Rename git-pack-intersect to git-pack-redundant

This patch renames git-pack-intersect to git-pack-redundant
as suggested by Petr Baudis. The new name reflects what the
program does, rather than how it does it.

Also fix a small argument parsing bug.

Signed-off-by: Lukas Sandström <lukass@etek.chalmers.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/.gitignore b/.gitignore
index 6ff25300e18c547d4cb5dd431db116d199c95e0b..1d1aa57676f961af98a46caf0b6377547fbfabcf 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -60,7 +60,7 @@ git-mktag
 git-name-rev
 git-mv
 git-octopus
-git-pack-intersect
+git-pack-redundant
 git-pack-objects
 git-parse-remote
 git-patch-id

diff --git a/Documentation/git-pack-intersect.txt b/Documentation/git-pack-intersect.txt
deleted file mode 100644 (file)
index e5d6fc7..0000000
--- a/Documentation/git-pack-intersect.txt
+++ /dev/null
@@ -1,47 +0,0 @@
-git-pack-intersect(1)
-=====================
-
-NAME
-----
-git-pack-intersect - Program used to find redundant pack files.
-
-
-SYNOPSIS
---------
-'git-pack-intersect [ -v ] < -a | .pack filename ... >'
-
-DESCRIPTION
------------
-This program computes which packs in your repository
-are redundant. The output is suitable for piping to
-'xargs rm' if you are in the root of the repository.
-
-OPTIONS
--------
-
--v::
-       Verbose. Outputs some statistics to stderr.
-       Has a small performance penalty.
-
--a::
-       All. Processes all the local packs. Any filenames on
-       the commandline are ignored.
-
-Author
-------
-Written by Lukas Sandström <lukass@etek.chalmers.se>
-
-Documentation
---------------
-Documentation by Lukas Sandström <lukass@etek.chalmers.se>
-
-See-Also
---------
-gitlink:git-pack-objects[1]
-gitlink:git-repack[1]
-gitlink:git-prune-packed[1]
-
-GIT
----
-Part of the gitlink:git[7] suite
-

diff --git a/Documentation/git-pack-redundant.txt b/Documentation/git-pack-redundant.txt
new file mode 100644 (file)
index 0000000..55c0d48
--- /dev/null
+++ b/Documentation/git-pack-redundant.txt
@@ -0,0 +1,47 @@
+git-pack-redundant(1)
+=====================
+
+NAME
+----
+git-pack-redundant - Program used to find redundant pack files.
+
+
+SYNOPSIS
+--------
+'git-pack-redundant [ -v ] < -a | .pack filename ... >'
+
+DESCRIPTION
+-----------
+This program computes which packs in your repository
+are redundant. The output is suitable for piping to
+'xargs rm' if you are in the root of the repository.
+
+OPTIONS
+-------
+
+-v::
+       Verbose. Outputs some statistics to stderr.
+       Has a small performance penalty.
+
+-a::
+       All. Processes all the local packs. Any filenames on
+       the commandline are ignored.
+
+Author
+------
+Written by Lukas Sandström <lukass@etek.chalmers.se>
+
+Documentation
+--------------
+Documentation by Lukas Sandström <lukass@etek.chalmers.se>
+
+See-Also
+--------
+gitlink:git-pack-objects[1]
+gitlink:git-repack[1]
+gitlink:git-prune-packed[1]
+
+GIT
+---
+Part of the gitlink:git[7] suite
+

diff --git a/Makefile b/Makefile
index 4c646c9e84ae37f3eaa458a601ac6d0f96f07d5e..b4dca5f228b2ce95d9c23405b99f534760a50481 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -122,7 +122,7 @@ PROGRAMS = \
        git-unpack-objects$X git-update-index$X git-update-server-info$X \
        git-upload-pack$X git-verify-pack$X git-write-tree$X \
        git-update-ref$X git-symbolic-ref$X git-check-ref-format$X \
-       git-name-rev$X git-pack-intersect$X $(SIMPLE_PROGRAMS)
+       git-name-rev$X git-pack-redundant$X $(SIMPLE_PROGRAMS)
 
 # Backward compatibility -- to be removed after 1.0
 PROGRAMS += git-ssh-pull$X git-ssh-push$X

diff --git a/git-repack.sh b/git-repack.sh
index 3f28300566bb78e736af12670027279ee18bce51..4ce00225da2c9181f2c69ded6c07ba0111a01584 100755 (executable)
--- a/git-repack.sh
+++ b/git-repack.sh
@@ -45,7 +45,7 @@ if [ -z "$name" ]; then
        if test "$remove_redandant" = t ; then
                echo "Removing redundant packs."
                sync
-               redundant=$(git-pack-intersect -a)
+               redundant=$(git-pack-redundant -a)
                if test "$redundant" != "" ; then
                        echo $redundant | xargs rm
                fi
@@ -63,7 +63,7 @@ exit
 if test "$remove_redandant" = t
 then
        sync
-       redundant=$(git-pack-intersect -a)
+       redundant=$(git-pack-redundant -a)
        if test "$redundant" != "" ; then
                echo $redundant | xargs rm
        fi

diff --git a/pack-intersect.c b/pack-intersect.c
deleted file mode 100644 (file)
index 2267478..0000000
--- a/pack-intersect.c
+++ /dev/null
@@ -1,577 +0,0 @@
-/*
-*
-* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
-*
-* This file is licensed under the GPL v2.
