introduce the active_list for searching.

[oweals/opkg-lede.git] / libopkg / active_list.c

diff --git a/libopkg/active_list.c b/libopkg/active_list.c
index b4bbef94da19ea08e77cb5ae7cc1950f99c980c1..1d38d8d6bc7c09e37c64dbbd02af2452f5ea2a42 100644 (file)
--- a/libopkg/active_list.c
+++ b/libopkg/active_list.c
@@ -18,12 +18,13 @@
 
 #include "active_list.h"
 #include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
 
 
 void active_list_init(struct active_list *ptr) {
     INIT_LIST_HEAD(&ptr->node);
     INIT_LIST_HEAD(&ptr->depend);
-    ptr->walked=0;
     ptr->depended = NULL;
 }
 
@@ -31,42 +32,78 @@ void active_list_init(struct active_list *ptr) {
  */ 
 struct active_list * active_list_next(struct active_list *head, struct active_list *ptr) {
     struct active_list *next=NULL;
-    if (!head || !ptr) {
-        fprintf(stderr, "active_list_prev head = %p, ptr = %p invalid value!!\n", head, ptr);
+    if ( !head ) {
+        fprintf(stderr, "active_list_next head = %p, ptr = %p invalid value!!\n", head, ptr);
         return NULL;
     }
-    if (ptr == head) {
-        head->walked = !head->walked;
-        next = list_entry(ptr->node.next, struct active_list, node);
-        if (next == head)
-            return NULL;
-        return active_list_next(head, next);
-    }
-    if (ptr->depend.next != &ptr->depend) {
-        next = list_entry(ptr->depend.next, struct active_list, node);
-        if (head->walked != next->walked) {
-            ptr->walked = head->walked;
-            return active_list_next(head, next);
-        }
-    } 
-    if (ptr->walked != head->walked) {
-        ptr->walked = head->walked;
-        return ptr;
+    if ( !ptr )
+        ptr = head;
+    next = list_entry(ptr->node.next, struct active_list, node);
+    if ( next == head ) {
+        return NULL;
     }
-
-    if (ptr->depended && ptr->node.next == &ptr->depended->depend ) {
+    if ( ptr->depended && &ptr->depended->depend == ptr->node.next ) {
         return ptr->depended;
     }
+    while ( next->depend.next != &next->depend ) {
+        next = list_entry(next->depend.next, struct active_list, node); 
+    }
+    return next;
+}
 
-    if (ptr->node.next != &head->node) {
-        next = list_entry(ptr->node.next, struct active_list, node);
-        return active_list_next(head, next);
+
+struct active_list * active_list_prev(struct active_list *head, struct active_list *ptr) {
+    struct active_list *prev=NULL;
+    if ( !head ) {
+        fprintf(stderr, "active_list_prev head = %p, ptr = %p invalid value!!\n", head, ptr);
+        return NULL;
+    }
+    if ( !ptr )
+        ptr = head;
+    if ( ptr->depend.prev != &ptr->depend ) {
+        prev = list_entry(ptr->depend.prev, struct active_list, node);
+        return prev;
     } 
-    return NULL;
+    if ( ptr->depended  && ptr->depended != head && &ptr->depended->depend == ptr->node.prev ) {
+        prev = list_entry(ptr->depended->node.prev, struct active_list, node);
+    } else 
+        prev = list_entry(ptr->node.prev, struct active_list, node);
+    if ( prev == head )
+        return NULL;
+    return prev;
 }
 
 
+struct active_list *active_list_move_node(struct active_list *old_head, struct active_list *new_head, struct active_list *node) {
+    struct active_list *prev;
+    if (!old_head || !new_head || !node)
+        return NULL;
+    if (old_head == new_head)
+        return node;
+    prev = active_list_prev(old_head, node);
+    active_list_add(new_head, node);
+    return prev;
+}
+
+static void list_head_clear (struct list_head *head) {
+    struct active_list *next;
+    struct list_head *n, *ptr;
+    if (!head)
+        return;
+    list_for_each_safe(ptr, n , head) {
+        next = list_entry(ptr, struct active_list, node);
+        if (next->depend.next != &next->depend) {
+            list_head_clear(&next->depend);
+        }
+        active_list_init(next);
+    }
+}
 void active_list_clear(struct active_list *head) {
+    list_head_clear(&head->node);
+    if (head->depend.next != &head->depend) {
+        list_head_clear(&head->depend);
+    }
+    active_list_init(head);
 }
 
 void active_list_add_depend(struct active_list *node, struct active_list *depend) {
@@ -78,4 +115,50 @@ void active_list_add_depend(struct active_list *node, struct active_list *depend
 void active_list_add(struct active_list *head, struct active_list *node) {
     list_del_init(&node->node);
     list_add_tail(&node->node, &head->node);
+    node->depended  = head;
+}
+
+struct active_list * active_list_head_new() {
+    struct active_list * head = calloc(1, sizeof(struct active_list));
+    active_list_init(head);
+    return head;
+}
+
+void active_list_head_delete(struct active_list *head) {
+    active_list_clear(head);
+    free(head);
+}
+
+/*
+ *  Using insert sort. 
+ *  Note. the list should not be large, or it will be very inefficient. 
+ *
+ */
+struct active_list * active_list_sort(struct active_list *head, int (*compare)(const void *, const void *)) {
+    struct active_list tmphead;
+    struct active_list *node, *ptr;
+    if ( !head )
+        return NULL;
+    active_list_init(&tmphead);
+    for (node = active_list_next(head, NULL); node; node = active_list_next(head, NULL)) {
+        if (tmphead.node.next == &tmphead.node) {
+            active_list_move_node(head, &tmphead, node);
+        } else {
+            for (ptr = active_list_next(&tmphead, NULL); ptr; ptr=active_list_next(&tmphead, ptr)) {
+                if (compare(ptr, node) <= 0) {
+                    break;
+                }
+            }
+            if (!ptr) {
+                active_list_move_node(head, &tmphead, node);
+            } else {
+                active_list_move_node(head, ptr, node);
+            }
+        }
+        node->depended = &tmphead;
+    }
+    for (ptr = active_list_prev(&tmphead, NULL); ptr; ptr=active_list_prev(&tmphead, NULL)) {
+        active_list_move_node(&tmphead, head, ptr);
+    }
+    return head;
 }