[PATCH 6/6] [RFC] subvert sorted-array to replace binary-search in unpack-objects.
Signed-off-by: Yann Dirson <ydirson@altern.org>
---
builtin/unpack-objects.c | 40 +++++++++++++++++++++++++---------------
1 files changed, 25 insertions(+), 15 deletions(-)
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index f63973c..6d7d113 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -11,6 +11,7 @@
#include "progress.h"
#include "decorate.h"
#include "fsck.h"
+#include "sorted-array.h"
static int dry_run, quiet, recover, has_errors, strict;
static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict] < pack-file";
@@ -157,7 +158,24 @@ struct obj_info {
#define FLAG_OPEN (1u<<20)
#define FLAG_WRITTEN (1u<<21)
-static struct obj_info *obj_list;
+/*
+ * FIXME: obj_info is a sorted array, but we read it as a whole, we
+ * don't need insertion features. This allows us to abuse unused
+ * obj_info_nr later as a means of specifying an upper bound for
+ * binary search. obj_info_alloc shall be eliminated by the compiler
+ * as unused.
+ */
+static int obj_info_cmp(off_t ref, struct obj_info *elem)
+{
+ if (ref == elem->offset)
+ return 0;
+ if (ref < elem->offset)
+ return -1;
+ return 1;
+}
+declare_sorted_array(static, struct obj_info, obj_list);
+declare_sorted_array_search_check(static, struct obj_info, obj_list_check,
+ off_t, obj_list, obj_info_cmp);
static unsigned nr_objects;
/*
@@ -356,7 +374,7 @@ static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
unsigned base_found = 0;
unsigned char *pack, c;
off_t base_offset;
- unsigned lo, mid, hi;
+ int pos;
pack = fill(1);
c = *pack;
@@ -380,19 +398,11 @@ static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
free(delta_data);
return;
}
- lo = 0;
- hi = nr;
- while (lo < hi) {
- mid = (lo + hi)/2;
- if (base_offset < obj_list[mid].offset) {
- hi = mid;
- } else if (base_offset > obj_list[mid].offset) {
- lo = mid + 1;
- } else {
- hashcpy(base_sha1, obj_list[mid].sha1);
- base_found = !is_null_sha1(base_sha1);
- break;
- }
+ obj_list_nr = nr; /* kludge to bound the search */
+ pos = obj_list_check(base_offset);
+ if (pos >= 0) {
+ hashcpy(base_sha1, obj_list[pos].sha1);
+ base_found = !is_null_sha1(base_sha1);
}
if (!base_found) {
/*
--
1.7.2.3
Yann Dirson <ydirson@altern.org>