libcurl extracted to the separate lib

git-svn-id: http://svn.miranda-ng.org/main/trunk@14683 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 288 insertions, 0 deletions

diff --git a/libs/libcurl/src/splay.c b/libs/libcurl/src/splay.c
new file mode 100644
index 0000000000..3570712d43
--- /dev/null
+++ b/libs/libcurl/src/splay.c
@@ -0,0 +1,288 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1997 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#include "splay.h"
+
+/*
+ * This macro compares two node keys i and j and returns:
+ *
+ *  negative value: when i is smaller than j
+ *  zero          : when i is equal   to   j
+ *  positive when : when i is larger  than j
+ */
+#define compare(i,j) Curl_splaycomparekeys((i),(j))
+
+/*
+ * Splay using the key i (which may or may not be in the tree.) The starting
+ * root is t.
+ */
+struct Curl_tree *Curl_splay(struct timeval i,
+                             struct Curl_tree *t)
+{
+  struct Curl_tree N, *l, *r, *y;
+  long comp;
+
+  if(t == NULL)
+    return t;
+  N.smaller = N.larger = NULL;
+  l = r = &N;
+
+  for(;;) {
+    comp = compare(i, t->key);
+    if(comp < 0) {
+      if(t->smaller == NULL)
+        break;
+      if(compare(i, t->smaller->key) < 0) {
+        y = t->smaller;                           /* rotate smaller */
+        t->smaller = y->larger;
+        y->larger = t;
+        t = y;
+        if(t->smaller == NULL)
+          break;
+      }
+      r->smaller = t;                               /* link smaller */
+      r = t;
+      t = t->smaller;
+    }
+    else if(comp > 0) {
+      if(t->larger == NULL)
+        break;
+      if(compare(i, t->larger->key) > 0) {
+        y = t->larger;                          /* rotate larger */
+        t->larger = y->smaller;
+        y->smaller = t;
+        t = y;
+        if(t->larger == NULL)
+          break;
+      }
+      l->larger = t;                              /* link larger */
+      l = t;
+      t = t->larger;
+    }
+    else
+      break;
+  }
+
+  l->larger = t->smaller;                                /* assemble */
+  r->smaller = t->larger;
+  t->smaller = N.larger;
+  t->larger = N.smaller;
+
+  return t;
+}
+
+/* Insert key i into the tree t.  Return a pointer to the resulting tree or
+ * NULL if something went wrong.
+ *
+ * @unittest: 1309
+ */
+struct Curl_tree *Curl_splayinsert(struct timeval i,
+                                   struct Curl_tree *t,
+                                   struct Curl_tree *node)
+{
+  static struct timeval KEY_NOTUSED = {-1,-1}; /* will *NEVER* appear */
+
+  if(node == NULL)
+    return t;
+
+  if(t != NULL) {
+    t = Curl_splay(i,t);
+    if(compare(i, t->key)==0) {
+      /* There already exists a node in the tree with the very same key. Build
+         a linked list of nodes. We make the new 'node' struct the new master
+         node and make the previous node the first one in the 'same' list. */
+
+      node->same = t;
+      node->key = i;
+      node->smaller = t->smaller;
+      node->larger = t->larger;
+
+      t->smaller = node; /* in the sub node for this same key, we use the
+                            smaller pointer to point back to the master
+                            node */
+
+      t->key = KEY_NOTUSED; /* and we set the key in the sub node to NOTUSED
+                               to quickly identify this node as a subnode */
+
+      return node; /* new root node */
+    }
+  }
+
+  if(t == NULL) {
+    node->smaller = node->larger = NULL;
+  }
+  else if(compare(i, t->key) < 0) {
+    node->smaller = t->smaller;
+    node->larger = t;
+    t->smaller = NULL;
+
+  }
+  else {
+    node->larger = t->larger;
+    node->smaller = t;
+    t->larger = NULL;
+  }
+  node->key = i;
+
+  node->same = NULL; /* no identical node (yet) */
+  return node;
+}
+
