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

Revision 491, 4.1 kB (checked in by jerome, 17 years ago)

Major code cleaning. Now clearer, although probably a bit slower since
a file can be opened several times.
Now universal line opening mode is only used when needed (PS, PDF and plain
text), and binary opening mode is used for the other formats.
This mean we will be able to remove mmap calls wherever possible, finally.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id 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 HP LIDIL format.
24
25   Documentation used :
26   
27        hplip-2.7.10/prnt/ldl.py
28        hplip-2.7.10/prnt/hpijs/ldlencap.h
29"""
30
31import struct
32
33import pdlparser
34
35HEADERSIZE = 10 # LIDIL header is 10 bytes long
36
37# Packet types taken from hplip-2.7.10/prnt/ldl.py
38PACKET_TYPE_COMMAND = 0
39PACKET_TYPE_DISABLE_PACING = 1
40PACKET_TYPE_ENABLE_PACING = 2
41PACKET_TYPE_RESUME_NORMAL_OPERATION = 3
42PACKET_TYPE_DISABLE_RESPONSES = 4
43PACKET_TYPE_ENABLE_RESPONSES = 5
44PACKET_TYPE_RESET_LIDIL = 6
45PACKET_TYPE_SYNC = 7
46PACKET_TYPE_SYNC_COMPLETE = 8
47
48# Command codes we are interested in.
49LDL_LOAD_PAGE = 1
50LDL_EJECT_PAGE = 2
51
52class Parser(pdlparser.PDLParser) :
53    """A parser for HP LIDIL documents."""
54    def isValid(self) :   
55        """Returns True if data is LIDIL, else False."""
56        # Beginning Of File marker is a Sync packet, followed with
57        # a Sync Complete packet followed with a Reset packet.
58        # We just look at the start of the Sync packet for simplicity's sake.
59        BOFMarker = "$\x01\x00\x00\x07"
60        # End Of File marker is a Sync Complete packet followed
61        # with a Reset packet. We ignore the preceding Sync packet
62        # for simplicity's sake.
63        EOFMarker = "$\x00\x10\x00\x08\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff$$\x00\x10\x00\x06\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff$" 
64        if self.firstblock.startswith(BOFMarker) \
65           and self.lastblock.endswith(EOFMarker) :
66            self.logdebug("DEBUG: Input file is in the Hewlett-Packard LIDIL format.")
67            return True
68        else :   
69            return False
70       
71    def getJobSize(self) :
72        """Computes the number of pages in a HP LIDIL document."""
73        unpack = struct.unpack
74        ejectpage = loadpage = 0
75        while True :
76            header = self.infile.read(HEADERSIZE)
77            if not header :
78                break
79            if (len(header) != HEADERSIZE) or (header[0] != "$") :
80                # Invalid header or no Frame Sync byte.
81                raise pdlparser.PDLParserError, "This file doesn't seem to be valid Hewlett-Packard LIDIL datas."
82            try :   
83                (framesync,     
84                 cmdlength,
85                 dummy,
86                 packettype,
87                 commandnumber,
88                 referencenumber,
89                 datalength) = unpack(">BHBBBHH", header)
90            except struct.error :   
91                raise pdlparser.PDLParserError, "This file doesn't seem to be valid Hewlett-Packard LIDIL datas."
92            if packettype == PACKET_TYPE_COMMAND :
93                if commandnumber == LDL_LOAD_PAGE :
94                    loadpage += 1
95                elif commandnumber == LDL_EJECT_PAGE :
96                    ejectpage += 1
97            self.infile.seek(cmdlength + datalength - len(header), 1) # relative seek
98           
99        # Number of page eject commands should be sufficient,
100        # but we never know : someone could try to cheat the printer
101        # by loading a page but not ejecting it, and ejecting it manually
102        # later on. Not sure if the printers would support this, but
103        # taking the max value works around the problem in any case.
104        self.logdebug("Load : %i    Eject : %i" % (loadpage, ejectpage))
105        return max(loadpage, ejectpage)
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