initial attempt, may need fixing

stdlib/bsearch.c

@@ -0,0 +1,31 @@
+#include <stdlib.h>
+
+void * bsearch(const void * key, const void * base, size_t nel, size_t width,
+               int (*compar)(const void *, const void*)) {
+  void * left; 
+  void * right;
+  void * mid;
+
+  if(nel == 0 || base == NULL) {
+    return NULL;
+  }
+
+  left = base;
+  right = base + (nel * width);
+
+  while(left <= right) {
+    mid = (left + right) / 2;
+    int t = compar(key, mid);
+    if(t == 0) {
+      return mid;
+    }
+    else if(t < 0) {
+      right = mid - width;
+    }
+    else if(t > 0) {
+      left = mid + width;
+    }
+  }
+
+  return NULL;
+}