add generic huffman tree builder

1 files changed, 31 insertions, 2 deletions

diff --git a/tests/thuffmantree.nim b/tests/thuffmantree.nim
index ec40bdb..705ac17 100644
--- a/tests/thuffmantree.nim
+++ b/tests/thuffmantree.nim
@@ -14,24 +14,43 @@
 # 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 unittest, streams, sequtils, tables, heapqueue
 import bitreader, bitwriter, huffmantree
 
 suite "huffmantree":
+  let stats = newCountTable(concat(repeat(1'u, 3), repeat(2'u, 1), repeat(3'u, 2)))
   let tree = huffmanBranch(
     huffmanLeaf(1'u),
     huffmanBranch(
       huffmanLeaf(2'u),
       huffmanLeaf(3'u)))
 
+  test "equivalence":
+    check huffmanLeaf(12'u) ~= huffmanLeaf(12'u)
+    check huffmanLeaf(12'u) ~= huffmanLeaf(12'u, 2)
+    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 huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 1)) ~= huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 2))
+    check huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 1)) !~ huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(12'u, 2))
+
   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 huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 1)) == huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 1))
+    check huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 1)) != huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 2))
     check tree == tree
 
+  test "weight comparison":
+    check huffmanLeaf(12'u, 1) < huffmanLeaf(12'u, 2)
+    check huffmanLeaf(12'u, 2) > huffmanLeaf(12'u, 1)
+    check huffmanLeaf(12'u, 1) < huffmanLeaf(12'u, 1) == false
+    check huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 1)) < huffmanBranch(huffmanLeaf(12'u, 1), huffmanLeaf(21'u, 2))
+
   test "maxValue":
     check tree.maxValue() == 3
 
@@ -52,7 +71,7 @@ suite "huffmantree":
 
     stream.setPosition(0)
     let bitReader = stream.bitReader()
-    check huffmantree.deserialise(bitReader, uint) == tree
+    check huffmantree.deserialise(bitReader, uint) ~= tree
 
   test "serialise":
     let stream = newStringStream()
@@ -72,3 +91,13 @@ suite "huffmantree":
     check bitReader.readBits(2, uint8) == 2
     check bitReader.readBool() == true   # 3 leaf
     check bitReader.readBits(2, uint8) == 3
+
+  test "symbolQueue":
+    var symbolQueue = symbolQueue(stats)
+    check symbolQueue.len == 3
+    check symbolQueue.pop() == huffmanLeaf(2'u, 1)
+    check symbolQueue.pop() == huffmanLeaf(3'u, 2)
+    check symbolQueue.pop() == huffmanLeaf(1'u, 3)
+
+  test "buildHuffmanTree":
+    check buildHuffmanTree(stats) ~= tree