-*
-*/
-
-#include "cache.h"
-
-static const char pack_intersect_usage[] =
-"git-pack-intersect [ -v ]  < -a | <.pack filename> ...>";
-
-int all = 0, verbose = 0;
-
-struct llist_item {
-       struct llist_item *next;
-       char *sha1;
-};
-struct llist {
-       struct llist_item *front;
-       struct llist_item *back;
-       size_t size;
-} *all_objects;
-
-struct pack_list {
-       struct pack_list *next;
-       struct packed_git *pack;
-       struct llist *unique_objects;
-       struct llist *all_objects;
-} *pack_list;
-
-struct pll {
-       struct pll *next;
-       struct pack_list *pl;
-};
-
-inline void llist_free(struct llist *list)
-{
-       while((list->back = list->front)) {
-               list->front = list->front->next;
-               free(list->back);
-       }
-       free(list);
-}
-
-inline void llist_init(struct llist **list)
-{
-       *list = xmalloc(sizeof(struct llist));
-       (*list)->front = (*list)->back = NULL;
-       (*list)->size = 0;
-}
-
-struct llist * llist_copy(struct llist *list)
-{
-       struct llist *ret;
-       struct llist_item *new, *old, *prev;
-       
-       llist_init(&ret);
-
-       if ((ret->size = list->size) == 0)
-               return ret;
-
-       new = ret->front = xmalloc(sizeof(struct llist_item));
-       new->sha1 = list->front->sha1;
-
-       old = list->front->next;
-       while (old) {
-               prev = new;
-               new = xmalloc(sizeof(struct llist_item));
-               prev->next = new;
-               new->sha1 = old->sha1;
-               old = old->next;
-       }
-       new->next = NULL;
-       ret->back = new;
-       
-       return ret;
-}
-
-inline struct llist_item * llist_insert(struct llist *list,
-                                       struct llist_item *after, char *sha1)
-{
-       struct llist_item *new = xmalloc(sizeof(struct llist_item));
-       new->sha1 = sha1;
-       new->next = NULL;
-
-       if (after != NULL) {
-               new->next = after->next;
-               after->next = new;
-               if (after == list->back)
-                       list->back = new;
-       } else {/* insert in front */
-               if (list->size == 0)
-                       list->back = new;
-               else
-                       new->next = list->front;
-               list->front = new;
-       }
-       list->size++;
-       return new;
-}
-
-inline struct llist_item * llist_insert_back(struct llist *list, char *sha1)
-{
-       return llist_insert(list, list->back, sha1);
-}
-
-inline struct llist_item * llist_insert_sorted_unique(struct llist *list,
-                                       char *sha1, struct llist_item *hint)
-{
-       struct llist_item *prev = NULL, *l;
-
-       l = (hint == NULL) ? list->front : hint;
-       while (l) {
-               int cmp = memcmp(l->sha1, sha1, 20);
-               if (cmp > 0) { /* we insert before this entry */
-                       return llist_insert(list, prev, sha1);
-               }
-               if(!cmp) { /* already exists */
-                       return l;
-               }
-               prev = l;
-               l = l->next;
-       }
-       /* insert at the end */
-       return llist_insert_back(list, sha1);
-}
-
-/* computes A\B */
-struct llist * llist_sorted_difference(struct llist_item *A,
-                                      struct llist_item *B)
-{
-       struct llist *ret;
-       llist_init(&ret);
-
-       while (A != NULL && B != NULL) {
-               int cmp = memcmp(A->sha1, B->sha1, 20);
-               if (!cmp) {
-                       A = A->next;
-                       B = B->next;
-                       continue;
-               }
-               if(cmp > 0) { /* we'll never find this B */
-                       B = B->next;
-                       continue;
-               }
-               /* A has the object, B doesn't */
-               llist_insert_back(ret, A->sha1);
-               A = A->next;
-       }
-       while (A != NULL) {
-               llist_insert_back(ret, A->sha1);
-               A = A->next;
-       }
-       return ret;
-}
-
-/* returns a pointer to an item in front of sha1 */
-inline struct llist_item * llist_sorted_remove(struct llist *list, char *sha1,
-                                              struct llist_item *hint)
-{
-       struct llist_item *prev, *l;
-
-redo_from_start:
-       l = (hint == NULL) ? list->front : hint;
-       prev = NULL;
-       while (l) {
-               int cmp = memcmp(l->sha1, sha1, 20);
-               if (cmp > 0) /* not in list, since sorted */
-                       return prev;
-               if(!cmp) { /* found */
-                       if (prev == NULL) {
-                               if (hint != NULL && hint != list->front) {
-                                       /* we don't know the previous element */
-                                       hint = NULL;
-                                       goto redo_from_start;
