isolate huffman encoding module

9 files changed, 55 insertions, 119 deletions

diff --git a/src/huffmandecoder.nim b/src/huffman/huffmandecoder.nim
index 5cf4ca5..9a58b55 100644
--- a/src/huffmandecoder.nim
+++ b/src/huffman/huffmandecoder.nim
@@ -14,7 +14,8 @@
 # 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 huffmantree, bitio/bitreader
+import ../bitio/bitreader
+import huffmantree
 
 type HuffmanDecoder*[T: SomeUnsignedInt] = object
   tree: HuffmanTreeNode[T]
diff --git a/src/huffmanencoder.nim b/src/huffman/huffmanencoder.nim
index 05ed64f..3ed41ec 100644
--- a/src/huffmanencoder.nim
+++ b/src/huffman/huffmanencoder.nim
@@ -15,7 +15,8 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import tables
-import integers, huffmantree, bitio/bitwriter
+import ../integers, ../bitio/bitwriter
+import huffmantree
 
 type HuffmanEncoder*[T, U: SomeUnsignedInt] = object
   codebook: TableRef[T, U]
diff --git a/src/huffmantree.nim b/src/huffman/huffmantree.nim
index 6208ecf..1140694 100644
--- a/src/huffmantree.nim
+++ b/src/huffman/huffmantree.nim
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import tables, heapqueue
-import integers, bitio/bitreader, bitio/bitwriter
+import ../integers, ../bitio/bitreader, ../bitio/bitwriter
 
 const valueLengthFieldBitLength* = 6  # 64
 
diff --git a/src/huffmantreebuilder.nim b/src/huffman/huffmantreebuilder.nim
index 5b33d34..4169099 100644
--- a/src/huffmantreebuilder.nim
+++ b/src/huffman/huffmantreebuilder.nim
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import tables, heapqueue
-import huffmantree, lzssencoder
+import huffmantree
 
 type WeighedHuffmanTreeNode[T] = ref object
   weight: int
diff --git a/src/lzsschain.nim b/src/lzsschain.nim
index 073aa5e..44200f2 100644
--- a/src/lzsschain.nim
+++ b/src/lzsschain.nim
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import lists, tables, sugar
-import polyfill, integers, lzssnode, huffmantree
+import polyfill, integers, lzssnode, huffman/huffmantree
 
 const maxChainByteLength = 32_000 * wordBitLength
 
diff --git a/tests/thuffmantree.nim b/tests/thuffman.nim
index 467fac5..0294694 100644
--- a/tests/thuffmantree.nim
+++ b/tests/thuffman.nim
@@ -15,15 +15,18 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import unittest, streams, sequtils, tables, heapqueue
-import bitio/bitreader, bitio/bitwriter, huffmantree
+import bitio/bitreader, bitio/bitwriter
+import huffman/huffmantree, huffman/huffmantreebuilder, huffman/huffmanencoder, huffman/huffmandecoder
 
-suite "huffmantree":
-  let tree = huffmanBranch(
+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)
@@ -72,3 +75,45 @@ suite "huffmantree":
     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] == 0b0
+    check codebook[2'u] == 0b01
+    check codebook[3'u] == 0b11
+
+  test "encode":
+    let encoder = tree.encoder(uint)
+    check encoder.encode(1'u) == 0b0
+    check encoder.encode(2'u) == 0b01
+    check encoder.encode(3'u) == 0b11
+
+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
diff --git a/tests/thuffmandecoder.nim b/tests/thuffmandecoder.nim
deleted file mode 100644
index 9b44e9d..0000000
--- a/tests/thuffmandecoder.nim
+++ /dev/null
@@ -1,43 +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, streams
-import bitio/bitreader, bitio/bitwriter
-import huffmantree, huffmandecoder
-
-suite "huffdecoder":
-  let tree = huffmanBranch(
-    huffmanLeaf(1'u),
-    huffmanBranch(
-      huffmanLeaf(2'u),
-      huffmanLeaf(3'u)))
-
-  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
diff --git a/tests/thuffmanencoder.nim b/tests/thuffmanencoder.nim
deleted file mode 100644
index 9c46eed..0000000
--- a/tests/thuffmanencoder.nim
+++ /dev/null
@@ -1,39 +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, streams, tables
-import bitio/bitreader, bitio/bitwriter
-import huffmantree, huffmanencoder
-
-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] == 0b0
-    check codebook[2'u] == 0b01
-    check codebook[3'u] == 0b11
-
-  test "encode":
-    let encoder = tree.encoder(uint)
-    check encoder.encode(1'u) == 0b0
-    check encoder.encode(2'u) == 0b01
-    check encoder.encode(3'u) == 0b11
diff --git a/tests/thuffmantreebuilder.nim b/tests/thuffmantreebuilder.nim
deleted file mode 100644
index f782b37..0000000
--- a/tests/thuffmantreebuilder.nim
+++ /dev/null
@@ -1,29 +0,0 @@
-# gzip-like LZSS compressor
-# Copyright (C) 2018  Pacien TRAN-GIRARD