[PATCH] packfile: use get_be64() for large offsets

[Derrick Stolee]

The pack-index version 2 format uses two 4-byte integers in network-byte order 
to represent one 8-byte value. The current implementation has several code 
clones for stitching these integers together.

Use get_be64() to create an 8-byte integer from two 4-byte integers represented 
this way.

Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
 pack-revindex.c | 6 ++----
 packfile.c      | 3 +--
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/pack-revindex.c b/pack-revindex.c
index 1b7ebd8d7e..ff5f62c033 100644
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -134,10 +134,8 @@ static void create_pack_revindex(struct packed_git *p)
                        if (!(off & 0x80000000)) {
                                p->revindex[i].offset = off;
                        } else {
-                               p->revindex[i].offset =
-                                       ((uint64_t)ntohl(*off_64++)) << 32;
-                               p->revindex[i].offset |=
-                                       ntohl(*off_64++);
+                               p->revindex[i].offset = get_be64(off_64);
+                               off_64 += 2;
                        }
                        p->revindex[i].nr = i;
                }
diff --git a/packfile.c b/packfile.c
index 4a5fe7ab18..228ed0d59a 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1702,8 +1702,7 @@ off_t nth_packed_object_offset(const struct packed_git 
*p, uint32_t n)
                        return off;
                index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
                check_pack_index_ptr(p, index);
-               return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
-                                  ntohl(*((uint32_t *)(index + 4)));
+               return get_be64(index);
        }
 }
 
-- 
2.15.0