+/* Finds and deletes the best-fit node from the tree. Return a pointer to the
+   resulting tree.  best-fit means the node with the given or lower key */
+struct Curl_tree *Curl_splaygetbest(struct timeval i,
+                                    struct Curl_tree *t,
+                                    struct Curl_tree **removed)
+{
+  struct Curl_tree *x;
+
+  if(!t) {
+    *removed = NULL; /* none removed since there was no root */
+    return NULL;
+  }
+
+  t = Curl_splay(i,t);
+  if(compare(i, t->key) < 0) {
+    /* too big node, try the smaller chain */
+    if(t->smaller)
+      t=Curl_splay(t->smaller->key, t);
+    else {
+      /* fail */
+      *removed = NULL;
+      return t;
+    }
+  }
+
+  if(compare(i, t->key) >= 0) {               /* found it */
+    /* FIRST! Check if there is a list with identical keys */
+    x = t->same;
+    if(x) {
+      /* there is, pick one from the list */
+
+      /* 'x' is the new root node */
+
+      x->key = t->key;
+      x->larger = t->larger;
+      x->smaller = t->smaller;
+
+      *removed = t;
+      return x; /* new root */
+    }
+
+    if(t->smaller == NULL) {
+      x = t->larger;
+    }
+    else {
+      x = Curl_splay(i, t->smaller);
+      x->larger = t->larger;
+    }
+    *removed = t;
+
+    return x;
+  }
+  else {
+    *removed = NULL; /* no match */
+    return t;        /* It wasn't there */
+  }
+}
+
+
+/* Deletes the very node we point out from the tree if it's there. Stores a
+ * pointer to the new resulting tree in 'newroot'.
+ *
+ * Returns zero on success and non-zero on errors! TODO: document error codes.
+ * When returning error, it does not touch the 'newroot' pointer.
+ *
+ * NOTE: when the last node of the tree is removed, there's no tree left so
+ * 'newroot' will be made to point to NULL.
+ *
+ * @unittest: 1309
+ */
+int Curl_splayremovebyaddr(struct Curl_tree *t,
+                           struct Curl_tree *removenode,
+                           struct Curl_tree **newroot)
+{
+  static struct timeval KEY_NOTUSED = {-1,-1}; /* will *NEVER* appear */
+  struct Curl_tree *x;
+
+  if(!t || !removenode)
+    return 1;
+
+  if(compare(KEY_NOTUSED, removenode->key) == 0) {
+    /* Key set to NOTUSED means it is a subnode within a 'same' linked list
+       and thus we can unlink it easily. The 'smaller' link of a subnode
+       links to the parent node. */
+    if(removenode->smaller == NULL)
+      return 3;
+
+    removenode->smaller->same = removenode->same;
+    if(removenode->same)
+      removenode->same->smaller = removenode->smaller;
+
+    /* Ensures that double-remove gets caught. */
+    removenode->smaller = NULL;
+
+    /* voila, we're done! */
+    *newroot = t; /* return the same root */
+    return 0;
+  }
+
+  t = Curl_splay(removenode->key, t);
+
+  /* First make sure that we got the same root node as the one we want
+     to remove, as otherwise we might be trying to remove a node that
+     isn't actually in the tree.
+
+     We cannot just compare the keys here as a double remove in quick
+     succession of a node with key != KEY_NOTUSED && same != NULL
+     could return the same key but a different node. */
+  if(t != removenode)
+    return 2;
+
+  /* Check if there is a list with identical sizes, as then we're trying to
+     remove the root node of a list of nodes with identical keys. */
+  x = t->same;
+  if(x) {
+    /* 'x' is the new root node, we just make it use the root node's
+       smaller/larger links */
+
+    x->key = t->key;
+    x->larger = t->larger;
+    x->smaller = t->smaller;
+  }
+  else {
+    /* Remove the root node */
+    if(t->smaller == NULL)
+      x = t->larger;
+    else {
+      x = Curl_splay(removenode->key, t->smaller);
+      x->larger = t->larger;
+    }
+  }
+
+  *newroot = x; /* store new root pointer */
+
+  return 0;
+}
+