Mercurial > hg > nginx
view src/core/ngx_radix_tree.c @ 5742:c45c9812cf11
Core: removed meaningless check from ngx_palloc_block().
The check became meaningless after refactoring in 2a92804f4109.
With the loop currently in place, "current" can't be NULL, hence
the check can be dropped.
Additionally, the local variable "current" was removed to
simplify code, and pool->current now used directly instead.
Found by Coverity (CID 714236).
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 26 Jun 2014 03:34:19 +0400 |
parents | 3be3de31d7dd |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> static ngx_radix_node_t *ngx_radix_alloc(ngx_radix_tree_t *tree); ngx_radix_tree_t * ngx_radix_tree_create(ngx_pool_t *pool, ngx_int_t preallocate) { uint32_t key, mask, inc; ngx_radix_tree_t *tree; tree = ngx_palloc(pool, sizeof(ngx_radix_tree_t)); if (tree == NULL) { return NULL; } tree->pool = pool; tree->free = NULL; tree->start = NULL; tree->size = 0; tree->root = ngx_radix_alloc(tree); if (tree->root == NULL) { return NULL; } tree->root->right = NULL; tree->root->left = NULL; tree->root->parent = NULL; tree->root->value = NGX_RADIX_NO_VALUE; if (preallocate == 0) { return tree; } /* * Preallocation of first nodes : 0, 1, 00, 01, 10, 11, 000, 001, etc. * increases TLB hits even if for first lookup iterations. * On 32-bit platforms the 7 preallocated bits takes continuous 4K, * 8 - 8K, 9 - 16K, etc. On 64-bit platforms the 6 preallocated bits * takes continuous 4K, 7 - 8K, 8 - 16K, etc. There is no sense to * to preallocate more than one page, because further preallocation * distributes the only bit per page. Instead, a random insertion * may distribute several bits per page. * * Thus, by default we preallocate maximum * 6 bits on amd64 (64-bit platform and 4K pages) * 7 bits on i386 (32-bit platform and 4K pages) * 7 bits on sparc64 in 64-bit mode (8K pages) * 8 bits on sparc64 in 32-bit mode (8K pages) */ if (preallocate == -1) { switch (ngx_pagesize / sizeof(ngx_radix_node_t)) { /* amd64 */ case 128: preallocate = 6; break; /* i386, sparc64 */ case 256: preallocate = 7; break; /* sparc64 in 32-bit mode */ default: preallocate = 8; } } mask = 0; inc = 0x80000000; while (preallocate--) { key = 0; mask >>= 1; mask |= 0x80000000; do { if (ngx_radix32tree_insert(tree, key, mask, NGX_RADIX_NO_VALUE) != NGX_OK) { return NULL; } key += inc; } while (key); inc >>= 1; } return tree; } ngx_int_t ngx_radix32tree_insert(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask, uintptr_t value) { uint32_t bit; ngx_radix_node_t *node, *next; bit = 0x80000000; node = tree->root; next = tree->root; while (bit & mask) { if (key & bit) { next = node->right; } else { next = node->left; } if (next == NULL) { break; } bit >>= 1; node = next; } if (next) { if (node->value != NGX_RADIX_NO_VALUE) { return NGX_BUSY; } node->value = value; return NGX_OK; } while (bit & mask) { next = ngx_radix_alloc(tree); if (next == NULL) { return NGX_ERROR; } next->right = NULL; next->left = NULL; next->parent = node; next->value = NGX_RADIX_NO_VALUE; if (key & bit) { node->right = next; } else { node->left = next; } bit >>= 1; node = next; } node->value = value; return NGX_OK; } ngx_int_t ngx_radix32tree_delete(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask) { uint32_t bit; ngx_radix_node_t *node; bit = 0x80000000; node = tree->root; while (node && (bit & mask)) { if (key & bit) { node = node->right; } else { node = node->left; } bit >>= 1; } if (node == NULL) { return NGX_ERROR; } if (node->right || node->left) { if (node->value != NGX_RADIX_NO_VALUE) { node->value = NGX_RADIX_NO_VALUE; return NGX_OK; } return NGX_ERROR; } for ( ;; ) { if (node->parent->right == node) { node->parent->right = NULL; } else { node->parent->left = NULL; } node->right = tree->free; tree->free = node; node = node->parent; if (node->right || node->left) { break; } if (node->value != NGX_RADIX_NO_VALUE) { break; } if (node->parent == NULL) { break; } } return NGX_OK; } uintptr_t ngx_radix32tree_find(ngx_radix_tree_t *tree, uint32_t key) { uint32_t bit; uintptr_t value; ngx_radix_node_t *node; bit = 0x80000000; value = NGX_RADIX_NO_VALUE; node = tree->root; while (node) { if (node->value != NGX_RADIX_NO_VALUE) { value = node->value; } if (key & bit) { node = node->right; } else { node = node->left; } bit >>= 1; } return value; } #if (NGX_HAVE_INET6) ngx_int_t ngx_radix128tree_insert(ngx_radix_tree_t *tree, u_char *key, u_char *mask, uintptr_t value) { u_char bit; ngx_uint_t i; ngx_radix_node_t *node, *next; i = 0; bit = 0x80; node = tree->root; next = tree->root; while (bit & mask[i]) { if (key[i] & bit) { next = node->right; } else { next = node->left; } if (next == NULL) { break; } bit >>= 1; node = next; if (bit == 0) { if (++i == 16) { break; } bit = 0x80; } } if (next) { if (node->value != NGX_RADIX_NO_VALUE) { return NGX_BUSY; } node->value = value; return NGX_OK; } while (bit & mask[i]) { next = ngx_radix_alloc(tree); if (next == NULL) { return NGX_ERROR; } next->right = NULL; next->left = NULL; next->parent = node; next->value = NGX_RADIX_NO_VALUE; if (key[i] & bit) { node->right = next; } else { node->left = next; } bit >>= 1; node = next; if (bit == 0) { if (++i == 16) { break; } bit = 0x80; } } node->value = value; return NGX_OK; } ngx_int_t ngx_radix128tree_delete(ngx_radix_tree_t *tree, u_char *key, u_char *mask) { u_char bit; ngx_uint_t i; ngx_radix_node_t *node; i = 0; bit = 0x80; node = tree->root; while (node && (bit & mask[i])) { if (key[i] & bit) { node = node->right; } else { node = node->left; } bit >>= 1; if (bit == 0) { if (++i == 16) { break; } bit = 0x80; } } if (node == NULL) { return NGX_ERROR; } if (node->right || node->left) { if (node->value != NGX_RADIX_NO_VALUE) { node->value = NGX_RADIX_NO_VALUE; return NGX_OK; } return NGX_ERROR; } for ( ;; ) { if (node->parent->right == node) { node->parent->right = NULL; } else { node->parent->left = NULL; } node->right = tree->free; tree->free = node; node = node->parent; if (node->right || node->left) { break; } if (node->value != NGX_RADIX_NO_VALUE) { break; } if (node->parent == NULL) { break; } } return NGX_OK; } uintptr_t ngx_radix128tree_find(ngx_radix_tree_t *tree, u_char *key) { u_char bit; uintptr_t value; ngx_uint_t i; ngx_radix_node_t *node; i = 0; bit = 0x80; value = NGX_RADIX_NO_VALUE; node = tree->root; while (node) { if (node->value != NGX_RADIX_NO_VALUE) { value = node->value; } if (key[i] & bit) { node = node->right; } else { node = node->left; } bit >>= 1; if (bit == 0) { i++; bit = 0x80; } } return value; } #endif static ngx_radix_node_t * ngx_radix_alloc(ngx_radix_tree_t *tree) { ngx_radix_node_t *p; if (tree->free) { p = tree->free; tree->free = tree->free->right; return p; } if (tree->size < sizeof(ngx_radix_node_t)) { tree->start = ngx_pmemalign(tree->pool, ngx_pagesize, ngx_pagesize); if (tree->start == NULL) { return NULL; } tree->size = ngx_pagesize; } p = (ngx_radix_node_t *) tree->start; tree->start += sizeof(ngx_radix_node_t); tree->size -= sizeof(ngx_radix_node_t); return p; }