291 lines
9.6 KiB
Python
291 lines
9.6 KiB
Python
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#Copyright ReportLab Europe Ltd. 2000-2017
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#see license.txt for license details
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#history https://hg.reportlab.com/hg-public/reportlab/log/tip/src/reportlab/pdfbase/pdfutils.py
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__version__='3.3.0'
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__doc__=''
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# pdfutils.py - everything to do with images, streams,
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# compression, and some constants
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import sys
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import os
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import binascii
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from reportlab import rl_config
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from reportlab.lib.utils import getBytesIO, ImageReader, isUnicode, isPy3
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from reportlab.lib.rl_accel import asciiBase85Encode, asciiBase85Decode
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def _chunker(src,dst=[],chunkSize=60):
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for i in range(0,len(src),chunkSize):
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dst.append(src[i:i+chunkSize])
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return dst
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##########################################################
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#
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# Image compression helpers. Preprocessing a directory
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# of images will offer a vast speedup.
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#
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##########################################################
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_mode2cs = {'RGB':'RGB', 'CMYK': 'CMYK', 'L': 'G'}
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_mode2bpp = {'RGB': 3, 'CMYK':4, 'L':1}
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def makeA85Image(filename,IMG=None, detectJpeg=False):
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import zlib
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img = ImageReader(filename)
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if IMG is not None:
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IMG.append(img)
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if detectJpeg and img.jpeg_fh():
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return None
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imgwidth, imgheight = img.getSize()
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raw = img.getRGBData()
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code = []
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append = code.append
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# this describes what is in the image itself
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append('BI')
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append('/W %s /H %s /BPC 8 /CS /%s /F [/A85 /Fl]' % (imgwidth, imgheight,_mode2cs[img.mode]))
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append('ID')
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#use a flate filter and Ascii Base 85
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assert len(raw) == imgwidth * imgheight*_mode2bpp[img.mode], "Wrong amount of data for image"
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compressed = zlib.compress(raw) #this bit is very fast...
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encoded = asciiBase85Encode(compressed) #...sadly this may not be
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#append in blocks of 60 characters
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_chunker(encoded,code)
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append('EI')
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return code
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def makeRawImage(filename,IMG=None,detectJpeg=False):
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import zlib
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img = ImageReader(filename)
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if IMG is not None:
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IMG.append(img)
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if detectJpeg and img.jpeg_fh():
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return None
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imgwidth, imgheight = img.getSize()
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raw = img.getRGBData()
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code = []
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append = code.append
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# this describes what is in the image itself
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append('BI')
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append('/W %s /H %s /BPC 8 /CS /%s /F [/Fl]' % (imgwidth, imgheight,_mode2cs[img.mode]))
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append('ID')
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#use a flate filter
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assert len(raw) == imgwidth * imgheight*_mode2bpp[img.mode], "Wrong amount of data for image"
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compressed = zlib.compress(raw) #this bit is very fast...
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#append in blocks of 60 characters
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_chunker(compressed,code)
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append('EI')
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return code
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def cacheImageFile(filename, returnInMemory=0, IMG=None):
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"Processes image as if for encoding, saves to a file with .a85 extension."
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cachedname = os.path.splitext(filename)[0] + (rl_config.useA85 and '.a85' or '.bin')
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if filename==cachedname:
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if cachedImageExists(filename):
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from reportlab.lib.utils import open_for_read
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if returnInMemory: return filter(None,open_for_read(cachedname).read().split('\r\n'))
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else:
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raise IOError('No such cached image %s' % filename)
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else:
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if rl_config.useA85:
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code = makeA85Image(filename,IMG)
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else:
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code = makeRawImage(filename,IMG)
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if returnInMemory: return code
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#save it to a file
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f = open(cachedname,'wb')
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f.write('\r\n'.join(code)+'\r\n')
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f.close()
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if rl_config.verbose:
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print('cached image as %s' % cachedname)
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def preProcessImages(spec):
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"""Preprocesses one or more image files.
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Accepts either a filespec ('C:\\mydir\\*.jpg') or a list
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of image filenames, crunches them all to save time. Run this
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to save huge amounts of time when repeatedly building image
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documents."""
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import glob
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if isinstance(spec,str):
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filelist = glob.glob(spec)
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else: #list or tuple OK
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filelist = spec
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for filename in filelist:
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if cachedImageExists(filename):
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if rl_config.verbose:
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print('cached version of %s already exists' % filename)
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else:
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cacheImageFile(filename)
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def cachedImageExists(filename):
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"""Determines if a cached image already exists for a given file.
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Determines if a cached image exists which has the same name
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and equal or newer date to the given file."""
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cachedname = os.path.splitext(filename)[0] + (rl_config.useA85 and '.a85' or 'bin')
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if os.path.isfile(cachedname):
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#see if it is newer
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original_date = os.stat(filename)[8]
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cached_date = os.stat(cachedname)[8]
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if original_date > cached_date:
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return 0
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else:
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return 1
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else:
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return 0
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##############################################################
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#
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# PDF Helper functions
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#
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##############################################################
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def _normalizeLineEnds(text,desired='\r\n',unlikely='\x00\x01\x02\x03'):
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"""Normalizes different line end character(s).
