text edit: new line processing mechanism [not finished]

src/utils/dlist.c

@@ -0,0 +1,63 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct dlist_el_t {
+  struct dlist_el_t *next;
+  struct dlist_el_t *previous;
+  void *el_ptr;
+} dlist_el_t;
+
+typedef struct dlist_t {
+  dlist_el_t *start;
+  dlist_el_t *current;
+  size_t len;
+} dlist_t;
+
+void dlist_add(dlist_t *dlist, void *el_ptr, int el_siz, bool prepend);
+
+dlist_t *dlist_init(void *el_ptr, int el_siz) {
+  dlist_t *dlist = malloc(sizeof(dlist_t));
+  dlist->len = 0;
+  dlist->current = NULL;
+  dlist->start = NULL;
+
+  if (el_ptr != NULL) {
+    dlist_add(dlist, el_ptr, el_siz, false);
+  }
+
+  return dlist;
+}
+
+void dlist_add(dlist_t *dlist, void *el_ptr, int el_siz, bool prepend) {
+  dlist_el_t *d_el = malloc(sizeof(dlist_el_t));
+  d_el->el_ptr = malloc(el_siz);
+  memcpy(d_el->el_ptr, el_ptr, el_siz);
+
+  if (dlist->start == NULL) {
+    d_el->previous = NULL;
+    d_el->next = NULL;
+    dlist->start = d_el;
+    dlist->current = d_el;
+  } else if (prepend) {
+    d_el->previous = NULL;
+    d_el->next = dlist->start;
+    dlist->start = d_el;
+  } else {
+    d_el->next = NULL;
+    dlist->current->next = d_el;
+    dlist->current = d_el;
+  }
+  dlist->len++;
+}
+
+void *dlist_get_current(dlist_t *dlist) {
+    return dlist->current->el_ptr;
+}
+
+void *dlist_it_prev(dlist_t *dlist) {
+    dlist->current = dlist->current->previous;
+    return dlist->current;
+}