""" Read Exif metadata from tiff and jpeg files. """ from .exif_log import get_logger from .classes import * from .tags import * from .utils import ord_ __version__ = '2.1.2' logger = get_logger() def increment_base(data, base): return ord_(data[base + 2]) * 256 + ord_(data[base + 3]) + 2 def process_file(f, stop_tag=DEFAULT_STOP_TAG, details=True, strict=False, debug=False): """ Process an image file (expects an open file object). This is the function that has to deal with all the arbitrary nasty bits of the EXIF standard. """ # by default do not fake an EXIF beginning fake_exif = 0 # determine whether it's a JPEG or TIFF data = f.read(12) if data[0:4] in [b'II*\x00', b'MM\x00*']: # it's a TIFF file logger.debug("TIFF format recognized in data[0:4]") f.seek(0) endian = f.read(1) f.read(1) offset = 0 elif data[0:2] == b'\xFF\xD8': # it's a JPEG file logger.debug("JPEG format recognized data[0:2]=0x%X%X", ord_(data[0]), ord_(data[1])) base = 2 logger.debug("data[2]=0x%X data[3]=0x%X data[6:10]=%s", ord_(data[2]), ord_(data[3]), data[6:10]) while ord_(data[2]) == 0xFF and data[6:10] in (b'JFIF', b'JFXX', b'OLYM', b'Phot'): length = ord_(data[4]) * 256 + ord_(data[5]) logger.debug(" Length offset is %s", length) f.read(length - 8) # fake an EXIF beginning of file # I don't think this is used. --gd data = b'\xFF\x00' + f.read(10) fake_exif = 1 if base > 2: logger.debug(" Added to base") base = base + length + 4 - 2 else: logger.debug(" Added to zero") base = length + 4 logger.debug(" Set segment base to 0x%X", base) # Big ugly patch to deal with APP2 (or other) data coming before APP1 f.seek(0) # in theory, this could be insufficient since 64K is the maximum size--gd data = f.read(base + 4000) # base = 2 while 1: logger.debug(" Segment base 0x%X", base) if data[base:base + 2] == b'\xFF\xE1': # APP1 logger.debug(" APP1 at base 0x%X", base) logger.debug(" Length: 0x%X 0x%X", ord_(data[base + 2]), ord_(data[base + 3])) logger.debug(" Code: %s", data[base + 4:base + 8]) if data[base + 4:base + 8] == b"Exif": logger.debug(" Decrement base by 2 to get to pre-segment header (for compatibility with later code)") base -= 2 break increment = increment_base(data, base) logger.debug(" Increment base by %s", increment) base += increment elif data[base:base + 2] == b'\xFF\xE0': # APP0 logger.debug(" APP0 at base 0x%X", base) logger.debug(" Length: 0x%X 0x%X", ord_(data[base + 2]), ord_(data[base + 3])) logger.debug(" Code: %s", data[base + 4:base + 8]) increment = increment_base(data, base) logger.debug(" Increment base by %s", increment) base += increment elif data[base:base + 2] == b'\xFF\xE2': # APP2 logger.debug(" APP2 at base 0x%X", base) logger.debug(" Length: 0x%X 0x%X", ord_(data[base + 2]), ord_(data[base + 3])) logger.debug(" Code: %s", data[base + 4:base + 8]) increment = increment_base(data, base) logger.debug(" Increment base by %s", increment) base += increment elif data[base:base + 2] == b'\xFF\xEE': # APP14 logger.debug(" APP14 Adobe segment at base 0x%X", base) logger.debug(" Length: 0x%X 0x%X", ord_(data[base + 2]), ord_(data[base + 3])) logger.debug(" Code: %s", data[base + 4:base + 8]) increment = increment_base(data, base) logger.debug(" Increment base by %s", increment) base += increment logger.debug(" There is useful EXIF-like data here, but we have no parser for it.") elif data[base:base + 2] == b'\xFF\xDB': logger.debug(" JPEG image data at base 0x%X No more segments are expected.", base) break elif data[base:base + 2] == b'\xFF\xD8': # APP12 logger.debug(" FFD8 segment at base 0x%X", base) logger.debug(" Got 0x%X 0x%X and %s instead", ord_(data[base]), ord_(data[base + 1]), data[4 + base:10 + base]) logger.debug(" Length: 0x%X 0x%X", ord_(data[base + 2]), ord_(data[base + 3])) logger.debug(" Code: %s", data[base + 4:base + 8]) increment = increment_base(data, base) logger.debug(" Increment base by %s", increment) base += increment elif data[base:base + 