implement lzss block

1 files changed, 34 insertions, 0 deletions

diff --git a/src/lzsshuffman/lzsshuffmanencoder.nim b/src/lzsshuffman/lzsshuffmanencoder.nim
new file mode 100644
index 0000000..ea89f85
--- /dev/null
+++ b/src/lzsshuffman/lzsshuffmanencoder.nim
@@ -0,0 +1,34 @@
+# 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 lists
+import ../bitio/bitwriter
+import ../lzss/listpolyfill, ../lzss/lzssnode, ../lzss/lzsschain, ../lzss/lzssencoder
+import ../huffman/huffmantree, ../huffman/huffmantreebuilder, ../huffman/huffmanencoder
+import lzsshuffmansymbol
+
+proc writeSymbol(bitWriter: BitWriter, encodedSymbol: tuple[bitLength: int, value: uint16]) =
+  bitWriter.writeBits(encodedSymbol.bitLength, encodedSymbol.value)
+
+proc writeChain*(lzssChain: LzssChain, symbolEncoder, positionEncoder: HuffmanEncoder[uint16, uint16], bitWriter: BitWriter) =
+  for node in lzssChain.items:
+    case node.kind:
+      of character:
+        bitWriter.writeSymbol(symbolEncoder.encode(node.character))
+      of reference:
+        bitWriter.writeSymbol(symbolEncoder.encode(shiftLzssLength(node.length)))
+        bitWriter.writeSymbol(positionEncoder.encode(node.relativePos.uint16))
+  bitWriter.writeSymbol(symbolEncoder.encode(endSymbol))