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- # Recognizing image files based on their first few bytes.
-
-
- #-------------------------#
- # Recognize image headers #
- #-------------------------#
-
- def what(file, h=None):
- if h is None:
- if type(file) == type(''):
- f = open(file, 'rb')
- h = f.read(32)
- else:
- location = file.tell()
- h = file.read(32)
- file.seek(location)
- f = None
- else:
- f = None
- try:
- for tf in tests:
- res = tf(h, f)
- if res:
- return res
- finally:
- if f: f.close()
- return None
-
-
- #---------------------------------#
- # Subroutines per image file type #
- #---------------------------------#
-
- tests = []
-
- def test_rgb(h, f):
- # SGI image library
- if h[:2] == '\001\332':
- return 'rgb'
-
- tests.append(test_rgb)
-
- def test_gif(h, f):
- # GIF ('87 and '89 variants)
- if h[:6] in ('GIF87a', 'GIF89a'):
- return 'gif'
-
- tests.append(test_gif)
-
- def test_pbm(h, f):
- # PBM (portable bitmap)
- if len(h) >= 3 and \
- h[0] == 'P' and h[1] in '14' and h[2] in ' \t\n\r':
- return 'pbm'
-
- tests.append(test_pbm)
-
- def test_pgm(h, f):
- # PGM (portable graymap)
- if len(h) >= 3 and \
- h[0] == 'P' and h[1] in '25' and h[2] in ' \t\n\r':
- return 'pgm'
-
- tests.append(test_pgm)
-
- def test_ppm(h, f):
- # PPM (portable pixmap)
- if len(h) >= 3 and \
- h[0] == 'P' and h[1] in '36' and h[2] in ' \t\n\r':
- return 'ppm'
-
- tests.append(test_ppm)
-
- def test_tiff(h, f):
- # TIFF (can be in Motorola or Intel byte order)
- if h[:2] in ('MM', 'II'):
- return 'tiff'
-
- tests.append(test_tiff)
-
- def test_rast(h, f):
- # Sun raster file
- if h[:4] == '\x59\xA6\x6A\x95':
- return 'rast'
-
- tests.append(test_rast)
-
- def test_xbm(h, f):
- # X bitmap (X10 or X11)
- s = '#define '
- if h[:len(s)] == s:
- return 'xbm'
-
- tests.append(test_xbm)
-
- def test_jpeg(h, f):
- # JPEG data in JFIF format
- if h[6:10] == 'JFIF':
- return 'jpeg'
-
- tests.append(test_jpeg)
-
- def test_bmp(h, f):
- if h[:2] == 'BM':
- return 'bmp'
-
- tests.append(test_bmp)
-
- def test_png(h, f):
- if h[:8] == "\211PNG\r\n\032\n":
- return 'png'
-
- tests.append(test_png)
-
- #--------------------#
- # Small test program #
- #--------------------#
-
- def test():
- import sys
- recursive = 0
- if sys.argv[1:] and sys.argv[1] == '-r':
- del sys.argv[1:2]
- recursive = 1
- try:
- if sys.argv[1:]:
- testall(sys.argv[1:], recursive, 1)
- else:
- testall(['.'], recursive, 1)
- except KeyboardInterrupt:
- sys.stderr.write('\n[Interrupted]\n')
- sys.exit(1)
-
- def testall(list, recursive, toplevel):
- import sys
- import os
- for filename in list:
- if os.path.isdir(filename):
- print filename + '/:',
- if recursive or toplevel:
- print 'recursing down:'
- import glob
- names = glob.glob(os.path.join(filename, '*'))
- testall(names, recursive, 0)
- else:
- print '*** directory (use -r) ***'
- else:
- print filename + ':',
- sys.stdout.flush()
- try:
- print what(filename)
- except IOError:
- print '*** not found ***'
-