/* Copyright (c) 2017 - 2019 LiteSpeed Technologies Inc.  See LICENSE. */
/*
 * lsquic_senhist.h -- History sent packets.
 *
 * We need to keep track of packet numbers in order to verify ACKs.  To
 * speed up processing, we make sure that there is never a gap in the
 * packet number sequence we generate.
 */

#ifndef LSQUIC_SENHIST_H
#define LSQUIC_SENHIST_H 1

#ifndef LSQUIC_SENHIST_FATAL
#   define LSQUIC_SENHIST_FATAL 0
#endif

typedef struct lsquic_senhist {
    lsquic_packno_t             sh_last_sent;
#if !LSQUIC_SENHIST_FATAL
    enum {
        SH_WARNED   = 1 << 0,   /* Warn once */
    }                           sh_flags;
#endif
} lsquic_senhist_t;

#define lsquic_senhist_init(hist) do {                                  \
    (hist)->sh_last_sent = 0;                                           \
} while (0)

#define lsquic_senhist_cleanup(hist)

#if LSQUIC_SENHIST_FATAL
#define lsquic_senhist_add(hist, packno) do {                           \
    assert((hist)->sh_last_sent == packno - 1);                         \
    (hist)->sh_last_sent = packno;                                      \
} while (0)
#else
#define lsquic_senhist_add(hist, packno) do {                           \
    if ((hist)->sh_last_sent == packno - 1)                             \
        (hist)->sh_last_sent = packno;                                  \
    else                                                                \
    {                                                                   \
        if (!((hist)->sh_flags & SH_WARNED))                            \
        {                                                               \
            LSQ_WARN("send history gap %"PRIu64" - %"PRIu64,            \
                (hist)->sh_last_sent, packno);                          \
            (hist)->sh_flags |= SH_WARNED;                              \
        }                                                               \
        (hist)->sh_last_sent = packno;                                  \
    }                                                                   \
} while (0)
#endif

/* Returns 0 if no packets have been sent yet */
#define lsquic_senhist_largest(hist) (+(hist)->sh_last_sent)

void
lsquic_senhist_tostr (lsquic_senhist_t *hist, char *buf, size_t bufsz);

#define lsquic_senhist_mem_used(hist) (sizeof(*(hist)))

#endif