Initial commit: SUB-OS 64-Bit Production Monolithic Operating System with LazyBox userland suite

lib/bitmap.c

@@ -0,0 +1,39 @@
+#include <lib/bitmap.h>
+
+int64_t bitmap_find_first_free(const bitmap_word_t* map, size_t total_bits) {
+    size_t words = (total_bits + BITS_PER_WORD - 1) / BITS_PER_WORD;
+
+    for (size_t w = 0; w < words; w++) {
+        if (map[w] != (bitmap_word_t)~0ULL) {
+            for (size_t b = 0; b < BITS_PER_WORD; b++) {
+                size_t bit_idx = w * BITS_PER_WORD + b;
+                if (bit_idx >= total_bits) return -1;
+                if (!bitmap_test(map, bit_idx)) {
+                    return (int64_t)bit_idx;
+                }
+            }
+        }
+    }
+    return -1;
+}
+
+int64_t bitmap_find_contiguous_free(const bitmap_word_t* map, size_t total_bits, size_t count) {
+    if (count == 0) return -1;
+    if (count == 1) return bitmap_find_first_free(map, total_bits);
+
+    size_t run = 0;
+    size_t start = 0;
+
+    for (size_t i = 0; i < total_bits; i++) {
+        if (!bitmap_test(map, i)) {
+            if (run == 0) start = i;
+            run++;
+            if (run == count) {
+                return (int64_t)start;
+            }
+        } else {
+            run = 0;
+        }
+    }
+    return -1;
+}