First curl_multi_socket() commit. Should primarily be considered as an internal

code rearrange to fit the future better.

1 files changed, 406 insertions, 0 deletions

diff --git a/lib/splay.c b/lib/splay.c
new file mode 100644
index 000000000..0ea078b6c
--- /dev/null
+++ b/lib/splay.c
@@ -0,0 +1,406 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1997 - 2006, 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.
+ *
+ * $Id$
+ ***************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "splay.h"
+
+#define compare(i,j) ((i)-(j))
+
+/* Set this to a key value that will *NEVER* appear otherwise */
+#define KEY_NOTUSED -1
+
+/*
+ * Splay using the key i (which may or may not be in the tree.) The starting
+ * root is t.
+ */
+struct Curl_tree *Curl_splay(int i, struct Curl_tree *t)
+{
+  struct Curl_tree N, *l, *r, *y;
+  int 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 = r->smaller = NULL;
+
+  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. */
+struct Curl_tree *Curl_splayinsert(int i, struct Curl_tree *t,
+                                   struct Curl_tree *area)
+{
+  if (area == NULL)
+    return t;
+
+  if (t != NULL) {
+    t = Curl_splay(i,t);
+    if (compare(i, t->key)==0) {
+      /* it already exists one of this size */
+
+      area->same = t;
+      area->key = i;
+      area->smaller = t->smaller;
+      area->larger = t->larger;
+
+      t->smaller = area;
+      t->key = KEY_NOTUSED;
+
+      return area; /* new root node */
+    }
+  }
+
+  if (t == NULL) {
+    area->smaller = area->larger = NULL;
+  }
+  else if (compare(i, t->key) < 0) {
+    area->smaller = t->smaller;
+    area->larger = t;
+    t->smaller = NULL;
+
+  }
+  else {
+    area->larger = t->larger;
+    area->smaller = t;
+    t->larger = NULL;
+  }
+  area->key = i;
+
+  area->same = NULL; /* no identical node (yet) */
+  return area;
+}
+
+/* Deletes 'i' from the tree if it's there (with an exact match). Returns a
+   pointer to the resulting tree.  */
+struct Curl_tree *Curl_splayremove(int i, struct Curl_tree *t,
+                                   struct Curl_tree **removed)
+{
+  struct Curl_tree *x;
+
+  if (t==NULL)
+    return NULL;
+
+  t = Curl_splay(i,t);
+  if (compare(i, t->key) == 0) {               /* found it */
+
+    /* FIRST! Check if there is a list with identical sizes */
+    if((x = t->same)) {
+      /* 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 */
+  }
+}
+
+/* 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 number */
+struct Curl_tree *Curl_splaygetbest(int 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 sizes */
+    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 node we point out from the tree if it's there. Return a pointer
+   to the resulting tree.  */
+struct Curl_tree *Curl_splayremovebyaddr(struct Curl_tree *t,
+                                         struct Curl_tree *remove)
+{
+  struct Curl_tree *x;
+
+  if (!t || !remove)
+    return NULL;
+
+  if(KEY_NOTUSED == remove->key) {
+    /* just unlink ourselves nice and quickly: */
+    remove->smaller->same = remove->same;
+    if(remove->same)
+      remove->same->smaller = remove->smaller;
+    /* voila, we're done! */
+    return t;
+  }
+
+  t = Curl_splay(remove->key, t);
+
+  /* Check if there is a list with identical sizes */
+
+  x = t->same;
+  if(x) {
+    /* 'x' is the new root node */
+
+    x->key = t->key;
+    x->larger = t->larger;
+    x->smaller = t->smaller;
+
+    return x; /* new root */
+  }
+
+  /* Remove the actualy root node: */
+  if (t->smaller == NULL)
+    x = t->larger;
+  else {
+    x = Curl_splay(remove->key, t->smaller);
+    x->larger = t->larger;
+  }
+
+  return x;
+}
+
+#ifdef CURLDEBUG
+
+int Curl_splayprint(struct Curl_tree * t, int d, char output)
+{
+  int distance=0;
+  struct Curl_tree *node;
+  int i;
+  if (t == NULL)
+    return 0;
+  distance += Curl_splayprint(t->larger, d+1, output);
+  for (i=0; i<d; i++)
+    if(output)
+      printf("  ");
+
+  if(output) {
+    printf("%d[%d]", t->key, i);
+  }
+
+  for(node = t->same; node; node = node->same) {
+    distance += i; /* this has the same "virtual" distance */
+
+    if(output)
+      printf(" [+]");
+  }
+  if(output)
+    puts("");
+
+  distance += i;
+
+  distance += Curl_splayprint(t->smaller, d+1, output);
+
+  return distance;
+}
+#endif
+
+#ifdef TEST_SPLAY
+
+/*#define TEST2 */
+#define MAX 50
+#define OUTPUT 0 /* 1 enables, 0 disables */
+
+/* A sample use of these functions.  Start with the empty tree, insert some
+   stuff into it, and then delete it */
+int main(int argc, char **argv)
+{
+  struct Curl_tree *root, *t;
+  void *ptrs[MAX];
+
+  long sizes[]={
+    50, 60, 50, 100, 60, 200, 120, 300, 400, 200, 256, 122, 60, 120, 200, 300,
+    220, 80, 90, 50, 100, 60, 200, 120, 300, 400, 200, 256, 122, 60, 120, 200,
+    300, 220, 80, 90, 50, 100, 60, 200, 120, 300, 400, 200, 256, 122, 60, 120,
+    200, 300, 220, 80, 90};
+  int i;
+  root = NULL;              /* the empty tree */
+
+  for (i = 0; i < MAX; i++) {
+    ptrs[i] = t = (struct Curl_tree *)malloc(sizeof(struct Curl_tree));
+    if(!t) {
+      puts("out of memory!");
+      return 0;
+    }
+#ifdef TEST2
+    root = Curl_splayinsert(sizes[i], root, t);
+#else
+    root = Curl_splayinsert((541*i)&1023, root, t);
+#endif
+  }
+
+#if 0
+  puts("Result:");
+  printtree(root, 0, 1);
+#endif
+
+#if 1
+  for (i=0; root; i+=30) {
+    Curl_splayprint(root, 0, 1);
+    do {
+      root = Curl_splaygetbest(i, root, &t);
+      if(t)
+        printf("bestfit %d became %d\n", i, t->key);
+      else
+        printf("bestfit %d failed!\n", i);
+    } while(t && root);
+  }
+#endif
+#if 0
+  for (i = 0; i < MAX; i++) {
+    printf("remove pointer %d size %d\n", i, sizes[i]);
+    root = removebyaddr(root, (struct Curl_tree *)ptrs[i]);
+    Curl_splayprint(root, 0, 1);
+  }
+#endif
+
+#if 0
+#ifdef WEIGHT
+  for (i = -1; i<=root->weight; i++) {
+    t = find_rank(i, root);
+    if (t == NULL) {
+      printf("could not find a node of rank %d.\n", i);
+    } else {
+      printf("%d is of rank %d\n", t->key, i);
+    }
+  }
+#endif
+#endif
+
+#if 0
+#ifdef TEST2
+  for (i = 0; i < MAX; i++) {
+    printf("remove size %d\n", sizes[i]);
+    root = Curl_splayremove(sizes[i], root, &t);
+    free(t);
+    Curl_splayprint(root, 0, 1);
+  }
+#endif
+#endif
+  return 0;
+}
+
+#endif /* TEST_SPLAY */