From: Kay Sievers Date: Wed, 12 Nov 2008 23:52:12 +0000 (+0100) Subject: merge trie nodes, childs and root into a single array X-Git-Tag: 174~1329 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=023ed7b0a360756e71394e08447e1c979799f5ac;p=systemd merge trie nodes, childs and root into a single array --- diff --git a/udev/udev-rules.c b/udev/udev-rules.c index 1f28e4f0..796d2c15 100644 --- a/udev/udev-rules.c +++ b/udev/udev-rules.c @@ -1,5 +1,6 @@ /* * Copyright (C) 2008 Kay Sievers + * Copyright (C) 2008 Alan Jenkins * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -41,17 +42,16 @@ struct uid_gid { }; }; -struct trie_child { - unsigned int next_idx; - unsigned int node_idx; - unsigned char key; -}; - struct trie_node { + /* this node's first child */ unsigned int child_idx; + /* the next child of our parent node's child list */ + unsigned int next_child_idx; + /* this node's last child (shortcut for append) */ unsigned int last_child_idx; unsigned int value_off; unsigned short value_len; + unsigned char key; }; struct udev_rules { @@ -70,13 +70,9 @@ struct udev_rules { unsigned int buf_count; /* during rule parsing, strings are indexed to find duplicates */ - unsigned int *trie_root; struct trie_node *trie_nodes; unsigned int trie_nodes_cur; unsigned int trie_nodes_max; - struct trie_child *trie_childs; - unsigned int trie_childs_cur; - unsigned int trie_childs_max; /* during rule parsing, uid/gid lookup results are cached */ struct uid_gid *uids; @@ -453,6 +449,7 @@ static int add_string(struct udev_rules *rules, const char *str) unsigned short len; unsigned int depth; unsigned int off; + struct trie_node *parent; len = strlen(str); @@ -460,37 +457,34 @@ static int add_string(struct udev_rules *rules, const char *str) if (len == 0) return 0; - /* descend root - start from last character of str */ - key = str[len - 1]; - node_idx = rules->trie_root[key]; - depth = 0; - - /* descend suffix trie */ - if (node_idx > 0) { - while (1) { - struct trie_node *node; - unsigned int child_idx; - - node = &rules->trie_nodes[node_idx]; - depth++; - off = node->value_off + node->value_len - len; - - /* match against current node */ - if (depth == len || (node->value_len >= len && memcmp(&rules->buf[off], str, len) == 0)) - return off; - - /* lookup child node */ - key = str[len - 1 - depth]; - child_idx = node->child_idx; - while (child_idx > 0) { - if (rules->trie_childs[child_idx].key == key) - break; - child_idx = rules->trie_childs[child_idx].next_idx; - } - if (child_idx == 0) + /* walk trie, start from last character of str to find matching tails */ + node_idx = 0; + key = str[len-1]; + for (depth = 0; depth <= len; depth++) { + struct trie_node *node; + unsigned int child_idx; + + node = &rules->trie_nodes[node_idx]; + off = node->value_off + node->value_len - len; + + /* match against current node */ + if (depth == len || (node->value_len >= len && memcmp(&rules->buf[off], str, len) == 0)) + return off; + + /* lookup child node */ + key = str[len - 1 - depth]; + child_idx = node->child_idx; + while (child_idx > 0) { + struct trie_node *child; + + child = &rules->trie_nodes[child_idx]; + if (child->key == key) break; - node_idx = rules->trie_childs[child_idx].node_idx; + child_idx = child->next_child_idx; } + if (child_idx == 0) + break; + node_idx = child_idx; } /* string not found, add it */ @@ -515,63 +509,26 @@ static int add_string(struct udev_rules *rules, const char *str) rules->trie_nodes_max += add; } - /* grow trie childs if needed */ - if (rules->trie_childs_cur >= rules->trie_childs_max) { - struct trie_child *childs; - unsigned int add; - - /* double the buffer size */ - add = rules->trie_childs_max; - if (add < 8) - add = 8; - - childs = realloc(rules->trie_childs, (rules->trie_childs_max + add) * sizeof(struct trie_child)); - if (childs == NULL) - return -1; - dbg(rules->udev, "extend trie childs from %u to %u\n", - rules->trie_childs_max, rules->trie_childs_max + add); - rules->trie_childs = childs; - rules->trie_childs_max += add; - } - - /* get new node */ + /* get a new node */ new_node_idx = rules->trie_nodes_cur; rules->trie_nodes_cur++; new_node = &rules->trie_nodes[new_node_idx]; + memset(new_node, 0x00, sizeof(struct trie_node)); new_node->value_off = off; new_node->value_len = len; - new_node->child_idx = 0; - new_node->last_child_idx = 0; + new_node->key = key; - if (depth == 0) { - /* add node to root */ - rules->trie_root[key] = new_node_idx; + /* join the parent's child list */ + parent = &rules->trie_nodes[node_idx]; + if (parent->child_idx == 0) { + parent->child_idx = new_node_idx; } else { - /* add node to parent */ - struct trie_node *parent; - struct trie_child *new_child; - unsigned int new_child_idx; - - /* get new child link for list of childs of parent */ - new_child_idx = rules->trie_childs_cur; - rules->trie_childs_cur++; - new_child = &rules->trie_childs[new_child_idx]; - new_child->next_idx = 0; - new_child->node_idx = new_node_idx; - new_child->key = key; - - /* append child link to list of childs of parent */ - parent = &rules->trie_nodes[node_idx]; - if (parent->child_idx == 0) { - parent->child_idx = new_child_idx; - } else { - struct trie_child *last_child; + struct trie_node *last_child; - last_child = &rules->trie_childs[parent->last_child_idx]; - last_child->next_idx = new_child_idx; - } - parent->last_child_idx = new_child_idx; + last_child = &rules->trie_nodes[parent->last_child_idx]; + last_child->next_child_idx = new_node_idx; } + parent->last_child_idx = new_node_idx; return off; } @@ -1766,18 +1723,10 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names) if (rules->trie_nodes == NULL) return NULL; rules->trie_nodes_max = PREALLOC_TRIE; - /* offset 0 is reserved for the null trie node */ + /* offset 0 is the trie root */ + memset(rules->trie_nodes, 0x00, sizeof(struct trie_node)); rules->trie_nodes_cur = 1; - rules->trie_childs = malloc(PREALLOC_TRIE * sizeof(struct trie_child)); - if (rules->trie_childs == NULL) - return NULL; - rules->trie_childs_max = PREALLOC_TRIE; - /* offset 0 is reserved for the null child node */ - rules->trie_childs_cur = 1; - - rules->trie_root = calloc(UCHAR_MAX + 1, sizeof(unsigned short)); - if (udev_get_rules_path(udev) != NULL) { /* custom rules location for testing */ add_matching_files(udev, &file_list, udev_get_rules_path(udev), ".rules"); @@ -1890,22 +1839,15 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names) } info(udev, "rules use %zu bytes tokens (%u * %zu bytes), %zu bytes buffer\n", rules->token_max * sizeof(struct token), rules->token_max, sizeof(struct token), rules->buf_max); - info(udev, "temporary index used %zu bytes (%u * %zu bytes nodes, %u * %zu bytes child links)\n", - rules->trie_nodes_cur * sizeof(struct trie_node) + rules->trie_childs_cur * sizeof(struct trie_child), - rules->trie_nodes_cur, sizeof(struct trie_node), - rules->trie_childs_cur, sizeof(struct trie_child)); + info(udev, "temporary index used %zu bytes (%u * %zu bytes)\n", + rules->trie_nodes_cur * sizeof(struct trie_node), + rules->trie_nodes_cur, sizeof(struct trie_node)); /* cleanup trie */ free(rules->trie_nodes); rules->trie_nodes = NULL; rules->trie_nodes_cur = 0; rules->trie_nodes_max = 0; - free(rules->trie_childs); - rules->trie_childs = NULL; - rules->trie_childs_cur = 0; - rules->trie_childs_max = 0; - free(rules->trie_root); - rules->trie_root = NULL; /* cleanup uid/gid cache */ free(rules->uids); @@ -1928,8 +1870,6 @@ void udev_rules_unref(struct udev_rules *rules) free(rules->tokens); free(rules->buf); free(rules->trie_nodes); - free(rules->trie_childs); - free(rules->trie_root); free(rules->uids); free(rules->gids); free(rules);