We define our varint format pretty much on the fly as we describe a pack
file entry. In preparation for referring to it in more places in this
document, define "varint" and refer to it.
Signed-off-by: Martin Ågren <martin.agren@xxxxxxxxx>
---
Documentation/technical/pack-format.txt | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index f96b2e605f..42198de74c 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -55,6 +55,15 @@ Valid object types are:
Type 5 is reserved for future expansion. Type 0 is invalid.
+=== Variable-length integer encoding
+
+This document uses "varint" encoding of non-negative integers: From
+each byte, the seven least significant bits are used to form the
+resulting integer. As long as the most significant bit is 1, this
+process continues; the byte with MSB 0 provides the last seven bits.
+The seven-bit chunks are concatenated. Later values are more
+significant.
+
=== Deltified representation
Conceptually there are only four object types: commit, tree, tag and
@@ -196,10 +205,10 @@ Pack file entry: <+
1-byte size extension bit (MSB)
type (next 3 bit)
size0 (lower 4-bit)
- n-byte sizeN (as long as MSB is set, each 7-bit)
- size0..sizeN form 4+7+7+..+7 bit integer, size0
- is the least significant part, and sizeN is the
- most significant part.
+ n-byte size1 (varint encoding; present if MSB is set)
+ If the MSB is set, the size is size0 + 16*size1, otherwise
+ it is size0. (Equivalently, the entire packed object header
+ is a varint encoding of (size/16)*128 + type*16 + size%16.)
packed object data:
If it is not DELTA, then deflated bytes (the size above
is the size before compression).
--
2.30.0.rc1
