242 lines
7.1 KiB
Python
Executable file
242 lines
7.1 KiB
Python
Executable file
#! /usr/bin/env python3
|
|
|
|
"""Conversions to/from quoted-printable transport encoding as per RFC 1521."""
|
|
|
|
# (Dec 1991 version).
|
|
|
|
__all__ = ["encode", "decode", "encodestring", "decodestring"]
|
|
|
|
ESCAPE = b'='
|
|
MAXLINESIZE = 76
|
|
HEX = b'0123456789ABCDEF'
|
|
EMPTYSTRING = b''
|
|
|
|
try:
|
|
from binascii import a2b_qp, b2a_qp
|
|
except ImportError:
|
|
a2b_qp = None
|
|
b2a_qp = None
|
|
|
|
|
|
def needsquoting(c, quotetabs, header):
|
|
"""Decide whether a particular byte ordinal needs to be quoted.
|
|
|
|
The 'quotetabs' flag indicates whether embedded tabs and spaces should be
|
|
quoted. Note that line-ending tabs and spaces are always encoded, as per
|
|
RFC 1521.
|
|
"""
|
|
assert isinstance(c, bytes)
|
|
if c in b' \t':
|
|
return quotetabs
|
|
# if header, we have to escape _ because _ is used to escape space
|
|
if c == b'_':
|
|
return header
|
|
return c == ESCAPE or not (b' ' <= c <= b'~')
|
|
|
|
def quote(c):
|
|
"""Quote a single character."""
|
|
assert isinstance(c, bytes) and len(c)==1
|
|
c = ord(c)
|
|
return ESCAPE + bytes((HEX[c//16], HEX[c%16]))
|
|
|
|
|
|
|
|
def encode(input, output, quotetabs, header=False):
|
|
"""Read 'input', apply quoted-printable encoding, and write to 'output'.
|
|
|
|
'input' and 'output' are binary file objects. The 'quotetabs' flag
|
|
indicates whether embedded tabs and spaces should be quoted. Note that
|
|
line-ending tabs and spaces are always encoded, as per RFC 1521.
|
|
The 'header' flag indicates whether we are encoding spaces as _ as per RFC
|
|
1522."""
|
|
|
|
if b2a_qp is not None:
|
|
data = input.read()
|
|
odata = b2a_qp(data, quotetabs=quotetabs, header=header)
|
|
output.write(odata)
|
|
return
|
|
|
|
def write(s, output=output, lineEnd=b'\n'):
|
|
# RFC 1521 requires that the line ending in a space or tab must have
|
|
# that trailing character encoded.
|
|
if s and s[-1:] in b' \t':
|
|
output.write(s[:-1] + quote(s[-1:]) + lineEnd)
|
|
elif s == b'.':
|
|
output.write(quote(s) + lineEnd)
|
|
else:
|
|
output.write(s + lineEnd)
|
|
|
|
prevline = None
|
|
while 1:
|
|
line = input.readline()
|
|
if not line:
|
|
break
|
|
outline = []
|
|
# Strip off any readline induced trailing newline
|
|
stripped = b''
|
|
if line[-1:] == b'\n':
|
|
line = line[:-1]
|
|
stripped = b'\n'
|
|
# Calculate the un-length-limited encoded line
|
|
for c in line:
|
|
c = bytes((c,))
|
|
if needsquoting(c, quotetabs, header):
|
|
c = quote(c)
|
|
if header and c == b' ':
|
|
outline.append(b'_')
|
|
else:
|
|
outline.append(c)
|
|
# First, write out the previous line
|
|
if prevline is not None:
|
|
write(prevline)
|
|
# Now see if we need any soft line breaks because of RFC-imposed
|
|
# length limitations. Then do the thisline->prevline dance.
|
|
thisline = EMPTYSTRING.join(outline)
|
|
while len(thisline) > MAXLINESIZE:
|
|
# Don't forget to include the soft line break `=' sign in the
|
|
# length calculation!
|
|
write(thisline[:MAXLINESIZE-1], lineEnd=b'=\n')
|
|
thisline = thisline[MAXLINESIZE-1:]
|
|
# Write out the current line
|
|
prevline = thisline
|
|
# Write out the last line, without a trailing newline
|
|
if prevline is not None:
|
|
write(prevline, lineEnd=stripped)
|
|
|
|
def encodestring(s, quotetabs=False, header=False):
|
|
if b2a_qp is not None:
|
|
return b2a_qp(s, quotetabs=quotetabs, header=header)
|
|
from io import BytesIO
|
|
infp = BytesIO(s)
|
|
outfp = BytesIO()
|
|
encode(infp, outfp, quotetabs, header)
|
|
return outfp.getvalue()
|
|
|
|
|
|
|
|
def decode(input, output, header=False):
|
|
"""Read 'input', apply quoted-printable decoding, and write to 'output'.
