1"""Recognize image file formats based on their first few bytes.""" 2 3from os import PathLike 4import warnings 5 6__all__ = ["what"] 7 8 9warnings._deprecated(__name__, remove=(3, 13)) 10 11 12#-------------------------# 13# Recognize image headers # 14#-------------------------# 15 16def what(file, h=None): 17 f = None 18 try: 19 if h is None: 20 if isinstance(file, (str, PathLike)): 21 f = open(file, 'rb') 22 h = f.read(32) 23 else: 24 location = file.tell() 25 h = file.read(32) 26 file.seek(location) 27 for tf in tests: 28 res = tf(h, f) 29 if res: 30 return res 31 finally: 32 if f: f.close() 33 return None 34 35 36#---------------------------------# 37# Subroutines per image file type # 38#---------------------------------# 39 40tests = [] 41 42def test_jpeg(h, f): 43 """JPEG data with JFIF or Exif markers; and raw JPEG""" 44 if h[6:10] in (b'JFIF', b'Exif'): 45 return 'jpeg' 46 elif h[:4] == b'\xff\xd8\xff\xdb': 47 return 'jpeg' 48 49tests.append(test_jpeg) 50 51def test_png(h, f): 52 if h.startswith(b'\211PNG\r\n\032\n'): 53 return 'png' 54 55tests.append(test_png) 56 57def test_gif(h, f): 58 """GIF ('87 and '89 variants)""" 59 if h[:6] in (b'GIF87a', b'GIF89a'): 60 return 'gif' 61 62tests.append(test_gif) 63 64def test_tiff(h, f): 65 """TIFF (can be in Motorola or Intel byte order)""" 66 if h[:2] in (b'MM', b'II'): 67 return 'tiff' 68 69tests.append(test_tiff) 70 71def test_rgb(h, f): 72 """SGI image library""" 73 if h.startswith(b'\001\332'): 74 return 'rgb' 75 76tests.append(test_rgb) 77 78def test_pbm(h, f): 79 """PBM (portable bitmap)""" 80 if len(h) >= 3 and \ 81 h[0] == ord(b'P') and h[1] in b'14' and h[2] in b' \t\n\r': 82 return 'pbm' 83 84tests.append(test_pbm) 85 86def test_pgm(h, f): 87 """PGM (portable graymap)""" 88 if len(h) >= 3 and \ 89 h[0] == ord(b'P') and h[1] in b'25' and h[2] in b' \t\n\r': 90 return 'pgm' 91 92tests.append(test_pgm) 93 94def test_ppm(h, f): 95 """PPM (portable pixmap)""" 96 if len(h) >= 3 and \ 97 h[0] == ord(b'P') and h[1] in b'36' and h[2] in b' \t\n\r': 98 return 'ppm' 99 100tests.append(test_ppm) 101 102def test_rast(h, f): 103 """Sun raster file""" 104 if h.startswith(b'\x59\xA6\x6A\x95'): 105 return 'rast' 106 107tests.append(test_rast) 108 109def test_xbm(h, f): 110 """X bitmap (X10 or X11)""" 111 if h.startswith(b'#define '): 112 return 'xbm' 113 114tests.append(test_xbm) 115 116def test_bmp(h, f): 117 if h.startswith(b'BM'): 118 return 'bmp' 119 120tests.append(test_bmp) 121 122def test_webp(h, f): 123 if h.startswith(b'RIFF') and h[8:12] == b'WEBP': 124 return 'webp' 125 126tests.append(test_webp) 127 128def test_exr(h, f): 129 if h.startswith(b'\x76\x2f\x31\x01'): 130 return 'exr' 131 132tests.append(test_exr) 133 134#--------------------# 135# Small test program # 136#--------------------# 137 138def test(): 139 import sys 140 recursive = 0 141 if sys.argv[1:] and sys.argv[1] == '-r': 142 del sys.argv[1:2] 143 recursive = 1 144 try: 145 if sys.argv[1:]: 146 testall(sys.argv[1:], recursive, 1) 147 else: 148 testall(['.'], recursive, 1) 149 except KeyboardInterrupt: 150 sys.stderr.write('\n[Interrupted]\n') 151 sys.exit(1) 152 153def testall(list, recursive, toplevel): 154 import sys 155 import os 156 for filename in list: 157 if os.path.isdir(filename): 158 print(filename + '/:', end=' ') 159 if recursive or toplevel: 160 print('recursing down:') 161 import glob 162 names = glob.glob(os.path.join(glob.escape(filename), '*')) 163 testall(names, recursive, 0) 164 else: 165 print('*** directory (use -r) ***') 166 else: 167 print(filename + ':', end=' ') 168 sys.stdout.flush() 169 try: 170 print(what(filename)) 171 except OSError: 172 print('*** not found ***') 173 174if __name__ == '__main__': 175 test() 176