/*******************************************************************************
 * Copyright (c) 2025, Jan Koester jan.koester@gmx.net
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 * modification, are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
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 *      notice, this list of conditions and the following disclaimer in the
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 *      derived from this software without specific prior written permission.
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 *******************************************************************************/

#include <cstring>
#include <fstream>
#include "sha512.h"

const unsigned long long authdb::sha512::sha512_k[80] = //ULL = uint64
            {0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL,
             0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
             0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
             0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
             0xd807aa98a3030242ULL, 0x12835b0145706fbeULL,
             0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
             0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL,
             0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
             0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
             0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
             0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL,
             0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
             0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL,
             0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
             0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
             0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
             0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL,
             0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
             0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL,
             0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
             0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
             0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
             0xd192e819d6ef5218ULL, 0xd69906245565a910ULL,
             0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
             0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL,
             0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
             0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
             0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
             0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL,
             0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
             0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL,
             0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
             0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
             0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
             0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL,
             0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
             0x28db77f523047d84ULL, 0x32caab7b40c72493ULL,
             0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
             0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
             0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL};

void authdb::sha512::transform(const unsigned char *message, unsigned int block_nb){
    uint64 w[80];
    uint64 wv[8];
    uint64 t1, t2;
    const unsigned char *sub_block;
    int i, j;
    for (i = 0; i < (int) block_nb; i++) {
        sub_block = message + (i << 7);
        for (j = 0; j < 16; j++) {
            SHA2_PACK64(&sub_block[j << 3], &w[j]);
        }
        for (j = 16; j < 80; j++) {
            w[j] =  SHA512_F4(w[j -  2]) + w[j -  7] + SHA512_F3(w[j - 15]) + w[j - 16];
        }
        for (j = 0; j < 8; j++) {
            wv[j] = m_h[j];
        }
        for (j = 0; j < 80; j++) {
            t1 = wv[7] + SHA512_F2(wv[4]) + SHA2_CH(wv[4], wv[5], wv[6])
                + sha512_k[j] + w[j];
            t2 = SHA512_F1(wv[0]) + SHA2_MAJ(wv[0], wv[1], wv[2]);
            wv[7] = wv[6];
            wv[6] = wv[5];
            wv[5] = wv[4];
            wv[4] = wv[3] + t1;
            wv[3] = wv[2];
            wv[2] = wv[1];
            wv[1] = wv[0];
            wv[0] = t1 + t2;
        }
        for (j = 0; j < 8; j++) {
            m_h[j] += wv[j];
        }

    }
}

void authdb::sha512::init(){
    m_h[0] = 0x6a09e667f3bcc908ULL;
    m_h[1] = 0xbb67ae8584caa73bULL;
    m_h[2] = 0x3c6ef372fe94f82bULL;
    m_h[3] = 0xa54ff53a5f1d36f1ULL;
    m_h[4] = 0x510e527fade682d1ULL;
    m_h[5] = 0x9b05688c2b3e6c1fULL;
    m_h[6] = 0x1f83d9abfb41bd6bULL;
    m_h[7] = 0x5be0cd19137e2179ULL;
    m_len = 0;
    m_tot_len = 0;
}

void authdb::sha512::update(const unsigned char *message, unsigned int len){
    unsigned int block_nb;
    unsigned int new_len, rem_len, tmp_len;
    const unsigned char *shifted_message;
    tmp_len = SHA384_512_BLOCK_SIZE - m_len;
    rem_len = len < tmp_len ? len : tmp_len;
    memcpy(&m_block[m_len], message, rem_len);
    if (m_len + len < SHA384_512_BLOCK_SIZE) {
        m_len += len;
        return;
    }
    new_len = len - rem_len;
    block_nb = new_len / SHA384_512_BLOCK_SIZE;
    shifted_message = message + rem_len;
    transform(m_block, 1);
    transform(shifted_message, block_nb);
    rem_len = new_len % SHA384_512_BLOCK_SIZE;
    memcpy(m_block, &shifted_message[block_nb << 7], rem_len);
    m_len = rem_len;
    m_tot_len += (block_nb + 1) << 7;
}

void authdb::sha512::final(unsigned char *digest)
{
    unsigned int block_nb;
    unsigned int pm_len;
    unsigned int len_b;
    int i;
    block_nb = 1 + ((SHA384_512_BLOCK_SIZE - 17)
                     < (m_len % SHA384_512_BLOCK_SIZE));
    len_b = (m_tot_len + m_len) << 3;
    pm_len = block_nb << 7;
    memset(m_block + m_len, 0, pm_len - m_len);
    m_block[m_len] = 0x80;
    SHA2_UNPACK32(len_b, m_block + pm_len - 4);
    transform(m_block, block_nb);
    for (i = 0 ; i < 8; i++) {
        SHA2_UNPACK64(m_h[i], &digest[i << 3]);
    }
}

void authdb::sha512::hash(const std::string input, std::string& output)
{
    unsigned char digest[authdb::sha512::DIGEST_SIZE];
    memset(digest,0,authdb::sha512::DIGEST_SIZE);
    sha512 ctx = sha512();
    ctx.init();
    ctx.update((unsigned char*)input.c_str(), input.length());
    ctx.final(digest);

    char *buf= new char[2*authdb::sha512::DIGEST_SIZE+1];
    buf[2*authdb::sha512::DIGEST_SIZE] = 0;
    for (int i = 0; i < (int)authdb::sha512::DIGEST_SIZE; i++)
        sprintf(buf+i*2, "%02x", digest[i]);
    output=buf;
    delete[] buf;
}
