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			215 lines
		
	
	
	
		
			6.7 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			215 lines
		
	
	
	
		
			6.7 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
"""text_file
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provides the TextFile class, which gives an interface to text files
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that (optionally) takes care of stripping comments, ignoring blank
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lines, and joining lines with backslashes."""
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# created 1999/01/12, Greg Ward
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__revision__ = "$Id$"
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from types import *
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import sys, os, string, re
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class TextFile:
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    filename = None
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    file = None
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    current_line = None
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    default_options = { 'strip_comments': 1,
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                        'comment_re':     re.compile (r'\s*#.*'),
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                        'skip_blanks':    1,
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                        'join_lines':     0,
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                        'lstrip_ws':      0,
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                        'rstrip_ws':      1,
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                      }
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    def __init__ (self, filename=None, **options):
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        # set values for all options -- either from client option hash
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        # or fallback to default_options
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        for opt in self.default_options.keys():
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            if options.has_key (opt):
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                if opt == 'comment_re' and type (options[opt]) is StringType:
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                    self.comment_re = re.compile (options[opt])
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                else:
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                    setattr (self, opt, options[opt])
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            else:
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                setattr (self, opt, self.default_options[opt])
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        # sanity check client option hash
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        for opt in options.keys():
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            if not self.default_options.has_key (opt):
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                raise KeyError, "invalid TextFile option '%s'" % opt
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        self.filename = filename
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        if self.filename:
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            self.open ()
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    def open (self, filename=None):
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        if not self.filename:
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            if not filename:
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                raise RuntimeError, "must provide a filename somehow"
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            self.filename = filename
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        self.file = open (self.filename, 'r')
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        self.current_line = 0
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    def close (self):
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        self.file.close ()
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        self.file = None
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        self.filename = None
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        self.current_line = None
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    def warn (self, msg):
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        sys.stderr.write (self.filename + ", ")
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        if type (self.current_line) is ListType:
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            sys.stderr.write ("lines %d-%d: " % tuple (self.current_line))
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        else:
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            sys.stderr.write ("line %d: " % self.current_line)
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        sys.stderr.write (msg + "\n")
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    def readline (self):
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        buildup_line = ''
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        while 1:
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            # read the line, optionally strip comments
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            line = self.file.readline()
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            if self.strip_comments and line:
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                line = self.comment_re.sub ('', line)
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            # did previous line end with a backslash? then accumulate
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            if self.join_lines and buildup_line:
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                # oops: end of file
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                if not line:
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                    self.warn ("continuation line immediately precedes "
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                               "end-of-file")
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                    return buildup_line
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                line = buildup_line + line
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                # careful: pay attention to line number when incrementing it
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                if type (self.current_line) is ListType:
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                    self.current_line[1] = self.current_line[1] + 1
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                else:
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                    self.current_line = [self.current_line, self.current_line+1]
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            # just an ordinary line, read it as usual
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            else:
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                if not line:
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                    return None
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                # still have to be careful about incrementing the line number!
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                if type (self.current_line) is ListType:
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                    self.current_line = self.current_line[1] + 1
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                else:
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                    self.current_line = self.current_line + 1
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            # strip whitespace however the client wants (leading and
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            # trailing, or one or the other, or neither)
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            if self.lstrip_ws and self.rstrip_ws:
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                line = string.strip (line)
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            else:
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                if self.lstrip_ws:
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                    line = string.lstrip (line)
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                if self.rstrip_ws:
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                    line = string.rstrip (line)
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            # blank line (whether we rstrip'ed or not)? skip to next line
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            # if appropriate
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            if line == '' or line == '\n' and self.skip_blanks:
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                continue
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            if self.join_lines:
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                if line[-1] == '\\':
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                    buildup_line = line[:-1]
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                    continue
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                if line[-2:] == '\\\n':
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                    buildup_line = line[0:-2] + '\n'
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                    continue
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            # well, I guess there's some actual content there: return it
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            return line
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    # end readline
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    def readlines (self):
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        lines = []
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        while 1:
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            line = self.readline()
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            if line is None:
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                return lines
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            lines.append (line)
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if __name__ == "__main__":
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    test_data = """# test file
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line 3 \\
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continues on next line
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"""
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    # result 1: no fancy options
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    result1 = map (lambda x: x + "\n", string.split (test_data, "\n")[0:-1])
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    # result 2: just strip comments
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    result2 = ["\n", "\n", "line 3 \\\n", "continues on next line\n"]
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    # result 3: just strip blank lines
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    result3 = ["# test file\n", "line 3 \\\n", "continues on next line\n"]
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    # result 4: default, strip comments, blank lines, and trailing whitespace
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    result4 = ["line 3 \\", "continues on next line"]
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    # result 5: full processing, strip comments and blanks, plus join lines
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    result5 = ["line 3 continues on next line"]
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    def test_input (count, description, file, expected_result):
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        result = file.readlines ()
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        # result = string.join (result, '')
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        if result == expected_result:
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            print "ok %d (%s)" % (count, description)
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        else:
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            print "not ok %d (%s):" % (count, description)
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            print "** expected:"
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            print expected_result
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            print "** received:"
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            print result
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    filename = "test.txt"
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    out_file = open (filename, "w")
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    out_file.write (test_data)
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    out_file.close ()
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    in_file = TextFile (filename, strip_comments=0, skip_blanks=0,
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                   lstrip_ws=0, rstrip_ws=0)
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    test_input (1, "no processing", in_file, result1)
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    in_file = TextFile (filename, strip_comments=1, skip_blanks=0,
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                   lstrip_ws=0, rstrip_ws=0)
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    test_input (2, "strip comments", in_file, result2)
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    in_file = TextFile (filename, strip_comments=0, skip_blanks=1,
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                   lstrip_ws=0, rstrip_ws=0)
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    test_input (3, "strip blanks", in_file, result3)
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    in_file = TextFile (filename)
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    test_input (4, "default processing", in_file, result4)
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    in_file = TextFile (filename, strip_comments=1, skip_blanks=1,
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                        join_lines=1, rstrip_ws=1)
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    test_input (5, "full processing", in_file, result5)
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    os.remove (filename)
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