-                               }
-                               list->front = l->next;
-                       } else
-                               prev->next = l->next;
-                       if (l == list->back)
-                               list->back = prev;
-                       free(l);
-                       list->size--;
-                       return prev;
-               }
-               prev = l;
-               l = l->next;
-       }
-       return prev;
-}
-
-inline struct pack_list * pack_list_insert(struct pack_list **pl,
-                                          struct pack_list *entry)
-{
-       struct pack_list *p = xmalloc(sizeof(struct pack_list));
-       memcpy(p, entry, sizeof(struct pack_list));
-       p->next = *pl;
-       *pl = p;
-       return p;
-}
-
-struct pack_list * pack_list_difference(struct pack_list *A,
-                                       struct pack_list *B)
-{
-       struct pack_list *ret, *pl;
-
-       if (A == NULL)
-               return NULL;
-
-       pl = B;
-       while (pl != NULL) {
-               if (A->pack == pl->pack)
-                       return pack_list_difference(A->next, B);
-               pl = pl->next;
-       }
-       ret = xmalloc(sizeof(struct pack_list));
-       memcpy(ret, A, sizeof(struct pack_list));
-       ret->next = pack_list_difference(A->next, B);
-       return ret;
-}
-
-void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
-{
-       int p1_off, p2_off;
-       void *p1_base, *p2_base;
-       struct llist_item *p1_hint = NULL, *p2_hint = NULL;
-       
-       p1_off = p2_off = 256 * 4 + 4;
-       p1_base = (void *)p1->pack->index_base;
-       p2_base = (void *)p2->pack->index_base;
-
-       while (p1_off <= p1->pack->index_size - 3 * 20 &&
-              p2_off <= p2->pack->index_size - 3 * 20)
-       {
-               int cmp = memcmp(p1_base + p1_off, p2_base + p2_off, 20);
-               /* cmp ~ p1 - p2 */
-               if (cmp == 0) {
-                       p1_hint = llist_sorted_remove(p1->unique_objects,
-                                       p1_base + p1_off, p1_hint);
-                       p2_hint = llist_sorted_remove(p2->unique_objects,
-                                       p1_base + p1_off, p2_hint);
-                       p1_off+=24;
-                       p2_off+=24;
-                       continue;
-               }
-               if (cmp < 0) { /* p1 has the object, p2 doesn't */
-                       p1_off+=24;
-               } else { /* p2 has the object, p1 doesn't */
-                       p2_off+=24;
-               }
-       }
-}
-
-/* all the permutations have to be free()d at the same time,
- * since they refer to each other
- */
-struct pll * get_all_permutations(struct pack_list *list)
-{
-       struct pll *subset, *pll, *new_pll = NULL; /*silence warning*/
-
-       if (list == NULL)
-               return NULL;
-
-       if (list->next == NULL) {
-               new_pll = xmalloc(sizeof(struct pll));
-               new_pll->next = NULL;
-               new_pll->pl = list;
-               return new_pll;
-       }
-
-       pll = subset = get_all_permutations(list->next);
-       while (pll) {
-               new_pll = xmalloc(sizeof(struct pll));
-               new_pll->next = pll->next;
-               pll->next = new_pll;
-
-               new_pll->pl = xmalloc(sizeof(struct pack_list));
-               memcpy(new_pll->pl, list, sizeof(struct pack_list));
-               new_pll->pl->next = pll->pl;
-
-               pll = new_pll->next;
-       }
-       /* add ourself to the end */
-       new_pll->next = xmalloc(sizeof(struct pll));
-       new_pll->next->pl = xmalloc(sizeof(struct pack_list));
-       new_pll->next->next = NULL;
-       memcpy(new_pll->next->pl, list, sizeof(struct pack_list));
-       new_pll->next->pl->next = NULL;
-
-       return subset;
-}
-
-int is_superset(struct pack_list *pl, struct llist *list)
-{
-       struct llist *diff, *old;
-
-       diff = llist_copy(list);
-
-       while (pl) {
-               old = diff;
-               diff = llist_sorted_difference(diff->front,
-                                              pl->all_objects->front);
-               llist_free(old);
-               if (diff->size == 0) { /* we're done */
-                       llist_free(diff);
-                       return 1;
-               }
-               pl = pl->next;
-       }
-       llist_free(diff);
-       return 0;
-}
-
-size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
-{
-       size_t ret = 0;
-       int p1_off, p2_off;
-       void *p1_base, *p2_base;
-
-       p1_off = p2_off = 256 * 4 + 4;
-       p1_base = (void *)p1->index_base;
-       p2_base = (void *)p2->index_base;
-
-       while (p1_off <= p1->index_size - 3 * 20 &&
-              p2_off <= p2->index_size - 3 * 20)
-       {
-               int cmp = memcmp(p1_base + p1_off, p2_base + p2_off, 20);
-               /* cmp ~ p1 - p2 */
