isolate lzss chain module

11 files changed, 126 insertions, 197 deletions

diff --git a/src/polyfill.nim b/src/lzss/listpolyfill.nim
index b252953..00b30ee 100644
--- a/src/polyfill.nim
+++ b/src/lzss/listpolyfill.nim
@@ -26,7 +26,7 @@ proc prepend*[T](L: var SinglyLinkedList[T], n: SinglyLinkedNode[T]) =
 
 proc prepend*[T](L: var SinglyLinkedList[T], value: T) =
   ## prepends a node to `L`. Efficiency: O(1).
-  polyfill.prepend(L, newSinglyLinkedNode(value))
+  listpolyfill.prepend(L, newSinglyLinkedNode(value))
 
 proc append*[T](L: var SinglyLinkedList[T], n: SinglyLinkedNode[T]) =
   ## appends a node `n` to `L`. Efficiency: O(1).
diff --git a/src/lzsschain.nim b/src/lzss/lzsschain.nim
index 44200f2..2ecff9e 100644
--- a/src/lzsschain.nim
+++ b/src/lzss/lzsschain.nim
@@ -15,7 +15,8 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import lists, tables, sugar
-import polyfill, integers, lzssnode, huffman/huffmantree
+import ../integers, ../huffman/huffmantree
+import listpolyfill, lzssnode
 
 const maxChainByteLength = 32_000 * wordBitLength
 
diff --git a/src/lzssencoder.nim b/src/lzss/lzssencoder.nim
index 05f3a16..8b750fb 100644
--- a/src/lzssencoder.nim
+++ b/src/lzss/lzssencoder.nim
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import lists
-import polyfill, matchtable, lzssnode, lzsschain
+import listpolyfill, matchtable, lzssnode, lzsschain
 
 const matchGroupLength = 3
 const maxRefByteLength = high(uint8).int + matchGroupLength
diff --git a/src/lzssnode.nim b/src/lzss/lzssnode.nim
index de5958d..de5958d 100644
--- a/src/lzssnode.nim
+++ b/src/lzss/lzssnode.nim
diff --git a/src/matchtable.nim b/src/lzss/matchtable.nim
index 5be652c..b17ce68 100644
--- a/src/matchtable.nim
+++ b/src/lzss/matchtable.nim
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import tables, lists
-import polyfill
+import listpolyfill
 
 type MatchTable*[K, V] =
   TableRef[K, SinglyLinkedList[V]]
@@ -28,5 +28,5 @@ proc matchList*[K, V](matchTable: MatchTable[K, V], pattern: K): SinglyLinkedLis
 
