1 files changed, 131 insertions, 0 deletions
diff --git a/src/list_management.c b/src/list_management.c
new file mode 100644
index 0000000..634b884
--- /dev/null
+++ b/src/list_management.c
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+/* Copyright 2025 Thorsten Töpper
+ *
+ * vim:ts=4:sw=4:expandtab
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include "output.h"
+#include "list_management.h"
+
+
+
+/* === IMPLEMENTATION === */
+inline struct list_node *create_node(char *fname, size_t fsize, time_t ftime) {
+    struct list_node *node = NULL;
+    
+    if (fname == NULL || fname[0] == '\0') {
+        LOGERR("ERROR: No valid filename given\n");
+        return NULL;
+    }
+
+    if ((node = calloc(1, sizeof(struct list_node))) == NULL) {
+        LOGERR("ERROR: Failed allocate memory for node: %s\n", strerror(errno));
+        return NULL;
+    }
+
+    node->next  = NULL;
+    node->fsize = fsize;
+    node->ftime = ftime;
+    /* With strncpy and strict compiler options it complained. A file name
+     * can't be longer than 256 bytes, including the string terminating \0
+     * byte at the end. As the code no longer's in the same file...*/
+    memcpy(node->fname, fname, 255);
+    node->fname[255] = '\0';
+    return node;
+}
+
+
+inline void destroy_list(struct list_head *list) {
+    struct list_node *ptr = NULL;
+    if (list == NULL)
+        return;
+    while (list->first != NULL) {
+        ptr = list->first->next;
+        if (ptr == NULL) {
+            free(list->first);
+            break;
+        }
+        list->first->next = ptr->next;
+        free(ptr);
+    }
+    free(list);
+}
+
+
+/* dirty... */
+#define INSERT_BY_NUMERIC_FIELD(list, node, field) \
+{ struct list_node *ptr = NULL; \
+    if (node->field > list->first->field) { \
+        node->next = list->first; list->first = node; return 0; } \
+    ptr = list->first; \
+    while (ptr != NULL) { \
+        if (ptr->next == NULL) { ptr->next = node; return 0; } \
+        if (node->field > ptr->next->field) { \
+            node->next = ptr->next; ptr->next = node; \
+            return 0; } \
+        ptr = ptr->next; \
+    } \
+}
+
+
+/* TODO: later when, other parameters are actively used move the action to a template */
+inline int insert_sorted_by_size(struct list_head *list, struct list_node *node) {
+    if (list == NULL) { LOGERR("ERROR: No list given.\n"); return -1; }
+    if (node == NULL) { LOGERR("ERROR: No node given.\n"); return -2; }
+
+    if (list->first == NULL) {
+        list->first = node;
+        return 0;
+    }
+    INSERT_BY_NUMERIC_FIELD(list, node, fsize);
+    return -3;
+}
+
+inline int insert_sorted_by_time(struct list_head *list, struct list_node *node) {
+    if (list == NULL) { LOGERR("ERROR: No list given.\n"); return -1; }
+    if (node == NULL) { LOGERR("ERROR: No node given.\n"); return -2; }
+
+    if (list->first == NULL) {
+        list->first = node;
+        return 0;
+    }
+    INSERT_BY_NUMERIC_FIELD(list, node, ftime);
+    return -3;
+}
+#undef INSERT_BY_NUMERIC_FIELD
+
+
+struct list_head *create_list_sort_reversed(struct list_head *list) {
+    struct list_head *lh = NULL;
+    struct list_node *cpynode = NULL, *ptr = NULL;
+    if (list == NULL) {
+        LOGERR("ERROR: No list given\n");
+        return NULL;
+    }
+    if ((lh = calloc(1, sizeof(struct list_head))) == NULL) {
+        LOGERR("ERROR: Failed to allocate memory for a struct list_head\n");
+        return NULL;
+    }
+
+    lh->first = NULL;
+    ptr = list->first;
+
+    while (ptr != NULL) {
+        cpynode = create_node(ptr->fname, ptr->fsize, ptr->ftime);
+        if (cpynode == NULL) {
+            destroy_list(lh);
+            return NULL;
+        }
+        cpynode->next = lh->first;
+        lh->first = cpynode;
+        ptr = ptr->next;
+    }
+
+    return lh;
+}
+