message: add basic support of isxdigit
diff: @@ -144,6 +144,23 @@ static inline int atoi(const char *str)
  return (int)_strtol(str, (char **)NULL, 10);
  }
  +/** @brief Checks whether c is a hexdecimal digit character.
  + *
  + * @return A value different from zero if indeed c is a hexadecimal digit.
  + * Zero otherwise.
  + */
  +static inline int isxdigit(int c)
  +{
  + if ((c >= '0') && (c <= '9'))
  + return 1;
  + else if ((c >= 'A') && (c <= 'F'))
  + return 1;
  + else if ((c >= 'a') && (c <= 'f'))
  + return 1;
  +
  + return 0;
  +}
  +
  #ifdef __cplusplus
  }
  #endif
  