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

#include "i_swap.h"
#include "sha1.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);
}