Use a hashtable for objects instead of a sorted list

In a simple test, this brings down the CPU time from 47 sec to 22 sec.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/fsck-objects.c b/fsck-objects.c
index 9950be264501a5c99eafe7c2438b27b857ba6402..6439d55126a615c04db1be16ebcaf8b0af9f7ae3 100644 (file)
--- a/fsck-objects.c
+++ b/fsck-objects.c
@@ -61,9 +61,12 @@ static void check_connectivity(void)
        int i;
 
        /* Look up all the requirements, warn about missing objects.. */
-       for (i = 0; i < nr_objs; i++) {
+       for (i = 0; i < obj_allocs; i++) {
                struct object *obj = objs[i];
 
+               if (!obj)
+                       continue;
+
                if (!obj->parsed) {
                        if (!standalone && has_sha1_file(obj->sha1))
                                ; /* it is in pack */

diff --git a/name-rev.c b/name-rev.c
index bbadb91aa0f51fe1ef7135866912d806c70fc457..0c3f547622245a2bc8984498289e86f89f87c362 100644 (file)
--- a/name-rev.c
+++ b/name-rev.c
@@ -232,9 +232,10 @@ int main(int argc, char **argv)
        } else if (all) {
                int i;
 
-               for (i = 0; i < nr_objs; i++)
-                       printf("%s %s\n", sha1_to_hex(objs[i]->sha1),
-                                       get_rev_name(objs[i]));
+               for (i = 0; i < obj_allocs; i++)
+                       if (objs[i])
+                               printf("%s %s\n", sha1_to_hex(objs[i]->sha1),
+                                               get_rev_name(objs[i]));
        } else
                for ( ; revs; revs = revs->next)
                        printf("%s %s\n", revs->name, get_rev_name(revs->item));

diff --git a/object.c b/object.c
index 1577f74281be776082fecebdf8947bcb8c7c6802..3259862ab2eeeb3adcd52c24c801fd4d4e3212b7 100644 (file)
--- a/object.c
+++ b/object.c
@@ -6,30 +6,32 @@
 #include "tag.h"
 
 struct object **objs;
-int nr_objs;
-static int obj_allocs;
+static int nr_objs;
+int obj_allocs;
 
 int track_object_refs = 1;
 
+static int hashtable_index(const unsigned char *sha1)
+{
+       unsigned int i = *(unsigned int *)sha1;
+       return (int)(i % obj_allocs);
+}
+
 static int find_object(const unsigned char *sha1)
 {
-       int first = 0, last = nr_objs;
-
-        while (first < last) {
-                int next = (first + last) / 2;
-                struct object *obj = objs[next];
-                int cmp;
-
-                cmp = memcmp(sha1, obj->sha1, 20);
-                if (!cmp)
-                        return next;
-                if (cmp < 0) {
-                        last = next;
-                        continue;
-                }
-                first = next+1;
-        }
-        return -first-1;
+       int i = hashtable_index(sha1);
+
+       if (!objs)
+               return -1;
+
+       while (objs[i]) {
+               if (memcmp(sha1, objs[i]->sha1, 20) == 0)
+                       return i;
+               i++;
+               if (i == obj_allocs)
+                       i = 0;
+       }
+       return -1 - i;
 }
 
 struct object *lookup_object(const unsigned char *sha1)
@@ -42,7 +44,7 @@ struct object *lookup_object(const unsigned char *sha1)
 
 void created_object(const unsigned char *sha1, struct object *obj)
 {
-       int pos = find_object(sha1);
+       int pos;
 
        obj->parsed = 0;
        memcpy(obj->sha1, sha1, 20);
@@ -50,18 +52,27 @@ void created_object(const unsigned char *sha1, struct object *obj)
        obj->refs = NULL;
        obj->used = 0;
 
-       if (pos >= 0)
-               die("Inserting %s twice\n", sha1_to_hex(sha1));
-       pos = -pos-1;
-
-       if (obj_allocs == nr_objs) {
-               obj_allocs = alloc_nr(obj_allocs);
+       if (obj_allocs - 1 <= nr_objs * 2) {
+               int i, count = obj_allocs;
+               obj_allocs = (obj_allocs < 32 ? 32 : 2 * obj_allocs);
                objs = xrealloc(objs, obj_allocs * sizeof(struct object *));
+               memset(objs + count, 0, (obj_allocs - count)
+                               * sizeof(struct object *));
+               for (i = 0; i < count; i++)
+                       if (objs[i]) {
+                               int j = find_object(objs[i]->sha1);
+                               if (j != i) {
+                                       j = -1 - j;
+                                       objs[j] = objs[i];
+                                       objs[i] = NULL;
+                               }
+                       }
        }
 
-       /* Insert it into the right place */
-       memmove(objs + pos + 1, objs + pos, (nr_objs - pos) * 
-               sizeof(struct object *));
+       pos = find_object(sha1);
+       if (pos >= 0)
+               die("Inserting %s twice\n", sha1_to_hex(sha1));
+       pos = -pos-1;
 
        objs[pos] = obj;
        nr_objs++;

diff --git a/object.h b/object.h
index 0e7618283cb8c85d89cc2935b8ab7430571a14a7..e08afbd29ff04cf463a4aacdc4fe141a2ab54ce6 100644 (file)
--- a/object.h
+++ b/object.h
@@ -23,7 +23,7 @@ struct object {
 };
 
 extern int track_object_refs;
-extern int nr_objs;
+extern int obj_allocs;
 extern struct object **objs;
 
 /** Internal only **/