use bitset for parameter state instead of separate boolean fields

include/libpst-types.h

@@ -8,7 +8,7 @@
 #ifndef INCLUDE_LIBPST_TYPES_H_
 #define INCLUDE_LIBPST_TYPES_H_
 
-#include <stdbool.h>
+#include <stdint.h>
 #include <libunwind.h>
 
 typedef struct  pst_function_info {
@@ -18,14 +18,18 @@ typedef struct  pst_function_info {
     unw_word_t  pc;     ///< address between LowPC & HighPC (plus base address offset). actually, address of currently executed command in function
 } pst_function_info;
 
+typedef enum {
+    PARAM_RETURN = 1,   ///< parameter is return value of a function
+    PARAM_VARIABLE = 2, ///< parameter is variable inside of a function
+    PARAM_HAS_VALUE = 4 ///< parameter has a valid value (if not set, then value is undefined)
+} pst_param_flags;
+
 typedef struct pst_parameter_info {
     char*           name;           ///< parameter's name
     uint32_t        line;           ///< line of parameter definition
     unw_word_t      size;           ///< size of parameter in bytes
     unw_word_t      value;          ///< value of parameter. currently only base types supported. use 'size' to determine number of actual bytes of value
-    bool            is_return;      ///< whether this parameter is return value of the function
-    bool            is_variable;    ///< whether this parameter is function variable or argument of function
-    bool            has_value;      ///< whether we got value of parameter or not
+    pst_param_flags flags;          ///< flags of various parameter's options
 } pst_parameter_info;
 
 #endif /* INCLUDE_LIBPST_TYPES_H_ */