[PATCH v2 06/16] pack-write.c: add pv4_encode_object_header

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 pack-write.c | 33 +++++++++++++++++++++++++++++++++
 pack.h       |  1 +
 2 files changed, 34 insertions(+)

diff --git a/pack-write.c b/pack-write.c
index 36b88a3..c1e9da4 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)
 {
@@ -349,6 +350,38 @@ int encode_in_pack_object_header(enum object_type type, uintmax_t size, unsigned
 	return n;
 }
 
+int pv4_encode_object_header(enum object_type type,
+			     uintmax_t size, unsigned char *hdr)
+{
+	uintmax_t val;
+
+	switch (type) {
+	case OBJ_COMMIT:
+	case OBJ_TREE:
+	case OBJ_BLOB:
+	case OBJ_TAG:
+	case OBJ_REF_DELTA:
+	case OBJ_PV4_COMMIT:
+	case OBJ_PV4_TREE:
+		break;
+	default:
+		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..4f10fa4 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_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