1 files changed, 32 insertions, 0 deletions

diff --git a/src/lzsshuffman/lzsshuffmanstats.nim b/src/lzsshuffman/lzsshuffmanstats.nim
new file mode 100644
index 0000000..037ce5f
--- /dev/null
+++ b/src/lzsshuffman/lzsshuffmanstats.nim
@@ -0,0 +1,32 @@
+# 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 tables, lists
+import ../lzss/lzssnode, ../lzss/lzsschain
+import lzsshuffmansymbol
+
+proc aggregateStats*(chain: LzssChain): tuple[symbolTable, positionTable: CountTableRef[uint16]] =
+  var (symbolTable, positionTable) = (newCountTable[uint16](), newCountTable[uint16]())
+  for node in chain.items:
+    case node.kind:
+      of character:
+        symbolTable.inc(node.character)
+      of reference:
+        symbolTable.inc(shiftLzssLength(node.length))
+        positionTable.inc(node.relativePos.uint16)
+  symbolTable.inc(endSymbol)
+  if positionTable.len < 1: positionTable.inc(0) # ensure non-empty tree
+  (symbolTable, positionTable)