/usr/share/pyshared/Photon/JPEG.py is in photon 0.4.6-3.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# http://www.funducode.com/freec/Fileformats/format3/format3b.htm
#
def read_headers(filename,size=65536):
h = None
f = open(filename,'rb')
if f:
h = f.read(size)
f.close()
return h
def identify(filename):
# I've some photos made from a pentax that store the thumbnail at the beginning
size = 65536
while True:
try:
h = read_headers(filename,size)
if h == None:
return None
# This is the JPEG/JFIF header
if h[0:2] == '\xff\xd8':
return find_marker_SOFx(h[2:])
return None
except IndexError, err:
size = size * 2
print "Jpeg Resize and reload header ",size
if size > 1048576:
print "Can't identify this file as an JPEG file %s" % filename
return None
def find_marker_SOFx(h):
i=0
while 1:
# Hum, this is not a valid chunk
if h[i] != "\xff":
return None
i+=1
# Skip any padding ff byte (this normal)
while h[i] == 0xff:
i+=1
# All SOF0 to SOF15 is valid (for me) not sure
#print "Found marker %2.2x at index %d"% (ord(h[i]),i)
if h[i] >= '\xc0' and h[i]<='\xcf' and h[i]!='\xc4' and h[i]!='\xcc':
i+=1
return ((ord(h[i+5])<<8 | ord(h[i+6])),(ord(h[i+3])<<8 | ord(h[i+4])))
i+=1
# Skip to next marker
i+= ord(h[i])<<8 | ord(h[i+1])
#print "New offset at " , i
if __name__ == "__main__":
# import profile
# profile.run('main()')
import sys
import JPEG
if len(sys.argv) < 2:
print 'Usage: %s files...\n' % sys.argv[0]
sys.exit(0)
for filename in sys.argv[1:]:
info=JPEG.identify(filename)
if info != None:
print "%s (size = %d,%d)" % (filename,info[0],info[1])
else:
print "%s is not a Jpeg file" % filename
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