root / pkpgcounter / trunk / pkpgpdls / dvi.py @ 463

Revision 463, 2.7 kB (checked in by jerome, 15 years ago)

Licensing terms changed to GNU GPL v3.0 or higher.
Removed old PCL3/4/5 parser which for a long time now wasn't used
anymore, and for which I was not the original copyright owner.
Version number bumped to 3.00alpha to reflect licensing changes.

  • Property svn:keywords set to Author Id Date Revision
Line 
1#! /usr/bin/env python
2# -*- coding: ISO-8859-15 -*-
3#
4# pkpgcounter : a generic Page Description Language parser
5#
6# (c) 2003, 2004, 2005, 2006, 2007 Jerome Alet <alet@librelogiciel.com>
7# This program is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11#
12# This program is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with this program.  If not, see <http://www.gnu.org/licenses/>.
19#
20# $Id$
21#
22
23"""This modules implements a page counter for DVI documents."""
24
25import sys
26import os
27import mmap
28from struct import unpack
29
30import pdlparser
31
32class Parser(pdlparser.PDLParser) :
33    """A parser for DVI documents."""
34    totiffcommands = [ 'cat >%(fname)s && dvips -q -o - %(fname)s | gs -sDEVICE=tiff24nc -dPARANOIDSAFER -dNOPAUSE -dBATCH -dQUIET -r%(dpi)i -sOutputFile="%(fname)s" -' ]
35    def isValid(self) :       
36        """Returns True if data is DVI, else False."""
37        try :
38            if (ord(self.firstblock[0]) == 0xf7) and (ord(self.lastblock[-1]) == 0xdf) :
39                self.logdebug("DEBUG: Input file is in the DVI format.")
40                return True
41            else :   
42                return False
43        except IndexError :         
44            return False
45           
46    def getJobSize(self) :
47        """Counts pages in a DVI document.
48       
49           Algorithm by Jerome Alet.
50           
51           The documentation used for this was :
52         
53           http://www.math.umd.edu/~asnowden/comp-cont/dvi.html
54        """
55        infileno = self.infile.fileno()
56        minfile = mmap.mmap(infileno, os.fstat(infileno)[6], prot=mmap.PROT_READ, flags=mmap.MAP_SHARED)
57        pagecount = 0
58        pos = -1
59        eofchar = chr(0xdf)
60        postchar = chr(0xf8)
61        try :
62            while minfile[pos] == eofchar :
63                pos -= 1
64            idbyte = minfile[pos]   
65            if idbyte != minfile[1] :
66                raise IndexError, "Invalid DVI file."
67            pos = unpack(">I", minfile[pos - 4:pos])[0]
68            if minfile[pos] != postchar :
69                raise IndexError, "Invalid DVI file."
70            pagecount = unpack(">H", minfile[pos + 27: pos + 29])[0]
71        except IndexError : # EOF ?
72            pass
73        minfile.close() # reached EOF
74        return pagecount
75       
76if __name__ == "__main__" :   
77    pdlparser.test(Parser)
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