fixed lz4hc assert error

when src ptr is in very low memory area (< 64K),
the virtual reference to data in dictionary
might end up in a very high memory address.

Since it's not a "real" memory address,
just a virtual one, to calculate distance,
it doesn't matter : only distance matters.

The assert was to restrictive.
Fixed.

2 files changed, 11 insertions, 11 deletions

diff --git a/lib/lz4.c b/lib/lz4.c
index 866855b..fc3fb88 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -225,15 +225,15 @@ static const int LZ4_minLength = (MFLIMIT+1);
 
 #if defined(LZ4_DEBUG) && (LZ4_DEBUG>=2)
 #  include <stdio.h>
-static int g_debuglog_enable = 1;
-#  define DEBUGLOG(l, ...) {                                  \
-                if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) {  \
-                    fprintf(stderr, __FILE__ ": ");           \
-                    fprintf(stderr, __VA_ARGS__);             \
-                    fprintf(stderr, " \n");                   \
-            }   }
+   static int g_debuglog_enable = 1;
+#  define DEBUGLOG(l, ...) {                          \
+        if ((g_debuglog_enable) && (l<=LZ4_DEBUG)) {  \
+            fprintf(stderr, __FILE__ ": ");           \
+            fprintf(stderr, __VA_ARGS__);             \
+            fprintf(stderr, " \n");                   \
+    }   }
 #else
-#  define DEBUGLOG(l, ...)      {}    /* disabled */
+#  define DEBUGLOG(l, ...) {}    /* disabled */
 #endif
 
 
diff --git a/lib/lz4hc.c b/lib/lz4hc.c
index 5922ed7..afadb3f 100644
--- a/lib/lz4hc.c
+++ b/lib/lz4hc.c
@@ -389,8 +389,8 @@ LZ4HC_InsertAndGetWiderMatch (
                                     if (lookBackLength==0) {  /* no back possible */
                                         size_t const maxML = MIN(currentSegmentLength, srcPatternLength);
                                         if ((size_t)longest < maxML) {
-                                            assert(base + matchIndex < ip);
-                                            if (ip - (base+matchIndex) > LZ4_DISTANCE_MAX) break;
+                                            assert(base + matchIndex != ip);
+                                            if ((size_t)(ip - base) - matchIndex > LZ4_DISTANCE_MAX) break;
                                             assert(maxML < 2 GB);
                                             longest = (int)maxML;
                                             *matchpos = base + matchIndex;   /* virtual pos, relative to ip, to retrieve offset */
@@ -1028,7 +1028,7 @@ int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr,
               const char* dictionary, int dictSize)
 {
     LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
-    DEBUGLOG(4, "LZ4_loadDictHC(%p, %p, %d)", LZ4_streamHCPtr, dictionary, dictSize);
+    DEBUGLOG(4, "LZ4_loadDictHC(ctx:%p, dict:%p, dictSize:%d)", LZ4_streamHCPtr, dictionary, dictSize);
     assert(LZ4_streamHCPtr != NULL);
     if (dictSize > 64 KB) {
         dictionary += (size_t)dictSize - 64 KB;