61 lines
1.9 KiB
Python
61 lines
1.9 KiB
Python
import StringIO
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import struct
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def getImageInfo(data):
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data = str(data)
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size = len(data)
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height = -1
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width = -1
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content_type = ''
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# handle GIFs
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if (size >= 10) and data[:6] in ('GIF87a', 'GIF89a'):
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# Check to see if content_type is correct
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content_type = 'image/gif'
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w, h = struct.unpack("<HH", data[6:10])
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width = int(w)
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height = int(h)
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# See PNG 2. Edition spec (http://www.w3.org/TR/PNG/)
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# Bytes 0-7 are below, 4-byte chunk length, then 'IHDR'
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# and finally the 4-byte width, height
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elif ((size >= 24) and data.startswith('\211PNG\r\n\032\n')
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and (data[12:16] == 'IHDR')):
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content_type = 'image/png'
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w, h = struct.unpack(">LL", data[16:24])
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width = int(w)
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height = int(h)
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# Maybe this is for an older PNG version.
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elif (size >= 16) and data.startswith('\211PNG\r\n\032\n'):
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# Check to see if we have the right content type
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content_type = 'image/png'
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w, h = struct.unpack(">LL", data[8:16])
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width = int(w)
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height = int(h)
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# handle JPEGs
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elif (size >= 2) and data.startswith('\377\330'):
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content_type = 'image/jpeg'
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jpeg = StringIO.StringIO(data)
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jpeg.read(2)
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b = jpeg.read(1)
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try:
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while (b and ord(b) != 0xDA):
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while (ord(b) != 0xFF): b = jpeg.read(1)
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while (ord(b) == 0xFF): b = jpeg.read(1)
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if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
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jpeg.read(3)
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h, w = struct.unpack(">HH", jpeg.read(4))
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break
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else:
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jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
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b = jpeg.read(1)
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width = int(w)
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height = int(h)
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except struct.error:
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pass
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except ValueError:
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pass
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return content_type, width, height |