/*****************************************************************************
 * Functions to compute SHA512 and SHA384 message digests according to       *
 * the NIST specification FIPS-180-2.                                        *
 *                                                                           *
 * Copyright (C) 2005, 2006, 2008                                            *
 *     by Free Software Foundation, Inc.                                     *
 *                                                                           *
 * This file was taken from coreutils-7.4 and adapted for digup.             *
 *                                                                           *
 * This program 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, or (at your option) any       *
 * later version.                                                            *
 *                                                                           *
 * This program 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, write to the Free Software Foundation,   *
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.        *
 *                                                                           *
 * Written by David Madore, considerably copypasting from                    *
 * Scott G. Miller's sha1.c                                                  *
 *****************************************************************************/

#include "sha512.h"

#include <stddef.h>
#include <string.h>

/* u64 type functions imported from u64.h */

typedef uint64_t u64;

#define u64hilo(hi, lo) ((u64) (((u64) (hi) << 32) + (lo)))
#define u64init(hi, lo) u64hilo (hi, lo)
#define u64lo(x) ((u64) (x))
#define u64lt(x, y) ((x) < (y))
#define u64and(x, y) ((x) & (y))
#define u64or(x, y) ((x) | (y))
#define u64xor(x, y) ((x) ^ (y))
#define u64plus(x, y) ((x) + (y))
#define u64shl(x, n) ((x) << (n))
#define u64shr(x, n) ((x) >> (n))
#define u64rol(x, n) u64or (u64shl (x, n), u64shr (x, 64 - n))

#if HAVE_ENDIAN_H

#include <endian.h>
#define WORDS_ARE_BIGENDIAN (__BYTE_ORDER == __BIG_ENDIAN)

#elif HAVE_SYS_PARAM_H

#include <sys/param.h>
#define WORDS_ARE_BIGENDIAN (BYTE_ORDER == BIG_ENDIAN)

#else
#error "Cannot determine system endianness."
#endif

#if WORDS_ARE_BIGENDIAN
# define SWAP(n) (n)
#else
# define SWAP(n) \
    u64or (u64or (u64or (u64shl (n, 56),				\
			 u64shl (u64and (n, u64lo (0x0000ff00)), 40)),	\
		  u64or (u64shl (u64and (n, u64lo (0x00ff0000)), 24),	\
			 u64shl (u64and (n, u64lo (0xff000000)),  8))),	\
	   u64or (u64or (u64and (u64shr (n,  8), u64lo (0xff000000)),	\
			 u64and (u64shr (n, 24), u64lo (0x00ff0000))),	\
		  u64or (u64and (u64shr (n, 40), u64lo (0x0000ff00)),	\
			 u64shr (n, 56))))
#endif

#define BLOCKSIZE 4096

#if BLOCKSIZE % 128 != 0
# error "invalid BLOCKSIZE"
#endif

/* This array contains the bytes used to pad the buffer to the next
   128-byte boundary.  */
static const unsigned char fillbuf[128] = { 0x80, 0 /* , 0, 0, ...  */ };


/*
  Takes a pointer to a 512 bit block of data (eight 64 bit ints) and
  initializes it to the start constants of the SHA512 algorithm.  This
  must be called before using hash in the call to sha512_hash
*/
void
sha512_init_ctx (struct sha512_ctx *ctx)
{
    ctx->state[0] = u64hilo (0x6a09e667, 0xf3bcc908);
    ctx->state[1] = u64hilo (0xbb67ae85, 0x84caa73b);
    ctx->state[2] = u64hilo (0x3c6ef372, 0xfe94f82b);
    ctx->state[3] = u64hilo (0xa54ff53a, 0x5f1d36f1);
    ctx->state[4] = u64hilo (0x510e527f, 0xade682d1);
    ctx->state[5] = u64hilo (0x9b05688c, 0x2b3e6c1f);
    ctx->state[6] = u64hilo (0x1f83d9ab, 0xfb41bd6b);
    ctx->state[7] = u64hilo (0x5be0cd19, 0x137e2179);

    ctx->total[0] = ctx->total[1] = u64lo (0);
    ctx->buflen = 0;
}

void
sha384_init_ctx (struct sha512_ctx *ctx)
{
  ctx->state[0] = u64hilo (0xcbbb9d5d, 0xc1059ed8);
  ctx->state[1] = u64hilo (0x629a292a, 0x367cd507);
  ctx->state[2] = u64hilo (0x9159015a, 0x3070dd17);
  ctx->state[3] = u64hilo (0x152fecd8, 0xf70e5939);
  ctx->state[4] = u64hilo (0x67332667, 0xffc00b31);
  ctx->state[5] = u64hilo (0x8eb44a87, 0x68581511);
  ctx->state[6] = u64hilo (0xdb0c2e0d, 0x64f98fa7);
  ctx->state[7] = u64hilo (0x47b5481d, 0xbefa4fa4);

  ctx->total[0] = ctx->total[1] = u64lo (0);
  ctx->buflen = 0;
}

/* Copy the value from V into the memory location pointed to by *CP,
   If your architecture allows unaligned access, this is equivalent to
   * (__typeof__ (v) *) cp = v  */
static inline void
set_uint64 (char *cp, u64 v)
{
    memcpy (cp, &v, sizeof v);
}

