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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, sequtils, tables, lists, algorithm
import lzss/matchring, lzss/matchtable, lzss/lzssnode, lzss/lzsschain, lzss/lzssencoder
suite "matchring":
test "items (empty)":
var ring = initMatchRing()
check toSeq(ring.items).len == 0
test "addMatch, items (partial)":
var ring = initMatchRing()
let items = [0, 1, 2]
for i in items: ring.addMatch(i)
check toSeq(ring.items) == items.reversed()
test "addMatch, items (rolling)":
var ring = initMatchRing()
let items = toSeq(0..13)
for i in items: ring.addMatch(i)
check toSeq(ring.items) == items[^matchLimit..<items.len].reversed()
suite "matchtable":
test "addMatch":
var matchTable = initMatchTable()
matchTable.addMatch([0'u8, 1, 2], 42)
matchTable.addMatch([2'u8, 1, 0], 24)
check toSeq(matchTable.candidates([0'u8, 1, 2]).items) == [42]
check toSeq(matchTable.candidates([2'u8, 1, 0]).items) == [24]
matchTable.addMatch([0'u8, 1, 2], 1337)
check toSeq(matchTable.candidates([0'u8, 1, 2]).items) == [1337, 42]
check toSeq(matchTable.candidates([2'u8, 1, 0]).items) == [24]
suite "lzssnode":
test "equality":
check lzssCharacter(1) == lzssCharacter(1)
check lzssCharacter(0) != lzssCharacter(1)
check lzssReference(0, 1) == lzssReference(0, 1)
check lzssReference(1, 0) != lzssReference(0, 1)
check lzssCharacter(0) != lzssReference(0, 1)
suite "lzsschain":
test "decode":
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)])
check chain.decode() == @[0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
suite "lzssencoder":
test "commonPrefixLength":
check commonPrefixLength([], [], 10) == 0
check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 10) == 2
check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 10) == 2
check commonPrefixLength([1'u8, 2, 3], [1'u8, 2, 4], 10) == 2
check commonPrefixLength([1'u8, 2, 3, 4], [1'u8, 2, 3, 4], 3) == 3
test "longestPrefix":
let buffer = [
0'u8, 1, 2, 9,
0, 1, 2, 3,
0, 1, 2,
0, 1, 2, 3, 4]
var candidatePos = [0, 4, 8]
var matchRing = initMatchRing()
for pos in candidatePos: matchRing.addMatch(pos)
let result = longestPrefix(matchRing, buffer.toOpenArray(0, 10), buffer.toOpenArray(11, buffer.len - 1))
check result.pos == 4
check result.length == 4
test "addGroups":
var matchTable = initMatchTable()
let buffer = toSeq(0'u8..10'u8)
matchTable.addGroups(buffer, 0, 1)
matchTable.addGroups(buffer, 2, 9)
check toSeq(matchTable.candidates([1'u8, 2, 3]).items).len == 0
check toSeq(matchTable.candidates([7'u8, 8, 9]).items).len == 0
check toSeq(matchTable.candidates([2'u8, 3, 4]).items) == [2]
check toSeq(matchTable.candidates([4'u8, 5, 6]).items) == [4]
check toSeq(matchTable.candidates([6'u8, 7, 8]).items) == [6]
test "lzssEncode":
let buffer = [0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
check lzssEncode(buffer) == [
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)]
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