varint: use explicit width for integers

The varint subsystem currently uses implicit widths for integers. On the
one hand we use `uintmax_t` for the actual value. On the other hand, we
use `int` for the length of the encoded varint.

Both of these have known maximum values, as we only support at most 16
bytes when encoding varints. Thus, we know that we won't ever exceed
`uint64_t` for the actual value and `uint8_t` for the prefix length.

Refactor the code to use explicit widths. Besides making the logic
platform-independent, it also makes our life a bit easier in the next
commit, where we reimplement "varint.c" in Rust.

Suggested-by: Ezekiel Newren <ezekielnewren@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/varint.c b/varint.c
index 409c4977a1..03cd54416b 100644
--- a/varint.c
+++ b/varint.c
@@ -1,11 +1,11 @@
 #include "git-compat-util.h"
 #include "varint.h"
 
-uintmax_t decode_varint(const unsigned char **bufp)
+uint64_t decode_varint(const unsigned char **bufp)
 {
 	const unsigned char *buf = *bufp;
 	unsigned char c = *buf++;
-	uintmax_t val = c & 127;
+	uint64_t val = c & 127;
 	while (c & 128) {
 		val += 1;
 		if (!val || MSB(val, 7))
@@ -17,7 +17,7 @@ uintmax_t decode_varint(const unsigned char **bufp)
 	return val;
 }
 
-int encode_varint(uintmax_t value, unsigned char *buf)
+uint8_t encode_varint(uint64_t value, unsigned char *buf)
 {
 	unsigned char varint[16];
 	unsigned pos = sizeof(varint) - 1;