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# bdiff.py - CFFI implementation of bdiff.c
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#
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# Copyright 2016 Maciej Fijalkowski <fijall@gmail.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 annotations
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import struct
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from typing import (
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List,
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Tuple,
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)
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from ..pure.bdiff import *
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from . import _bdiff # pytype: disable=import-error
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ffi = _bdiff.ffi
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lib = _bdiff.lib
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def blocks(sa: bytes, sb: bytes) -> List[Tuple[int, int, int, int]]:
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a = ffi.new("struct bdiff_line**")
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b = ffi.new("struct bdiff_line**")
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ac = ffi.new("char[]", bytes(sa))
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bc = ffi.new("char[]", bytes(sb))
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l = ffi.new("struct bdiff_hunk*")
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try:
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an = lib.bdiff_splitlines(ac, len(sa), a)
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bn = lib.bdiff_splitlines(bc, len(sb), b)
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if not a[0] or not b[0]:
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raise MemoryError
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count = lib.bdiff_diff(a[0], an, b[0], bn, l)
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if count < 0:
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raise MemoryError
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rl = [(0, 0, 0, 0)] * count
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h = l.next
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i = 0
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while h:
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rl[i] = (h.a1, h.a2, h.b1, h.b2)
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h = h.next
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i += 1
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finally:
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lib.free(a[0])
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lib.free(b[0])
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lib.bdiff_freehunks(l.next)
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return rl
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def bdiff(sa: bytes, sb: bytes) -> bytes:
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a = ffi.new("struct bdiff_line**")
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b = ffi.new("struct bdiff_line**")
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ac = ffi.new("char[]", bytes(sa))
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bc = ffi.new("char[]", bytes(sb))
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l = ffi.new("struct bdiff_hunk*")
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try:
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an = lib.bdiff_splitlines(ac, len(sa), a)
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bn = lib.bdiff_splitlines(bc, len(sb), b)
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if not a[0] or not b[0]:
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raise MemoryError
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count = lib.bdiff_diff(a[0], an, b[0], bn, l)
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if count < 0:
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raise MemoryError
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rl = []
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h = l.next
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la = lb = 0
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while h:
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if h.a1 != la or h.b1 != lb:
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lgt = (b[0] + h.b1).l - (b[0] + lb).l
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rl.append(
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struct.pack(
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b">lll",
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(a[0] + la).l - a[0].l,
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(a[0] + h.a1).l - a[0].l,
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lgt,
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)
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)
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rl.append(bytes(ffi.buffer((b[0] + lb).l, lgt)))
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la = h.a2
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lb = h.b2
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h = h.next
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finally:
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lib.free(a[0])
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lib.free(b[0])
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lib.bdiff_freehunks(l.next)
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return b"".join(rl)
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