diff options
Diffstat (limited to 'src/basic/strbuf.c')
| -rw-r--r-- | src/basic/strbuf.c | 204 |
1 files changed, 0 insertions, 204 deletions
diff --git a/src/basic/strbuf.c b/src/basic/strbuf.c deleted file mode 100644 index 00aaf9e621..0000000000 --- a/src/basic/strbuf.c +++ /dev/null @@ -1,204 +0,0 @@ -/*** - This file is part of systemd. - - Copyright 2012 Kay Sievers <kay@vrfy.org> - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <errno.h> -#include <stdlib.h> -#include <string.h> - -#include "alloc-util.h" -#include "strbuf.h" - -/* - * Strbuf stores given strings in a single continuous allocated memory - * area. Identical strings are de-duplicated and return the same offset - * as the first string stored. If the tail of a string already exists - * in the buffer, the tail is returned. - * - * A trie (http://en.wikipedia.org/wiki/Trie) is used to maintain the - * information about the stored strings. - * - * Example of udev rules: - * $ ./udevadm test . - * ... - * read rules file: /usr/lib/udev/rules.d/99-systemd.rules - * rules contain 196608 bytes tokens (16384 * 12 bytes), 39742 bytes strings - * 23939 strings (207859 bytes), 20404 de-duplicated (171653 bytes), 3536 trie nodes used - * ... - */ - -struct strbuf *strbuf_new(void) { - struct strbuf *str; - - str = new0(struct strbuf, 1); - if (!str) - return NULL; - - str->buf = new0(char, 1); - if (!str->buf) - goto err; - str->len = 1; - - str->root = new0(struct strbuf_node, 1); - if (!str->root) - goto err; - str->nodes_count = 1; - return str; -err: - free(str->buf); - free(str->root); - return mfree(str); -} - -static void strbuf_node_cleanup(struct strbuf_node *node) { - size_t i; - - for (i = 0; i < node->children_count; i++) - strbuf_node_cleanup(node->children[i].child); - free(node->children); - free(node); -} - -/* clean up trie data, leave only the string buffer */ -void strbuf_complete(struct strbuf *str) { - if (!str) - return; - if (str->root) - strbuf_node_cleanup(str->root); - str->root = NULL; -} - -/* clean up everything */ -void strbuf_cleanup(struct strbuf *str) { - if (!str) - return; - if (str->root) - strbuf_node_cleanup(str->root); - free(str->buf); - free(str); -} - -static int strbuf_children_cmp(const struct strbuf_child_entry *n1, - const struct strbuf_child_entry *n2) { - return n1->c - n2->c; -} - -static void bubbleinsert(struct strbuf_node *node, - uint8_t c, - struct strbuf_node *node_child) { - - struct strbuf_child_entry new = { - .c = c, - .child = node_child, - }; - int left = 0, right = node->children_count; - - while (right > left) { - int middle = (right + left) / 2 ; - if (strbuf_children_cmp(&node->children[middle], &new) <= 0) - left = middle + 1; - else - right = middle; - } - - memmove(node->children + left + 1, node->children + left, - sizeof(struct strbuf_child_entry) * (node->children_count - left)); - node->children[left] = new; - - node->children_count++; -} - -/* add string, return the index/offset into the buffer */ -ssize_t strbuf_add_string(struct strbuf *str, const char *s, size_t len) { - uint8_t c; - struct strbuf_node *node; - size_t depth; - char *buf_new; - struct strbuf_child_entry *child; - struct strbuf_node *node_child; - ssize_t off; - - if (!str->root) - return -EINVAL; - - /* search string; start from last character to find possibly matching tails */ - if (len == 0) - return 0; - str->in_count++; - str->in_len += len; - - node = str->root; - c = s[len-1]; - for (depth = 0; depth <= len; depth++) { - struct strbuf_child_entry search; - - /* match against current node */ - off = node->value_off + node->value_len - len; - if (depth == len || (node->value_len >= len && memcmp(str->buf + off, s, len) == 0)) { - str->dedup_len += len; - str->dedup_count++; - return off; - } - - c = s[len - 1 - depth]; - - /* bsearch is not allowed on a NULL sequence */ - if (node->children_count == 0) - break; - - /* lookup child node */ - search.c = c; - child = bsearch(&search, node->children, node->children_count, - sizeof(struct strbuf_child_entry), - (__compar_fn_t) strbuf_children_cmp); - if (!child) - break; - node = child->child; - } - - /* add new string */ - buf_new = realloc(str->buf, str->len + len+1); - if (!buf_new) - return -ENOMEM; - str->buf = buf_new; - off = str->len; - memcpy(str->buf + off, s, len); - str->len += len; - str->buf[str->len++] = '\0'; - - /* new node */ - node_child = new0(struct strbuf_node, 1); - if (!node_child) - return -ENOMEM; - node_child->value_off = off; - node_child->value_len = len; - - /* extend array, add new entry, sort for bisection */ - child = realloc(node->children, (node->children_count + 1) * sizeof(struct strbuf_child_entry)); - if (!child) { - free(node_child); - return -ENOMEM; - } - - str->nodes_count++; - - node->children = child; - bubbleinsert(node, c, node_child); - - return off; -} |