def __init__(self, tag, parent):
if DEBUG:
print repr(tag)
self.parent = parent
self.endian = parent.endian
tiff = parent.tiff
self.id = tag[:2]
self.type = util.getNr(tag[2:4], self.endian)
self.count = util.getNr(tag[4:8], self.endian)
try:
self.bytes = self.typeMap[self.type]
self.len = self.bytes * self.count
except:
raise ValueError, "Value type %s is not supported for %s - %s" % (self.type, self.niceID(), repr(tag))
if self.len <= 4:
self.valueFlat = tag[8:] #as it needs to be written back into the file
self.value = self._getVal(tag[8:])
else:
offset = util.getNr(tag[8:], self.endian)
self.valueFlat = tiff[offset: offset + self.len]
self.value = self._getVal(tiff[offset: offset + self.len])
if DEBUG:
self.display()
def niceID(self):
"return tag hex value and also a description if available"
id = exif_tags_description.get(self.endian == "MM" and self.id or util.reverse(self.id), None)
if id == None:
id = hex(util.getNr(self.id, self.endian))
else:
id = hex(util.getNr(self.id, self.endian)) + " - " + (type(id) == type(()) and id[0] or id)
return id
def _getVal(self, val): #from binary to python
if self.type in [1,3,4]: #byte, sort, long
if len(val)> self.len:
val = self.endian == "II" and val[:self.bytes] or val[self.bytes:]
r = [util.getNr(''.join(t), self.endian) for t in util.unzip(val, self.bytes)]
if len(r)==1: return r[0]
return r
if self.type == 5: #rational
r = util.unzip([util.getNr(''.join(t), self.endian) for t in util.unzip(val, 4)], 2)
if len(r)==1: return r[0]
return r
if self.type == 2: #string
return val[:-1] #strip NULL from NULL terminated string
return val # unknown
def _write(value, file, marker):
"""-Overwrights <marker> segment with given <value>
-if <marker> segment does not already exist then it will write it
right before the image segment (SOF - FFC0)
"""
markerSeg, sof, length, im = _process(file, marker)
if markerSeg or sof:
lenHex = util.setNr(len(value) + 2, "short") #the length on 2 bytes
segment = "\xFF" + marker + lenHex + value #segment = marker + value length + value
pos = im.tell() - 4
im.seek(0)
before = im.read(pos)
if markerSeg:
im.seek(util.getNr(length) + 2,
1) #skip over existing segment, including marker
after = im.read()
im.reset()
im.write(before)
im.write(segment)
im.write(after)
im.close()
return im
else:
im.close()
raise NoImageFound, "There is no image in this image file ?"
def _write(value, file, marker):
"""-Overwrights <marker> segment with given <value>
-if <marker> segment does not already exist then it will write it
right before the image segment (SOF - FFC0)
"""
markerSeg, sof, length, im = _process(file, marker)
if markerSeg or sof:
lenHex = util.setNr(len(value)+2, "short") #the length on 2 bytes
segment = "\xFF" + marker + lenHex + value #segment = marker + value length + value
pos = im.tell() - 4
im.seek(0)
before = im.read(pos)
if markerSeg:
im.seek(util.getNr(length) + 2, 1) #skip over existing segment, including marker
after = im.read()
im.reset()
im.write(before)
im.write(segment)
im.write(after)
im.close()
return im
else:
im.close()
raise NoImageFound, "There is no image in this image file ?"
def parse_ifd(self, ifdOffset, context, next=None):
""" Construct a modifiable Exif.
Get nr of tags and parse each tag. If a pointer tags to other ifd is found,
recurse inside that ifd as well
"""
ifd = self.tiff[ifdOffset:]
nrTags = util.getNr(ifd[:2], self.endian)
if DEBUG:
print self.ifdName(context), "nr tags", nrTags
offset = 2 #position after nr tags bytes
for i in range(nrTags):
try:
tag = Tag(ifd[offset : offset+12], self)
except Exception, e: #mainly unsuported tag types, etc
# TODO: if a tag is buggy is it ok to just ignore it and go on or should we crash alltoghether
if DEBUG:
print "Can't create tag", str(e)
offset += 12
continue
context.append(tag)
if next is not None: # and tag.value is not None:
for ix in range(len(next)):
nxtId = next[ix][0]
if (tag.id == nxtId) or (self.endian=="II" and tag.id == util.reverse(nxtId)):
next[ix][1] = tag.value
offset += 12
def __init__(self, marker, type, value, record):
self.marker = marker
self.type = type
self.value = value
self.record = record
self.nrType = util.getNr(type) #nr_datasets dictionary key
self.name = nr_datasets.get(self.nrType, None)
def __init__(self, marker, type, value, record):
self.marker = marker
self.type = type
self.value = value
self.record = record
self.nrType = util.getNr(type) #nr_datasets dictionary key
self.name = nr_datasets.get(self.nrType, None)
def dict(self):
"return a dictionary {tag description: (ifd, tag id, value)} of all parsed tags"
d = {}
for ifd in self.ifds:
for tag in ifd:
id = exif_tags_description.get(self.endian == "MM" and tag.id or util.reverse(tag.id), repr(tag.id))
id = type(id) == type(()) and id[0] or id
d[id] = (self.ifdName(ifd), hex(util.getNr(tag.id, self.endian)), tag.value)
return d
def _read(file, marker):
"return value of <marker> segment if exists, or None otherwise"
segmentValue=None
try: markerSeg, sof, length, im = _process(file, marker)
except: return ""
if markerSeg:
im.seek(-2, 1) #retract right after marker ID
segmentValue = im.read(util.getNr(length))[2:]
im.close()
if not markerSeg and not sof:
raise NoImageFound, "There is no image in this image file ?"
