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# gzip-like LZSS compressor
# Copyright (C) 2018 Pacien TRAN-GIRARD
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import lists
import ../lzss/lzssnode, ../lzss/lzssencoder
type Symbol* = uint16
const endSymbol* = 256.Symbol
proc isEndMarker*(symbol: Symbol): bool =
symbol == endSymbol
proc isCharacter*(symbol: Symbol): bool =
symbol < endSymbol
proc unpackLzssReference*(symbol: Symbol, position: uint16): LzssNode =
lzssReference(symbol.int - endSymbol.int - 1 + matchGroupLength, position.int)
proc shiftLzssLength*(length: int): uint16 =
(length + endSymbol.int + 1 - matchGroupLength).uint16
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