openssl/crypto/quic_vlint.c
Hugo Landau 416d0a638c QUIC wire format support
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18382)
2022-05-27 08:00:52 +02:00

78 lines
2.0 KiB
C

#include "internal/quic_vlint.h"
#include "internal/e_os.h"
void ossl_quic_vlint_encode_n(uint8_t *buf, uint64_t v, int n)
{
if (n == 1) {
buf[0] = (uint8_t)v;
} else if (n == 2) {
buf[0] = (uint8_t)(0x40 | ((v >> 8) & 0x3F));
buf[1] = (uint8_t)v;
} else if (n == 4) {
buf[0] = (uint8_t)(0x80 | ((v >> 24) & 0x3F));
buf[1] = (uint8_t)(v >> 16);
buf[2] = (uint8_t)(v >> 8);
buf[3] = (uint8_t)v;
} else {
buf[0] = (uint8_t)(0xC0 | ((v >> 56) & 0x3F));
buf[1] = (uint8_t)(v >> 48);
buf[2] = (uint8_t)(v >> 40);
buf[3] = (uint8_t)(v >> 32);
buf[4] = (uint8_t)(v >> 24);
buf[5] = (uint8_t)(v >> 16);
buf[6] = (uint8_t)(v >> 8);
buf[7] = (uint8_t)v;
}
}
void ossl_quic_vlint_encode(uint8_t *buf, uint64_t v)
{
ossl_quic_vlint_encode_n(buf, v, ossl_quic_vlint_encode_len(v));
}
uint64_t ossl_quic_vlint_decode_unchecked(const unsigned char *buf)
{
uint8_t first_byte = buf[0];
size_t sz = ossl_quic_vlint_decode_len(first_byte);
if (sz == 1)
return first_byte & 0x3F;
if (sz == 2)
return ((uint64_t)(first_byte & 0x3F) << 8)
| buf[1];
if (sz == 4)
return ((uint64_t)(first_byte & 0x3F) << 24)
| ((uint64_t)buf[1] << 16)
| ((uint64_t)buf[2] << 8)
| buf[3];
return ((uint64_t)(first_byte & 0x3F) << 56)
| ((uint64_t)buf[1] << 48)
| ((uint64_t)buf[2] << 40)
| ((uint64_t)buf[3] << 32)
| ((uint64_t)buf[4] << 24)
| ((uint64_t)buf[5] << 16)
| ((uint64_t)buf[6] << 8)
| buf[7];
}
int ossl_quic_vlint_decode(const unsigned char *buf, size_t buf_len, uint64_t *v)
{
size_t dec_len;
uint64_t x;
if (buf_len < 1)
return 0;
dec_len = ossl_quic_vlint_decode_len(buf[0]);
if (buf_len < dec_len)
return 0;
x = ossl_quic_vlint_decode_unchecked(buf);
*v = x;
return dec_len;
}