/* Put result from CTX in first 64 bytes following RESBUF.
   The result must be in little endian byte order.  */
void *
sha512_read_ctx (const struct sha512_ctx *ctx, void *resbuf)
{
    int i;
    char *r = resbuf;

    for (i = 0; i < 8; i++)
	set_uint64 (r + i * sizeof ctx->state[0], SWAP (ctx->state[i]));

    return resbuf;
}

void *
sha384_read_ctx (const struct sha512_ctx *ctx, void *resbuf)
{
    int i;
    char *r = resbuf;

    for (i = 0; i < 6; i++)
	set_uint64 (r + i * sizeof ctx->state[0], SWAP (ctx->state[i]));

    return resbuf;
}

/* Process the remaining bytes in the internal buffer and the usual
   prolog according to the standard and write the result to RESBUF.  */
static void
sha512_conclude_ctx (struct sha512_ctx *ctx)
{
    /* Take yet unprocessed bytes into account.  */
    size_t bytes = ctx->buflen;
    size_t size = (bytes < 112) ? 128 / 8 : 128 * 2 / 8;

    /* Now count remaining bytes.  */
    ctx->total[0] = u64plus (ctx->total[0], u64lo (bytes));
    if (u64lt (ctx->total[0], u64lo (bytes)))
	ctx->total[1] = u64plus (ctx->total[1], u64lo (1));

    /* Put the 128-bit file length in *bits* at the end of the buffer.
       Use set_uint64 rather than a simple assignment, to avoid risk of
       unaligned access.  */
    set_uint64 ((char *) &ctx->buffer[size - 2],
		SWAP (u64or (u64shl (ctx->total[1], 3),
			     u64shr (ctx->total[0], 61))));
    set_uint64 ((char *) &ctx->buffer[size - 1],
		SWAP (u64shl (ctx->total[0], 3)));

    memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 8 - bytes);

    /* Process last bytes.  */
    sha512_process_block (ctx->buffer, size * 8, ctx);
}

void *
sha512_finish_ctx (struct sha512_ctx *ctx, void *resbuf)
{
    sha512_conclude_ctx (ctx);
    return sha512_read_ctx (ctx, resbuf);
}

void *
sha384_finish_ctx (struct sha512_ctx *ctx, void *resbuf)
{
    sha512_conclude_ctx (ctx);
    return sha384_read_ctx (ctx, resbuf);
}

/* Compute SHA512 message digest for LEN bytes beginning at BUFFER.  The
   result is always in little endian byte order, so that a byte-wise
   output yields to the wanted ASCII representation of the message
   digest.  */
void *
sha512_buffer (const char *buffer, size_t len, void *resblock)
{
    struct sha512_ctx ctx;

    /* Initialize the computation context.  */
    sha512_init_ctx (&ctx);

    /* Process whole buffer but last len % 128 bytes.  */
    sha512_process_bytes (buffer, len, &ctx);

    /* Put result in desired memory area.  */
    return sha512_finish_ctx (&ctx, resblock);
}

void *
sha384_buffer (const char *buffer, size_t len, void *resblock)
{
    struct sha512_ctx ctx;

    /* Initialize the computation context.  */
    sha384_init_ctx (&ctx);

    /* Process whole buffer but last len % 128 bytes.  */
    sha512_process_bytes (buffer, len, &ctx);

    /* Put result in desired memory area.  */
    return sha384_finish_ctx (&ctx, resblock);
}

void
sha512_process_bytes (const void *buffer, size_t len, struct sha512_ctx *ctx)
{
    /* When we already have some bits in our internal buffer concatenate
       both inputs first.  */
    if (ctx->buflen != 0)
    {
	size_t left_over = ctx->buflen;
	size_t add = 256 - left_over > len ? len : 256 - left_over;

	memcpy (&((char *) ctx->buffer)[left_over], buffer, add);
	ctx->buflen += add;

	if (ctx->buflen > 128)
	{
	    sha512_process_block (ctx->buffer, ctx->buflen & ~127, ctx);

	    ctx->buflen &= 127;
	    /* The regions in the following copy operation cannot overlap.  */
	    memcpy (ctx->buffer,
		    &((char *) ctx->buffer)[(left_over + add) & ~127],
		    ctx->buflen);
	}

