/*

 * Copyright (c) 2017 Fastly, Kazuho Oku

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include "quicly/constants.h"

#include "quicly/recvstate.h"

void quicly_recvstate_init(quicly_recvstate_t *state)

{

    quicly_ranges_init_with_range(&state->received, 0, 0);

    state->data_off = 0;

    state->eos = UINT64_MAX;

}

void quicly_recvstate_init_closed(quicly_recvstate_t *state)

{

    quicly_ranges_init(&state->received);

    state->data_off = 0;

    state->eos = 0;

}

void quicly_recvstate_dispose(quicly_recvstate_t *state)

{

    quicly_ranges_clear(&state->received);

}

int quicly_recvstate_update(quicly_recvstate_t *state, uint64_t off, size_t *len, int is_fin, size_t max_ranges)

{

    int ret;

    assert(!quicly_recvstate_transfer_complete(state));

    /* eos handling */

    if (state->eos == UINT64_MAX) {

        if (is_fin) {

            state->eos = off + *len;

            if (state->eos < state->received.ranges[state->received.num_ranges - 1].end)

                return QUICLY_TRANSPORT_ERROR_FINAL_SIZE;

        }

    } else {

        if (off + *len > state->eos)

            return QUICLY_TRANSPORT_ERROR_FINAL_SIZE;

    }

    /* no state change; entire data has already been received */

    if (off + *len <= state->data_off) {

        *len = 0;

        if (state->received.ranges[0].end == state->eos)

            goto Complete;

        return 0;

    }

    /* adjust if partially received */

    if (off < state->data_off) {

        size_t delta = state->data_off - off;

        off += delta;

        *len -= delta;

    }

    /* update received range */

    if (*len != 0) {

        if ((ret = quicly_ranges_add(&state->received, off, off + *len)) != 0)

            return ret;

        if (state->received.num_ranges > max_ranges)

            return QUICLY_ERROR_STATE_EXHAUSTION;

    }

    if (state->received.num_ranges == 1 && state->received.ranges[0].start == 0 && state->received.ranges[0].end == state->eos)

        goto Complete;

    return 0;

Complete:

    quicly_ranges_clear(&state->received);

    return 0;

}

int quicly_recvstate_reset(quicly_recvstate_t *state, uint64_t eos_at, uint64_t *bytes_missing)

{

    assert(!quicly_recvstate_transfer_complete(state));

    /* validate */

    if (state->eos != UINT64_MAX && state->eos != eos_at)

        return QUICLY_TRANSPORT_ERROR_FINAL_SIZE;

    if (eos_at < state->received.ranges[state->received.num_ranges - 1].end)

        return QUICLY_TRANSPORT_ERROR_FINAL_SIZE;

    /* calculate bytes missing */

    *bytes_missing = eos_at - state->received.ranges[state->received.num_ranges - 1].end;

    /* clear the received range */

    quicly_ranges_clear(&state->received);

    return 0;

}