Module refinery.units.strings.snip
Expand source code Browse git
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from __future__ import annotations
from copy import copy
from refinery.units import Arg, Unit
from refinery.lib.tools import lookahead
class snip(Unit):
"""
Snips the input data based on a Python slice expression. For example, the
initialization `slice 0::1 1::1` would yield a unit that first extracts
every byte at an even position and then, every byte at an odd position. In
this case, multiple outputs are produced. The unit can be used in reverse
mode, in which case the specified ranges are deleted sequentially from the
input.
"""
def __init__(
self,
slices: Arg(help='Specify start:stop:step in Python slice syntax.') = [slice(None, None)],
length: Arg.Switch('-l',
help='Interpret the end of a slice as a length rather than as an offset.') = False,
remove: Arg.Switch('-r',
help='Remove the slices from the input rather than selecting them.') = False,
):
super().__init__(slices=slices, length=length, remove=remove)
def process(self, data: bytearray):
slices: list[slice] = list(self.args.slices)
if self.args.length:
for k, s in enumerate(slices):
if s.stop is None:
continue
slices[k] = slice(s.start, (s.start or 0) + s.stop, s.step)
if self.args.remove:
for last, bounds in lookahead(slices):
chunk = data if last else copy(data)
del chunk[bounds]
yield chunk
else:
for bounds in slices:
yield data[bounds]
Classes
class snip (slices=[slice(None, None, None)], length=False, remove=False)
-
Snips the input data based on a Python slice expression. For example, the initialization
slice 0::1 1::1
would yield a unit that first extracts every byte at an even position and then, every byte at an odd position. In this case, multiple outputs are produced. The unit can be used in reverse mode, in which case the specified ranges are deleted sequentially from the input.Expand source code Browse git
class snip(Unit): """ Snips the input data based on a Python slice expression. For example, the initialization `slice 0::1 1::1` would yield a unit that first extracts every byte at an even position and then, every byte at an odd position. In this case, multiple outputs are produced. The unit can be used in reverse mode, in which case the specified ranges are deleted sequentially from the input. """ def __init__( self, slices: Arg(help='Specify start:stop:step in Python slice syntax.') = [slice(None, None)], length: Arg.Switch('-l', help='Interpret the end of a slice as a length rather than as an offset.') = False, remove: Arg.Switch('-r', help='Remove the slices from the input rather than selecting them.') = False, ): super().__init__(slices=slices, length=length, remove=remove) def process(self, data: bytearray): slices: list[slice] = list(self.args.slices) if self.args.length: for k, s in enumerate(slices): if s.stop is None: continue slices[k] = slice(s.start, (s.start or 0) + s.stop, s.step) if self.args.remove: for last, bounds in lookahead(slices): chunk = data if last else copy(data) del chunk[bounds] yield chunk else: for bounds in slices: yield data[bounds]
Ancestors
Class variables
var required_dependencies
var optional_dependencies
Inherited members