mercurial/pure/base85.py
author Anton Shestakov <av6@dwimlabs.net>
Fri, 10 Nov 2017 18:45:43 +0800
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child 35944 01b4d88ccb24
permissions -rw-r--r--
paper: apply styles from annotate tooltip to followlines popup These new colors and styles are already used in the tooltip that gets shown when user hovers over line numbers on annotate page. The old styles, replaced in this patch, look completely unrelated to paper or any other hgweb theme.
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# base85.py: pure python base85 codec
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#
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# Copyright (C) 2009 Brendan Cully <brendan@kublai.com>
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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from __future__ import absolute_import
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import struct
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_b85chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
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            "abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
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_b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
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_b85dec = {}
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def _mkb85dec():
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    for i, c in enumerate(_b85chars):
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        _b85dec[c] = i
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def b85encode(text, pad=False):
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    """encode text in base85 format"""
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    l = len(text)
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    r = l % 4
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    if r:
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        text += '\0' * (4 - r)
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    longs = len(text) >> 2
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    words = struct.unpack('>%dL' % (longs), text)
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    out = ''.join(_b85chars[(word // 52200625) % 85] +
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                  _b85chars2[(word // 7225) % 7225] +
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                  _b85chars2[word % 7225]
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                  for word in words)
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    if pad:
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        return out
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    # Trim padding
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    olen = l % 4
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    if olen:
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        olen += 1
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    olen += l // 4 * 5
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    return out[:olen]
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def b85decode(text):
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    """decode base85-encoded text"""
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    if not _b85dec:
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        _mkb85dec()
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    l = len(text)
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    out = []
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    for i in range(0, len(text), 5):
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        chunk = text[i:i + 5]
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        acc = 0
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        for j, c in enumerate(chunk):
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            try:
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                acc = acc * 85 + _b85dec[c]
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            except KeyError:
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                raise ValueError('bad base85 character at position %d'
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                                 % (i + j))
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        if acc > 4294967295:
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            raise ValueError('Base85 overflow in hunk starting at byte %d' % i)
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        out.append(acc)
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    # Pad final chunk if necessary
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    cl = l % 5
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    if cl:
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        acc *= 85 ** (5 - cl)
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        if cl > 1:
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            acc += 0xffffff >> (cl - 2) * 8
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        out[-1] = acc
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    out = struct.pack('>%dL' % (len(out)), *out)
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    if cl:
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        out = out[:-(5 - cl)]
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    return out