-               if (cmp == 0) {
-                       ret++;
-                       p1_off+=24;
-                       p2_off+=24;
-                       continue;
-               }
-               if (cmp < 0) { /* p1 has the object, p2 doesn't */
-                       p1_off+=24;
-               } else { /* p2 has the object, p1 doesn't */
-                       p2_off+=24;
-               }
-       }
-       return ret;
-}
-
-/* another O(n^2) function ... */
-size_t get_pack_redundancy(struct pack_list *pl)
-{
-       struct pack_list *subset;
-       size_t ret = 0;
-       while ((subset = pl->next)) {
-               while(subset) {
-                       ret += sizeof_union(pl->pack, subset->pack);
-                       subset = subset->next;
-               }
-               pl = pl->next;
-       }
-       return ret;
-}
-
-inline size_t pack_set_bytecount(struct pack_list *pl)
-{
-       size_t ret = 0;
-       while (pl) {
-               ret += pl->pack->pack_size;
-               ret += pl->pack->index_size;
-               pl = pl->next;
-       }
-       return ret;
-}
-
-void minimize(struct pack_list **min)
-{
-       struct pack_list *pl, *unique = NULL,
-               *non_unique = NULL, *min_perm = NULL;
-       struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
-       struct llist *missing, *old;
-       size_t min_perm_size = (size_t)-1, perm_size;
-
-       pl = pack_list;
-       while (pl) {
-               if(pl->unique_objects->size)
-                       pack_list_insert(&unique, pl);
-               else
-                       pack_list_insert(&non_unique, pl);
-               pl = pl->next;
-       }
-       /* find out which objects are missing from the set of unique packs */
-       missing = llist_copy(all_objects);
-       pl = unique;
-       while (pl) {
-               old = missing;
-               missing = llist_sorted_difference(missing->front,
-                                                 pl->all_objects->front);
-               llist_free(old);
-               pl = pl->next;
-       }
-
-       if (missing->size == 0) {
-               *min = unique;
-               return;
-       }
-
-       /* find the permutations which contain all missing objects */
-       perm_all = perm = get_all_permutations(non_unique);
-       while (perm) {
-               if (is_superset(perm->pl, missing)) {
-                       new_perm = xmalloc(sizeof(struct pll));
-                       new_perm->pl = perm->pl;
-                       new_perm->next = perm_ok;
-                       perm_ok = new_perm;
-               }
-               perm = perm->next;
-       }
-       
-       if (perm_ok == NULL)
-               die("Internal error: No complete sets found!\n");
-
-       /* find the permutation with the smallest size */
-       perm = perm_ok;
-       while (perm) {
-               perm_size = pack_set_bytecount(perm->pl);
-               if (min_perm_size > perm_size) {
-                       min_perm_size = perm_size;
-                       min_perm = perm->pl;
-               }
-               perm = perm->next;
-       }
-       *min = min_perm;
-       /* add the unique packs to the list */
-       pl = unique;
-       while(pl) {
-               pack_list_insert(min, pl);
-               pl = pl->next;
-       }
-}
-
-void load_all_objects()
-{
-       struct pack_list *pl = pack_list;
-       struct llist_item *hint, *l;
-       int i;
-
-       llist_init(&all_objects);
-
-       while (pl) {
-               i = 0;
-               hint = NULL;
-               l = pl->all_objects->front;
-               while (l) {
-                       hint = llist_insert_sorted_unique(all_objects,
-                                                         l->sha1, hint);
-                       l = l->next;
-               }
-               pl = pl->next;
-       }
-}
-
-/* this scales like O(n^2) */
-void cmp_packs()
-{
-       struct pack_list *subset, *curr = pack_list;
-
-       while ((subset = curr)) {
-               while((subset = subset->next))
-                       cmp_two_packs(curr, subset);
-               curr = curr->next;
-       }
-}
-
-struct pack_list * add_pack(struct packed_git *p)
-{
-       struct pack_list l;
-       size_t off;
-       void *base;
-
-       l.pack = p;
-       llist_init(&l.all_objects);
-
-       off = 256 * 4 + 4;
-       base = (void *)p->index_base;
-       while (off <= p->index_size - 3 * 20) {
-               llist_insert_back(l.all_objects, base + off);
-               off+=24;
-       }
-       /* this list will be pruned in cmp_two_packs later */
-       l.unique_objects = llist_copy(l.all_objects);
-       return pack_list_insert(&pack_list, &l);
-}
-
-struct pack_list * add_pack_file(char *filename)
-{
-       struct packed_git *p = packed_git;
-
-       if (strlen(filename) < 40)
-               die("Bad pack filename: %s\n", filename);
-
-       while (p) {
