[PATCH] path.c: do not alloc for .contents in the trie
- From
Rubén Justo <rjusto@gmail.com>
- Date
- Oct 17, 2022, 06:14 UTC
- Message-ID
- <4db3d1ed-d530-2429-f578-33196ff71fb1@gmail.com>
In 4e09cf2ac (path: optimize common dir checking, 2015-08-31) a trie was introduced to search non-linearly over common_list. The nodes in the trie are constructed from the values in that static variable. Each of those nodes can have in .contents a heap allocated string with the characters to be considered for the node, and in .len the count of this characters. Having this .len there is no need to have a local copy of the string, we can just have in .contents a pointer to a specific position in the specific string in the specific value in common_list. Only .len characters will be considered.
Let's make .contents const and remove that unneeded xstrndups.
Signed-off-by: Rubén Justo <rjusto@gmail.com> --- path.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/path.c b/path.c index a3cfcd8a6e..94483d98f9 100644 --- a/path.c +++ b/path.c @@ -159,7 +159,7 @@ static struct common_dir common_list[] = { struct trie { struct trie *children[256]; int len; - char *contents; + const char *contents; void *value; }; @@ -167,10 +167,8 @@ static struct trie *make_trie_node(const char *key, void *value) { struct trie *new_node = xcalloc(1, sizeof(*new_node)); new_node->len = strlen(key); - if (new_node->len) { - new_node->contents = xmalloc(new_node->len); - memcpy(new_node->contents, key, new_node->len); - } + if (new_node->len) + new_node->contents = key; new_node->value = value; return new_node; } @@ -204,10 +202,8 @@ static void *add_to_trie(struct trie *root, const char *key, void *value) memcpy(child->children, root->children, sizeof(root->children)); child->len = root->len - i - 1; - if (child->len) { - child->contents = xstrndup(root->contents + i + 1, - child->len); - } + if (child->len) + child->contents = root->contents + i + 1; child->value = root->value; root->value = NULL; root->len = i;
-- 2.36.1