mirror of
https://github.com/koverstreet/bcachefs-tools.git
synced 2025-02-03 00:00:07 +03:00
43 lines
712 B
C
43 lines
712 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
#include <linux/bitops.h>
|
|
#include <asm/unaligned.h>
|
|
|
|
#include "varint.h"
|
|
|
|
int bch2_varint_encode(u8 *out, u64 v)
|
|
{
|
|
unsigned bits = fls64(v|1);
|
|
unsigned bytes = DIV_ROUND_UP(bits, 7);
|
|
|
|
if (likely(bytes < 9)) {
|
|
v <<= bytes;
|
|
v |= ~(~0 << (bytes - 1));
|
|
} else {
|
|
*out++ = 255;
|
|
bytes = 9;
|
|
}
|
|
|
|
put_unaligned_le64(v, out);
|
|
return bytes;
|
|
}
|
|
|
|
int bch2_varint_decode(const u8 *in, const u8 *end, u64 *out)
|
|
{
|
|
u64 v = get_unaligned_le64(in);
|
|
unsigned bytes = ffz(v & 255) + 1;
|
|
|
|
if (unlikely(in + bytes > end))
|
|
return -1;
|
|
|
|
if (likely(bytes < 9)) {
|
|
v >>= bytes;
|
|
v &= ~(~0ULL << (7 * bytes));
|
|
} else {
|
|
v = get_unaligned_le64(++in);
|
|
}
|
|
|
|
*out = v;
|
|
return bytes;
|
|
}
|