/*
 * Argon2 source code package
 *
 * Written by Daniel Dinu and Dmitry Khovratovich, 2015
 *
 * This work is licensed under a Creative Commons CC0 1.0 License/Waiver.
 *
 * You should have received a copy of the CC0 Public Domain Dedication along
 * with
 * this software. If not, see
 * <http://creativecommons.org/publicdomain/zero/1.0/>.
 */

#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "argon2-core.h"
#include "argon2.h"
#include "blamka-round-ref.h"
#include "private/common.h"

static void
fill_block(const block *prev_block, const block *ref_block, block *next_block)
{
    block    blockR, block_tmp;
    unsigned i;

    copy_block(&blockR, ref_block);
    xor_block(&blockR, prev_block);
    copy_block(&block_tmp, &blockR);
    /* Now blockR = ref_block + prev_block and bloc_tmp = ref_block + prev_block
       Apply Blake2 on columns of 64-bit words: (0,1,...,15), then
       (16,17,..31)... finally (112,113,...127) */
    for (i = 0; i < 8; ++i) {
        BLAKE2_ROUND_NOMSG(
            blockR.v[16 * i], blockR.v[16 * i + 1], blockR.v[16 * i + 2],
            blockR.v[16 * i + 3], blockR.v[16 * i + 4], blockR.v[16 * i + 5],
            blockR.v[16 * i + 6], blockR.v[16 * i + 7], blockR.v[16 * i + 8],
            blockR.v[16 * i + 9], blockR.v[16 * i + 10], blockR.v[16 * i + 11],
            blockR.v[16 * i + 12], blockR.v[16 * i + 13], blockR.v[16 * i + 14],
            blockR.v[16 * i + 15]);
    }

    /* Apply Blake2 on rows of 64-bit words: (0,1,16,17,...112,113), then
       (2,3,18,19,...,114,115).. finally (14,15,30,31,...,126,127) */
    for (i = 0; i < 8; i++) {
        BLAKE2_ROUND_NOMSG(
            blockR.v[2 * i], blockR.v[2 * i + 1], blockR.v[2 * i + 16],
            blockR.v[2 * i + 17], blockR.v[2 * i + 32], blockR.v[2 * i + 33],
            blockR.v[2 * i + 48], blockR.v[2 * i + 49], blockR.v[2 * i + 64],
            blockR.v[2 * i + 65], blockR.v[2 * i + 80], blockR.v[2 * i + 81],
            blockR.v[2 * i + 96], blockR.v[2 * i + 97], blockR.v[2 * i + 112],
            blockR.v[2 * i + 113]);
    }

    copy_block(next_block, &block_tmp);
    xor_block(next_block, &blockR);
}

static void
fill_block_with_xor(const block *prev_block, const block *ref_block,
                    block *next_block)
{
    block    blockR, block_tmp;
    unsigned i;

    copy_block(&blockR, ref_block);
    xor_block(&blockR, prev_block);
    copy_block(&block_tmp, &blockR);
    xor_block(&block_tmp,
              next_block); /* Saving the next block contents for XOR over */
    /* Now blockR = ref_block + prev_block and bloc_tmp = ref_block + prev_block
     * + next_block */
    /* Apply Blake2 on columns of 64-bit words: (0,1,...,15) , then
       (16,17,..31)... finally (112,113,...127) */
    for (i = 0; i < 8; ++i) {
        BLAKE2_ROUND_NOMSG(
            blockR.v[16 * i], blockR.v[16 * i + 1], blockR.v[16 * i + 2],
            blockR.v[16 * i + 3], blockR.v[16 * i + 4], blockR.v[16 * i + 5],
            blockR.v[16 * i + 6], blockR.v[16 * i + 7], blockR.v[16 * i + 8],
            blockR.v[16 * i + 9], blockR.v[16 * i + 10], blockR.v[16 * i + 11],
            blockR.v[16 * i + 12], blockR.v[16 * i + 13], blockR.v[16 * i + 14],
            blockR.v[16 * i + 15]);
    }

    /* Apply Blake2 on rows of 64-bit words: (0,1,16,17,...112,113), then
       (2,3,18,19,...,114,115).. finally (14,15,30,31,...,126,127) */
    for (i = 0; i < 8; i++) {
        BLAKE2_ROUND_NOMSG(
            blockR.v[2 * i], blockR.v[2 * i + 1], blockR.v[2 * i + 16],
            blockR.v[2 * i + 17], blockR.v[2 * i + 32], blockR.v[2 * i + 33],
            blockR.v[2 * i + 48], blockR.v[2 * i + 49], blockR.v[2 * i + 64],
            blockR.v[2 * i + 65], blockR.v[2 * i + 80], blockR.v[2 * i + 81],
            blockR.v[2 * i + 96], blockR.v[2 * i + 97], blockR.v[2 * i + 112],
            blockR.v[2 * i + 113]);
    }