return segmentValue
def parse(self, value): # 8BIM Records
if value:
marker = value[:4]
type = value[4:6]
padding = value[6:10]
length = util.getNr(value[10:12])
rValue = value[12:12 + length]
self.records.append(Record(marker, type, padding, rValue, self))
#Skip a NULL (\x00 terminated value) if not even size
if length % 2 != 0: length += 1
self.parse(value[12 + length:])
def parse(self, value): # 8BIM Records
if value:
marker = value[:4]
type = value[4:6]
padding = value[6:10]
length = util.getNr(value[10:12])
rValue = value[12:12+length]
self.records.append(Record(marker, type, padding, rValue, self))
#Skip a NULL (\x00 terminated value) if not even size
if length % 2 != 0: length += 1
self.parse(value[12+length:])
def _process(file, target):
"""seek target marker in JPEG file, and return tuple:
(found marker segment boolean, reached image segment boolean, marker segment length,
the open file object positioned at the begining of value)
"""
comment = image = False
im = ImgObj(file)
marker = im.read(2)
if marker != "\xFF\xD8":
raise NoJPEGFound, "Not a JPEG image"
l = 2
while im.read(1) == "\xFF":
markerType = im.read(1)
length = im.read(2)
l += util.getNr(length) + 2
if markerType == "\xC0": #SOF - got to the image, stop
return (False, True, length, im)
if markerType == target:
return (True, False, length, im)
#skip over current segment
#-2 to move <length> positions starting right after marker
im.seek(util.getNr(length) - 2, 1)
return (False, False, length, im)
def _process(file, target):
"""seek target marker in JPEG file, and return tuple:
(found marker segment boolean, reached image segment boolean, marker segment length,
the open file object positioned at the begining of value)
"""
comment = image = False
im = ImgObj(file)
marker = im.read(2)
if marker != "\xFF\xD8":
raise NoJPEGFound, "Not a JPEG image"
l=2
while im.read(1) == "\xFF":
markerType = im.read(1)
length = im.read(2)
l += util.getNr(length) + 2
if markerType == "\xC0": #SOF - got to the image, stop
return (False, True, length, im)
if markerType == target:
return (True, False, length, im)
#skip over current segment
#-2 to move <length> positions starting right after marker
im.seek(util.getNr(length) - 2, 1)
return (False, False, length, im)
def _read(file, marker):
"return value of <marker> segment if exists, or None otherwise"
segmentValue = None
try:
markerSeg, sof, length, im = _process(file, marker)
except:
return ""
if markerSeg:
im.seek(-2, 1) #retract right after marker ID
segmentValue = im.read(util.getNr(length))[2:]
im.close()
if not markerSeg and not sof:
raise NoImageFound, "There is no image in this image file ?"
return segmentValue
def parse(self, value): # sub-segments for 8BIM segment
if value:
marker = value[:2]
type = value[2:3]
length = util.getNr(value[3:5])
rValue = value[5:5 + length]
self.datasets.append(DataSet(marker, type, rValue, self))
# Skip a NULL (\x00 terminated value) if not even size
try:
if length % 2 != 0 and value[5 + length + 1] == '\x00':
length += 1
except IndexError, e:
pass
self.parse(value[5 + length:])
def parse(self, value): # sub-segments for 8BIM segment
if value:
marker = value[:2]
type = value[2:3]
length = util.getNr(value[3:5])
rValue = value[5:5+length]
self.datasets.append(DataSet(marker, type, rValue, self))
# Skip a NULL (\x00 terminated value) if not even size
try:
if length % 2 != 0 and value[5+length+1]=='\x00':
length += 1
except IndexError, e:
pass
self.parse(value[5+length:])
def __init__(self, value=None):
if value is None:
raise "EXIF must not be empty"
self.origValue = value
self.tiff = value[6:]
self.endian = value[6:8]
self.fixed42 = "\x00\x2A" #42 value[8:10]
#IFD's data structure
self.ifd0 = []
self.exif = []
self.gps = []
self.interop = []
self.ifd1 = None #we are not messing with ifd1 (thumbnail etc.) in this app at all
self.ifds = [self.ifd0, self.exif, self.gps, self.interop]
if DEBUG:
print "endian", self.endian
#parse IFD's into above data structure:
self.parse_ifd(util.getNr(value[10:14], self.endian),
self.ifd0,
[["\x87\x69", None, self.exif, # EXIFOffset
[["\xA0\x05", None, self.interop, None]]], # Interopelability IFD offset
["\x88\x25", None, self.gps, None]]) # GPSOffset
