root / pkpgcounter / trunk / pkpgpdls / pdlparser.py @ 2434

Revision 564, 5.8 kB (checked in by jerome, 17 years ago)

Changed copyright years.
Removed unnecessary shebang lines.
Changed default encoding to UTF-8 from ISO-8859-15 (only
ascii is used anyway).

  • Property svn:eol-style set to native
  • Property svn:keywords set to Auth Date Id Rev
Line 
1# -*- coding: UTF-8 -*-
2#
3# pkpgcounter : a generic Page Description Language parser
4#
5# (c) 2003, 2004, 2005, 2006, 2007, 2008 Jerome Alet <alet@librelogiciel.com>
6# This program is free software: you can redistribute it and/or modify
7# it under the terms of the GNU General Public License as published by
8# the Free Software Foundation, either version 3 of the License, or
9# (at your option) any later version.
10#
11# This program is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14# GNU General Public License for more details.
15#
16# You should have received a copy of the GNU General Public License
17# along with this program.  If not, see <http://www.gnu.org/licenses/>.
18#
19# $Id$
20#
21
22"""This module defines the base class for all Page Description Language parsers."""
23
24import sys
25import os
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    required = []               # Default list of required commands
45    openmode = "rb"             # Default file opening mode
46    format = "Unknown"          # Default file format
47    def __init__(self, parent, filename, (firstblock, lastblock)) :
48        """Initialize the generic parser."""
49        self.parent = parent
50        # We need some copies for later inclusion of parsers which
51        # would modify the parent's values
52        self.filename = filename[:]
53        self.firstblock = firstblock[:]
54        self.lastblock = lastblock[:]
55        self.infile = None
56        if not self.isValid() :
57            raise PDLParserError, "Invalid file format !"
58        else :   
59            self.logdebug("Input file is in the '%s' file format." % self.format)
60        try :
61            import psyco 
62        except ImportError :   
63            pass # Psyco is not installed
64        else :   
65            # Psyco is installed, tell it to compile
66            # the CPU intensive methods : PCL and PCLXL
67            # parsing will greatly benefit from this.
68            psyco.bind(self.getJobSize)
69        self.infile = open(self.filename, self.openmode)
70        # self.logdebug("Opened %s in '%s' mode." % (self.filename, self.openmode))
71           
72    def __del__(self) :
73        """Ensures the input file gets closed."""
74        if self.infile :
75            self.infile.close()
76           
77    def findExecutable(self, command) :
78        """Finds an executable in the PATH and returns True if found else False."""
79        for cmd in [p.strip() for p in command.split("|")] : # | can separate alternatives for similar commands (e.g. a2ps|enscript)
80            for path in os.environ.get("PATH", "").split(":") :
81                fullname = os.path.abspath(os.path.join(os.path.expanduser(path), cmd))
82                if os.path.isfile(fullname) and os.access(fullname, os.X_OK) :
83                    return True
84        return False
85       
86    def isMissing(self, commands) :   
87        """Returns True if some required commands are missing, else False.""" 
88        howmanythere = 0
89        for command in commands :
90            if not self.findExecutable(command) :
91                sys.stderr.write("ERROR: %(command)s is missing or not executable. You MUST install it for pkpgcounter to be able to do what you want.\n" % locals())
92                sys.stderr.flush()
93            else :   
94                howmanythere += 1
95        if howmanythere == len(commands) :
96            return False
97        else :   
98            return True
99       
100    def logdebug(self, message) :       
101        """Logs a debug message if needed."""
102        if self.parent.options.debug :
103            sys.stderr.write("%s\n" % message)
104           
105    def isValid(self) :   
106        """Returns True if data is in the expected format, else False."""
107        raise RuntimeError, "Not implemented !"
108       
109    def getJobSize(self) :   
110        """Counts pages in a document."""
111        raise RuntimeError, "Not implemented !"
112       
113    def convertToTiffMultiPage24NC(self, outfname, dpi) :
114        """Converts the input file to TIFF format, X dpi, 24 bits per pixel, uncompressed.
115           Writes TIFF datas to the file named by outfname.
116        """   
117        if self.totiffcommands :
118            if self.isMissing(self.required) :
119                raise PDLParserError, "At least one of the following commands is missing and should be installed for the computation of ink coverage : %s" % repr(self.required)
120            infname = self.filename
121            for totiffcommand in self.totiffcommands :
122                error = False
123                commandline = totiffcommand % locals()
124                # self.logdebug("Executing '%s'" % commandline)
125                status = os.system(commandline)
126                if os.WIFEXITED(status) :
127                    if os.WEXITSTATUS(status) :
128                        error = True
129                else :       
130                    error = True
131                if not os.path.exists(outfname) :
132                    error = True
133                elif not os.stat(outfname).st_size :
134                    error = True
135                else :       
136                    break       # Conversion worked fine it seems.
137                sys.stderr.write("Command failed : %s\n" % repr(commandline))
138            if error :
139                raise PDLParserError, "Problem during conversion to TIFF."
140        else :       
141            raise PDLParserError, "Impossible to compute ink coverage for this file format."
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