| """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. |
| |
| Performance: this module is unfortunately one of the slower ways of |
| processing large numbers of input lines. Nevertheless, a significant |
| speed-up has been obtained by using readlines(bufsize) instead of |
| readline(). A new keyword argument, bufsize=N, is present on the |
| input() function and the FileInput() class to override the default |
| buffer size. |
| |
| 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 |
| |
| DEFAULT_BUFSIZE = 8*1024 |
| |
| def input(files=None, inplace=0, backup="", bufsize=0, |
| mode="r", openhook=None): |
| """input([files[, inplace[, backup[, mode[, openhook]]]]]) |
| |
| Create an instance of the FileInput class. The instance will be used |
| as global state for the functions of this module, and is also returned |
| to use during iteration. The parameters to this function will be passed |
| along to the constructor of the FileInput class. |
| """ |
| 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: |
| """class FileInput([files[, inplace[, backup[, 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._bufsize = bufsize or DEFAULT_BUFSIZE |
| self._savestdout = None |
| self._output = None |
| self._filename = None |
| self._lineno = 0 |
| self._filelineno = 0 |
| self._file = None |
| self._isstdin = False |
| self._backupfilename = None |
| self._buffer = [] |
| self._bufindex = 0 |
| # 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): |
| self.nextfile() |
| self._files = () |
| |
| def __iter__(self): |
| return self |
| |
| def next(self): |
| try: |
| line = self._buffer[self._bufindex] |
| except IndexError: |
| pass |
| else: |
| self._bufindex += 1 |
| self._lineno += 1 |
| self._filelineno += 1 |
| return line |
| line = self.readline() |
| if not line: |
| raise StopIteration |
| return line |
| |
| 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 |
| if output: |
| output.close() |
| |
| file = self._file |
| self._file = 0 |
| if file and not self._isstdin: |
| file.close() |
| |
| backupfilename = self._backupfilename |
| self._backupfilename = 0 |
| if backupfilename and not self._backup: |
| try: os.unlink(backupfilename) |
| except OSError: pass |
| |
| self._isstdin = False |
| self._buffer = [] |
| self._bufindex = 0 |
| |
| def readline(self): |
| try: |
| line = self._buffer[self._bufindex] |
| except IndexError: |
| pass |
| else: |
| self._bufindex += 1 |
| self._lineno += 1 |
| self._filelineno += 1 |
| return line |
| if not self._file: |
| if not self._files: |
| return "" |
| self._filename = self._files[0] |
| self._files = self._files[1:] |
| 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._buffer = self._file.readlines(self._bufsize) |
| self._bufindex = 0 |
| if not self._buffer: |
| self.nextfile() |
| # Recursive call |
| return self.readline() |
| |
| def filename(self): |
| return self._filename |
| |
| def lineno(self): |
| return self._lineno |
| |
| 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 codecs |
| def openhook(filename, mode): |
| return codecs.open(filename, mode, encoding) |
| 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() |
