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C/C(extra) ExtraAssignments/BitStuff/shared/bit_stuff.c

@@ -0,0 +1,44 @@
+#include "bit_stuff.h"
+#include <limits.h>
+#include <stddef.h>
+
+// leave resource_detector.h as last include!
+#include "resource_detector.h"
+
+unsigned int count_ones(unsigned int value){
+    unsigned int count = 0;
+    while (value){
+        count += value & 1;
+        value >>= 1;
+    }
+    return count;
+}
+
+void make_bitmask(unsigned int width, unsigned int shift, unsigned int* mask){
+    if (width == 0 || width > sizeof(unsigned int)*CHAR_BIT) return; 
+    if (width == sizeof(unsigned int) * CHAR_BIT) *mask = ~0U << shift;
+    else *mask = ((1U << width) - 1) << shift;
+}
+
+void apply_bitmask(unsigned int value, unsigned int mask, unsigned int* masked_value) {
+    if (masked_value != NULL) {
+        *masked_value = value & mask;
+    }
+}
+
+void flip_bit(unsigned int value, unsigned int bit_index, unsigned int* updated_value){
+
+    if (updated_value == 0 || bit_index >= sizeof(unsigned int) * CHAR_BIT) return;
+    *updated_value = value ^ (1U << bit_index);
+}
+
+void extract_nibbles_from_byte(uint8_t value, uint8_t* high_nibble, uint8_t* low_nibble){
+    if (high_nibble == NULL || low_nibble == NULL) return;
+    *high_nibble = (value >> 4) & 0xF;
+    *low_nibble = value & 0xF;
+}
+
+void combine_nibles_to_byte(uint8_t high_nibble, uint8_t low_nibble, uint8_t* value){
+    if (value == NULL) return;
+    *value = (high_nibble << 4) | (low_nibble);
+}

C/C(extra) ExtraAssignments/BitStuff/shared/bit_stuff.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <stdint.h>
+
+/* pre : -
+ * post: the number of bits with value 1 is counted and returned
+ */
+unsigned int count_ones(unsigned int value);
+
+/* pre : -
+ * post: a bitmask with a given width and a given shift is generated (so w=5 and
+ *       s=1 gives 00111110)
+ */
+void make_bitmask(unsigned int width, unsigned int shift, unsigned int* mask);
+
+/* pre : -
+ * post: 'masked_value' is assigned the value of 'value' with the 'mask' applied
+ */
+void apply_bitmask(unsigned int value, unsigned int mask, unsigned int* masked_value);
+
+/* pre : -
+ * post: the bit of index 'bit_index' of 'value' is flipped: 0 --> 1, 1 --> 0.
+ */
+void flip_bit(unsigned int value, unsigned int bit_index, unsigned int* updated_value);
+
+/* pre : -
+ * post: the high and low nibbles of 'value' of stored in 'high_nibble' and
+ *       'low_nibble'.
+ */
+void extract_nibbles_from_byte(uint8_t value, uint8_t* high_nibble, uint8_t* low_nibbe);
+
+/* pre : -
+ * post: the nibble values of the 'high_nibble' and 'low_nibble' are combined
+ *       and stored in 'value'
+ */
+void combine_nibles_to_byte(uint8_t high_nibble, uint8_t low_nibbe, uint8_t* value);