first proposal for LZ4_USER_MEMORY_FUNCTIONS

makes it possible to replace at link time
malloc, calloc and free
by user-provided functions
which must be named LZ4_malloc(), LZ4_calloc() and LZ4_free().

answer #937

3 files changed, 28 insertions, 12 deletions

diff --git a/lib/README.md b/lib/README.md
index 318106d..e2af868 100644
--- a/lib/README.md
+++ b/lib/README.md
@@ -69,6 +69,10 @@ The following build macro can be selected to adjust source code behavior at comp
   This build macro offers another project-specific method
   by defining `LZ4_DISABLE_DEPRECATE_WARNINGS` before including the LZ4 header files.
 
+- `LZ4_USER_MEMORY_FUNCTIONS` : replace calls to <stdlib>'s `malloc`, `calloc` and `free`
+  by user-defined functions, which must be called `LZ4_malloc()`, `LZ4_calloc()` and `LZ4_free()`.
+  User functions must be available at link time.
+
 - `LZ4_FORCE_SW_BITCOUNT` : by default, the compression algorithm tries to determine lengths
   by using bitcount instructions, generally implemented as fast single instructions in many cpus.
   In case the target cpus doesn't support it, or compiler intrinsic doesn't work, or feature bad performance,
diff --git a/lib/lz4.c b/lib/lz4.c
index 427673e..a8cc420 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -188,10 +188,23 @@
 /*-************************************
 *  Memory routines
 **************************************/
-#include <stdlib.h>   /* malloc, calloc, free */
-#define ALLOC(s)          malloc(s)
-#define ALLOC_AND_ZERO(s) calloc(1,s)
-#define FREEMEM(p)        free(p)
+#ifdef LZ4_USER_MEMORY_FUNCTIONS
+/* memory management functions can be customized by user project.
+ * Below functions must exist somewhere in the Project
+ * and be available at link time */
+void* LZ4_malloc(size_t s);
+void* LZ4_calloc(size_t s);
+void  LZ4_free(void* p);
+# define ALLOC(s)          LZ4_malloc(s)
+# define ALLOC_AND_ZERO(s) LZ4_calloc(s)
+# define FREEMEM(p)        LZ4_free(p)
+#else
+# include <stdlib.h>   /* malloc, calloc, free */
+# define ALLOC(s)          malloc(s)
+# define ALLOC_AND_ZERO(s) calloc(1,s)
+# define FREEMEM(p)        free(p)
+#endif
+
 #include <string.h>   /* memset, memcpy */
 #define MEM_INIT(p,v,s)   memset((p),(v),(s))
 
diff --git a/lib/lz4hc.c b/lib/lz4hc.c
index 8875f1a..8320f33 100644
--- a/lib/lz4hc.c
+++ b/lib/lz4hc.c
@@ -93,7 +93,7 @@ static U32 LZ4HC_hashPtr(const void* ptr) { return HASH_FUNCTION(LZ4_read32(ptr)
 **************************************/
 static void LZ4HC_clearTables (LZ4HC_CCtx_internal* hc4)
 {
-    MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));
+    MEM_INIT(hc4->hashTable, 0, sizeof(hc4->hashTable));
     MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
 }
 
@@ -983,11 +983,10 @@ int LZ4_compress_HC_destSize(void* state, const char* source, char* dest, int* s
 /* allocation */
 LZ4_streamHC_t* LZ4_createStreamHC(void)
 {
-    LZ4_streamHC_t* const state = (LZ4_streamHC_t*)ALLOC(sizeof(LZ4_streamHC_t));
-    if (LZ4_initStreamHC(state, sizeof(*state)) == NULL) {
-        free(state);
-        return NULL;
-    }
+    LZ4_streamHC_t* const state =
+        (LZ4_streamHC_t*)ALLOC_AND_ZERO(sizeof(LZ4_streamHC_t));
+    if (state == NULL) return NULL;
+    LZ4_setCompressionLevel(state, LZ4HC_CLEVEL_DEFAULT);
     return state;
 }
 
@@ -1323,7 +1322,7 @@ static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx,
     int retval = 0;
 #define TRAILING_LITERALS 3
 #ifdef LZ4HC_HEAPMODE
-    LZ4HC_optimal_t* const opt = (LZ4HC_optimal_t*)malloc(sizeof(LZ4HC_optimal_t) * (LZ4_OPT_NUM + TRAILING_LITERALS));
+    LZ4HC_optimal_t* const opt = (LZ4HC_optimal_t*)ALLOC(sizeof(LZ4HC_optimal_t) * (LZ4_OPT_NUM + TRAILING_LITERALS));
 #else
     LZ4HC_optimal_t opt[LZ4_OPT_NUM + TRAILING_LITERALS];   /* ~64 KB, which is a bit large for stack... */
 #endif
@@ -1606,7 +1605,7 @@ if (limit == fillOutput) {
 }
 _return_label:
 #ifdef LZ4HC_HEAPMODE
-     free(opt);
+     FREEMEM(opt);
 #endif
      return retval;
 }