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"""Recognize image file formats based on their first few bytes.""" |
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from os import PathLike |
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__all__ = ["what"] |
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def what(file, h=None): |
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f = None |
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try: |
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if h is None: |
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if isinstance(file, (str, PathLike)): |
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f = open(file, 'rb') |
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h = f.read(32) |
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else: |
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location = file.tell() |
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h = file.read(32) |
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file.seek(location) |
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for tf in tests: |
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res = tf(h, f) |
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if res: |
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return res |
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finally: |
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if f: f.close() |
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return None |
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tests = [] |
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def test_jpeg(h, f): |
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"""JPEG data in JFIF or Exif format""" |
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if h[6:10] in (b'JFIF', b'Exif'): |
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return 'jpeg' |
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tests.append(test_jpeg) |
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def test_png(h, f): |
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if h.startswith(b'\211PNG\r\n\032\n'): |
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return 'png' |
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tests.append(test_png) |
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def test_gif(h, f): |
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"""GIF ('87 and '89 variants)""" |
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if h[:6] in (b'GIF87a', b'GIF89a'): |
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return 'gif' |
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tests.append(test_gif) |
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def test_tiff(h, f): |
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"""TIFF (can be in Motorola or Intel byte order)""" |
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if h[:2] in (b'MM', b'II'): |
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return 'tiff' |
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tests.append(test_tiff) |
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def test_rgb(h, f): |
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"""SGI image library""" |
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if h.startswith(b'\001\332'): |
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return 'rgb' |
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tests.append(test_rgb) |
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def test_pbm(h, f): |
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"""PBM (portable bitmap)""" |
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if len(h) >= 3 and \ |
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h[0] == ord(b'P') and h[1] in b'14' and h[2] in b' \t\n\r': |
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return 'pbm' |
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tests.append(test_pbm) |
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def test_pgm(h, f): |
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"""PGM (portable graymap)""" |
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if len(h) >= 3 and \ |
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h[0] == ord(b'P') and h[1] in b'25' and h[2] in b' \t\n\r': |
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return 'pgm' |
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tests.append(test_pgm) |
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def test_ppm(h, f): |
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"""PPM (portable pixmap)""" |
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if len(h) >= 3 and \ |
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h[0] == ord(b'P') and h[1] in b'36' and h[2] in b' \t\n\r': |
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return 'ppm' |
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tests.append(test_ppm) |
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def test_rast(h, f): |
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"""Sun raster file""" |
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if h.startswith(b'\x59\xA6\x6A\x95'): |
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return 'rast' |
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tests.append(test_rast) |
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def test_xbm(h, f): |
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"""X bitmap (X10 or X11)""" |
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if h.startswith(b'#define '): |
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return 'xbm' |
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tests.append(test_xbm) |
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def test_bmp(h, f): |
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if h.startswith(b'BM'): |
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return 'bmp' |
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tests.append(test_bmp) |
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def test_webp(h, f): |
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if h.startswith(b'RIFF') and h[8:12] == b'WEBP': |
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return 'webp' |
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tests.append(test_webp) |
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def test_exr(h, f): |
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if h.startswith(b'\x76\x2f\x31\x01'): |
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return 'exr' |
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tests.append(test_exr) |
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def test(): |
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import sys |
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recursive = 0 |
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if sys.argv[1:] and sys.argv[1] == '-r': |
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del sys.argv[1:2] |
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recursive = 1 |
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try: |
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if sys.argv[1:]: |
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testall(sys.argv[1:], recursive, 1) |
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else: |
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testall(['.'], recursive, 1) |
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except KeyboardInterrupt: |
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sys.stderr.write('\n[Interrupted]\n') |
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sys.exit(1) |
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def testall(list, recursive, toplevel): |
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import sys |
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import os |
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for filename in list: |
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if os.path.isdir(filename): |
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print(filename + '/:', end=' ') |
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if recursive or toplevel: |
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print('recursing down:') |
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import glob |
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names = glob.glob(os.path.join(glob.escape(filename), '*')) |
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testall(names, recursive, 0) |
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else: |
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print('*** directory (use -r) ***') |
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else: |
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print(filename + ':', end=' ') |
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sys.stdout.flush() |
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try: |
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print(what(filename)) |
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except OSError: |
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print('*** not found ***') |
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if __name__ == '__main__': |
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test() |
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