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[release] / src / liblimb / shldata.h / shldata_finalw.c 

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/* This file is part of limb                           https://lila.oss/limb
 * Copyright (C) 2023 Olivier Brunel                          jjk@jjacky.com */
/* SPDX-License-Identifier: GPL-2.0-only */
#include <errno.h>
#include <string.h>
#include <limb/patrim.h>
#include <limb/shldata.h>
#include "shldata.h"

ssize_t
shldata_finalw(char *dst, size_t dlen, shldata_ctx *ctx)
{
    if (!ctx->len || ctx->len != ctx->done)
        return (errno = EINVAL, -1);

    char mac[16];
    ccpl_final(mac, &ctx->ccpl);

    int r;
    r = patrim_put(dst, dlen, 0, ID_MAC, sizeof(mac));
    if (r < 0 || dlen - r < sizeof(mac))
        return (errno = ENOBUFS, -1);
    memcpy(dst + r, mac, sizeof(mac));

    return r + sizeof(mac);
}