Mercurial > hg
view mercurial/pure/base85.py @ 38047:dabc2237963c
crecord: fallback to text mode if diffs are too big for curses mode
crecord uses curses.newpad to create a region that we can then scroll around in
by moving the main 'screen' as a veiwport into the (probably larger than the
actual screen) pad. Internally, at least in ncurses, pads are implemented using
windows, which have their dimensions limited to a certain size. Depending on
compilation options for ncurses, this size might be pretty small: (signed)
short, or it might be larger ((signed) int).
crecord wants to have enough room to have all of the contents of the main area
of the chunkselector in the pad; this means that the full size with everything
expanded must be less than these (undocumented, afaict) limits.
It's not easy to write tests for this because the limits are platform- and
installation- dependent and undocumented / unqueryable, as far as I can tell.
Differential Revision: https://phab.mercurial-scm.org/D3577
author | Kyle Lippincott <spectral@google.com> |
---|---|
date | Thu, 17 May 2018 23:11:24 -0700 |
parents | 80301c90a2dc |
children | 2372284d9457 |
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# base85.py: pure python base85 codec # # Copyright (C) 2009 Brendan Cully <brendan@kublai.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import struct from .. import pycompat _b85chars = pycompat.bytestr("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef" "ghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~") _b85chars2 = [(a + b) for a in _b85chars for b in _b85chars] _b85dec = {} def _mkb85dec(): for i, c in enumerate(_b85chars): _b85dec[c] = i def b85encode(text, pad=False): """encode text in base85 format""" l = len(text) r = l % 4 if r: text += '\0' * (4 - r) longs = len(text) >> 2 words = struct.unpack('>%dL' % (longs), text) out = ''.join(_b85chars[(word // 52200625) % 85] + _b85chars2[(word // 7225) % 7225] + _b85chars2[word % 7225] for word in words) if pad: return out # Trim padding olen = l % 4 if olen: olen += 1 olen += l // 4 * 5 return out[:olen] def b85decode(text): """decode base85-encoded text""" if not _b85dec: _mkb85dec() l = len(text) out = [] for i in range(0, len(text), 5): chunk = text[i:i + 5] chunk = pycompat.bytestr(chunk) acc = 0 for j, c in enumerate(chunk): try: acc = acc * 85 + _b85dec[c] except KeyError: raise ValueError('bad base85 character at position %d' % (i + j)) if acc > 4294967295: raise ValueError('Base85 overflow in hunk starting at byte %d' % i) out.append(acc) # Pad final chunk if necessary cl = l % 5 if cl: acc *= 85 ** (5 - cl) if cl > 1: acc += 0xffffff >> (cl - 2) * 8 out[-1] = acc out = struct.pack('>%dL' % (len(out)), *out) if cl: out = out[:-(5 - cl)] return out