1 files changed, 56 insertions, 0 deletions

diff --git a/src/gziplike.nim b/src/gziplike.nim
new file mode 100644
index 0000000..cf76f5e
--- /dev/null
+++ b/src/gziplike.nim
@@ -0,0 +1,56 @@
+# 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 os, streams, sugar
+import bitio/bitreader, bitio/bitwriter, blocks/streamblock
+
+proc transform*(operation: (BitReader, BitWriter) -> void, input, output: string) =
+  let inputStream = openFileStream(input, fmRead)
+  defer: inputStream.close()
+  let outputStream = openFileStream(output, fmWrite)
+  defer: outputStream.close()
+  operation(inputStream.bitReader(), outputStream.bitWriter())
+
+proc compress*(bitReader: BitReader, bitWriter: BitWriter) =
+  while not bitReader.atEnd():
+    let streamBlock = streamblock.readRaw(bitReader)
+    streamBlock.writeSerialisedTo(bitWriter)
+  bitWriter.flush()
+
+proc decompress*(bitReader: BitReader, bitWriter: BitWriter) =
+  var hasMore = true
+  while hasMore:
+    let streamBlock = streamblock.readSerialised(bitReader)
+    streamBlock.writeRawTo(bitWriter)
+    hasMore = not streamBlock.isLast()
+  bitWriter.flush()
+
+proc printUsage(output: File) =
+  output.writeLine("Usage: " & paramStr(0) & " <compress|decompress> <input file> <output file>")
+
+when isMainModule:
+  if paramCount() != 3:
+    stderr.writeLine("Error: invalid argument count.")
+    printUsage(stderr)
+    quit(1)
+
+  case paramStr(1):
+    of "compress": compress.transform(paramStr(2), paramStr(3))
+    of "decompress": decompress.transform(paramStr(2), paramStr(3))
+    else:
+      stderr.writeLine("Error: invalid operation.")
+      printUsage(stderr)
+      quit(1)