',) + else: + files = tuple(files) + self._files = files + self._inplace = inplace + self._backup = backup + self._savestdout = None + self._output = None + self._filename = None + self._startlineno = 0 + self._filelineno = 0 + self._file = None + self._isstdin = False + self._backupfilename = None + # restrict mode argument to reading modes + if mode not in ('r', 'rU', 'U', 'rb'): + raise ValueError("FileInput opening mode must be one of " + "'r', 'rU', 'U' and 'rb'") + self._mode = mode + if inplace and openhook: + raise ValueError("FileInput cannot use an opening hook in inplace mode") + elif openhook and not hasattr(openhook, '__call__'): + raise ValueError("FileInput openhook must be callable") + self._openhook = openhook + + def __del__(self): + self.close() + + def close(self): + try: + self.nextfile() + finally: + self._files = () + + def __iter__(self): + return self + + def next(self): + while 1: + line = self._readline() + if line: + self._filelineno += 1 + return line + if not self._file: + raise StopIteration + self.nextfile() + # repeat with next file + + def __getitem__(self, i): + if i != self.lineno(): + raise RuntimeError, "accessing lines out of order" + try: + return self.next() + except StopIteration: + raise IndexError, "end of input reached" + + def nextfile(self): + savestdout = self._savestdout + self._savestdout = 0 + if savestdout: + sys.stdout = savestdout + + output = self._output + self._output = 0 + try: + if output: + output.close() + finally: + file = self._file + self._file = None + try: + del self._readline # restore FileInput._readline + except AttributeError: + pass + try: + if file and not self._isstdin: + file.close() + finally: + backupfilename = self._backupfilename + self._backupfilename = 0 + if backupfilename and not self._backup: + try: os.unlink(backupfilename) + except OSError: pass + + self._isstdin = False + + def readline(self): + while 1: + line = self._readline() + if line: + self._filelineno += 1 + return line + if not self._file: + return line + self.nextfile() + # repeat with next file + + def _readline(self): + if not self._files: + return "" + self._filename = self._files[0] + self._files = self._files[1:] + self._startlineno = self.lineno() + self._filelineno = 0 + self._file = None + self._isstdin = False + self._backupfilename = 0 + if self._filename == '-': + self._filename = '<stdin>' + self._file = sys.stdin + self._isstdin = True + else: + if self._inplace: + self._backupfilename = ( + self._filename + (self._backup or os.extsep+"bak")) + try: os.unlink(self._backupfilename) + except os.error: pass + # The next few lines may raise IOError + os.rename(self._filename, self._backupfilename) + self._file = open(self._backupfilename, self._mode) + try: + perm = os.fstat(self._file.fileno()).st_mode + except OSError: + self._output = open(self._filename, "w") + else: + fd = os.open(self._filename, + os.O_CREAT | os.O_WRONLY | os.O_TRUNC, + perm) + self._output = os.fdopen(fd, "w") + try: + if hasattr(os, 'chmod'): + os.chmod(self._filename, perm) + except OSError: + pass + self._savestdout = sys.stdout + sys.stdout = self._output + else: + # This may raise IOError + if self._openhook: + self._file = self._openhook(self._filename, self._mode) + else: + self._file = open(self._filename, self._mode) + + self._readline = self._file.readline # hide FileInput._readline + return self._readline() + + def filename(self): + return self._filename + + def lineno(self): + return self._startlineno + self._filelineno + + def filelineno(self): + return self._filelineno + + def fileno(self): + if self._file: + try: + return self._file.fileno() + except ValueError: + return -1 + else: + return -1 + + def isfirstline(self): + return self._filelineno == 1 + + def isstdin(self): + return self._isstdin + + +def hook_compressed(filename, mode): + ext = os.path.splitext(filename)[1] + if ext == '.gz': + import gzip + return gzip.open(filename, mode) + elif ext == '.bz2': + import bz2 + return bz2.BZ2File(filename, mode) + else: + return open(filename, mode) + + +def hook_encoded(encoding): + import io + def openhook(filename, mode): + mode = mode.replace('U', '').replace('b', '') or 'r' + return io.open(filename, mode, encoding=encoding, newline='') + return openhook + + +def _test(): + import getopt + inplace = 0 + backup = 0 + opts, args = getopt.getopt(sys.argv[1:], "ib:") + for o, a in opts: + if o == '-i': inplace = 1 + if o == '-b': backup = a + for line in input(args, inplace=inplace, backup=backup): + if line[-1:] == '\n': line = line[:-1] + if line[-1:] == '\r': line = line[:-1] + print "%d: %s[%d]%s %s" % (lineno(), filename(), filelineno(), + isfirstline() and "*" or "", line) + print "%d: %s[%d]" % (lineno(), filename(), filelineno()) + +if __name__ == '__main__': + _test() |