Mercurial > hg > nginx
view src/core/ngx_rbtree.c @ 4019:5364d2e711cc
SIGWINCH/NOACCEPT signal is disabled now in non-daemon mode.
Non-daemon mode is currently used by supervisord, daemontools and so on
or during debugging. The NOACCEPT signal is only used for online upgrade
which is not supported when nginx is run under supervisord, etc.,
so this change should not break existant setups.
author | Igor Sysoev <igor@sysoev.ru> |
---|---|
date | Mon, 22 Aug 2011 12:34:48 +0000 |
parents | bead8ca82404 |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> /* * The red-black tree code is based on the algorithm described in * the "Introduction to Algorithms" by Cormen, Leiserson and Rivest. */ static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node); static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node); void ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree, ngx_rbtree_node_t *node) { ngx_rbtree_node_t **root, *temp, *sentinel; /* a binary tree insert */ root = (ngx_rbtree_node_t **) &tree->root; sentinel = tree->sentinel; if (*root == sentinel) { node->parent = NULL; node->left = sentinel; node->right = sentinel; ngx_rbt_black(node); *root = node; return; } tree->insert(*root, node, sentinel); /* re-balance tree */ while (node != *root && ngx_rbt_is_red(node->parent)) { if (node->parent == node->parent->parent->left) { temp = node->parent->parent->right; if (ngx_rbt_is_red(temp)) { ngx_rbt_black(node->parent); ngx_rbt_black(temp); ngx_rbt_red(node->parent->parent); node = node->parent->parent; } else { if (node == node->parent->right) { node = node->parent; ngx_rbtree_left_rotate(root, sentinel, node); } ngx_rbt_black(node->parent); ngx_rbt_red(node->parent->parent); ngx_rbtree_right_rotate(root, sentinel, node->parent->parent); } } else { temp = node->parent->parent->left; if (ngx_rbt_is_red(temp)) { ngx_rbt_black(node->parent); ngx_rbt_black(temp); ngx_rbt_red(node->parent->parent); node = node->parent->parent; } else { if (node == node->parent->left) { node = node->parent; ngx_rbtree_right_rotate(root, sentinel, node); } ngx_rbt_black(node->parent); ngx_rbt_red(node->parent->parent); ngx_rbtree_left_rotate(root, sentinel, node->parent->parent); } } } ngx_rbt_black(*root); } void ngx_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; for ( ;; ) { p = (node->key < temp->key) ? &temp->left : &temp->right; if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } void ngx_rbtree_insert_timer_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; for ( ;; ) { /* * Timer values * 1) are spread in small range, usually several minutes, * 2) and overflow each 49 days, if milliseconds are stored in 32 bits. * The comparison takes into account that overflow. */ /* node->key < temp->key */ p = ((ngx_rbtree_key_int_t) node->key - (ngx_rbtree_key_int_t) temp->key < 0) ? &temp->left : &temp->right; if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } void ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree, ngx_rbtree_node_t *node) { ngx_uint_t red; ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w; /* a binary tree delete */ root = (ngx_rbtree_node_t **) &tree->root; sentinel = tree->sentinel; if (node->left == sentinel) { temp = node->right; subst = node; } else if (node->right == sentinel) { temp = node->left; subst = node; } else { subst = ngx_rbtree_min(node->right, sentinel); if (subst->left != sentinel) { temp = subst->left; } else { temp = subst->right; } } if (subst == *root) { *root = temp; ngx_rbt_black(temp); /* DEBUG stuff */ node->left = NULL; node->right = NULL; node->parent = NULL; node->key = 0; return; } red = ngx_rbt_is_red(subst); if (subst == subst->parent->left) { subst->parent->left = temp; } else { subst->parent->right = temp; } if (subst == node) { temp->parent = subst->parent; } else { if (subst->parent == node) { temp->parent = subst; } else { temp->parent = subst->parent; } subst->left = node->left; subst->right = node->right; subst->parent = node->parent; ngx_rbt_copy_color(subst, node); if (node == *root) { *root = subst; } else { if (node == node->parent->left) { node->parent->left = subst; } else { node->parent->right = subst; } } if (subst->left != sentinel) { subst->left->parent = subst; } if (subst->right != sentinel) { subst->right->parent = subst; } } /* DEBUG stuff */ node->left = NULL; node->right = NULL; node->parent = NULL; node->key = 0; if (red) { return; } /* a delete fixup */ while (temp != *root && ngx_rbt_is_black(temp)) { if (temp == temp->parent->left) { w = temp->parent->right; if (ngx_rbt_is_red(w)) { ngx_rbt_black(w); ngx_rbt_red(temp->parent); ngx_rbtree_left_rotate(root, sentinel, temp->parent); w = temp->parent->right; } if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) { ngx_rbt_red(w); temp = temp->parent; } else { if (ngx_rbt_is_black(w->right)) { ngx_rbt_black(w->left); ngx_rbt_red(w); ngx_rbtree_right_rotate(root, sentinel, w); w = temp->parent->right; } ngx_rbt_copy_color(w, temp->parent); ngx_rbt_black(temp->parent); ngx_rbt_black(w->right); ngx_rbtree_left_rotate(root, sentinel, temp->parent); temp = *root; } } else { w = temp->parent->left; if (ngx_rbt_is_red(w)) { ngx_rbt_black(w); ngx_rbt_red(temp->parent); ngx_rbtree_right_rotate(root, sentinel, temp->parent); w = temp->parent->left; } if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) { ngx_rbt_red(w); temp = temp->parent; } else { if (ngx_rbt_is_black(w->left)) { ngx_rbt_black(w->right); ngx_rbt_red(w); ngx_rbtree_left_rotate(root, sentinel, w); w = temp->parent->left; } ngx_rbt_copy_color(w, temp->parent); ngx_rbt_black(temp->parent); ngx_rbt_black(w->left); ngx_rbtree_right_rotate(root, sentinel, temp->parent); temp = *root; } } } ngx_rbt_black(temp); } static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node) { ngx_rbtree_node_t *temp; temp = node->right; node->right = temp->left; if (temp->left != sentinel) { temp->left->parent = node; } temp->parent = node->parent; if (node == *root) { *root = temp; } else if (node == node->parent->left) { node->parent->left = temp; } else { node->parent->right = temp; } temp->left = node; node->parent = temp; } static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node) { ngx_rbtree_node_t *temp; temp = node->left; node->left = temp->right; if (temp->right != sentinel) { temp->right->parent = node; } temp->parent = node->parent; if (node == *root) { *root = temp; } else if (node == node->parent->right) { node->parent->right = temp; } else { node->parent->left = temp; } temp->right = node; node->parent = temp; }