#include <string.h>

#ifdef __GNUC__
#   include <x86intrin.h>
#else
#   include <intrin.h>
#endif

#include "core.h"

static void fill_block(__m128i *s, const block *ref_block, block *next_block,
                       int with_xor)
{
    __m128i block_XY[ARGON2_OWORDS_IN_BLOCK];
    unsigned int i;

    if (with_xor) {
        for (i = 0; i < ARGON2_OWORDS_IN_BLOCK; i++) {
            s[i] = _mm_xor_si128(
                        s[i], _mm_loadu_si128((const __m128i *)ref_block->v + i));
            block_XY[i] = _mm_xor_si128(
                        s[i], _mm_loadu_si128((const __m128i *)next_block->v + i));
        }
    } else {
        for (i = 0; i < ARGON2_OWORDS_IN_BLOCK; i++) {
            block_XY[i] = s[i] = _mm_xor_si128(
                        s[i], _mm_loadu_si128((const __m128i *)ref_block->v + i));
        }
    }

    for (i = 0; i < 8; ++i) {
        BLAKE2_ROUND(
            s[8 * i + 0], s[8 * i + 1], s[8 * i + 2], s[8 * i + 3],
            s[8 * i + 4], s[8 * i + 5], s[8 * i + 6], s[8 * i + 7]);
    }

    for (i = 0; i < 8; ++i) {
        BLAKE2_ROUND(
            s[8 * 0 + i], s[8 * 1 + i], s[8 * 2 + i], s[8 * 3 + i],
            s[8 * 4 + i], s[8 * 5 + i], s[8 * 6 + i], s[8 * 7 + i]);
    }

    for (i = 0; i < ARGON2_OWORDS_IN_BLOCK; i++) {
        s[i] = _mm_xor_si128(s[i], block_XY[i]);
        _mm_storeu_si128((__m128i *)next_block->v + i, s[i]);
    }
}

static void next_addresses(block *address_block, block *input_block)
{
    /*Temporary zero-initialized blocks*/
    __m128i zero_block[ARGON2_OWORDS_IN_BLOCK];
    __m128i zero2_block[ARGON2_OWORDS_IN_BLOCK];

    memset(zero_block, 0, sizeof(zero_block));
    memset(zero2_block, 0, sizeof(zero2_block));

    /*Increasing index counter*/
    input_block->v[6]++;

    /*First iteration of G*/
    fill_block(zero_block, input_block, address_block, 0);

    /*Second iteration of G*/
    fill_block(zero2_block, address_block, address_block, 0);
}

static void fill_segment_128(const argon2_instance_t *instance,
                             argon2_position_t position)
{
    block *ref_block = NULL, *curr_block = NULL;
    block address_block, input_block;
    uint64_t pseudo_rand, ref_index, ref_lane;
    uint32_t prev_offset, curr_offset;
    uint32_t starting_index, i;
    __m128i state[ARGON2_OWORDS_IN_BLOCK];
    int data_independent_addressing;

    if (instance == NULL) {
        return;
    }

    data_independent_addressing = (instance->type == Argon2_i) ||
            (instance->type == Argon2_id && (position.pass == 0) &&
             (position.slice < ARGON2_SYNC_POINTS / 2));

    if (data_independent_addressing) {
        init_block_value(&input_block, 0);

        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;
    }

    starting_index = 0;

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

        /* Don't forget to generate the first block of addresses: */
        if (data_independent_addressing) {
            next_addresses(&address_block, &input_block);
        }
    }

    /* 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;
    }

    memcpy(state, ((instance->memory + prev_offset)->v), ARGON2_BLOCK_SIZE);

    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) {
            if (i % ARGON2_ADDRESSES_IN_BLOCK == 0) {
                next_addresses(&address_block, &input_block);
            }
            pseudo_rand = address_block.v[i % ARGON2_ADDRESSES_IN_BLOCK];
        } else {
            pseudo_rand = instance->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->memory + instance->lane_length * ref_lane + ref_index;
        curr_block = instance->memory + curr_offset;

        /* version 1.2.1 and earlier: overwrite, not XOR */
        if (0 == position.pass || ARGON2_VERSION_10 == instance->version) {
            fill_block(state, ref_block, curr_block, 0);
        } else {
            fill_block(state, ref_block, curr_block, 1);
        }
    }
}
