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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 unittest, tables, sequtils, streams
import bitio/bitwriter, bitio/bitreader
import lzss/lzssnode, lzss/lzsschain
import huffman/huffmantree, huffman/huffmantreebuilder, huffman/huffmanencoder, huffman/huffmandecoder
import lzsshuffman/lzsshuffmansymbol, lzsshuffman/lzsshuffmanstats, lzsshuffman/lzsshuffmanencoder, lzsshuffman/lzsshuffmandecoder
suite "lzsshuffmansymbol":
test "isEndMarker":
check 'a'.Symbol.isEndMarker() == false
check endSymbol.isEndMarker()
test "isCharacter":
check 'a'.Symbol.isCharacter()
check endSymbol.isCharacter() == false
check 300.Symbol.isCharacter() == false
test "unpackLzssReference":
check unpackLzssReference(257.Symbol, 10) == lzssReference(3, 10)
check unpackLzssReference(300.Symbol, 10) == lzssReference(46, 10)
test "shiftLzssLength":
check shiftLzssLength(3) == 257'u16
check shiftLzssLength(10) == 264'u16
suite "lzsshuffmanstats":
test "aggretateStats":
let chain = lzssChain([
lzssCharacter(0), lzssCharacter(1), lzssCharacter(2),
lzssCharacter(3), lzssCharacter(4), lzssCharacter(5),
lzssReference(4, 6), lzssCharacter(0), lzssCharacter(1),
lzssReference(3, 8), lzssCharacter(5),
lzssReference(3, 3), lzssCharacter(5)])
let (symbolTable, positionTable) = chain.aggregateStats()
check symbolTable == newCountTable(concat(
repeat(0'u16, 2), repeat(1'u16, 2), repeat(2'u16, 1), repeat(3'u16, 1), repeat(4'u16, 1), repeat(5'u16, 3),
repeat(endSymbol.uint16, 1),
repeat(257'u16, 2), repeat(258'u16, 1)))
check positionTable == newCountTable(concat(
repeat(3'u16, 1), repeat(6'u16, 1), repeat(8'u16, 1)))
suite "lzsshuffmanencoder":
test "writeChain (empty)":
let chain = lzssChain(newSeq[LzssNode]())
let symbolTree = huffmanLeaf(endSymbol.uint16)
let positionTree = huffmanLeaf(0'u16)
let stream = newStringStream()
defer: stream.close()
let bitWriter = stream.bitWriter()
writeChain(chain, symbolTree.encoder(uint16), positionTree.encoder(uint16), bitWriter)
bitWriter.flush()
stream.setPosition(0)
check stream.atEnd()
test "writeChain (minimal)":
let chain = lzssChain([
lzssCharacter(0), lzssCharacter(1), lzssCharacter(2),
lzssReference(3, 3), lzssReference(3, 4)])
let symbolTree = huffmanBranch(
huffmanBranch(
huffmanLeaf(0'u16),
huffmanLeaf(1'u16)),
huffmanBranch(
huffmanLeaf(257'u16),
huffmanBranch(
huffmanLeaf(2'u16),
huffmanLeaf(256'u16))))
let positionTree = huffmanBranch(
huffmanLeaf(3'u16),
huffmanLeaf(4'u16))
let stream = newStringStream()
defer: stream.close()
let bitWriter = stream.bitWriter()
writeChain(chain, symbolTree.encoder(uint16), positionTree.encoder(uint16), bitWriter)
bitWriter.flush()
stream.setPosition(0)
let bitReader = stream.bitReader()
check bitReader.readBits(2, uint8) == 0b00'u8 # char 0
check bitReader.readBits(2, uint8) == 0b10'u8 # char 1
check bitReader.readBits(3, uint8) == 0b011'u8 # char 2
check bitReader.readBits(2, uint8) == 0b01'u8 # ref len 3
check bitReader.readBits(1, uint8) == 0b0'u8 # ref pos 3
check bitReader.readBits(2, uint8) == 0b01'u8 # ref len 3
check bitReader.readBits(1, uint8) == 0b1'u8 # ref pos 4
check bitReader.readBits(3, uint8) == 0b111'u8 # eof
suite "lzsshuffmandecoder":
test "readChain (empty)":
let symbolTree = huffmanLeaf(endSymbol.uint16)
let positionTree = huffmanLeaf(0'u16)
let stream = newStringStream()
defer: stream.close()
stream.write(0'u8) # eof
stream.setPosition(0)
let bitReader = stream.bitReader()
let result = readChain(bitReader, symbolTree.decoder(), positionTree.decoder(), 32_000)
check result.len == 0
test "readChain (minimal)":
let symbolTree = huffmanBranch(
huffmanBranch(
huffmanLeaf(0'u16),
huffmanLeaf(1'u16)),
huffmanBranch(
huffmanLeaf(257'u16),
huffmanBranch(
huffmanLeaf(2'u16),
huffmanLeaf(256'u16))))
let positionTree = huffmanBranch(
huffmanLeaf(3'u16),
huffmanLeaf(4'u16))
let stream = newStringStream()
defer: stream.close()
let bitWriter = stream.bitWriter()
bitWriter.writeBits(2, 0b00'u8)
bitWriter.writeBits(2, 0b10'u8)
bitWriter.writeBits(3, 0b011'u8)
bitWriter.writeBits(2, 0b01'u8)
bitWriter.writeBits(1, 0b0'u8)
bitWriter.writeBits(2, 0b01'u8)
bitWriter.writeBits(1, 0b1'u8)
bitWriter.writeBits(3, 0b111'u8)
bitWriter.flush()
stream.setPosition(0)
let bitReader = stream.bitReader()
let result = readChain(bitReader, symbolTree.decoder(), positionTree.decoder(), 32_000)
check result == [
lzssCharacter(0), lzssCharacter(1), lzssCharacter(2),
lzssReference(3, 3), lzssReference(3, 4)]
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