/usr/share/pyshared/kaa/metadata/image/png.py is in python-kaa-metadata 0.7.7+svn4596-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | # -*- coding: iso-8859-1 -*-
# -----------------------------------------------------------------------------
# png.py - png file parsing
# -----------------------------------------------------------------------------
# $Id: png.py 3079 2008-02-13 20:10:40Z dmeyer $
#
# -----------------------------------------------------------------------------
# kaa-Metadata - Media Metadata for Python
# Copyright (C) 2003-2006 Thomas Schueppel, Dirk Meyer
#
# First Edition: Thomas Schueppel <stain@acm.org>
# Maintainer: Dirk Meyer <dischi@freevo.org>
#
# Please see the file AUTHORS for a complete list of authors.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MER-
# CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# -----------------------------------------------------------------------------
__all__ = ['Parser']
# python imports
import struct
import zlib
import logging
# kaa imports
import kaa
# import kaa.metadata.image core
import core
# get logging object
log = logging.getLogger('metadata')
# interesting file format info:
# http://www.libpng.org/pub/png/png-sitemap.html#programming
# http://pmt.sourceforge.net/pngmeta/
# http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html
PNGSIGNATURE = "\211PNG\r\n\032\n"
class PNG(core.Image):
def __init__(self,file):
core.Image.__init__(self)
self.mime = 'image/png'
self.type = 'PNG image'
signature = file.read(8)
if ( signature != PNGSIGNATURE ):
raise core.ParseError()
self.meta = {}
while self._readChunk(file):
pass
if len(self.meta.keys()):
self._appendtable( 'PNGMETA', self.meta )
for key, value in self.meta.items():
if key.startswith('Thumb:') or key == 'Software':
self._set(key, value)
def _readChunk(self,file):
try:
(length, type) = struct.unpack('>I4s', file.read(8))
except (OSError, IOError, struct.error):
return 0
key = None
if type == 'IEND':
return 0
elif type == 'IHDR':
data = file.read(length+4)
self.width, self.height, self.depth = struct.unpack(">IIb", data[:9])
elif type == 'tEXt':
log.debug('latin-1 Text found.')
(data, crc) = struct.unpack('>%isI' % length,file.read(length+4))
(key, value) = data.split('\0')
self.meta[key] = kaa.str_to_unicode(value)
elif type == 'zTXt':
log.debug('Compressed Text found.')
(data,crc) = struct.unpack('>%isI' % length,file.read(length+4))
split = data.split('\0')
key = split[0]
value = "".join(split[1:])
compression = ord(value[0])
value = value[1:]
if compression == 0:
decompressed = zlib.decompress(value)
log.debug("%s (Compressed %i) -> %s" % \
(key,compression,decompressed))
else:
log.debug("%s has unknown Compression %c" % (key,compression))
self.meta[key] = kaa.str_to_unicode(value)
elif type == 'iTXt':
log.debug('International Text found.')
(data,crc) = struct.unpack('>%isI' % length,file.read(length+4))
(key, value) = data.split('\0')
self.meta[key] = kaa.str_to_unicode(value)
else:
file.seek(length+4,1)
log.debug("%s of length %d ignored." % (type, length))
if key is not None and key.lower() == "comment":
self.comment = self.meta[key]
return 1
Parser = PNG
|