| Guido van Rossum | f194546 | 1995-06-14 23:43:44 +0000 | [diff] [blame] | 1 | # Conversions to/from quoted-printable transport encoding as per RFC-XXXX |
| 2 | # (Dec 1991 version). |
| 3 | |
| 4 | ESCAPE = '=' |
| 5 | MAXLINESIZE = 76 |
| 6 | HEX = '0123456789ABCDEF' |
| 7 | |
| 8 | def needsquoting(c, quotetabs): |
| 9 | if c == '\t': |
| 10 | return not quotetabs |
| 11 | return c == ESCAPE or not(' ' <= c <= '~') |
| 12 | |
| 13 | def quote(c): |
| 14 | if c == ESCAPE: |
| 15 | return ESCAPE * 2 |
| 16 | else: |
| 17 | i = ord(c) |
| 18 | return ESCAPE + HEX[i/16] + HEX[i%16] |
| 19 | |
| 20 | def encode(input, output, quotetabs): |
| 21 | while 1: |
| 22 | line = input.readline() |
| 23 | if not line: break |
| 24 | new = '' |
| 25 | last = line[-1:] |
| 26 | if last == '\n': line = line[:-1] |
| 27 | else: last = '' |
| 28 | prev = '' |
| 29 | for c in line: |
| 30 | if needsquoting(c, quotetabs): |
| 31 | c = quote(c) |
| 32 | if len(new) + len(c) >= MAXLINESIZE: |
| 33 | output.write(new + ESCAPE + '\n') |
| 34 | new = '' |
| 35 | new = new + c |
| 36 | prev = c |
| 37 | if prev in (' ', '\t'): |
| 38 | output.write(new + ESCAPE + '\n\n') |
| 39 | else: |
| 40 | output.write(new + '\n') |
| 41 | |
| 42 | def decode(input, output): |
| 43 | new = '' |
| 44 | while 1: |
| 45 | line = input.readline() |
| 46 | if not line: break |
| 47 | i, n = 0, len(line) |
| 48 | if n > 0 and line[n-1] == '\n': |
| 49 | partial = 0; n = n-1 |
| 50 | # Strip trailing whitespace |
| 51 | while n > 0 and line[n-1] in (' ', '\t'): |
| 52 | n = n-1 |
| 53 | else: |
| 54 | partial = 1 |
| 55 | while i < n: |
| 56 | c = line[i] |
| 57 | if c <> ESCAPE: |
| 58 | new = new + c; i = i+1 |
| 59 | elif i+1 == n and not partial: |
| 60 | partial = 1; break |
| 61 | elif i+1 < n and line[i+1] == ESCAPE: |
| 62 | new = new + ESCAPE; i = i+2 |
| 63 | elif i+2 < n and ishex(line[i+1]) and ishex(line[i+2]): |
| 64 | new = new + chr(unhex(line[i+1:i+3])); i = i+3 |
| 65 | else: # Bad escape sequence -- leave it in |
| 66 | new = new + c; i = i+1 |
| 67 | if not partial: |
| 68 | output.write(new + '\n') |
| 69 | new = '' |
| 70 | if new: |
| 71 | output.write(new) |
| 72 | |
| 73 | def ishex(c): |
| 74 | return '0' <= c <= '9' or 'a' <= c <= 'f' or 'A' <= c <= 'F' |
| 75 | |
| 76 | def unhex(s): |
| 77 | bits = 0 |
| 78 | for c in s: |
| 79 | if '0' <= c <= '9': |
| 80 | i = ord('0') |
| 81 | elif 'a' <= c <= 'f': |
| 82 | i = ord('a')-10 |
| 83 | elif 'A' <= c <= 'F': |
| 84 | i = ord('A')-10 |
| 85 | else: |
| 86 | break |
| 87 | bits = bits*16 + (ord(c) - i) |
| 88 | return bits |
| 89 | |
| 90 | def test(): |
| 91 | import sys |
| 92 | if sys.argv[1:]: |
| 93 | if sys.argv[1] == '-t': # Quote tabs |
| 94 | encode(sys.stdin, sys.stdout, 1) |
| 95 | else: |
| 96 | decode(sys.stdin, sys.stdout) |
| 97 | else: |
| 98 | encode(sys.stdin, sys.stdout, 0) |
| 99 | |
| 100 | if __name__ == '__main__': |
| 101 | main() |