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  • Committer: John Arbash Meinel
  • Date: 2009-03-27 22:29:55 UTC
  • mto: (3735.39.2 clean)
  • mto: This revision was merged to the branch mainline in revision 4280.
  • Revision ID: john@arbash-meinel.com-20090327222955-utifmfm888zerixt
Implement apply_delta_to_source which doesn't have to malloc another string.

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bzrlib/_groupcompress_py.py
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        pos += 1
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        if cmd & 0x80:
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            offset, length, pos = decode_copy_instruction(delta, cmd, pos)
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            lines.append(basis[offset:offset+length])
 
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            last = offset + length
 
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            if last > len(basis):
 
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                raise ValueError('data would copy bytes past the'
 
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                                 'end of source')
 
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            lines.append(basis[offset:last])
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        else: # Insert of 'cmd' bytes
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            if cmd == 0:
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                raise ValueError('Command == 0 not supported yet')
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        raise ValueError('Delta claimed to be %d long, but ended up'
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                         ' %d long' % (target_length, len(bytes)))
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    return bytes
 
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def apply_delta_to_source(source, delta_start, delta_end):
 
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    """Extract a delta from source bytes, and apply it."""
 
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    source_size = len(source)
 
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    if delta_start >= source_size:
 
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        raise ValueError('delta starts after source')
 
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    if delta_end > source_size:
 
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        raise ValueError('delta ends after source')
 
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    if delta_start >= delta_end:
 
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        raise ValueError('delta starts after it ends')
 
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    delta_bytes = source[delta_start:delta_end]
 
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    return apply_delta(source, delta_bytes)