71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256 | def get(fhandle: io.BytesIO) -> tuple[int, int]:
"""Return (width, height) for a given image file content.
Args:
fhandle: A BytesIO object containing image data.
Returns:
A tuple of (width, height). Returns (-1, -1) if the format is not recognized.
Raises:
ValueError: If the file data is invalid for its detected format.
"""
height = -1
width = -1
try:
head = fhandle.read(31)
size = len(head)
# handle GIFs
if size >= 10 and head[:6] in (b'GIF87a', b'GIF89a'):
# Check to see if content_type is correct
try:
width, height = struct.unpack("<hh", head[6:10])
except struct.error:
raise ValueError("Invalid GIF file") from None
# see png edition spec bytes are below chunk length then and finally the
elif size >= 24 and head.startswith(b'\211PNG\r\n\032\n') and head[12:16] == b'IHDR':
try:
width, height = struct.unpack(">LL", head[16:24])
except struct.error:
raise ValueError("Invalid PNG file") from None
# Maybe this is for an older PNG version.
elif size >= 16 and head.startswith(b'\211PNG\r\n\032\n'):
# Check to see if we have the right content type
try:
width, height = struct.unpack(">LL", head[8:16])
except struct.error:
raise ValueError("Invalid PNG file") from None
# handle JPEGs
elif size >= 2 and head.startswith(b'\377\330'):
try:
fhandle.seek(0) # Read 0xff next
size = 2
ftype = 0
while not 0xc0 <= ftype <= 0xcf or ftype in [0xc4, 0xc8, 0xcc]:
fhandle.seek(size, 1)
byte = fhandle.read(1)
while ord(byte) == 0xff:
byte = fhandle.read(1)
ftype = ord(byte)
size = struct.unpack('>H', fhandle.read(2))[0] - 2
# We are at a SOFn block
fhandle.seek(1, 1) # Skip `precision' byte.
height, width = struct.unpack('>HH', fhandle.read(4))
except (struct.error, TypeError):
raise ValueError("Invalid JPEG file") from None
# handle JPEG2000s
elif size >= 12 and head.startswith(b'\x00\x00\x00\x0cjP \r\n\x87\n'):
fhandle.seek(48)
try:
height, width = struct.unpack('>LL', fhandle.read(8))
except struct.error:
raise ValueError("Invalid JPEG2000 file") from None
# handle big endian TIFF
elif size >= 8 and head.startswith(b"\x4d\x4d\x00\x2a"):
offset = struct.unpack('>L', head[4:8])[0]
fhandle.seek(offset)
ifdsize = struct.unpack(">H", fhandle.read(2))[0]
for _i in range(ifdsize):
tag, datatype, _count, data = struct.unpack(">HHLL", fhandle.read(12))
if tag == 256:
if datatype == 3:
width = int(data / 65536)
elif datatype == 4:
width = data
else:
raise ValueError("Invalid TIFF file: width column data type should be SHORT/LONG.")
elif tag == 257:
if datatype == 3:
height = int(data / 65536)
elif datatype == 4:
height = data
else:
raise ValueError("Invalid TIFF file: height column data type should be SHORT/LONG.")
if width != -1 and height != -1:
break
if width == -1 or height == -1:
raise ValueError("Invalid TIFF file: width and/or height IDS entries are missing.")
elif size >= 8 and head.startswith(b"\x49\x49\x2a\x00"):
offset = struct.unpack('<L', head[4:8])[0]
fhandle.seek(offset)
ifdsize = struct.unpack("<H", fhandle.read(2))[0]
for _i in range(ifdsize):
tag, datatype, _count, data = struct.unpack("<HHLL", fhandle.read(12))
if tag == 256:
width = data
elif tag == 257:
height = data
if width != -1 and height != -1:
break
if width == -1 or height == -1:
raise ValueError("Invalid TIFF file: width and/or height IDS entries are missing.")
# handle little endian BigTiff
elif size >= 8 and head.startswith(b"\x49\x49\x2b\x00"):
bytesize_offset = struct.unpack('<L', head[4:8])[0]
if bytesize_offset != 8:
raise ValueError(f'Invalid BigTIFF file: Expected offset to be 8, found {offset} instead.')
offset = struct.unpack('<Q', head[8:16])[0]
fhandle.seek(offset)
ifdsize = struct.unpack("<Q", fhandle.read(8))[0]
for _i in range(ifdsize):
tag, datatype, _count, data = struct.unpack("<HHQQ", fhandle.read(20))
if tag == 256:
width = data
elif tag == 257:
height = data
if width != -1 and height != -1:
break
if width == -1 or height == -1:
raise ValueError("Invalid BigTIFF file: width and/or height IDS entries are missing.")
# handle SVGs
elif size >= 5 and (head.startswith(b'<?xml') or head.startswith(b'<svg')):
fhandle.seek(0)
data = fhandle.read(1024)
try:
data = data.decode('utf-8')
width = re.search(r'[^-]width="(.*?)"', data).group(1)
height = re.search(r'[^-]height="(.*?)"', data).group(1)
except Exception:
raise ValueError("Invalid SVG file") from None
width = _convertToPx(width)
height = _convertToPx(height)
# handle Netpbm
elif head[:1] == b"P" and head[1:2] in b"123456":
fhandle.seek(2)
sizes = []
while True:
next_chr = fhandle.read(1)
if next_chr.isspace():
continue
if next_chr == b"":
raise ValueError("Invalid Netpbm file")
if next_chr == b"#":
fhandle.readline()
continue
if not next_chr.isdigit():
raise ValueError("Invalid character found on Netpbm file")
size = next_chr
next_chr = fhandle.read(1)
while next_chr.isdigit():
size += next_chr
next_chr = fhandle.read(1)
sizes.append(int(size))
if len(sizes) == 2:
break
fhandle.seek(-1, os.SEEK_CUR)
width, height = sizes
elif head.startswith(b"RIFF") and head[8:12] == b"WEBP":
if head[12:16] == b"VP8 ":
width, height = struct.unpack("<HH", head[26:30])
elif head[12:16] == b"VP8X":
width = struct.unpack("<I", head[24:27] + b"\0")[0]
height = struct.unpack("<I", head[27:30] + b"\0")[0]
elif head[12:16] == b"VP8L":
b = head[21:25]
width = (((b[1] & 63) << 8) | b[0]) + 1
height = (((b[3] & 15) << 10) | (b[2] << 2) | ((b[1] & 192) >> 6)) + 1
else:
raise ValueError("Unsupported WebP file")
finally:
fhandle.close()
return width, height
|