-               if (strstr(p->pack_name, filename))
-                       /* this will silently ignore packs in alt-odb */
-                       return add_pack(p);
-               p = p->next;
-       }
-       die("Filename %s not found in packed_git\n", filename);
-}
-
-void load_all()
-{
-       struct packed_git *p = packed_git;
-
-       while (p) {
-               if (p->pack_local) /* ignore alt-odb for now */
-                       add_pack(p);
-               p = p->next;
-       }
-}
-
-int main(int argc, char **argv)
-{
-       int i;
-       struct pack_list *min, *red, *pl;
-
-       for (i = 1; i < argc; i++) {
-               const char *arg = argv[i];
-               if(!strcmp(arg, "--"))
-                       break;
-               if(!strcmp(arg, "-a")) {
-                       all = 1;
-                       continue;
-               }
-               if(!strcmp(arg, "-v")) {
-                       verbose = 1;
-                       continue;
-               }
-               if(*arg == '-')
-                       usage(pack_intersect_usage);
-               else
-                       break;
-       }
-
-       prepare_packed_git();
-
-       if(all)
-               load_all();
-       else
-               while (*(argv + i) != NULL)
-                       add_pack_file(*(argv + i++));
-
-       if (pack_list == NULL)
-               die("Zero packs found!\n");
-
-       cmp_packs();
-
-       load_all_objects();
-
-       minimize(&min);
-       if (verbose) {
-               fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
-               pl = min;
-               while (pl) {
-                       fprintf(stderr, "\t%s\n", pl->pack->pack_name);
-                       pl = pl->next;
-               }
-               fprintf(stderr, "containing %ld duplicate objects "
-                               "with a total size of %ldkb.\n",
-                       get_pack_redundancy(min), pack_set_bytecount(min)/1024);
-               fprintf(stderr, "Redundant packs (with indexes):\n");
-       }
-       pl = red = pack_list_difference(pack_list, min);
-       while (pl) {
-               printf("%s\n%s\n",
-                      sha1_pack_index_name(pl->pack->sha1), pl->pack->pack_name);
-               pl = pl->next;
-       }
-
-       return 0;
-}

diff --git a/pack-redundant.c b/pack-redundant.c
new file mode 100644 (file)
index 0000000..db3dcde
--- /dev/null
+++ b/pack-redundant.c
@@ -0,0 +1,579 @@
+/*
+*
+* Copyright 2005, Lukas Sandstrom <lukass@etek.chalmers.se>
+*
+* This file is licensed under the GPL v2.
+*
+*/
+
+#include "cache.h"
+
+static const char pack_redundant_usage[] =
+"git-pack-redundant [ -v ]  < -a | <.pack filename> ...>";
+
+int all = 0, verbose = 0;
+
+struct llist_item {
+       struct llist_item *next;
+       char *sha1;
+};
+struct llist {
+       struct llist_item *front;
+       struct llist_item *back;
+       size_t size;
+} *all_objects;
+
+struct pack_list {
+       struct pack_list *next;
+       struct packed_git *pack;
+       struct llist *unique_objects;
+       struct llist *all_objects;
+} *pack_list;
+
+struct pll {
+       struct pll *next;
+       struct pack_list *pl;
+};
+
+inline void llist_free(struct llist *list)
+{
+       while((list->back = list->front)) {
+               list->front = list->front->next;
+               free(list->back);
+       }
+       free(list);
+}
+
+inline void llist_init(struct llist **list)
+{
+       *list = xmalloc(sizeof(struct llist));
+       (*list)->front = (*list)->back = NULL;
+       (*list)->size = 0;
+}
+
+struct llist * llist_copy(struct llist *list)
+{
+       struct llist *ret;
+       struct llist_item *new, *old, *prev;
+       
+       llist_init(&ret);
+
+       if ((ret->size = list->size) == 0)
+               return ret;
+
+       new = ret->front = xmalloc(sizeof(struct llist_item));
+       new->sha1 = list->front->sha1;
+
+       old = list->front->next;
+       while (old) {
+               prev = new;
+               new = xmalloc(sizeof(struct llist_item));
+               prev->next = new;
+               new->sha1 = old->sha1;
+               old = old->next;
+       }
+       new->next = NULL;
+       ret->back = new;
+       
+       return ret;
+}
+
+inline struct llist_item * llist_insert(struct llist *list,
+                                       struct llist_item *after, char *sha1)
+{
+       struct llist_item *new = xmalloc(sizeof(struct llist_item));
+       new->sha1 = sha1;
+       new->next = NULL;
+
+       if (after != NULL) {
+               new->next = after->next;
+               after->next = new;
+               if (after == list->back)
+                       list->back = new;
+       } else {/* insert in front */
+               if (list->size == 0)
+                       list->back = new;
+               else
+                       new->next = list->front;
+               list->front = new;
+       }
+       list->size++;
