1 | # |
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2 | # pkpgcounter : a generic Page Description Language parser |
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3 | # |
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4 | # (c) 2003, 2004, 2005, 2006 Jerome Alet <alet@librelogiciel.com> |
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5 | # This program is free software; you can redistribute it and/or modify |
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6 | # it under the terms of the GNU General Public License as published by |
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7 | # the Free Software Foundation; either version 2 of the License, or |
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8 | # (at your option) any later version. |
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9 | # |
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10 | # This program is distributed in the hope that it will be useful, |
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11 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 | # GNU General Public License for more details. |
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14 | # |
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15 | # You should have received a copy of the GNU General Public License |
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16 | # along with this program; if not, write to the Free Software |
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17 | # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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18 | # |
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19 | # $Id$ |
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20 | # |
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21 | |
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22 | import sys |
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23 | |
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24 | KILOBYTE = 1024 |
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25 | MEGABYTE = 1024 * KILOBYTE |
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26 | FIRSTBLOCKSIZE = 16 * KILOBYTE |
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27 | LASTBLOCKSIZE = int(KILOBYTE / 4) |
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28 | |
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29 | class PDLParserError(Exception): |
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30 | """An exception for PDLParser related stuff.""" |
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31 | def __init__(self, message = ""): |
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32 | self.message = message |
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33 | Exception.__init__(self, message) |
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34 | def __repr__(self): |
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35 | return self.message |
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36 | __str__ = __repr__ |
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37 | |
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38 | class PDLParser : |
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39 | """Generic PDL parser.""" |
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40 | def __init__(self, infile, debug=0, firstblock=None, lastblock=None) : |
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41 | """Initialize the generic parser.""" |
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42 | self.infile = infile |
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43 | self.debug = debug |
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44 | if firstblock is None : |
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45 | self.infile.seek(0) |
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46 | firstblock = self.infile.read(FIRSTBLOCKSIZE) |
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47 | try : |
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48 | self.infile.seek(-LASTBLOCKSIZE, 2) |
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49 | lastblock = self.infile.read(LASTBLOCKSIZE) |
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50 | except IOError : |
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51 | lastblock = "" |
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52 | self.infile.seek(0) |
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53 | self.firstblock = firstblock |
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54 | self.lastblock = lastblock |
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55 | if not self.isValid() : |
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56 | raise PDLParserError, "Invalid file format !" |
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57 | try : |
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58 | import psyco |
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59 | except ImportError : |
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60 | pass # Psyco is not installed |
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61 | else : |
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62 | # Psyco is installed, tell it to compile |
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63 | # the CPU intensive methods : PCL and PCLXL |
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64 | # parsing will greatly benefit from this, |
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65 | # for PostScript and PDF the difference is |
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66 | # barely noticeable since they are already |
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67 | # almost optimal, and much more speedy anyway. |
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68 | psyco.bind(self.getJobSize) |
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69 | |
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70 | def logdebug(self, message) : |
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71 | """Logs a debug message if needed.""" |
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72 | if self.debug : |
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73 | sys.stderr.write("%s\n" % message) |
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74 | |
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75 | def isValid(self) : |
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76 | """Returns 1 if data is in the expected format, else 0.""" |
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77 | raise RuntimeError, "Not implemented !" |
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78 | |
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79 | def getJobSize(self) : |
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80 | """Counts pages in a document.""" |
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81 | raise RuntimeError, "Not implemented !" |
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