root / pkpgcounter / trunk / pkpgpdls / pdlparser.py @ 518

Revision 493, 4.1 kB (checked in by jerome, 17 years ago)

Re-optimize disk access by not reopening and re-reading first and last block
more than once.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Auth Date Id Rev
Line 
1#
2# pkpgcounter : a generic Page Description Language parser
3#
4# (c) 2003, 2004, 2005, 2006, 2007 Jerome Alet <alet@librelogiciel.com>
5# This program is free software: you can redistribute it and/or modify
6# it under the terms of the GNU General Public License as published by
7# the Free Software Foundation, either version 3 of the License, or
8# (at your option) any later version.
9#
10# This program is distributed in the hope that it will be useful,
11# but WITHOUT ANY WARRANTY; without even the implied warranty of
12# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13# GNU General Public License for more details.
14#
15# You should have received a copy of the GNU General Public License
16# along with this program.  If not, see <http://www.gnu.org/licenses/>.
17#
18# $Id$
19#
20
21"""This module defines the base class for all Page Description Language parsers."""
22
23import sys
24import os
25import popen2
26
27KILOBYTE = 1024   
28MEGABYTE = 1024 * KILOBYTE   
29FIRSTBLOCKSIZE = 16 * KILOBYTE
30LASTBLOCKSIZE = int(KILOBYTE / 4)
31
32class PDLParserError(Exception):
33    """An exception for PDLParser related stuff."""
34    def __init__(self, message = ""):
35        self.message = message
36        Exception.__init__(self, message)
37    def __repr__(self):
38        return self.message
39    __str__ = __repr__
40       
41class PDLParser :
42    """Generic PDL parser."""
43    totiffcommands = None        # Default command to convert to TIFF
44    openmode = "rb"              # Default file opening mode
45    def __init__(self, filename, firstblock, lastblock, debug=0) :
46        """Initialize the generic parser."""
47        self.filename = filename
48        self.debug = debug
49        self.infile = None
50        (self.firstblock, self.lastblock) = (firstblock, lastblock)
51        if not self.isValid() :
52            raise PDLParserError, "Invalid file format !"
53        try :
54            import psyco 
55        except ImportError :   
56            pass # Psyco is not installed
57        else :   
58            # Psyco is installed, tell it to compile
59            # the CPU intensive methods : PCL and PCLXL
60            # parsing will greatly benefit from this.
61            psyco.bind(self.getJobSize)
62        self.infile = open(self.filename, self.openmode)
63        # self.logdebug("Opened %s in '%s' mode." % (self.filename, self.openmode))
64           
65    def __del__(self) :
66        """Ensures the input file gets closed."""
67        if self.infile :
68            self.infile.close()
69           
70    def logdebug(self, message) :       
71        """Logs a debug message if needed."""
72        if self.debug :
73            sys.stderr.write("%s\n" % message)
74           
75    def isValid(self) :   
76        """Returns True if data is in the expected format, else False."""
77        raise RuntimeError, "Not implemented !"
78       
79    def getJobSize(self) :   
80        """Counts pages in a document."""
81        raise RuntimeError, "Not implemented !"
82       
83    def convertToTiffMultiPage24NC(self, outfname, dpi) :
84        """Converts the input file to TIFF format, X dpi, 24 bits per pixel, uncompressed.
85           Writes TIFF datas to the file named by outfname.
86        """   
87        if self.totiffcommands :
88            infname = self.filename
89            for totiffcommand in self.totiffcommands :
90                error = False
91                commandline = totiffcommand % locals()
92                # self.logdebug("Executing '%s'" % commandline)
93                status = os.system(commandline)
94                if os.WIFEXITED(status) :
95                    if os.WEXITSTATUS(status) :
96                        error = True
97                else :       
98                    error = True
99                if not os.path.exists(outfname) :
100                    error = True
101                elif not os.stat(outfname).st_size :
102                    error = True
103                else :       
104                    break       # Conversion worked fine it seems.
105                sys.stderr.write("Command failed : %s\n" % repr(commandline))
106            if error :
107                raise PDLParserError, "Problem during conversion to TIFF."
108        else :       
109            raise PDLParserError, "Impossible to compute ink coverage for this file format."
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