/*
 * Copyright (c) 2020 YuQing <384681@qq.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

#ifndef _SF_IOV_H
#define _SF_IOV_H

#include "fastcommon/shared_func.h"
#include "sf_types.h"

#define SF_IOV_FIXED_SIZE    256

typedef struct sf_dynamic_iov_array {
    struct iovec holder[SF_IOV_FIXED_SIZE];
    struct iovec *ptr;

    struct {
        const struct iovec *iov;
        int cnt;
    } input;

    struct iovec *iov;
    int cnt;
} SFDynamicIOVArray;

#define sf_iova_init(iova, _iov, _cnt)  \
    (iova).input.iov = _iov;            \
    (iova).iov = (struct iovec *)_iov;  \
    (iova).cnt = (iova).input.cnt = _cnt

#define sf_iova_destroy(iova) \
    if ((iova).iov != (struct iovec *)(iova).input.iov && \
            (iova).ptr != (iova).holder)  \
            free((iova).ptr)

#ifdef __cplusplus
extern "C" {
#endif

static inline int sf_iova_check_alloc(SFDynamicIOVArray *iova)
{
    if (iova->iov == (struct iovec *)iova->input.iov) {
        if (iova->input.cnt <= SF_IOV_FIXED_SIZE) {
            iova->ptr = iova->holder;
        } else {
            iova->ptr = fc_malloc(iova->input.cnt *
                    sizeof(struct iovec));
            if (iova->ptr == NULL) {
                return ENOMEM;
            }
        }

        memcpy(iova->ptr, iova->input.iov, iova->input.cnt *
                sizeof(struct iovec));
        iova->iov = iova->ptr;
    }

    return 0;
}

int sf_iova_consume(SFDynamicIOVArray *iova, const int consume_len);

int sf_iova_first_slice(SFDynamicIOVArray *iova, const int slice_len);

int sf_iova_next_slice(SFDynamicIOVArray *iova,
        const int consume_len, const int slice_len);

int sf_iova_memset_ex(const struct iovec *iov, const int iovcnt,
        int c, const int offset, const int length);

#define sf_iova_memset(iova, c, offset, length) \
    sf_iova_memset_ex((iova).iov, (iova).cnt, c, offset, length)

static inline void sf_iova_memcpy_ex(const struct iovec *iov,
        const int iovcnt, const char *buff, const int length)
{
    const struct iovec *iob;
    const struct iovec *end;
    const char *current;
    int remain;
    int bytes;

    current = buff;
    remain = length;
    end = iov + iovcnt;
    for (iob=iov; iob<end; iob++) {
        bytes = FC_MIN(remain, iob->iov_len);
        memcpy(iob->iov_base, current, bytes);

        remain -= bytes;
        if (remain == 0) {
            break;
        }
        current += bytes;
    }
}

#define sf_iova_memcpy(iova, buff, length) \
    sf_iova_memcpy_ex((iova).iov, (iova).cnt, buff, length)

#ifdef __cplusplus
}
#endif

#endif