|
|
'input' and 'output' are binary file objects.
|
|
If 'header' is true, decode underscore as space (per RFC 1522)."""
|
|
|
|
if a2b_qp is not None:
|
|
data = input.read()
|
|
odata = a2b_qp(data, header=header)
|
|
output.write(odata)
|
|
return
|
|
|
|
new = b''
|
|
while 1:
|
|
line = input.readline()
|
|
if not line: break
|
|
i, n = 0, len(line)
|
|
if n > 0 and line[n-1:n] == b'\n':
|
|
partial = 0; n = n-1
|
|
# Strip trailing whitespace
|
|
while n > 0 and line[n-1:n] in b" \t\r":
|
|
n = n-1
|
|
else:
|
|
partial = 1
|
|
while i < n:
|
|
c = line[i:i+1]
|
|
if c == b'_' and header:
|
|
new = new + b' '; i = i+1
|
|
elif c != ESCAPE:
|
|
new = new + c; i = i+1
|
|
elif i+1 == n and not partial:
|
|
partial = 1; break
|
|
elif i+1 < n and line[i+1:i+2] == ESCAPE:
|
|
new = new + ESCAPE; i = i+2
|
|
elif i+2 < n and ishex(line[i+1:i+2]) and ishex(line[i+2:i+3]):
|
|
new = new + bytes((unhex(line[i+1:i+3]),)); i = i+3
|
|
else: # Bad escape sequence -- leave it in
|
|
new = new + c; i = i+1
|
|
if not partial:
|
|
output.write(new + b'\n')
|
|
new = b''
|
|
if new:
|
|
output.write(new)
|
|
|
|
def decodestring(s, header=False):
|
|
if a2b_qp is not None:
|
|
return a2b_qp(s, header=header)
|
|
from io import BytesIO
|
|
infp = BytesIO(s)
|
|
outfp = BytesIO()
|
|
decode(infp, outfp, header=header)
|
|
return outfp.getvalue()
|
|
|
|
|
|
|
|
# Other helper functions
|
|
def ishex(c):
|
|
"""Return true if the byte ordinal 'c' is a hexadecimal digit in ASCII."""
|
|
assert isinstance(c, bytes)
|
|
return b'0' <= c <= b'9' or b'a' <= c <= b'f' or b'A' <= c <= b'F'
|
|
|
|
def unhex(s):
|
|
"""Get the integer value of a hexadecimal number."""
|
|
bits = 0
|
|
for c in s:
|
|
c = bytes((c,))
|
|
if b'0' <= c <= b'9':
|
|
i = ord('0')
|
|
elif b'a' <= c <= b'f':
|
|
i = ord('a')-10
|
|
elif b'A' <= c <= b'F':
|
|
i = ord(b'A')-10
|
|
else:
|
|
assert False, "non-hex digit "+repr(c)
|
|
bits = bits*16 + (ord(c) - i)
|
|
return bits
|
|
|
|
|
|
|
|
def main():
|
|
import sys
|
|
import getopt
|
|
try:
|
|
opts, args = getopt.getopt(sys.argv[1:], 'td')
|
|
except getopt.error as msg:
|
|
sys.stdout = sys.stderr
|
|
print(msg)
|
|
print("usage: quopri [-t | -d] [file] ...")
|
|
print("-t: quote tabs")
|
|
print("-d: decode; default encode")
|
|
sys.exit(2)
|
|
deco = 0
|
|
tabs = 0
|
|
for o, a in opts:
|
|
if o == '-t': tabs = 1
|
|
if o == '-d': deco = 1
|
|
if tabs and deco:
|
|
sys.stdout = sys.stderr
|
|
print("-t and -d are mutually exclusive")
|
|
sys.exit(2)
|
|
if not args: args = ['-']
|
|
sts = 0
|
|
for file in args:
|
|
if file == '-':
|
|
fp = sys.stdin.buffer
|
|
else:
|
|
try:
|
|
fp = open(file, "rb")
|
|
except OSError as msg:
|
|
sys.stderr.write("%s: can't open (%s)\n" % (file, msg))
|
|
sts = 1
|
|
continue
|
|
try:
|
|
if deco:
|
|
decode(fp, sys.stdout.buffer)
|
|
else:
|
|
encode(fp, sys.stdout.buffer, tabs)
|
|
finally:
|
|
if file != '-':
|
|
fp.close()
|
|
if sts:
|
|
sys.exit(sts)
|
|
|
|
|
|
|
|
if __name__ == '__main__':
|
|
main()
|