minor code refactor

lib/error_private.h

@@ -28,7 +28,7 @@
    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
    You can contact the author at :
-   - Source repository : https://github.com/Cyan4973/zstd
+   - Homepage : http://www.zstd.net
 ****************************************************************** */
 /* Note : this module is expected to remain private, do not expose it */
 
@@ -62,7 +62,7 @@ extern "C" {
 
 
 /*-****************************************
-*  Customization
+*  Customization (error_public.h)
 ******************************************/
 typedef ZSTD_ErrorCode ERR_enum;
 #define PREFIX(name) ZSTD_error_##name
@@ -74,7 +74,7 @@ typedef ZSTD_ErrorCode ERR_enum;
 #ifdef ERROR
 #  undef ERROR   /* reported already defined on VS 2015 (Rich Geldreich) */
 #endif
-#define ERROR(name) (size_t)-PREFIX(name)
+#define ERROR(name) ((size_t)-PREFIX(name))
 
 ERR_STATIC unsigned ERR_isError(size_t code) { return (code > ERROR(maxCode)); }
 
@@ -101,12 +101,12 @@ ERR_STATIC const char* ERR_getErrorName(size_t code)
     case PREFIX(dstSize_tooSmall): return "Destination buffer is too small";
     case PREFIX(srcSize_wrong): return "Src size incorrect";
     case PREFIX(corruption_detected): return "Corrupted block detected";
-    case PREFIX(tableLog_tooLarge): return "tableLog requires too much memory";
-    case PREFIX(maxSymbolValue_tooLarge): return "Unsupported max possible Symbol Value : too large";
+    case PREFIX(tableLog_tooLarge): return "tableLog requires too much memory : unsupported";
+    case PREFIX(maxSymbolValue_tooLarge): return "Unsupported max Symbol Value : too large";
     case PREFIX(maxSymbolValue_tooSmall): return "Specified maxSymbolValue is too small";
     case PREFIX(dictionary_corrupted): return "Dictionary is corrupted";
     case PREFIX(maxCode):
-    default: return notErrorCode;   /* should be impossible, due to ERR_getError() */
+    default: return notErrorCode;   /* impossible, due to ERR_getError() */
     }
 }