[pacman-dev] [PATCH 3/3] Improve splitname memory allocation

[Dan McGee]

We don't need to create a temporary copy of the string if we are smart with
our pointer manipulation and string copying. This saves a bunch of string
duplication during database parsing, both local and sync.

Signed-off-by: Dan McGee <d...@archlinux.org>
---
 lib/libalpm/util.c |   27 +++++++++++++--------------
 1 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index 81d950e..7a73c6f 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -864,25 +864,23 @@ int _alpm_splitname(const char *target, pmpkg_t *pkg)
         * package name can contain hyphens, so parse from the back- go back
         * two hyphens and we have split the version from the name.
         */
-       char *tmp, *p, *q;
+       const char *version, *end;
 
        if(target == NULL || pkg == NULL) {
                return(-1);
        }
-       STRDUP(tmp, target, RET_ERR(PM_ERR_MEMORY, -1));
-       p = tmp + strlen(tmp);
+       end = target + strlen(target);
 
        /* remove any trailing '/' */
-       while (*(p - 1) == '/') {
-         --p;
-         *p = '\0';
+       while (*(end - 1) == '/') {
+         --end;
        }
 
        /* do the magic parsing- find the beginning of the version string
         * by doing two iterations of same loop to lop off two hyphens */
-       for(q = --p; *q && *q != '-'; q--);
-       for(p = --q; *p && *p != '-'; p--);
-       if(*p != '-' || p == tmp) {
+       for(version = end - 1; *version && *version != '-'; version--);
+       for(version = version - 1; *version && *version != '-'; version--);
+       if(*version != '-' || version == target) {
                return(-1);
        }
 
@@ -890,16 +888,17 @@ int _alpm_splitname(const char *target, pmpkg_t *pkg)
        if(pkg->version) {
                FREE(pkg->version);
        }
-       STRDUP(pkg->version, p+1, RET_ERR(PM_ERR_MEMORY, -1));
-       /* insert a terminator at the end of the name (on hyphen)- then copy it 
*/
-       *p = '\0';
+       /* version actually points to the dash, so need to increment 1 and 
account
+        * for potential end character */
+       STRNDUP(pkg->version, version + 1, end - version -1,
+                       RET_ERR(PM_ERR_MEMORY, -1));
+
        if(pkg->name) {
                FREE(pkg->name);
        }
-       STRDUP(pkg->name, tmp, RET_ERR(PM_ERR_MEMORY, -1));
+       STRNDUP(pkg->name, target, version - target, RET_ERR(PM_ERR_MEMORY, 
-1));
        pkg->name_hash = _alpm_hash_sdbm(pkg->name);
 
-       free(tmp);
        return(0);
 }
 
-- 
1.7.3.5