/* crc32_fold.c -- crc32 folding interface

 * Copyright (C) 2021 Nathan Moinvaziri

 * For conditions of distribution and use, see copyright notice in zlib.h

 */

#include "zbuild.h"

#include "zutil.h"

#include "functable.h"

#include "crc32.h"

Z_INTERNAL uint32_t crc32_fold_reset_c(crc32_fold *crc) {

    crc->value = CRC32_INITIAL_VALUE;

    return crc->value;

}

Z_INTERNAL void crc32_fold_copy_c(crc32_fold *crc, uint8_t *dst, const uint8_t *src, size_t len) {

    crc->value = FUNCTABLE_CALL(crc32)(crc->value, src, len);

    memcpy(dst, src, len);

}

Z_INTERNAL void crc32_fold_c(crc32_fold *crc, const uint8_t *src, size_t len, uint32_t init_crc) {

    /* Note: while this is basically the same thing as the vanilla CRC function, we still need

     * a functable entry for it so that we can generically dispatch to this function with the

     * same arguments for the versions that _do_ do a folding CRC but we don't want a copy. The

     * init_crc is an unused argument in this context */

    Z_UNUSED(init_crc);

    crc->value = FUNCTABLE_CALL(crc32)(crc->value, src, len);

}

Z_INTERNAL uint32_t crc32_fold_final_c(crc32_fold *crc) {

    return crc->value;

}