    copy_block(next_block, &block_tmp);
    xor_block(next_block, &blockR);
}

/*
 * Generate pseudo-random values to reference blocks in the segment and puts
 * them into the array
 * @param instance Pointer to the current instance
 * @param position Pointer to the current position
 * @param pseudo_rands Pointer to the array of 64-bit values
 * @pre pseudo_rands must point to @a instance->segment_length allocated values
 */
static void
generate_addresses(const argon2_instance_t *instance,
                   const argon2_position_t *position, uint64_t *pseudo_rands)
{
    block    zero_block, input_block, address_block, tmp_block;
    uint32_t i;

    init_block_value(&zero_block, 0);
    init_block_value(&input_block, 0);

    if (instance != NULL && position != NULL) {
        input_block.v[0] = position->pass;
        input_block.v[1] = position->lane;
        input_block.v[2] = position->slice;
        input_block.v[3] = instance->memory_blocks;
        input_block.v[4] = instance->passes;
        input_block.v[5] = instance->type;

        for (i = 0; i < instance->segment_length; ++i) {
            if (i % ARGON2_ADDRESSES_IN_BLOCK == 0) {
                input_block.v[6]++;
                init_block_value(&tmp_block, 0);
                init_block_value(&address_block, 0);
                fill_block_with_xor(&zero_block, &input_block, &tmp_block);
                fill_block_with_xor(&zero_block, &tmp_block, &address_block);
            }

            pseudo_rands[i] = address_block.v[i % ARGON2_ADDRESSES_IN_BLOCK];
        }
    }
}

void
argon2_fill_segment_ref(const argon2_instance_t *instance,
                        argon2_position_t position)
{
    block    *ref_block = NULL, *curr_block = NULL;
    /* Pseudo-random values that determine the reference block position */
    uint64_t *pseudo_rands = NULL;
    uint64_t  pseudo_rand, ref_index, ref_lane;
    uint32_t  prev_offset, curr_offset;
    uint32_t  starting_index;
    uint32_t  i;
    int       data_independent_addressing = 1;

    if (instance == NULL) {
        return;
    }

    if (instance->type == Argon2_id &&
        (position.pass != 0 || position.slice >= ARGON2_SYNC_POINTS / 2)) {
        data_independent_addressing = 0;
    }

    pseudo_rands = instance->pseudo_rands;

    if (data_independent_addressing) {
        generate_addresses(instance, &position, pseudo_rands);
    }

    starting_index = 0;

    if ((0 == position.pass) && (0 == position.slice)) {
        starting_index = 2; /* we have already generated the first two blocks */
    }

    /* Offset of the current block */
    curr_offset = position.lane * instance->lane_length +
                  position.slice * instance->segment_length + starting_index;

    if (0 == curr_offset % instance->lane_length) {
        /* Last block in this lane */
        prev_offset = curr_offset + instance->lane_length - 1;
    } else {
        /* Previous block */
        prev_offset = curr_offset - 1;
    }

    for (i = starting_index; i < instance->segment_length;
         ++i, ++curr_offset, ++prev_offset) {
        /*1.1 Rotating prev_offset if needed */
        if (curr_offset % instance->lane_length == 1) {
            prev_offset = curr_offset - 1;
        }

        /* 1.2 Computing the index of the reference block */
        /* 1.2.1 Taking pseudo-random value from the previous block */
        if (data_independent_addressing) {
#pragma warning(push)
#pragma warning(disable : 6385)
            pseudo_rand = pseudo_rands[i];
#pragma warning(pop)
        } else {
            pseudo_rand = instance->region->memory[prev_offset].v[0];
        }

        /* 1.2.2 Computing the lane of the reference block */
        ref_lane = ((pseudo_rand >> 32)) % instance->lanes;

        if ((position.pass == 0) && (position.slice == 0)) {
            /* Can not reference other lanes yet */
            ref_lane = position.lane;
        }

        /* 1.2.3 Computing the number of possible reference block within the
         * lane.
         */
        position.index = i;
        ref_index = index_alpha(instance, &position, pseudo_rand & 0xFFFFFFFF,
                                ref_lane == position.lane);

        /* 2 Creating a new block */
        ref_block = instance->region->memory +
                    instance->lane_length * ref_lane + ref_index;
        curr_block = instance->region->memory + curr_offset;
        if (position.pass != 0) {
            fill_block_with_xor(instance->region->memory + prev_offset,
                                ref_block, curr_block);
        } else {
            fill_block(instance->region->memory + prev_offset, ref_block,
                       curr_block);
        }
    }
}