+       return new;
+}
+
+inline struct llist_item * llist_insert_back(struct llist *list, char *sha1)
+{
+       return llist_insert(list, list->back, sha1);
+}
+
+inline struct llist_item * llist_insert_sorted_unique(struct llist *list,
+                                       char *sha1, struct llist_item *hint)
+{
+       struct llist_item *prev = NULL, *l;
+
+       l = (hint == NULL) ? list->front : hint;
+       while (l) {
+               int cmp = memcmp(l->sha1, sha1, 20);
+               if (cmp > 0) { /* we insert before this entry */
+                       return llist_insert(list, prev, sha1);
+               }
+               if(!cmp) { /* already exists */
+                       return l;
+               }
+               prev = l;
+               l = l->next;
+       }
+       /* insert at the end */
+       return llist_insert_back(list, sha1);
+}
+
+/* computes A\B */
+struct llist * llist_sorted_difference(struct llist_item *A,
+                                      struct llist_item *B)
+{
+       struct llist *ret;
+       llist_init(&ret);
+
+       while (A != NULL && B != NULL) {
+               int cmp = memcmp(A->sha1, B->sha1, 20);
+               if (!cmp) {
+                       A = A->next;
+                       B = B->next;
+                       continue;
+               }
+               if(cmp > 0) { /* we'll never find this B */
+                       B = B->next;
+                       continue;
+               }
+               /* A has the object, B doesn't */
+               llist_insert_back(ret, A->sha1);
+               A = A->next;
+       }
+       while (A != NULL) {
+               llist_insert_back(ret, A->sha1);
+               A = A->next;
+       }
+       return ret;
+}
+
+/* returns a pointer to an item in front of sha1 */
+inline struct llist_item * llist_sorted_remove(struct llist *list, char *sha1,
+                                              struct llist_item *hint)
+{
+       struct llist_item *prev, *l;
+
+redo_from_start:
+       l = (hint == NULL) ? list->front : hint;
+       prev = NULL;
+       while (l) {
+               int cmp = memcmp(l->sha1, sha1, 20);
+               if (cmp > 0) /* not in list, since sorted */
+                       return prev;
+               if(!cmp) { /* found */
+                       if (prev == NULL) {
+                               if (hint != NULL && hint != list->front) {
+                                       /* we don't know the previous element */
+                                       hint = NULL;
+                                       goto redo_from_start;
+                               }
+                               list->front = l->next;
+                       } else
+                               prev->next = l->next;
+                       if (l == list->back)
+                               list->back = prev;
+                       free(l);
+                       list->size--;
+                       return prev;
+               }
+               prev = l;
+               l = l->next;
+       }
+       return prev;
+}
+
+inline struct pack_list * pack_list_insert(struct pack_list **pl,
+                                          struct pack_list *entry)
+{
+       struct pack_list *p = xmalloc(sizeof(struct pack_list));
+       memcpy(p, entry, sizeof(struct pack_list));
+       p->next = *pl;
+       *pl = p;
+       return p;
+}
+
+struct pack_list * pack_list_difference(struct pack_list *A,
+                                       struct pack_list *B)
+{
+       struct pack_list *ret, *pl;
+
+       if (A == NULL)
+               return NULL;
+
+       pl = B;
+       while (pl != NULL) {
+               if (A->pack == pl->pack)
+                       return pack_list_difference(A->next, B);
+               pl = pl->next;
+       }
+       ret = xmalloc(sizeof(struct pack_list));
+       memcpy(ret, A, sizeof(struct pack_list));
+       ret->next = pack_list_difference(A->next, B);
+       return ret;
+}
+
+void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
+{
+       int p1_off, p2_off;
+       void *p1_base, *p2_base;
+       struct llist_item *p1_hint = NULL, *p2_hint = NULL;
+       
+       p1_off = p2_off = 256 * 4 + 4;
+       p1_base = (void *)p1->pack->index_base;
+       p2_base = (void *)p2->pack->index_base;
+
+       while (p1_off <= p1->pack->index_size - 3 * 20 &&
+              p2_off <= p2->pack->index_size - 3 * 20)
+       {
+               int cmp = memcmp(p1_base + p1_off, p2_base + p2_off, 20);
+               /* cmp ~ p1 - p2 */
+               if (cmp == 0) {
+                       p1_hint = llist_sorted_remove(p1->unique_objects,
+                                       p1_base + p1_off, p1_hint);
+                       p2_hint = llist_sorted_remove(p2->unique_objects,
+                                       p1_base + p1_off, p2_hint);
+                       p1_off+=24;
+                       p2_off+=24;
+                       continue;
