UtilDefs_SeqReadWrite.c

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/*
 * Copyright (c) 2025 The Johns Hopkins University Applied Physics
 * Laboratory LLC.
 *
 * This file is part of the Bundle Protocol Security Library (BSL).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This work was performed for the Jet Propulsion Laboratory, California
 * Institute of Technology, sponsored by the United States Government under
 * the prime contract 80NM0018D0004 between the Caltech and NASA under
 * subcontract 1700763.
 */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include <BPSecLib_Private.h>
 
#include "backend/UtilDefs_SeqReadWrite.h"
 
int BSL_SeqReader_Deinit(BSL_SeqReader_t *obj _U_)
{
    // nothing to do here
    return BSL_SUCCESS;
}
 
int BSL_SeqReader_InitFlat(BSL_SeqReader_t *obj, const uint8_t *buf, size_t bufsize)
{
    CHK_ARG_NONNULL(obj);
    CHK_ARG_NONNULL(buf);
    // CHK_ARG_EXPR(bufsize > 0);
 
    obj->cursor = buf;
    obj->remain = bufsize;
 
    return BSL_SUCCESS;
}
 
int BSL_SeqReader_Get(BSL_SeqReader_t *obj, uint8_t *buf, size_t *bufsize)
{
    CHK_ARG_NONNULL(obj);
    CHK_ARG_NONNULL(buf);
    CHK_ARG_NONNULL(bufsize);
    CHK_ARG_EXPR(*bufsize > 0);
 
    const size_t got = (obj->remain < *bufsize ? obj->remain : *bufsize);
    if (got > 0)
    {
        memcpy(buf, obj->cursor, got);
        obj->cursor += got;
        obj->remain -= got;
    }
    *bufsize = got;
    return BSL_SUCCESS;
}
 
int BSL_SeqWriter_InitFlat(BSL_SeqWriter_t *obj, uint8_t **buf, size_t *bufsize)
{
    CHK_ARG_NONNULL(obj);
    CHK_ARG_NONNULL(buf);
    CHK_ARG_NONNULL(bufsize);
 
    obj->fd = open_memstream((char **)buf, bufsize);
 
    CHK_POSTCONDITION(obj->fd != NULL);
    return BSL_SUCCESS;
}
 
int BSL_SeqWriter_Deinit(BSL_SeqWriter_t *obj)
{
    CHK_ARG_NONNULL(obj);
 
    // NOLINTNEXTLINE
    fclose(obj->fd);
    obj->fd = NULL;
 
    return BSL_SUCCESS;
}
 
int BSL_SeqWriter_Put(BSL_SeqWriter_t *obj, const uint8_t *buf, size_t *bufsize)
{
    CHK_ARG_NONNULL(obj);
    CHK_ARG_NONNULL(buf);
    CHK_ARG_NONNULL(bufsize);
    // CHK_ARG_EXPR(*bufsize > 0);
 
    const size_t got = fwrite(buf, 1, *bufsize, obj->fd);
    if (got > 0)
    {
        *bufsize = got;
    }
    return BSL_SUCCESS;
}