varint.h

#ifndef VARINT_H
#define VARINT_H
 
#include "common/bytes/span/span.h"
#include "common/platform/sys/syscall.h"
 
/* RFC 9000 16. Variable-length integer encoding.
 * 2-bit prefix in MSB of first byte selects length 1/2/4/8. */
 
#define VARINT_MAX 0x3FFFFFFFFFFFFFFFULL
 
/* Bytes needed to encode v. Returns 0 if v exceeds the 62-bit range. */
usz varint_len(u64 v);
 
/* Encode v into buf (must hold varint_len(v) bytes).
 * Returns bytes written, or 0 if v out of range. */
usz varint_encode(u8* buf, u64 v);
 
/* Decode from buf of n readable bytes into *out.
 * Returns bytes consumed, or 0 if n too small for the encoded length. */
usz varint_decode(const u8* buf, usz n, u64* out);
 
/* Cursor helpers shared by TLV codecs (frames, transport params). Each
 * decodes/encodes one varint at buf+*off and advances *off on success. */
 
/* Returns 1 ok, 0 if truncated. */
int varint_take(wired_span buf, usz* off, u64* out);
 
/* Returns 1 ok, 0 if out of range or no room within cap. */
int varint_put(wired_mspan buf, usz* off, u64 v);
 
#endif