	buffer = (const char *) buffer + add;
	len -= add;
    }

    /* Process available complete blocks.  */
    if (len >= 128)
    {
#if !_STRING_ARCH_unaligned
# define alignof(type) offsetof (struct { char c; type x; }, x)
# define UNALIGNED_P(p) (((size_t) p) % alignof (u64) != 0)
	if (UNALIGNED_P (buffer))
	    while (len > 128)
	    {
		sha512_process_block (memcpy (ctx->buffer, buffer, 128), 128, ctx);
		buffer = (const char *) buffer + 128;
		len -= 128;
	    }
	else
#endif
	{
	    sha512_process_block (buffer, len & ~127, ctx);
	    buffer = (const char *) buffer + (len & ~127);
	    len &= 127;
	}
    }

    /* Move remaining bytes in internal buffer.  */
    if (len > 0)
    {
	size_t left_over = ctx->buflen;

	memcpy (&((char *) ctx->buffer)[left_over], buffer, len);
	left_over += len;
	if (left_over >= 128)
	{
	    sha512_process_block (ctx->buffer, 128, ctx);
	    left_over -= 128;
	    memcpy (ctx->buffer, &ctx->buffer[16], left_over);
	}
	ctx->buflen = left_over;
    }
}

/* --- Code below is the primary difference between sha1.c and sha512.c --- */

/* SHA512 round constants */
#define K(I) sha512_round_constants[I]
static u64 const sha512_round_constants[80] = {
    u64init (0x428a2f98, 0xd728ae22), u64init (0x71374491, 0x23ef65cd),
    u64init (0xb5c0fbcf, 0xec4d3b2f), u64init (0xe9b5dba5, 0x8189dbbc),
    u64init (0x3956c25b, 0xf348b538), u64init (0x59f111f1, 0xb605d019),
    u64init (0x923f82a4, 0xaf194f9b), u64init (0xab1c5ed5, 0xda6d8118),
    u64init (0xd807aa98, 0xa3030242), u64init (0x12835b01, 0x45706fbe),
    u64init (0x243185be, 0x4ee4b28c), u64init (0x550c7dc3, 0xd5ffb4e2),
    u64init (0x72be5d74, 0xf27b896f), u64init (0x80deb1fe, 0x3b1696b1),
    u64init (0x9bdc06a7, 0x25c71235), u64init (0xc19bf174, 0xcf692694),
    u64init (0xe49b69c1, 0x9ef14ad2), u64init (0xefbe4786, 0x384f25e3),
    u64init (0x0fc19dc6, 0x8b8cd5b5), u64init (0x240ca1cc, 0x77ac9c65),
    u64init (0x2de92c6f, 0x592b0275), u64init (0x4a7484aa, 0x6ea6e483),
    u64init (0x5cb0a9dc, 0xbd41fbd4), u64init (0x76f988da, 0x831153b5),
    u64init (0x983e5152, 0xee66dfab), u64init (0xa831c66d, 0x2db43210),
    u64init (0xb00327c8, 0x98fb213f), u64init (0xbf597fc7, 0xbeef0ee4),
    u64init (0xc6e00bf3, 0x3da88fc2), u64init (0xd5a79147, 0x930aa725),
    u64init (0x06ca6351, 0xe003826f), u64init (0x14292967, 0x0a0e6e70),
    u64init (0x27b70a85, 0x46d22ffc), u64init (0x2e1b2138, 0x5c26c926),
    u64init (0x4d2c6dfc, 0x5ac42aed), u64init (0x53380d13, 0x9d95b3df),
    u64init (0x650a7354, 0x8baf63de), u64init (0x766a0abb, 0x3c77b2a8),
    u64init (0x81c2c92e, 0x47edaee6), u64init (0x92722c85, 0x1482353b),
    u64init (0xa2bfe8a1, 0x4cf10364), u64init (0xa81a664b, 0xbc423001),
    u64init (0xc24b8b70, 0xd0f89791), u64init (0xc76c51a3, 0x0654be30),
    u64init (0xd192e819, 0xd6ef5218), u64init (0xd6990624, 0x5565a910),
    u64init (0xf40e3585, 0x5771202a), u64init (0x106aa070, 0x32bbd1b8),
    u64init (0x19a4c116, 0xb8d2d0c8), u64init (0x1e376c08, 0x5141ab53),
    u64init (0x2748774c, 0xdf8eeb99), u64init (0x34b0bcb5, 0xe19b48a8),
    u64init (0x391c0cb3, 0xc5c95a63), u64init (0x4ed8aa4a, 0xe3418acb),
    u64init (0x5b9cca4f, 0x7763e373), u64init (0x682e6ff3, 0xd6b2b8a3),
    u64init (0x748f82ee, 0x5defb2fc), u64init (0x78a5636f, 0x43172f60),
    u64init (0x84c87814, 0xa1f0ab72), u64init (0x8cc70208, 0x1a6439ec),
    u64init (0x90befffa, 0x23631e28), u64init (0xa4506ceb, 0xde82bde9),
    u64init (0xbef9a3f7, 0xb2c67915), u64init (0xc67178f2, 0xe372532b),
    u64init (0xca273ece, 0xea26619c), u64init (0xd186b8c7, 0x21c0c207),
    u64init (0xeada7dd6, 0xcde0eb1e), u64init (0xf57d4f7f, 0xee6ed178),
    u64init (0x06f067aa, 0x72176fba), u64init (0x0a637dc5, 0xa2c898a6),
    u64init (0x113f9804, 0xbef90dae), u64init (0x1b710b35, 0x131c471b),
    u64init (0x28db77f5, 0x23047d84), u64init (0x32caab7b, 0x40c72493),
    u64init (0x3c9ebe0a, 0x15c9bebc), u64init (0x431d67c4, 0x9c100d4c),
    u64init (0x4cc5d4be, 0xcb3e42b6), u64init (0x597f299c, 0xfc657e2a),
    u64init (0x5fcb6fab, 0x3ad6faec), u64init (0x6c44198c, 0x4a475817),
};

