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PdfFileTransformer/PyPDF2/utils.py
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309
PdfFileTransformer/PyPDF2/utils.py
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# Copyright (c) 2006, Mathieu Fenniak
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# * Redistributions of source code must retain the above copyright notice,
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# this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above copyright notice,
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# this list of conditions and the following disclaimer in the documentation
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# and/or other materials provided with the distribution.
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# * The name of the author may not be used to endorse or promote products
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# derived from this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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"""
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Utility functions for PDF library.
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"""
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__author__ = "Mathieu Fenniak"
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__author_email__ = "biziqe@mathieu.fenniak.net"
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import sys
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try:
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import __builtin__ as builtins
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except ImportError: # Py3
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import builtins
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xrange_fn = getattr(builtins, "xrange", range)
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_basestring = getattr(builtins, "basestring", str)
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bytes_type = type(bytes()) # Works the same in Python 2.X and 3.X
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string_type = getattr(builtins, "unicode", str)
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int_types = (int, long) if sys.version_info[0] < 3 else (int,)
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# Make basic type tests more consistent
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def isString(s):
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"""Test if arg is a string. Compatible with Python 2 and 3."""
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return isinstance(s, _basestring)
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def isInt(n):
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"""Test if arg is an int. Compatible with Python 2 and 3."""
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return isinstance(n, int_types)
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def isBytes(b):
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"""Test if arg is a bytes instance. Compatible with Python 2 and 3."""
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return isinstance(b, bytes_type)
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#custom implementation of warnings.formatwarning
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def formatWarning(message, category, filename, lineno, line=None):
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file = filename.replace("/", "\\").rsplit("\\", 1)[1] # find the file name
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return "%s: %s [%s:%s]\n" % (category.__name__, message, file, lineno)
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def readUntilWhitespace(stream, maxchars=None):
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"""
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Reads non-whitespace characters and returns them.
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Stops upon encountering whitespace or when maxchars is reached.
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"""
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txt = b_("")
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while True:
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tok = stream.read(1)
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if tok.isspace() or not tok:
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break
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txt += tok
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if len(txt) == maxchars:
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break
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return txt
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def readNonWhitespace(stream):
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"""
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Finds and reads the next non-whitespace character (ignores whitespace).
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"""
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tok = WHITESPACES[0]
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while tok in WHITESPACES:
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tok = stream.read(1)
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return tok
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def skipOverWhitespace(stream):
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"""
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Similar to readNonWhitespace, but returns a Boolean if more than
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one whitespace character was read.
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"""
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tok = WHITESPACES[0]
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cnt = 0;
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while tok in WHITESPACES:
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tok = stream.read(1)
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cnt+=1
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return (cnt > 1)
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def skipOverComment(stream):
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tok = stream.read(1)
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stream.seek(-1, 1)
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if tok == b_('%'):
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while tok not in (b_('\n'), b_('\r')):
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tok = stream.read(1)
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def readUntilRegex(stream, regex, ignore_eof=False):
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"""
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Reads until the regular expression pattern matched (ignore the match)
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Raise PdfStreamError on premature end-of-file.
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:param bool ignore_eof: If true, ignore end-of-line and return immediately
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"""
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name = b_('')
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while True:
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tok = stream.read(16)
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if not tok:
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# stream has truncated prematurely
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if ignore_eof == True:
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return name
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else:
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raise PdfStreamError("Stream has ended unexpectedly")
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m = regex.search(tok)
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if m is not None:
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name += tok[:m.start()]
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stream.seek(m.start()-len(tok), 1)
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break
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name += tok
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return name
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class ConvertFunctionsToVirtualList(object):
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def __init__(self, lengthFunction, getFunction):
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self.lengthFunction = lengthFunction
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self.getFunction = getFunction
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def __len__(self):
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return self.lengthFunction()
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def __getitem__(self, index):
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if isinstance(index, slice):
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indices = xrange_fn(*index.indices(len(self)))
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cls = type(self)
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return cls(indices.__len__, lambda idx: self[indices[idx]])
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if not isInt(index):
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raise TypeError("sequence indices must be integers")
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len_self = len(self)
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if index < 0:
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# support negative indexes
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index = len_self + index
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if index < 0 or index >= len_self:
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raise IndexError("sequence index out of range")
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return self.getFunction(index)
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def RC4_encrypt(key, plaintext):
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S = [i for i in range(256)]
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j = 0
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for i in range(256):
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j = (j + S[i] + ord_(key[i % len(key)])) % 256
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S[i], S[j] = S[j], S[i]
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i, j = 0, 0
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retval = []
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for x in range(len(plaintext)):
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i = (i + 1) % 256
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j = (j + S[i]) % 256
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S[i], S[j] = S[j], S[i]
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t = S[(S[i] + S[j]) % 256]
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retval.append(b_(chr(ord_(plaintext[x]) ^ t)))
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return b_("").join(retval)
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def matrixMultiply(a, b):
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return [[sum([float(i)*float(j)
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for i, j in zip(row, col)]
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) for col in zip(*b)]
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for row in a]
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def markLocation(stream):
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"""Creates text file showing current location in context."""
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# Mainly for debugging
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RADIUS = 5000
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stream.seek(-RADIUS, 1)
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outputDoc = open('PyPDF2_pdfLocation.txt', 'w')
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outputDoc.write(stream.read(RADIUS))
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outputDoc.write('HERE')
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outputDoc.write(stream.read(RADIUS))
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outputDoc.close()
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stream.seek(-RADIUS, 1)
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class PyPdfError(Exception):
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pass
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class PdfReadError(PyPdfError):
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pass
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class PageSizeNotDefinedError(PyPdfError):
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pass
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class PdfReadWarning(UserWarning):
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pass
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class PdfStreamError(PdfReadError):
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pass
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if sys.version_info[0] < 3:
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def b_(s):
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return s
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else:
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B_CACHE = {}
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def b_(s):
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bc = B_CACHE
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if s in bc:
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return bc[s]
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if type(s) == bytes:
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return s
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else:
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r = s.encode('latin-1')
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if len(s) < 2:
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bc[s] = r
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return r
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def u_(s):
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if sys.version_info[0] < 3:
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return unicode(s, 'unicode_escape')
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else:
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return s
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def str_(b):
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if sys.version_info[0] < 3:
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return b
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else:
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if type(b) == bytes:
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return b.decode('latin-1')
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else:
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return b
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def ord_(b):
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if sys.version_info[0] < 3 or type(b) == str:
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return ord(b)
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else:
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return b
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def chr_(c):
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if sys.version_info[0] < 3:
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return c
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else:
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return chr(c)
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def barray(b):
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if sys.version_info[0] < 3:
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return b
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else:
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return bytearray(b)
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def hexencode(b):
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if sys.version_info[0] < 3:
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return b.encode('hex')
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else:
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import codecs
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coder = codecs.getencoder('hex_codec')
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return coder(b)[0]
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def hexStr(num):
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return hex(num).replace('L', '')
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WHITESPACES = [b_(x) for x in [' ', '\n', '\r', '\t', '\x00']]
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def paethPredictor(left, up, up_left):
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p = left + up - up_left
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dist_left = abs(p - left)
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dist_up = abs(p - up)
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dist_up_left = abs(p - up_left)
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if dist_left <= dist_up and dist_left <= dist_up_left:
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return left
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elif dist_up <= dist_up_left:
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return up
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else:
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return up_left
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