"""Recognize image file formats based on their first few bytes."""__all__ = ["what"]#-------------------------## 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_exif(h, f): """JPEG data in Exif format""" if h[6:10] == 'Exif': return 'jpeg'tests.append(test_exif)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 ***'
"""Recognize image file formats based on their first few bytes."""
__all__ = ["what"]
#-------------------------#
# 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_exif(h, f):
"""JPEG data in Exif format"""
if h[6:10] == 'Exif':
return 'jpeg'
tests.append(test_exif)
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 ***'