/* sha1.c - SHA1 hash function
 *	Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
 *
 * Please see below for more legal information!
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

/*  Test vectors:
 *
 *  "abc"
 *  A999 3E36 4706 816A BA3E  2571 7850 C26C 9CD0 D89D
 *
 *  "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
 *  8498 3E44 1C3B D26E BAAE  4AA1 F951 29E5 E546 70F1
 */

#include "sha1.h"

#include "i_swap.h"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void SHA1_Init(sha1_context_t* hd) {
    hd->h0 = 0x67452301;
    hd->h1 = 0xefcdab89;
    hd->h2 = 0x98badcfe;
    hd->h3 = 0x10325476;
    hd->h4 = 0xc3d2e1f0;
    hd->nblocks = 0;
    hd->count = 0;
}

/****************
 * Transform the message X which consists of 16 32-bit-words
 */
static void Transform(sha1_context_t* hd, byte* data) {
    uint32_t a, b, c, d, e, tm;
    uint32_t x[16];

    /* get values from the chaining vars */
    a = hd->h0;
    b = hd->h1;
    c = hd->h2;
    d = hd->h3;
    e = hd->h4;

#ifdef SYS_BIG_ENDIAN
    memcpy(x, data, 64);
#else
    {
        int i;
        byte* p2;
        for (i = 0, p2 = (byte*) x; i < 16; i++, p2 += 4) {
            p2[3] = *data++;
            p2[2] = *data++;
            p2[1] = *data++;
            p2[0] = *data++;
        }
    }
#endif

#define K1 0x5A827999L
#define K2 0x6ED9EBA1L
#define K3 0x8F1BBCDCL
#define K4 0xCA62C1D6L
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) (x ^ y ^ z)
#define F3(x, y, z) ((x & y) | (z & (x | y)))
#define F4(x, y, z) (x ^ y ^ z)

#define rol(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

#define M(i)                                                                                       \
    (tm = x[i & 0x0f] ^ x[(i - 14) & 0x0f] ^ x[(i - 8) & 0x0f] ^ x[(i - 3) & 0x0f],                \
        (x[i & 0x0f] = rol(tm, 1)))

#define R(a, b, c, d, e, f, k, m)                                                                  \
    do {                                                                                           \
        e += rol(a, 5) + f(b, c, d) + k + m;                                                       \
        b = rol(b, 30);                                                                            \
    } while (0)
    R(a, b, c, d, e, F1, K1, x[0]);
    R(e, a, b, c, d, F1, K1, x[1]);
    R(d, e, a, b, c, F1, K1, x[2]);
    R(c, d, e, a, b, F1, K1, x[3]);
    R(b, c, d, e, a, F1, K1, x[4]);
    R(a, b, c, d, e, F1, K1, x[5]);
    R(e, a, b, c, d, F1, K1, x[6]);
    R(d, e, a, b, c, F1, K1, x[7]);
    R(c, d, e, a, b, F1, K1, x[8]);
    R(b, c, d, e, a, F1, K1, x[9]);
    R(a, b, c, d, e, F1, K1, x[10]);
    R(e, a, b, c, d, F1, K1, x[11]);
    R(d, e, a, b, c, F1, K1, x[12]);
    R(c, d, e, a, b, F1, K1, x[13]);
    R(b, c, d, e, a, F1, K1, x[14]);
    R(a, b, c, d, e, F1, K1, x[15]);
    R(e, a, b, c, d, F1, K1, M(16));
    R(d, e, a, b, c, F1, K1, M(17));
    R(c, d, e, a, b, F1, K1, M(18));
    R(b, c, d, e, a, F1, K1, M(19));
    R(a, b, c, d, e, F2, K2, M(20));
    R(e, a, b, c, d, F2, K2, M(21));
    R(d, e, a, b, c, F2, K2, M(22));
    R(c, d, e, a, b, F2, K2, M(23));
    R(b, c, d, e, a, F2, K2, M(24));
    R(a, b, c, d, e, F2, K2, M(25));
    R(e, a, b, c, d, F2, K2, M(26));
    R(d, e, a, b, c, F2, K2, M(27));
    R(c, d, e, a, b, F2, K2, M(28));
    R(b, c, d, e, a, F2, K2, M(29));
    R(a, b, c, d, e, F2, K2, M(30));
    R(e, a, b, c, d, F2, K2, M(31));
    R(d, e, a, b, c, F2, K2, M(32));
    R(c, d, e, a, b, F2, K2, M(33));
    R(b, c, d, e, a, F2, K2, M(34));
    R(a, b, c, d, e, F2, K2, M(35));
    R(e, a, b, c, d, F2, K2, M(36));
    R(d, e, a, b, c, F2, K2, M(37));
    R(c, d, e, a, b, F2, K2, M(38));
    R(b, c, d, e, a, F2, K2, M(39));
    R(a, b, c, d, e, F3, K3, M(40));
    R(e, a, b, c, d, F3, K3, M(41));
    R(d, e, a, b, c, F3, K3, M(42));
    R(c, d, e, a, b, F3, K3, M(43));
    R(b, c, d, e, a, F3, K3, M(44));
    R(a, b, c, d, e, F3, K3, M(45));
    R(e, a, b, c, d, F3, K3, M(46));
    R(d, e, a, b, c, F3, K3, M(47));
    R(c, d, e, a, b, F3, K3, M(48));
    R(b, c, d, e, a, F3, K3, M(49));
    R(a, b, c, d, e, F3, K3, M(50));
    R(e, a, b, c, d, F3, K3, M(51));
    R(d, e, a, b, c, F3, K3, M(52));
    R(c, d, e, a, b, F3, K3, M(53));
    R(b, c, d, e, a, F3, K3, M(54));
    R(a, b, c, d, e, F3, K3, M(55));
    R(e, a, b, c, d, F3, K3, M(56));
    R(d, e, a, b, c, F3, K3, M(57));
    R(c, d, e, a, b, F3, K3, M(58));
    R(b, c, d, e, a, F3, K3, M(59));
    R(a, b, c, d, e, F4, K4, M(60));
    R(e, a, b, c, d, F4, K4, M(61));
    R(d, e, a, b, c, F4, K4, M(62));
    R(c, d, e, a, b, F4, K4, M(63));
    R(b, c, d, e, a, F4, K4, M(64));
    R(a, b, c, d, e, F4, K4, M(65));
    R(e, a, b, c, d, F4, K4, M(66));
    R(d, e, a, b, c, F4, K4, M(67));
    R(c, d, e, a, b, F4, K4, M(68));
    R(b, c, d, e, a, F4, K4, M(69));
    R(a, b, c, d, e, F4, K4, M(70));
    R(e, a, b, c, d, F4, K4, M(71));
    R(d, e, a, b, c, F4, K4, M(72));
    R(c, d, e, a, b, F4, K4, M(73));
    R(b, c, d, e, a, F4, K4, M(74));
    R(a, b, c, d, e, F4, K4, M(75));
    R(e, a, b, c, d, F4, K4, M(76));
    R(d, e, a, b, c, F4, K4, M(77));
    R(c, d, e, a, b, F4, K4, M(78));
    R(b, c, d, e, a, F4, K4, M(79));

