Added bitmap in lib

kernel/lib/bitmap/src/bitmap.c

@@ -0,0 +1,66 @@
+#include "lib/bitmap.h"
+
+/*
+ * bitmap_set:
+ * -----------
+ *
+ */
+
+void bitmap_set(uint32_t *bitmap, int bit) {
+    bitmap[bit / 32] |= (1 << (bit % 32));
+}
+
+/*
+ * bitmap_unset:
+ * -------------
+ *
+ */
+
+void bitmap_unset(uint32_t *bitmap, int bit) {
+    bitmap[bit / 32] &= ~(1 << (bit % 32));
+}
+
+/*
+ * bitmap_test:
+ * ------------
+ *
+ */
+
+int bitmap_test(uint32_t *bitmap, int bit) {
+    return bitmap[bit / 32] & (1 << (bit % 32)); 
+}
+
+/*
+ * bitmap_first_unset:
+ * -------------------
+ *
+ *  Search in each double word for an unset bit. If a double
+ *  word is fully set then skip testing it.
+ *
+ *  It may be the case that at the end of the bitmap there are
+ *  some bits that do not fully fit a double word. Last if's job
+ *  is to test these reamining bits.
+ *
+ */
+
+
+int bitmap_first_unset(uint32_t *bitmap, size_t size) {
+
+    uint32_t rem_bits = size % 32;
+
+    for (uint32_t i = 0; i < size / 32; i++)
+        if (bitmap[i] != 0XFFFFFFFF)
+            for (int j = 0; j < 32; j++)
+                if (!(bitmap[i] & (1 << j)))
+                    return (i * 32) + j;
+
+    if (rem_bits) {
+
+        for (uint32_t j = 0; j < rem_bits; j++)
+            if (!(bitmap[size / 32] & (1 << j)))
+                    return ((size / 32) * 32) + j;
+
+    }
+
+    return -1;
+}

kernel/lib/include/lib/bitmap.h

@@ -0,0 +1,55 @@
+#ifndef BITMAP_H_
+#define BITMAP_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+/*
+ * bitmap_set:
+ *  Sets bit at index bit in bitmap
+ *
+ * @param bitmap - Bitmap
+ * @param bit    - Index to set
+ *
+ */
+
+void bitmap_set(uint32_t *bitmap, int bit);
+
+/*
+ * bitmap_unset:
+ *  Unsets bit at index bit in bitmap
+ *
+ * @param bitmap - Bitmap
+ * @param bit    - Index to unset
+ *
+ */
+
+void bitmap_unset(uint32_t *bitmap, int bit);
+
+/*
+ * bitmap_test:
+ *  Tests bit at index bit in bitmap
+ *
+ * @param bitmap - Bitmap
+ * @param bit    - Index to test
+ *
+ * @return - State of the respective bit
+ *
+ */
+
+int bitmap_test(uint32_t *bitmap, int bit);
+
+/*
+ * bitmap_first_unset:
+ *  Finds the index of the first unset bit.
+ *
+ * @param bitmap - Bitmap
+ * @param size   - Size of bitmap
+ *
+ * @return - Index of first unset bit
+ *
+ */
+
+int bitmap_first_unset(uint32_t *bitmap, size_t size);
+
+#endif