+               }
+               if (cmp < 0) { /* p1 has the object, p2 doesn't */
+                       p1_off+=24;
+               } else { /* p2 has the object, p1 doesn't */
+                       p2_off+=24;
+               }
+       }
+}
+
+/* all the permutations have to be free()d at the same time,
+ * since they refer to each other
+ */
+struct pll * get_all_permutations(struct pack_list *list)
+{
+       struct pll *subset, *pll, *new_pll = NULL; /*silence warning*/
+
+       if (list == NULL)
+               return NULL;
+
+       if (list->next == NULL) {
+               new_pll = xmalloc(sizeof(struct pll));
+               new_pll->next = NULL;
+               new_pll->pl = list;
+               return new_pll;
+       }
+
+       pll = subset = get_all_permutations(list->next);
+       while (pll) {
+               new_pll = xmalloc(sizeof(struct pll));
+               new_pll->next = pll->next;
+               pll->next = new_pll;
+
+               new_pll->pl = xmalloc(sizeof(struct pack_list));
+               memcpy(new_pll->pl, list, sizeof(struct pack_list));
+               new_pll->pl->next = pll->pl;
+
+               pll = new_pll->next;
+       }
+       /* add ourself to the end */
+       new_pll->next = xmalloc(sizeof(struct pll));
+       new_pll->next->pl = xmalloc(sizeof(struct pack_list));
+       new_pll->next->next = NULL;
+       memcpy(new_pll->next->pl, list, sizeof(struct pack_list));
+       new_pll->next->pl->next = NULL;
+
+       return subset;
+}
+
+int is_superset(struct pack_list *pl, struct llist *list)
+{
+       struct llist *diff, *old;
+
+       diff = llist_copy(list);
+
+       while (pl) {
+               old = diff;
+               diff = llist_sorted_difference(diff->front,
+                                              pl->all_objects->front);
+               llist_free(old);
+               if (diff->size == 0) { /* we're done */
+                       llist_free(diff);
+                       return 1;
+               }
+               pl = pl->next;
+       }
+       llist_free(diff);
+       return 0;
+}
+
+size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
+{
+       size_t ret = 0;
+       int p1_off, p2_off;
+       void *p1_base, *p2_base;
+
+       p1_off = p2_off = 256 * 4 + 4;
+       p1_base = (void *)p1->index_base;
+       p2_base = (void *)p2->index_base;
+
+       while (p1_off <= p1->index_size - 3 * 20 &&
+              p2_off <= p2->index_size - 3 * 20)
+       {
+               int cmp = memcmp(p1_base + p1_off, p2_base + p2_off, 20);
+               /* cmp ~ p1 - p2 */
+               if (cmp == 0) {
+                       ret++;
+                       p1_off+=24;
+                       p2_off+=24;
+                       continue;
+               }
+               if (cmp < 0) { /* p1 has the object, p2 doesn't */
+                       p1_off+=24;
+               } else { /* p2 has the object, p1 doesn't */
+                       p2_off+=24;
+               }
+       }
+       return ret;
+}
+
+/* another O(n^2) function ... */
+size_t get_pack_redundancy(struct pack_list *pl)
+{
+       struct pack_list *subset;
+       size_t ret = 0;
+       while ((subset = pl->next)) {
+               while(subset) {
+                       ret += sizeof_union(pl->pack, subset->pack);
+                       subset = subset->next;
+               }
+               pl = pl->next;
+       }
+       return ret;
+}
+
+inline size_t pack_set_bytecount(struct pack_list *pl)
+{
+       size_t ret = 0;
+       while (pl) {
+               ret += pl->pack->pack_size;
+               ret += pl->pack->index_size;
+               pl = pl->next;
+       }
+       return ret;
+}
+
+void minimize(struct pack_list **min)
+{
+       struct pack_list *pl, *unique = NULL,
+               *non_unique = NULL, *min_perm = NULL;
+       struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm;
+       struct llist *missing, *old;
+       size_t min_perm_size = (size_t)-1, perm_size;
+
+       pl = pack_list;
+       while (pl) {
+               if(pl->unique_objects->size)
+                       pack_list_insert(&unique, pl);
+               else
+                       pack_list_insert(&non_unique, pl);
+               pl = pl->next;
+       }
+       /* find out which objects are missing from the set of unique packs */
+       missing = llist_copy(all_objects);
+       pl = unique;
+       while (pl) {
+               old = missing;
+               missing = llist_sorted_difference(missing->front,
+                                                 pl->all_objects->front);
+               llist_free(old);
+               pl = pl->next;
+       }
+
+       if (missing->size == 0) {
+               *min = unique;
+               return;
+       }
+
+       /* find the permutations which contain all missing objects */
+       perm_all = perm = get_all_permutations(non_unique);
+       while (perm) {