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Ensures all instances of CR, LF and CRLF end up as
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the specified one."""
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return (text
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.replace('\r\n', unlikely)
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.replace('\r', unlikely)
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.replace('\n', unlikely)
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.replace(unlikely, desired))
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def _AsciiHexEncode(input):
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"""Encodes input using ASCII-Hex coding.
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This is a verbose encoding used for binary data within
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a PDF file. One byte binary becomes two bytes of ASCII.
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Helper function used by images."""
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if isUnicode(input):
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input = input.encode('utf-8')
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output = getBytesIO()
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output.write(binascii.b2a_hex(input))
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output.write(b'>')
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return output.getvalue()
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def _AsciiHexDecode(input):
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"""Decodes input using ASCII-Hex coding.
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Not used except to provide a test of the inverse function."""
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#strip out all whitespace
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if not isUnicode(input):
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input = input.decode('utf-8')
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stripped = ''.join(input.split())
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assert stripped[-1] == '>', 'Invalid terminator for Ascii Hex Stream'
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stripped = stripped[:-1] #chop off terminator
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assert len(stripped) % 2 == 0, 'Ascii Hex stream has odd number of bytes'
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return ''.join([chr(int(stripped[i:i+2],16)) for i in range(0,len(stripped),2)])
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def _wrap(input, columns=60):
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"Wraps input at a given column size by inserting \r\n characters."
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output = []
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length = len(input)
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i = 0
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pos = columns * i
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while pos < length:
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output.append(input[pos:pos+columns])
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i = i + 1
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pos = columns * i
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#avoid HP printer problem
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if len(output[-1])==1:
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output[-2:] = [output[-2][:-1],output[-2][-1]+output[-1]]
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return '\r\n'.join(output)
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#########################################################################
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#
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# JPEG processing code - contributed by Eric Johnson
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#
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#########################################################################
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# Read data from the JPEG file. We should probably be using PIL to
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# get this information for us -- but this way is more fun!
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# Returns (width, height, color components) as a triple
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# This is based on Thomas Merz's code from GhostScript (viewjpeg.ps)
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def readJPEGInfo(image):
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"Read width, height and number of components from open JPEG file."
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import struct
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from reportlab.pdfbase.pdfdoc import PDFError
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#Acceptable JPEG Markers:
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# SROF0=baseline, SOF1=extended sequential or SOF2=progressive
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validMarkers = [0xC0, 0xC1, 0xC2]
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#JPEG markers without additional parameters
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noParamMarkers = \
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[ 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0x01 ]
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#Unsupported JPEG Markers
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unsupportedMarkers = \
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[ 0xC3, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCD, 0xCE, 0xCF ]
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#read JPEG marker segments until we find SOFn marker or EOF
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done = 0
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while not done:
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x = struct.unpack('B', image.read(1))
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if x[0] == 0xFF: #found marker
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x = struct.unpack('B', image.read(1))
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#print "Marker: ", '%0.2x' % x[0]
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#check marker type is acceptable and process it
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if x[0] in validMarkers:
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image.seek(2, 1) #skip segment length
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x = struct.unpack('B', image.read(1)) #data precision
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if x[0] != 8:
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raise PDFError('JPEG must have 8 bits per component')
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y = struct.unpack('BB', image.read(2))
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height = (y[0] << 8) + y[1]
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y = struct.unpack('BB', image.read(2))
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width = (y[0] << 8) + y[1]
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y = struct.unpack('B', image.read(1))
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color = y[0]
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return width, height, color
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elif x[0] in unsupportedMarkers:
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raise PDFError('JPEG Unsupported JPEG marker: %0.2x' % x[0])
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elif x[0] not in noParamMarkers:
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#skip segments with parameters
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#read length and skip the data
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x = struct.unpack('BB', image.read(2))
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image.seek( (x[0] << 8) + x[1] - 2, 1)
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class _fusc:
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def __init__(self,k, n):
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assert k, 'Argument k should be a non empty string'
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self._k = k
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self._klen = len(k)
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self._n = int(n) or 7
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def encrypt(self,s):
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return self.__rotate(asciiBase85Encode(''.join(map(chr,self.__fusc(list(map(ord,s)))))),self._n)
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def decrypt(self,s):
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return ''.join(map(chr,self.__fusc(list(map(ord,asciiBase85Decode(self.__rotate(s,-self._n)))))))
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def __rotate(self,s,n):
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l = len(s)
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if n<0: n = l+n
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n %= l
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if not n: return s
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return s[-n:]+s[:l-n]
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def __fusc(self,s):
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slen = len(s)
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return list(map(lambda x,y: x ^ y,s,list(map(ord,((int(slen/self._klen)+1)*self._k)[:slen]))))
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