[PATCH 02/31] pack-bitmap: make bitmap header handling hash agnostic

["brian m. carlson" <sandals@crustytoothpaste.net>]

Increase the checksum field in struct bitmap_disk_header to be
GIT_MAX_RAWSZ bytes in length and ensure that we hash the proper number
of bytes out when computing the bitmap checksum.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 pack-bitmap-write.c | 2 +-
 pack-bitmap.c       | 2 +-
 pack-bitmap.h       | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 5566e94abe..c82fb01fd7 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -535,7 +535,7 @@ void bitmap_writer_finish(struct pack_idx_entry **index,
 	header.entry_count = htonl(writer.selected_nr);
 	hashcpy(header.checksum, writer.pack_checksum);
 
-	hashwrite(f, &header, sizeof(header));
+	hashwrite(f, &header, sizeof(header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz);
 	dump_bitmap(f, writer.commits);
 	dump_bitmap(f, writer.trees);
 	dump_bitmap(f, writer.blobs);
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 4695aaf6b4..b53f37243c 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -163,7 +163,7 @@ static int load_bitmap_header(struct bitmap_index *index)
 	}
 
 	index->entry_count = ntohl(header->entry_count);
-	index->map_pos += sizeof(*header);
+	index->map_pos += sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;
 	return 0;
 }
 
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 8418ba8c79..344ba23af9 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -14,7 +14,7 @@ struct bitmap_disk_header {
 	uint16_t version;
 	uint16_t options;
 	uint32_t entry_count;
-	unsigned char checksum[20];
+	unsigned char checksum[GIT_MAX_RAWSZ];
 };
 
 static const char BITMAP_IDX_SIGNATURE[] = {'B', 'I', 'T', 'M'};