simple euristic for further free packing improvements

diff --git a/pack-check.c b/pack-check.c
index eca32b6cabeaf8881abb9c93d9ca89fc556a937c..e57587909e54d9317a18e3bfd43559562a40f0d5 100644 (file)
--- a/pack-check.c
+++ b/pack-check.c
@@ -29,12 +29,12 @@ static int verify_packfile(struct packed_git *p)
        pack_base = p->pack_base;
        SHA1_Update(&ctx, pack_base, pack_size - 20);
        SHA1_Final(sha1, &ctx);
-       if (memcmp(sha1, index_base + index_size - 40, 20))
-               return error("Packfile %s SHA1 mismatch with idx",
-                            p->pack_name);
        if (memcmp(sha1, pack_base + pack_size - 20, 20))
                return error("Packfile %s SHA1 mismatch with itself",
                             p->pack_name);
+       if (memcmp(sha1, index_base + index_size - 40, 20))
+               return error("Packfile %s SHA1 mismatch with idx",
+                            p->pack_name);
 
        /* Make sure everything reachable from idx is valid.  Since we
         * have verified that nr_objects matches between idx and pack,
@@ -70,13 +70,17 @@ static int verify_packfile(struct packed_git *p)
 }
 
 
+#define MAX_CHAIN 40
+
 static void show_pack_info(struct packed_git *p)
 {
        struct pack_header *hdr;
        int nr_objects, i;
+       unsigned int chain_histogram[MAX_CHAIN];
 
        hdr = p->pack_base;
        nr_objects = ntohl(hdr->hdr_entries);
+       memset(chain_histogram, 0, sizeof(chain_histogram));
 
        for (i = 0; i < nr_objects; i++) {
                unsigned char sha1[20], base_sha1[20];
@@ -97,11 +101,25 @@ static void show_pack_info(struct packed_git *p)
                printf("%s ", sha1_to_hex(sha1));
                if (!delta_chain_length)
                        printf("%-6s %lu %u\n", type, size, e.offset);
-               else
+               else {
                        printf("%-6s %lu %u %u %s\n", type, size, e.offset,
                               delta_chain_length, sha1_to_hex(base_sha1));
+                       if (delta_chain_length < MAX_CHAIN)
+                               chain_histogram[delta_chain_length]++;
+                       else
+                               chain_histogram[0]++;
+               }
        }
 
+       for (i = 0; i < MAX_CHAIN; i++) {
+               if (!chain_histogram[i])
+                       continue;
+               printf("chain length %s %d: %d object%s\n",
+                      i ? "=" : ">=",
+                      i ? i : MAX_CHAIN,
+                      chain_histogram[i],
+                      1 < chain_histogram[i] ? "s" : "");
+       }
 }
 
 int verify_pack(struct packed_git *p, int verbose)