/*
 * Copyright (C) 2024 - 2026, Stephan Mueller <smueller@chronox.de>
 *
 * License: see LICENSE file in root directory
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
/*
 * This code is derived in parts from the code distribution provided with
 * https://github.com/sphincs/sphincsplus
 *
 * That code is released under Public Domain
 * (https://creativecommons.org/share-your-work/public-domain/cc0/).
 */

#ifndef SPHINCS_UTILSX4_AVX2_H
#define SPHINCS_UTILSX4_AVX2_H

#include "sphincs_internal.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * For a given leaf index, computes the authentication path and the resulting
 * root node using Merkle's TreeHash algorithm.
 * Expects the layer and tree parts of the tree_addr to be set, as well as the
 * tree type (i.e. SPX_ADDR_TYPE_HASHTREE or SPX_ADDR_TYPE_FORSTREE).
 * Applies the offset idx_offset to indices before building addresses, so that
 * it is possible to continue counting indices across trees.
 *
 * This implementation uses AVX to compute internal nodes 4 at a time (in
 * parallel)
 */
void treehashx4(
	unsigned char *root, unsigned char *auth_path, const spx_ctx *ctx,
	uint32_t leaf_idx, uint32_t idx_offset, uint32_t tree_height,
	void (*gen_leafx4)(unsigned char * /* Where to write the leaves */,
			   const spx_ctx * /* ctx */, uint32_t addr_idx,
			   void *info, uint8_t *ws_buf, uint8_t *thash_buf),
	uint32_t tree_addrx4[4 * 8], void *info, uint8_t *stackx4, void *ws_buf,
	uint8_t *thash_buf);

#ifdef __cplusplus
}
#endif

#endif /* SPHINCS_UTILSX4_AVX2_H */
