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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, streams, sequtils, tables, heapqueue
import bitio/bitreader, bitio/bitwriter
import huffman/huffmantree, huffman/huffmantreebuilder, huffman/huffmanencoder, huffman/huffmandecoder
let
stats = newCountTable(concat(repeat(1'u, 3), repeat(2'u, 1), repeat(3'u, 2)))
tree = huffmanBranch(
huffmanLeaf(1'u),
huffmanBranch(
huffmanLeaf(2'u),
huffmanLeaf(3'u)))
suite "huffmantree":
test "equality":
check huffmanLeaf(12'u) == huffmanLeaf(12'u)
check huffmanLeaf(12'u) != huffmanLeaf(21'u)
check huffmanLeaf(12'u) != huffmanBranch(huffmanLeaf(12'u), huffmanLeaf(12'u))
check huffmanBranch(huffmanLeaf(12'u), huffmanLeaf(21'u)) == huffmanBranch(huffmanLeaf(12'u), huffmanLeaf(21'u))
check huffmanBranch(huffmanLeaf(12'u), huffmanLeaf(21'u)) != huffmanBranch(huffmanLeaf(12'u), huffmanLeaf(1'u))
check tree == tree
test "maxValue":
check tree.maxValue() == 3
test "deserialise":
let stream = newStringStream()
defer: stream.close()
let bitWriter = stream.bitWriter()
bitWriter.writeBits(valueLengthFieldBitLength, 2'u8)
bitWriter.writeBool(false) # root
bitWriter.writeBool(true) # 1 leaf
bitWriter.writeBits(2, 1'u)
bitWriter.writeBool(false) # right branch
bitWriter.writeBool(true) # 2 leaf
bitWriter.writeBits(2, 2'u)
bitWriter.writeBool(true) # 3 leaf
bitWriter.writeBits(2, 3'u)
bitWriter.flush()
stream.setPosition(0)
let bitReader = stream.bitReader()
check huffmantree.deserialise(bitReader, uint) == tree
test "serialise":
let stream = newStringStream()
defer: stream.close()
let bitWriter = stream.bitWriter()
tree.serialise(bitWriter)
bitWriter.flush()
stream.setPosition(0)
let bitReader = stream.bitReader()
check bitReader.readBits(valueLengthFieldBitLength, uint8) == 2
check bitReader.readBool() == false # root
check bitReader.readBool() == true # 1 leaf
check bitReader.readBits(2, uint8) == 1
check bitReader.readBool() == false # right branch
check bitReader.readBool() == true # 2 leaf
check bitReader.readBits(2, uint8) == 2
check bitReader.readBool() == true # 3 leaf
check bitReader.readBits(2, uint8) == 3
suite "huffmantreebuilder":
test "buildHuffmanTree":
check buildHuffmanTree(stats) == tree
suite "huffencoder":
let tree = huffmanBranch(
huffmanLeaf(1'u),
huffmanBranch(
huffmanLeaf(2'u),
huffmanLeaf(3'u)))
test "buildCodebook":
let codebook = buildCodebook(tree, uint)
check codebook.len == 3
check codebook[1'u] == (1, 0b0'u)
check codebook[2'u] == (2, 0b01'u)
check codebook[3'u] == (2, 0b11'u)
test "encode":
let encoder = tree.encoder(uint)
check encoder.encode(1'u) == (1, 0b0'u)
check encoder.encode(2'u) == (2, 0b01'u)
check encoder.encode(3'u) == (2, 0b11'u)
suite "huffdecoder":
test "decode":
let stream = newStringStream()
defer: stream.close()
let bitWriter = stream.bitWriter()
bitWriter.writeBool(true) # 2
bitWriter.writeBool(false)
bitWriter.writeBool(false) # 1
bitWriter.writeBool(true) # 3
bitWriter.writeBool(true)
bitWriter.flush()
stream.setPosition(0)
let bitReader = stream.bitReader()
let decoder = tree.decoder()
check decoder.decode(bitReader) == 2'u
check decoder.decode(bitReader) == 1'u
check decoder.decode(bitReader) == 3'u
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