+               if (is_superset(perm->pl, missing)) {
+                       new_perm = xmalloc(sizeof(struct pll));
+                       new_perm->pl = perm->pl;
+                       new_perm->next = perm_ok;
+                       perm_ok = new_perm;
+               }
+               perm = perm->next;
+       }
+       
+       if (perm_ok == NULL)
+               die("Internal error: No complete sets found!\n");
+
+       /* find the permutation with the smallest size */
+       perm = perm_ok;
+       while (perm) {
+               perm_size = pack_set_bytecount(perm->pl);
+               if (min_perm_size > perm_size) {
+                       min_perm_size = perm_size;
+                       min_perm = perm->pl;
+               }
+               perm = perm->next;
+       }
+       *min = min_perm;
+       /* add the unique packs to the list */
+       pl = unique;
+       while(pl) {
+               pack_list_insert(min, pl);
+               pl = pl->next;
+       }
+}
+
+void load_all_objects()
+{
+       struct pack_list *pl = pack_list;
+       struct llist_item *hint, *l;
+       int i;
+
+       llist_init(&all_objects);
+
+       while (pl) {
+               i = 0;
+               hint = NULL;
+               l = pl->all_objects->front;
+               while (l) {
+                       hint = llist_insert_sorted_unique(all_objects,
+                                                         l->sha1, hint);
+                       l = l->next;
+               }
+               pl = pl->next;
+       }
+}
+
+/* this scales like O(n^2) */
+void cmp_packs()
+{
+       struct pack_list *subset, *curr = pack_list;
+
+       while ((subset = curr)) {
+               while((subset = subset->next))
+                       cmp_two_packs(curr, subset);
+               curr = curr->next;
+       }
+}
+
+struct pack_list * add_pack(struct packed_git *p)
+{
+       struct pack_list l;
+       size_t off;
+       void *base;
+
+       l.pack = p;
+       llist_init(&l.all_objects);
+
+       off = 256 * 4 + 4;
+       base = (void *)p->index_base;
+       while (off <= p->index_size - 3 * 20) {
+               llist_insert_back(l.all_objects, base + off);
+               off+=24;
+       }
+       /* this list will be pruned in cmp_two_packs later */
+       l.unique_objects = llist_copy(l.all_objects);
+       return pack_list_insert(&pack_list, &l);
+}
+
+struct pack_list * add_pack_file(char *filename)
+{
+       struct packed_git *p = packed_git;
+
+       if (strlen(filename) < 40)
+               die("Bad pack filename: %s\n", filename);
+
+       while (p) {
+               if (strstr(p->pack_name, filename))
+                       /* this will silently ignore packs in alt-odb */
+                       return add_pack(p);
+               p = p->next;
+       }
+       die("Filename %s not found in packed_git\n", filename);
+}
+
+void load_all()
+{
+       struct packed_git *p = packed_git;
+
+       while (p) {
+               if (p->pack_local) /* ignore alt-odb for now */
+                       add_pack(p);
+               p = p->next;
+       }
+}
+
+int main(int argc, char **argv)
+{
+       int i;
+       struct pack_list *min, *red, *pl;
+
+       for (i = 1; i < argc; i++) {
+               const char *arg = argv[i];
+               if(!strcmp(arg, "--")) {
+                       i++;
+                       break;
+               }
+               if(!strcmp(arg, "-a")) {
+                       all = 1;
+                       continue;
+               }
+               if(!strcmp(arg, "-v")) {
+                       verbose = 1;
+                       continue;
+               }
+               if(*arg == '-')
+                       usage(pack_redundant_usage);
+               else
+                       break;
+       }
+
+       prepare_packed_git();
+
+       if(all)
+               load_all();
+       else
+               while (*(argv + i) != NULL)
+                       add_pack_file(*(argv + i++));
+
+       if (pack_list == NULL)
+               die("Zero packs found!\n");
+
+       cmp_packs();
+
+       load_all_objects();
+
+       minimize(&min);
+       if (verbose) {
+               fprintf(stderr, "The smallest (bytewise) set of packs is:\n");
+               pl = min;
+               while (pl) {
+                       fprintf(stderr, "\t%s\n", pl->pack->pack_name);
+                       pl = pl->next;
+               }
+               fprintf(stderr, "containing %ld duplicate objects "
+                               "with a total size of %ldkb.\n",
+                       get_pack_redundancy(min), pack_set_bytecount(min)/1024);
+               fprintf(stderr, "Redundant packs (with indexes):\n");
+       }
+       pl = red = pack_list_difference(pack_list, min);
+       while (pl) {
+               printf("%s\n%s\n",
+                      sha1_pack_index_name(pl->pack->sha1), pl->pack->pack_name);
+               pl = pl->next;
+       }
+
+       return 0;
+}