/* Round functions.  */
#define F2(A, B, C) u64or (u64and (A, B), u64and (C, u64or (A, B)))
#define F1(E, F, G) u64xor (G, u64and (E, u64xor (F, G)))

/* Process LEN bytes of BUFFER, accumulating context into CTX.
   It is assumed that LEN % 128 == 0.
   Most of this code comes from GnuPG's cipher/sha1.c.  */

void
sha512_process_block (const void *buffer, size_t len, struct sha512_ctx *ctx)
{
    u64 const *words = buffer;
    u64 const *endp = words + len / sizeof (u64);
    u64 x[16];
    u64 a = ctx->state[0];
    u64 b = ctx->state[1];
    u64 c = ctx->state[2];
    u64 d = ctx->state[3];
    u64 e = ctx->state[4];
    u64 f = ctx->state[5];
    u64 g = ctx->state[6];
    u64 h = ctx->state[7];

    /* First increment the byte count.  FIPS PUB 180-2 specifies the possible
       length of the file up to 2^128 bits.  Here we only compute the
       number of bytes.  Do a double word increment.  */
    ctx->total[0] = u64plus (ctx->total[0], u64lo (len));
    if (u64lt (ctx->total[0], u64lo (len)))
	ctx->total[1] = u64plus (ctx->total[1], u64lo (1));

#define S0(x) u64xor (u64rol(x, 63), u64xor (u64rol (x, 56), u64shr (x, 7)))
#define S1(x) u64xor (u64rol (x, 45), u64xor (u64rol (x, 3), u64shr (x, 6)))
#define SS0(x) u64xor (u64rol (x, 36), u64xor (u64rol (x, 30), u64rol (x, 25)))
#define SS1(x) u64xor (u64rol(x, 50), u64xor (u64rol (x, 46), u64rol (x, 23)))

#define M(I) (x[(I) & 15]						  \
	      = u64plus (x[(I) & 15],					  \
			 u64plus (S1 (x[((I) - 2) & 15]),		  \
				  u64plus (x[((I) - 7) & 15],		  \
					   S0 (x[((I) - 15) & 15])))))

#define R(A, B, C, D, E, F, G, H, K, M)					  \
  do									  \
    {									  \
      u64 t0 = u64plus (SS0 (A), F2 (A, B, C));				  \
      u64 t1 =								  \
	u64plus (H, u64plus (SS1 (E),					  \
			     u64plus (F1 (E, F, G), u64plus (K, M))));	  \
      D = u64plus (D, t1);						  \
      H = u64plus (t0, t1);						  \
    }									  \
  while (0)

    while (words < endp)
    {
	int t;
	/* FIXME: see sha1.c for a better implementation.  */
	for (t = 0; t < 16; t++)
	{
	    x[t] = SWAP (*words);
	    words++;
	}

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

	a = ctx->state[0] = u64plus (ctx->state[0], a);
	b = ctx->state[1] = u64plus (ctx->state[1], b);
	c = ctx->state[2] = u64plus (ctx->state[2], c);
	d = ctx->state[3] = u64plus (ctx->state[3], d);
	e = ctx->state[4] = u64plus (ctx->state[4], e);
	f = ctx->state[5] = u64plus (ctx->state[5], f);
	g = ctx->state[6] = u64plus (ctx->state[6], g);
	h = ctx->state[7] = u64plus (ctx->state[7], h);
    }
}

/*****************************************************************************/