[PATCH 05/11] pack-write.c: add pv4_encode_in_pack_object_header
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
pack-write.c | 29 +++++++++++++++++++++++++++++
pack.h | 1 +
2 files changed, 30 insertions(+)
diff --git a/pack-write.c b/pack-write.c
index 88e4788..6f11104 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -1,6 +1,7 @@
#include "cache.h"
#include "pack.h"
#include "csum-file.h"
+#include "varint.h"
void reset_pack_idx_option(struct pack_idx_option *opts)
{
@@ -340,6 +341,34 @@ int encode_in_pack_object_header(enum object_type type, uintmax_t size, unsigned
return n;
}
+/*
+ * The per-object header is a pretty dense thing, which is
+ * - first byte: low four bits are "size", then three bits of "type",
+ * and the high bit is "size continues".
+ * - each byte afterwards: low seven bits are size continuation,
+ * with the high bit being "size continues"
+ */
+int pv4_encode_in_pack_object_header(enum object_type type,
+ uintmax_t size, unsigned char *hdr)
+{
+ uintmax_t val;
+ if (type < OBJ_COMMIT || type > OBJ_PV4_TREE || type == OBJ_OFS_DELTA)
+ die("bad type %d", type);
+
+ /*
+ * We allocate 4 bits in the LSB for the object type which
+ * should be good for quite a while, given that we effectively
+ * encodes only 5 object types: commit, tree, blob, delta,
+ * tag.
+ */
+ val = size;
+ if (MSB(val, 4))
+ die("fixme: the code doesn't currently cope with big sizes");
+ val <<= 4;
+ val |= type;
+ return encode_varint(val, hdr);
+}
+
struct sha1file *create_tmp_packfile(char **pack_tmp_name)
{
char tmpname[PATH_MAX];
diff --git a/pack.h b/pack.h
index 855f6c6..38f869d 100644
--- a/pack.h
+++ b/pack.h
@@ -83,6 +83,7 @@ extern off_t write_pack_header(struct sha1file *f, int, uint32_t);
extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
extern char *index_pack_lockfile(int fd);
extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
+extern int pv4_encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
#define PH_ERROR_EOF (-1)
#define PH_ERROR_PACK_SIGNATURE (-2)
--
1.8.2.83.gc99314b
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>