    /* update chainig vars */
    hd->h0 += a;
    hd->h1 += b;
    hd->h2 += c;
    hd->h3 += d;
    hd->h4 += e;
}

/* Update the message digest with the contents
 * of INBUF with length INLEN.
 */
void SHA1_Update(sha1_context_t* hd, byte* inbuf, size_t inlen) {
    if (hd->count == 64) {
        /* flush the buffer */
        Transform(hd, hd->buf);
        hd->count = 0;
        hd->nblocks++;
    }
    if (!inbuf)
        return;
    if (hd->count) {
        for (; inlen && hd->count < 64; inlen--)
            hd->buf[hd->count++] = *inbuf++;
        SHA1_Update(hd, NULL, 0);
        if (!inlen)
            return;
    }

    while (inlen >= 64) {
        Transform(hd, inbuf);
        hd->count = 0;
        hd->nblocks++;
        inlen -= 64;
        inbuf += 64;
    }
    for (; inlen && hd->count < 64; inlen--)
        hd->buf[hd->count++] = *inbuf++;
}

/* The routine final terminates the computation and
 * returns the digest.
 * The handle is prepared for a new cycle, but adding bytes to the
 * handle will the destroy the returned buffer.
 * Returns: 20 bytes representing the digest.
 */

void SHA1_Final(sha1_digest_t digest, sha1_context_t* hd) {
    uint32_t t, msb, lsb;
    byte* p;

    SHA1_Update(hd, NULL, 0); /* flush */
    ;

    t = hd->nblocks;
    /* multiply by 64 to make a byte count */
    lsb = t << 6;
    msb = t >> 26;
    /* add the count */
    t = lsb;
    if ((lsb += hd->count) < t)
        msb++;
    /* multiply by 8 to make a bit count */
    t = lsb;
    lsb <<= 3;
    msb <<= 3;
    msb |= t >> 29;

    if (hd->count < 56) {
        /* enough room */
        hd->buf[hd->count++] = 0x80; /* pad */
        while (hd->count < 56)
            hd->buf[hd->count++] = 0; /* pad */
    } else {
        /* need one extra block */
        hd->buf[hd->count++] = 0x80; /* pad character */
        while (hd->count < 64)
            hd->buf[hd->count++] = 0;
        SHA1_Update(hd, NULL, 0); /* flush */
        ;
        memset(hd->buf, 0, 56); /* fill next block with zeroes */
    }
    /* append the 64 bit count */
    hd->buf[56] = msb >> 24;
    hd->buf[57] = msb >> 16;
    hd->buf[58] = msb >> 8;
    hd->buf[59] = msb;
    hd->buf[60] = lsb >> 24;
    hd->buf[61] = lsb >> 16;
    hd->buf[62] = lsb >> 8;
    hd->buf[63] = lsb;
    Transform(hd, hd->buf);

    p = hd->buf;
#ifdef SYS_BIG_ENDIAN
#define X(a)                                                                                       \
    do {                                                                                           \
        *(uint32_t*) p = hd->h##a;                                                                 \
        p += 4;                                                                                    \
    } while (0)
#else /* little endian */
#define X(a)                                                                                       \
    do {                                                                                           \
        *p++ = hd->h##a >> 24;                                                                     \
        *p++ = hd->h##a >> 16;                                                                     \
        *p++ = hd->h##a >> 8;                                                                      \
        *p++ = hd->h##a;                                                                           \
    } while (0)
#endif
    X(0);
    X(1);
    X(2);
    X(3);
    X(4);
#undef X

    memcpy(digest, hd->buf, sizeof(sha1_digest_t));
}

void SHA1_UpdateInt32(sha1_context_t* context, unsigned int val) {
    byte buf[4];

    buf[0] = (val >> 24) & 0xff;
    buf[1] = (val >> 16) & 0xff;
    buf[2] = (val >> 8) & 0xff;
    buf[3] = val & 0xff;

    SHA1_Update(context, buf, 4);
}

void SHA1_UpdateString(sha1_context_t* context, char* str) {
    SHA1_Update(context, (byte*) str, strlen(str) + 1);
}
