From a32509f319b1c966faf08c63d44497f3c0cf48a8 Mon Sep 17 00:00:00 2001
From: Gilles Vollant <info@winimage.com>
Date: Mon, 27 Dec 2021 01:22:39 +0100
Subject: [PATCH] add support of LZFSE in fastlzlib source

---
 fastlzlib.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 fastlzlib.h |  1 +
 2 files changed, 43 insertions(+)

diff --git a/fastlzlib.c b/fastlzlib.c
index e8a9273..e2f8c2c 100644
--- a/fastlzlib.c
+++ b/fastlzlib.c
@@ -57,6 +57,10 @@
 #include "fastlz/fastlz.h"
 #endif
 
+#ifdef ZFAST_USE_LZFSE
+#include "lzfse/src/lzfse.h"
+#endif
+
 /* undefined because we use the internal one */
 #undef fastlzlibReset
 
@@ -309,6 +313,37 @@ static int fastlz_backend_compress(int level, const void* input, int length,
 
 #endif
 
+
+#ifdef ZFAST_USE_LZFSE
+
+/* compression backend for LZFSE */
+/*   if compressed data are greather than input (incompressible data), 
+            lzfse_encode_buffer return 0
+            fastlzlib wait length to decide store a RAW block, so we transform return value */
+static int lzfse_backend_compress(int level, const void* input, int length,
+                                  void* output) {
+  void* scratch_buffer = (void*)malloc(lzfse_encode_scratch_size());
+  if (scratch_buffer == NULL)
+    return 0;
+  int size_compressed = (int)lzfse_encode_buffer(output, (size_t)length, input, (size_t)length, scratch_buffer);
+  free(scratch_buffer);
+  return (size_compressed == 0) ? length : size_compressed;
+}
+
+/* decompression backend for LZFSE */
+static int lzfse_backend_decompress(const void* input, int length, void* output,
+                                    int maxout) {
+  int size_decoded;
+  void* scratch_buffer = (void*)malloc(lzfse_decode_scratch_size());
+  if (scratch_buffer == NULL)
+    return 0;
+  size_decoded = lzfse_decode_buffer(output, maxout, input, length, scratch_buffer);
+  free(scratch_buffer);
+  return size_decoded;
+  /* return LZ4_uncompress(input, output, maxout); */
+}
+#endif
+
 /* initialize private fields */
 static int fastlzlibInit(zfast_stream *s, int block_size) {
   if (s != NULL) {
@@ -396,6 +431,13 @@ int fastlzlibSetCompressor(zfast_stream *s,
     fastlzlibSetDecompress(s, fastlz_backend_decompress);
     return Z_OK;
   }
+#endif
+#ifdef ZFAST_USE_LZFSE
+  if (compressor == COMPRESSOR_LZFSE) {
+    fastlzlibSetCompress(s, lzfse_backend_compress);
+    fastlzlibSetDecompress(s, lzfse_backend_decompress);
+    return Z_OK;
+  }
 #endif
   return Z_VERSION_ERROR;
 }
diff --git a/fastlzlib.h b/fastlzlib.h
index 11b75fb..74099b2 100644
--- a/fastlzlib.h
+++ b/fastlzlib.h
@@ -74,6 +74,7 @@ typedef z_stream zfast_stream;
 typedef enum zfast_stream_compressor {
   COMPRESSOR_FASTLZ,
   COMPRESSOR_LZ4,
+  COMPRESSOR_LZFSE,
   COMPRESSOR_DEFAULT = COMPRESSOR_FASTLZ
 } zfast_stream_compressor;