first commit, initial layout and some ideas I want to implement, included my linked list impl

tests/test_linkedlist.c

@@ -0,0 +1,87 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <time.h>
+
+#include "nickel/linkedlist.h"
+
+// helper function to format bytes out.
+char* get_bytes_f(long bytes, char* str) {
+  if(str != NULL) {
+    if (bytes > 0)
+      {
+        if (bytes < 1024) {
+          sprintf(str, "%ld bytes", bytes);
+        }
+        if ((bytes >= 1024) & (bytes < 1024*1024)) {
+          sprintf(str, "%.3f Kbytes", ((double)bytes/(double)1024.00));
+        }
+        if (bytes >= 1024*1024) {
+          sprintf(str, "%.3f Mbytes",(double)bytes/(double)(1024*1024));
+        }
+      }
+    }
+  else {
+    return NULL;
+    }
+  return str;
+}
+
+typedef struct test_data {
+    uint64_t data1;
+    uint64_t data2;
+    uint64_t data3;
+    uint64_t data4;
+
+    ni_list_node link;
+} test_data;
+
+int main (void)
+{
+    time_t time_now;
+    srand(time(&time_now));
+
+    ni_list data_instances;
+    ni_list__init(&data_instances);
+
+    printf("list is allocated at %p\n", (void*)&data_instances);
+    size_t test_size = 10;
+    for(size_t i = 0; i < test_size; i++) {
+        test_data* t = malloc(sizeof(test_data));
+        printf("n = %d allocated data...link at %p...\n", i, &t->link);
+
+        t->data1 = rand() % UINT64_MAX;
+        t->data2 = rand() % UINT64_MAX;
+        t->data3 = rand() % UINT64_MAX;
+        t->data4 = rand() % UINT64_MAX;
+
+        ni_list__push_back(&data_instances, &(t->link));
+
+        printf("write: n = %d: %ld %ld %ld %ld \n\tnext: %p\n\tprev: %p\n",
+            i, t->data1, t->data2, t->data3, t->data4, t->link.next, t->link.prev);
+    }
+
+    printf("Inserted %d count entries into test list...\n", data_instances.count);
+
+    { // scope for access to iter and list
+        size_t i = 0;
+        NI_LIST__FOREACH(&data_instances) {
+          test_data* t = NI_LIST_CONTAINER_OF(it, test_data, link);
+          printf("read: %d: %ld %ld %ld %ld \n\tnext: %p\n\tprev: %p\n",
+            i, t->data1, t->data2, t->data3, t->data4, (void*)it->next, (void*)it->prev);
+          i++; 
+        }
+    }
+
+      while (!ni_list__is_empty(&data_instances)) {
+        ni_list_node* tail = ni_list__get_back(&data_instances);
+        ni_list__remove(&data_instances, tail);
+
+        test_data* t = NI_LIST_CONTAINER_OF(tail, test_data, link);
+        free(t);
+      }
+
+    /* all done! */
+}