 proc addMatch*[K, V](matchTable: MatchTable[K, V], pattern: K, value: V) =
   var matchList = matchTable.matchList(pattern)
-  polyfill.prepend(matchList, value)
+  listpolyfill.prepend(matchList, value)
   matchTable[pattern] = matchList
diff --git a/tests/tlzss.nim b/tests/tlzss.nim
new file mode 100644
index 0000000..7325d5b
--- /dev/null
+++ b/tests/tlzss.nim
@@ -0,0 +1,120 @@
+# 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
+import lzss/listpolyfill, lzss/matchtable, lzss/lzssnode, lzss/lzsschain, lzss/lzssencoder
+
+suite "listpolyfill":
+  test "append":
+    const data = [1, 2, 3, 4, 5, 6]
+    var L: SinglyLinkedList[int]
+    for d in items(data): listpolyfill.prepend(L, d)
+    for d in items(data): listpolyfill.append(L, d)
+    check $L == "[6, 5, 4, 3, 2, 1, 1, 2, 3, 4, 5, 6]"
+    check 4 in L
+
+suite "matchtable":
+  test "matchList":
+    let matchTable = initMatchTable(seq[int], int)
+    check toSeq(matchTable.matchList(@[0, 1, 2]).items).len == 0
+
+  test "addMatch":
+    let matchTable = initMatchTable(seq[int], int)
+    matchTable.addMatch(@[0, 1, 2], 42)
+    matchTable.addMatch(@[2, 1, 0], 24)
+    check matchTable.len == 2
+    check toSeq(matchTable.matchList(@[0, 1, 2]).items) == @[42]
+    check toSeq(matchTable.matchList(@[2, 1, 0]).items) == @[24]
+    matchTable.addMatch(@[0, 1, 2], 1337)
+    check matchTable.len == 2
+    check toSeq(matchTable.matchList(@[0, 1, 2]).items) == @[1337, 42]
+    check toSeq(matchTable.matchList(@[2, 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":
+  proc chain(): LzssChain =
+    let chainArray = [
+      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)]
+    var chain = lzssChain()
+    for node in chainArray: chain.append(node)
+    result = chain
+ 
+  test "decode":
+    check chain().decode() == @[0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
+ 
+  test "stats":
+    let stats = chain().stats()
+    check stats.characters == newCountTable(concat(
+      repeat(0'u8, 2), repeat(1'u8, 2), repeat(2'u8, 1), repeat(3'u8, 1), repeat(4'u8, 1), repeat(5'u8, 3)))
+    check stats.lengths == newCountTable(concat(
+      repeat(3, 2), repeat(4, 1)))
+    check stats.positions == newCountTable(concat(
+      repeat(3, 1), repeat(6, 1), repeat(8, 1)))
+
+suite "lzssencoder":
+  test "commonPrefixLength":
+    check commonPrefixLength([], [], 0, 10) == 0
+    check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 0, 10) == 2
+    check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 1, 10) == 2
+    check commonPrefixLength([1'u8, 2, 3], [1'u8, 2, 4], 1, 10) == 2
+    check commonPrefixLength([1'u8, 2, 3, 4], [1'u8, 2, 3, 4], 1, 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 = initSinglyLinkedList[int]()
+    listpolyfill.prepend(candidatePos, 0)
+    listpolyfill.prepend(candidatePos, 4)
+    listpolyfill.prepend(candidatePos, 8)
+    let result = longestPrefix(candidatePos, buffer.toOpenArray(0, 10), buffer.toOpenArray(11, buffer.len - 1))
+    check result.pos == 4
+    check result.length == 4
+
+  test "addGroups":
+    let matchTable = initMatchTable(seq[uint8], int)
+    let buffer = toSeq(0'u8..10'u8)
+    matchTable.addGroups(buffer, 0, 1)
+    check matchTable.len == 0
+    matchTable.addGroups(buffer, 2, 9)
+    check matchTable.len == 5
+    check toSeq(matchTable.matchList(@[1'u8, 2, 3]).items).len == 0
+    check toSeq(matchTable.matchList(@[7'u8, 8, 9]).items).len == 0
+    check toSeq(matchTable.matchList(@[2'u8, 3, 4]).items) == @[2]
+    check toSeq(matchTable.matchList(@[4'u8, 5, 6]).items) == @[4]
+    check toSeq(matchTable.matchList(@[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 toSeq(lzssEncode(buffer).items) == @[
+      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)]
diff --git a/tests/tlzsschain.nim b/tests/tlzsschain.nim
deleted file mode 100644
index a8c2012..0000000
--- a/tests/tlzsschain.nim
+++ /dev/null
@@ -1,42 +0,0 @@
-# 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
-import polyfill, lzssnode, lzsschain
-
-suite "lzsschain":
-  proc chain(): LzssChain =
-    let chainArray = [
-      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)]
-    var chain = lzssChain()
-    for node in chainArray: chain.append(node)
-    result = chain
-
-  test "decode":
-    check chain().decode() == @[0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
-
-  test "stats":
-    let stats = chain().stats()
-    check stats.characters == newCountTable(concat(
-      repeat(0'u8, 2), repeat(1'u8, 2), repeat(2'u8, 1), repeat(3'u8, 1), repeat(4'u8, 1), repeat(5'u8, 3)))
-    check stats.lengths == newCountTable(concat(
-      repeat(3, 2), repeat(4, 1)))
-    check stats.positions == newCountTable(concat(
-      repeat(3, 1), repeat(6, 1), repeat(8, 1)))