From 1025546347d75ec94f584294a36132527a45d46c Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Fri, 3 Nov 2017 11:28:28 -0700
Subject: [PATCH] unified HC levels

LZ4_setCompressionLevel() can be users accross the whole range of HC levels
No more transition issue between Optimal and HC modes
---
 lib/lz4hc.c    | 12 ++++--------
 lib/lz4hc.h    |  3 +--
 tests/fuzzer.c | 12 ++++++------
 3 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/lib/lz4hc.c b/lib/lz4hc.c
index cea83f2..042e034 100644
--- a/lib/lz4hc.c
+++ b/lib/lz4hc.c
@@ -49,6 +49,7 @@
 
 
 /*===    Dependency    ===*/
+#define LZ4_HC_STATIC_LINKING_ONLY
 #include "lz4hc.h"
 
 
@@ -726,18 +727,13 @@ void LZ4_resetStreamHC (LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel)
 {
     LZ4_STATIC_ASSERT(sizeof(LZ4HC_CCtx_internal) <= sizeof(size_t) * LZ4_STREAMHCSIZE_SIZET);   /* if compilation fails here, LZ4_STREAMHCSIZE must be increased */
     LZ4_streamHCPtr->internal_donotuse.base = NULL;
-    if (compressionLevel > LZ4HC_CLEVEL_MAX) compressionLevel = LZ4HC_CLEVEL_MAX;  /* cap compression level */
-    LZ4_streamHCPtr->internal_donotuse.compressionLevel = compressionLevel;
+    LZ4_setCompressionLevel(LZ4_streamHCPtr, compressionLevel);
 }
 
 void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel)
 {
-    /* note : 1-10 / 11-12 separation might no longer be necessary since optimal parser uses hash chain too */
-    int const currentCLevel = LZ4_streamHCPtr->internal_donotuse.compressionLevel;
-    int const minCLevel = currentCLevel < LZ4HC_CLEVEL_OPT_MIN ? 1 : LZ4HC_CLEVEL_OPT_MIN;
-    int const maxCLevel = currentCLevel < LZ4HC_CLEVEL_OPT_MIN ? LZ4HC_CLEVEL_OPT_MIN-1 : LZ4HC_CLEVEL_MAX;
-    compressionLevel = MIN(compressionLevel, minCLevel);
-    compressionLevel = MAX(compressionLevel, maxCLevel);
+    if (compressionLevel < 1) compressionLevel = 1;
+    if (compressionLevel > LZ4HC_CLEVEL_MAX) compressionLevel = LZ4HC_CLEVEL_MAX;
     LZ4_streamHCPtr->internal_donotuse.compressionLevel = compressionLevel;
 }
 
diff --git a/lib/lz4hc.h b/lib/lz4hc.h
index 13a0179..04153e6 100644
--- a/lib/lz4hc.h
+++ b/lib/lz4hc.h
@@ -265,8 +265,7 @@ int LZ4_compress_HC_continue_destSize(LZ4_streamHC_t* LZ4_streamHCPtr,
 
 /*! LZ4_setCompressionLevel() : v1.8.0 (experimental)
  *  It's possible to change compression level between 2 invocations of LZ4_compress_HC_continue*(),
- *  but it requires to stay in the same mode (aka 1-10 or 11-12).
- *  This function ensures this condition.
+ *  though it requires to stay in the same mode (aka fast or HC).
  */
 void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel);
 
diff --git a/tests/fuzzer.c b/tests/fuzzer.c
index 2e22912..ddd293c 100644
--- a/tests/fuzzer.c
+++ b/tests/fuzzer.c
@@ -376,9 +376,9 @@ static int FUZ_test(U32 seed, U32 nbCycles, const U32 startCycle, const double c
                 FUZ_CHECKTEST(ret<0, "LZ4_decompress_safe() failed on data compressed by LZ4_compressHC_destSize");
                 FUZ_CHECKTEST(ret!=srcSize, "LZ4_decompress_safe() failed : did not fully decompressed data");
                 FUZ_CHECKTEST(decodedBuffer[srcSize] != canary, "LZ4_decompress_safe() overwrite dst buffer !");
-                { U32 const crcDec = XXH32(decodedBuffer, srcSize, 0);
-                  FUZ_CHECKTEST(crcDec!=crcBase, "LZ4_decompress_safe() corrupted decoded data"); }
-
+                {   U32 const crcDec = XXH32(decodedBuffer, srcSize, 0);
+                    FUZ_CHECKTEST(crcDec!=crcBase, "LZ4_decompress_safe() corrupted decoded data");
+                }
                 DISPLAYLEVEL(5, " OK \n");
             }
             else
@@ -460,8 +460,7 @@ static int FUZ_test(U32 seed, U32 nbCycles, const U32 startCycle, const double c
 
         // Test decoding with output size being 10 bytes too short => must fail
         FUZ_DISPLAYTEST;
-        if (blockSize>10)
-        {
+        if (blockSize>10) {
             decodedBuffer[blockSize-10] = 0;
             ret = LZ4_decompress_safe(compressedBuffer, decodedBuffer, compressedSize, blockSize-10);
             FUZ_CHECKTEST(ret>=0, "LZ4_decompress_safe should have failed, due to Output Size being 10 bytes too short");
@@ -632,6 +631,7 @@ static int FUZ_test(U32 seed, U32 nbCycles, const U32 startCycle, const double c
         if (dict < (char*)CNBuffer) dict = (char*)CNBuffer;
         LZ4_resetStreamHC (&LZ4dictHC, compressionLevel);
         LZ4_loadDictHC(&LZ4dictHC, dict, dictSize);
+        LZ4_setCompressionLevel(&LZ4dictHC, compressionLevel-1);
         blockContinueCompressedSize = LZ4_compress_HC_continue(&LZ4dictHC, block, compressedBuffer, blockSize, (int)compressedBufferSize);
         FUZ_CHECKTEST(blockContinueCompressedSize==0, "LZ4_compress_HC_continue failed");
 
@@ -657,7 +657,7 @@ static int FUZ_test(U32 seed, U32 nbCycles, const U32 startCycle, const double c
         FUZ_CHECKTEST(crcCheck!=crcOrig, "LZ4_decompress_safe_usingDict corrupted decoded data");
 
         /* Compress HC continue destSize */
-            FUZ_DISPLAYTEST;
+        FUZ_DISPLAYTEST;
         {   int const availableSpace = (FUZ_rand(&randState) % blockSize) + 5;
             int consumedSize = blockSize;
             FUZ_DISPLAYTEST;
-- 
2.7.4