Merge pull request #3447 from OlegHahm/fix_unsigned_char_in_od

od: signedness and constantness of input parameter

sys/include/od.h

@@ -136,7 +136,7 @@ extern "C" {
  * @param[in] flags     Flags as defined in @ref od_flags_address and
  *                      @ref od_flags_bytes
  */
-void od(void *data, size_t data_len, uint8_t width, uint16_t flags);
+void od(const void *data, size_t data_len, uint8_t width, uint16_t flags);
 
 /**
  * @brief Dumps memory stored at *data* up to *data_len* in octal, decimal, or
@@ -148,7 +148,7 @@ void od(void *data, size_t data_len, uint8_t width, uint16_t flags);
  * @param[in] width     Number of bytes per line. If *width* is 0,
  *                      @ref OD_WIDTH_DEFAULT is assumed as a default value.
  */
-static inline void od_hex_dump(void *data, size_t data_len, uint8_t width)
+static inline void od_hex_dump(const void *data, size_t data_len, uint8_t width)
 {
     od(data, data_len, width, OD_FLAGS_ADDRESS_HEX | OD_FLAGS_BYTES_HEX | OD_FLAGS_LENGTH_1);
 }

sys/od/od.c

@@ -178,13 +178,13 @@ static inline void _bytes_format(char *format, uint16_t flags)
     }
 }
 
-static void _print_date(void *data, size_t offset, char *format, uint8_t length,
+static void _print_date(const void *data, size_t offset, char *format, uint8_t length,
                         uint16_t flags)
 {
     switch (length) {
         case 1:
             if (flags & OD_FLAGS_BYTES_CHAR) {
-                switch (((char *)data)[offset]) {
+                switch (((signed char *)data)[offset]) {
                     case '\0':
                         printf("   \\0");
                         return;
@@ -218,11 +218,11 @@ static void _print_date(void *data, size_t offset, char *format, uint8_t length,
                         return;
 
                     default:
-                        if (((char *)data)[offset] < 0) {
+                        if (((signed char *)data)[offset] < 0) {
                             printf("  %03o", ((unsigned char *)data)[offset]);
                             return;
                         }
-                        else if (((char *)data)[offset] < 32) {
+                        else if (((signed char *)data)[offset] < 32) {
                             printf("  %03o", ((char *)data)[offset]);
                             return;
                         }
@@ -287,7 +287,7 @@ static int _log10(uint8_t a)
     return ++res;
 }
 
-void od(void *data, size_t data_len, uint8_t width, uint16_t flags)
+void od(const void *data, size_t data_len, uint8_t width, uint16_t flags)
 {
     char address_format[5];
     uint8_t date_length = _length(flags);