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c8b45a385a
* gh-118673: Remove shebang and executable bits from stdlib modules. * Removed shebangs and exe bits on turtledemo scripts. The setting was inappropriate for '__main__' and inconsistent across the other modules. The scripts can still be executed directly by invoking with the desired interpreter.
236 lines
7.0 KiB
Python
236 lines
7.0 KiB
Python
"""Conversions to/from quoted-printable transport encoding as per RFC 1521."""
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# (Dec 1991 version).
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__all__ = ["encode", "decode", "encodestring", "decodestring"]
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ESCAPE = b'='
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MAXLINESIZE = 76
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HEX = b'0123456789ABCDEF'
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EMPTYSTRING = b''
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try:
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from binascii import a2b_qp, b2a_qp
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except ImportError:
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a2b_qp = None
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b2a_qp = None
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def needsquoting(c, quotetabs, header):
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"""Decide whether a particular byte ordinal needs to be quoted.
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The 'quotetabs' flag indicates whether embedded tabs and spaces should be
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quoted. Note that line-ending tabs and spaces are always encoded, as per
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RFC 1521.
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"""
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assert isinstance(c, bytes)
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if c in b' \t':
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return quotetabs
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# if header, we have to escape _ because _ is used to escape space
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if c == b'_':
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return header
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return c == ESCAPE or not (b' ' <= c <= b'~')
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def quote(c):
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"""Quote a single character."""
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assert isinstance(c, bytes) and len(c)==1
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c = ord(c)
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return ESCAPE + bytes((HEX[c//16], HEX[c%16]))
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def encode(input, output, quotetabs, header=False):
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"""Read 'input', apply quoted-printable encoding, and write to 'output'.
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'input' and 'output' are binary file objects. The 'quotetabs' flag
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indicates whether embedded tabs and spaces should be quoted. Note that
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line-ending tabs and spaces are always encoded, as per RFC 1521.
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The 'header' flag indicates whether we are encoding spaces as _ as per RFC
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1522."""
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if b2a_qp is not None:
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data = input.read()
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odata = b2a_qp(data, quotetabs=quotetabs, header=header)
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output.write(odata)
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return
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def write(s, output=output, lineEnd=b'\n'):
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# RFC 1521 requires that the line ending in a space or tab must have
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# that trailing character encoded.
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if s and s[-1:] in b' \t':
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output.write(s[:-1] + quote(s[-1:]) + lineEnd)
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elif s == b'.':
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output.write(quote(s) + lineEnd)
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else:
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output.write(s + lineEnd)
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prevline = None
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while line := input.readline():
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outline = []
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# Strip off any readline induced trailing newline
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stripped = b''
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if line[-1:] == b'\n':
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line = line[:-1]
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stripped = b'\n'
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# Calculate the un-length-limited encoded line
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for c in line:
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c = bytes((c,))
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if needsquoting(c, quotetabs, header):
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c = quote(c)
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if header and c == b' ':
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outline.append(b'_')
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else:
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outline.append(c)
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# First, write out the previous line
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if prevline is not None:
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write(prevline)
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# Now see if we need any soft line breaks because of RFC-imposed
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# length limitations. Then do the thisline->prevline dance.
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thisline = EMPTYSTRING.join(outline)
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while len(thisline) > MAXLINESIZE:
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# Don't forget to include the soft line break `=' sign in the
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# length calculation!
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write(thisline[:MAXLINESIZE-1], lineEnd=b'=\n')
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thisline = thisline[MAXLINESIZE-1:]
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# Write out the current line
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prevline = thisline
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# Write out the last line, without a trailing newline
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if prevline is not None:
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write(prevline, lineEnd=stripped)
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def encodestring(s, quotetabs=False, header=False):
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if b2a_qp is not None:
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return b2a_qp(s, quotetabs=quotetabs, header=header)
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from io import BytesIO
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infp = BytesIO(s)
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outfp = BytesIO()
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encode(infp, outfp, quotetabs, header)
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return outfp.getvalue()
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def decode(input, output, header=False):
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"""Read 'input', apply quoted-printable decoding, and write to 'output'.
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'input' and 'output' are binary file objects.
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If 'header' is true, decode underscore as space (per RFC 1522)."""
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if a2b_qp is not None:
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data = input.read()
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odata = a2b_qp(data, header=header)
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output.write(odata)
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return
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new = b''
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while line := input.readline():
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i, n = 0, len(line)
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if n > 0 and line[n-1:n] == b'\n':
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partial = 0; n = n-1
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# Strip trailing whitespace
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while n > 0 and line[n-1:n] in b" \t\r":
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n = n-1
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else:
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partial = 1
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while i < n:
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c = line[i:i+1]
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if c == b'_' and header:
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new = new + b' '; i = i+1
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elif c != ESCAPE:
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new = new + c; i = i+1
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elif i+1 == n and not partial:
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partial = 1; break
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elif i+1 < n and line[i+1:i+2] == ESCAPE:
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new = new + ESCAPE; i = i+2
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elif i+2 < n and ishex(line[i+1:i+2]) and ishex(line[i+2:i+3]):
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new = new + bytes((unhex(line[i+1:i+3]),)); i = i+3
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else: # Bad escape sequence -- leave it in
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new = new + c; i = i+1
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if not partial:
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output.write(new + b'\n')
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new = b''
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if new:
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output.write(new)
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def decodestring(s, header=False):
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if a2b_qp is not None:
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return a2b_qp(s, header=header)
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from io import BytesIO
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infp = BytesIO(s)
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outfp = BytesIO()
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decode(infp, outfp, header=header)
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return outfp.getvalue()
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# Other helper functions
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def ishex(c):
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"""Return true if the byte ordinal 'c' is a hexadecimal digit in ASCII."""
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assert isinstance(c, bytes)
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return b'0' <= c <= b'9' or b'a' <= c <= b'f' or b'A' <= c <= b'F'
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def unhex(s):
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"""Get the integer value of a hexadecimal number."""
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bits = 0
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for c in s:
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c = bytes((c,))
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if b'0' <= c <= b'9':
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i = ord('0')
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elif b'a' <= c <= b'f':
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i = ord('a')-10
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elif b'A' <= c <= b'F':
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i = ord(b'A')-10
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else:
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assert False, "non-hex digit "+repr(c)
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bits = bits*16 + (ord(c) - i)
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return bits
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def main():
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import sys
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import getopt
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try:
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opts, args = getopt.getopt(sys.argv[1:], 'td')
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except getopt.error as msg:
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sys.stdout = sys.stderr
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print(msg)
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print("usage: quopri [-t | -d] [file] ...")
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print("-t: quote tabs")
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print("-d: decode; default encode")
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sys.exit(2)
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deco = False
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tabs = False
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for o, a in opts:
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if o == '-t': tabs = True
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if o == '-d': deco = True
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if tabs and deco:
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sys.stdout = sys.stderr
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print("-t and -d are mutually exclusive")
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sys.exit(2)
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if not args: args = ['-']
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sts = 0
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for file in args:
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if file == '-':
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fp = sys.stdin.buffer
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else:
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try:
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fp = open(file, "rb")
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except OSError as msg:
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sys.stderr.write("%s: can't open (%s)\n" % (file, msg))
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sts = 1
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continue
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try:
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if deco:
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decode(fp, sys.stdout.buffer)
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else:
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encode(fp, sys.stdout.buffer, tabs)
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finally:
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if file != '-':
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fp.close()
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if sts:
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sys.exit(sts)
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if __name__ == '__main__':
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main()
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