2] == b'\xFF\xEC': # APP12 logger.debug(" APP12 XMP (Ducky) or Pictureinfo segment at base 0x%X", base) logger.debug(" Got 0x%X and 0x%X instead", ord_(data[base]), ord_(data[base + 1])) logger.debug(" Length: 0x%X 0x%X", ord_(data[base + 2]), ord_(data[base + 3])) logger.debug("Code: %s", data[base + 4:base + 8]) increment = increment_base(data, base) logger.debug(" Increment base by %s", increment) base += increment logger.debug( " There is useful EXIF-like data here (quality, comment, copyright), but we have no parser for it.") else: try: increment = increment_base(data, base) logger.debug(" Got 0x%X and 0x%X instead", ord_(data[base]), ord_(data[base + 1])) except IndexError: logger.debug(" Unexpected/unhandled segment type or file content.") return {} else: logger.debug(" Increment base by %s", increment) base += increment f.seek(base + 12) if ord_(data[2 + base]) == 0xFF and data[6 + base:10 + base] == b'Exif': # detected EXIF header offset = f.tell() endian = f.read(1) #HACK TEST: endian = 'M' elif ord_(data[2 + base]) == 0xFF and data[6 + base:10 + base + 1] == b'Ducky': # detected Ducky header. logger.debug("EXIF-like header (normally 0xFF and code): 0x%X and %s", ord_(data[2 + base]), data[6 + base:10 + base + 1]) offset = f.tell() endian = f.read(1) elif ord_(data[2 + base]) == 0xFF and data[6 + base:10 + base + 1] == b'Adobe': # detected APP14 (Adobe) logger.debug("EXIF-like header (normally 0xFF and code): 0x%X and %s", ord_(data[2 + base]), data[6 + base:10 + base + 1]) offset = f.tell() endian = f.read(1) else: # no EXIF information logger.debug("No EXIF header expected data[2+base]==0xFF and data[6+base:10+base]===Exif (or Duck)") logger.debug("Did get 0x%X and %s", ord_(data[2 + base]), data[6 + base:10 + base + 1]) return {} else: # file format not recognized logger.debug("File format not recognized.") return {} endian = chr(ord_(endian[0])) # deal with the EXIF info we found logger.debug("Endian format is %s (%s)", endian, { 'I': 'Intel', 'M': 'Motorola', '\x01': 'Adobe Ducky', 'd': 'XMP/Adobe unknown' }[endian]) hdr = ExifHeader(f, endian, offset, fake_exif, strict, debug, details) ifd_list = hdr.list_ifd() thumb_ifd = False ctr = 0 for ifd in ifd_list: if ctr == 0: ifd_name = 'Image' elif ctr == 1: ifd_name = 'Thumbnail' thumb_ifd = ifd else: ifd_name = 'IFD %d' % ctr logger.debug('IFD %d (%s) at offset %s:', ctr, ifd_name, ifd) hdr.dump_ifd(ifd, ifd_name, stop_tag=stop_tag) ctr += 1 # EXIF IFD exif_off = hdr.tags.get('Image ExifOffset') if exif_off: logger.debug('Exif SubIFD at offset %s:', exif_off.values[0]) hdr.dump_ifd(exif_off.values[0], 'EXIF', stop_tag=stop_tag) # deal with MakerNote contained in EXIF IFD # (Some apps use MakerNote tags but do not use a format for which we # have a description, do not process these). if details and 'EXIF MakerNote' in hdr.tags and 'Image Make' in hdr.tags: hdr.decode_maker_note() # extract thumbnails if details and thumb_ifd: hdr.extract_tiff_thumbnail(thumb_ifd) hdr.extract_jpeg_thumbnail() # parse XMP tags (experimental) if debug and details: xmp_string = b'' # Easy we already have them if 'Image ApplicationNotes' in hdr.tags: logger.debug('XMP present in Exif') xmp_string = make_string(hdr.tags['Image ApplicationNotes'].values) # We need to look in the entire file for the XML else: logger.debug('XMP not in Exif, searching file for XMP info...') xml_started = False xml_finished = False for line in f: open_tag = line.find(b'') if open_tag != -1: xml_started = True line = line[open_tag:] logger.debug('XMP found opening tag at line position %s' % open_tag) if close_tag != -1: logger.debug('XMP found closing tag at line position %s' % close_tag) line_offset = 0 if open_tag != -1: line_offset = open_tag line = line[:(close_tag - line_offset) + 12] xml_finished = True if xml_started: xmp_string += line if xml_finished: break logger.debug('XMP Finished searching for info') if xmp_string: hdr.parse_xmp(xmp_string) return hdr.tags