| 1 | #! /usr/bin/env python
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| 2 |
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| 3 | """Conversions to/from quoted-printable transport encoding as per RFC 1521."""
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| 4 |
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| 5 | # (Dec 1991 version).
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| 6 |
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| 7 | __all__ = ["encode", "decode", "encodestring", "decodestring"]
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| 8 |
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| 9 | ESCAPE = '='
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| 10 | MAXLINESIZE = 76
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| 11 | HEX = '0123456789ABCDEF'
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| 12 | EMPTYSTRING = ''
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| 13 |
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| 14 | try:
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| 15 | from binascii import a2b_qp, b2a_qp
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| 16 | except ImportError:
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| 17 | a2b_qp = None
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| 18 | b2a_qp = None
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| 19 |
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| 20 |
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| 21 | def needsquoting(c, quotetabs, header):
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| 22 | """Decide whether a particular character needs to be quoted.
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| 23 |
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| 24 | The 'quotetabs' flag indicates whether embedded tabs and spaces should be
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| 25 | quoted. Note that line-ending tabs and spaces are always encoded, as per
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| 26 | RFC 1521.
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| 27 | """
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| 28 | if c in ' \t':
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| 29 | return quotetabs
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| 30 | # if header, we have to escape _ because _ is used to escape space
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| 31 | if c == '_':
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| 32 | return header
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| 33 | return c == ESCAPE or not (' ' <= c <= '~')
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| 34 |
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| 35 | def quote(c):
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| 36 | """Quote a single character."""
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| 37 | i = ord(c)
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| 38 | return ESCAPE + HEX[i//16] + HEX[i%16]
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| 39 |
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| 40 |
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| 41 |
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| 42 | def encode(input, output, quotetabs, header = 0):
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| 43 | """Read 'input', apply quoted-printable encoding, and write to 'output'.
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| 44 |
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| 45 | 'input' and 'output' are files with readline() and write() methods.
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| 46 | The 'quotetabs' flag indicates whether embedded tabs and spaces should be
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| 47 | quoted. Note that line-ending tabs and spaces are always encoded, as per
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| 48 | RFC 1521.
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| 49 | The 'header' flag indicates whether we are encoding spaces as _ as per
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| 50 | RFC 1522.
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| 51 | """
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| 52 |
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| 53 | if b2a_qp is not None:
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| 54 | data = input.read()
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| 55 | odata = b2a_qp(data, quotetabs = quotetabs, header = header)
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| 56 | output.write(odata)
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| 57 | return
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| 58 |
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| 59 | def write(s, output=output, lineEnd='\n'):
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| 60 | # RFC 1521 requires that the line ending in a space or tab must have
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| 61 | # that trailing character encoded.
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| 62 | if s and s[-1:] in ' \t':
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| 63 | output.write(s[:-1] + quote(s[-1]) + lineEnd)
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| 64 | elif s == '.':
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| 65 | output.write(quote(s) + lineEnd)
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| 66 | else:
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| 67 | output.write(s + lineEnd)
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| 68 |
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| 69 | prevline = None
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| 70 | while 1:
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| 71 | line = input.readline()
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