/* (PD) 2001 The Bitzi Corporation
 * Please see file COPYING or http://bitzi.com/publicdomain 
 * for more info.
 *
 * NIST Secure Hash Algorithm 
 * heavily modified by Uwe Hollerbach <uh@alumni.caltech edu> 
 * from Peter C. Gutmann's implementation as found in 
 * Applied Cryptography by Bruce Schneier 
 * Further modifications to include the "UNRAVEL" stuff, below 
 *
 * This code is in the public domain 
 *
 * $Id: sha1.c,v 1.2 2008-02-27 10:42:08 slomo Exp $
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <glib.h>
#define SHA_BYTE_ORDER G_BYTE_ORDER

#include <string.h>
#include "sha1.h"

/* UNRAVEL should be fastest & biggest */
/* UNROLL_LOOPS should be just as big, but slightly slower */
/* both undefined should be smallest and slowest */

#define UNRAVEL
/* #define UNROLL_LOOPS */

/* SHA f()-functions */

#define f1(x,y,z)	((x & y) | (~x & z))
#define f2(x,y,z)	(x ^ y ^ z)
#define f3(x,y,z)	((x & y) | (x & z) | (y & z))
#define f4(x,y,z)	(x ^ y ^ z)

/* SHA constants */

#define CONST1		0x5a827999L
#define CONST2		0x6ed9eba1L
#define CONST3		0x8f1bbcdcL
#define CONST4		0xca62c1d6L

/* truncate to 32 bits -- should be a null op on 32-bit machines */

#define T32(x)	((x) & 0xffffffffL)

/* 32-bit rotate */

#define R32(x,n)	T32(((x << n) | (x >> (32 - n))))

/* the generic case, for when the overall rotation is not unraveled */

#define FG(n)	\
    T = T32(R32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n);	\
    E = D; D = C; C = R32(B,30); B = A; A = T

/* specific cases, for when the overall rotation is unraveled */

#define FA(n)	\
    T = T32(R32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n); B = R32(B,30)

#define FB(n)	\
    E = T32(R32(T,5) + f##n(A,B,C) + D + *WP++ + CONST##n); A = R32(A,30)

#define FC(n)	\
    D = T32(R32(E,5) + f##n(T,A,B) + C + *WP++ + CONST##n); T = R32(T,30)

#define FD(n)	\
    C = T32(R32(D,5) + f##n(E,T,A) + B + *WP++ + CONST##n); E = R32(E,30)

#define FE(n)	\
    B = T32(R32(C,5) + f##n(D,E,T) + A + *WP++ + CONST##n); D = R32(D,30)

#define FT(n)	\
    A = T32(R32(B,5) + f##n(C,D,E) + T + *WP++ + CONST##n); C = R32(C,30)

/* do SHA transformation */

static void
sha_transform (SHA_INFO * sha_info)
{
  int i;
  SHA_BYTE *dp;
  SHA_LONG T, A, B, C, D, E, W[80], *WP;

  dp = sha_info->data;

/*
the following makes sure that at least one code block below is
traversed or an error is reported, without the necessity for nested
preprocessor if/else/endif blocks, which are a great pain in the
nether regions of the anatomy...
*/
#undef SWAP_DONE

#if (SHA_BYTE_ORDER == 1234)
#define SWAP_DONE
  for (i = 0; i < 16; ++i) {
    memcpy (&T, dp, sizeof (SHA_LONG));
    dp += 4;
    W[i] = ((T << 24) & 0xff000000) | ((T << 8) & 0x00ff0000) |
        ((T >> 8) & 0x0000ff00) | ((T >> 24) & 0x000000ff);
  }
#endif /* SHA_BYTE_ORDER == 1234 */

#if (SHA_BYTE_ORDER == 4321)
#define SWAP_DONE
  for (i = 0; i < 16; ++i) {
    memcpy (&T, dp, sizeof (SHA_LONG));
    dp += 4;
    W[i] = T32 (T);
  }
#endif /* SHA_BYTE_ORDER == 4321 */

#if (SHA_BYTE_ORDER == 12345678)
#define SWAP_DONE
  for (i = 0; i < 16; i += 2) {
    memcpy (&T, dp, sizeof (SHA_LONG));
    dp += 8;
    W[i] = ((T << 24) & 0xff000000) | ((T << 8) & 0x00ff0000) |
        ((T >> 8) & 0x0000ff00) | ((T >> 24) & 0x000000ff);
    T >>= 32;
    W[i + 1] = ((T << 24) & 0xff000000) | ((T << 8) & 0x00ff0000) |
        ((T >> 8) & 0x0000ff00) | ((T >> 24) & 0x000000ff);
  }
#endif /* SHA_BYTE_ORDER == 12345678 */

#if (SHA_BYTE_ORDER == 87654321)
#define SWAP_DONE
  for (i = 0; i < 16; i += 2) {
    memcpy (&T, dp, sizeof (SHA_LONG));
    dp += 8;
    W[i] = T32 (T >> 32);
    W[i + 1] = T32 (T);
  }
#endif /* SHA_BYTE_ORDER == 87654321 */

#ifndef SWAP_DONE
#error Unknown byte order -- you need to add code here
#endif /* SWAP_DONE */

  for (i = 16; i < 80; ++i) {
    W[i] = W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16];
#if (SHA_VERSION == 1)
    W[i] = R32 (W[i], 1);
#endif /* SHA_VERSION */
  }
  A = sha_info->digest[0];
  B = sha_info->digest[1];
  C = sha_info->digest[2];
  D = sha_info->digest[3];
  E = sha_info->digest[4];
  WP = W;
#ifdef UNRAVEL
  FA (1);
  FB (1);
  FC (1);
  FD (1);
  FE (1);
  FT (1);
  FA (1);
  FB (1);
  FC (1);
  FD (1);
  FE (1);
  FT (1);
  FA (1);
  FB (1);
  FC (1);
  FD (1);
  FE (1);
  FT (1);
  FA (1);
  FB (1);
  FC (2);
  FD (2);
  FE (2);
  FT (2);
  FA (2);
  FB (2);
  FC (2);
  FD (2);
  FE (2);
  FT (2);
  FA (2);
  FB (2);
  FC (2);
  FD (2);
  FE (2);
  FT (2);
  FA (2);
  FB (2);
  FC (2);
  FD (2);
  FE (3);
  FT (3);
  FA (3);
  FB (3);
  FC (3);
  FD (3);
  FE (3);
  FT (3);
  FA (3);
  FB (3);
  FC (3);
  FD (3);
  FE (3);
  FT (3);
  FA (3);
  FB (3);
  FC (3);
  FD (3);
  FE (3);
  FT (3);
  FA (4);
  FB (4);
  FC (4);
  FD (4);
  FE (4);
  FT (4);
  FA (4);
  FB (4);
  FC (4);
  FD (4);
  FE (4);
  FT (4);
  FA (4);
  FB (4);
  FC (4);
  FD (4);
  FE (4);
  FT (4);
  FA (4);
  FB (4);
  sha_info->digest[0] = T32 (sha_info->digest[0] + E);
  sha_info->digest[1] = T32 (sha_info->digest[1] + T);
  sha_info->digest[2] = T32 (sha_info->digest[2] + A);
  sha_info->digest[3] = T32 (sha_info->digest[3] + B);
  sha_info->digest[4] = T32 (sha_info->digest[4] + C);
#else /* !UNRAVEL */
#ifdef UNROLL_LOOPS
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (1);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (2);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (3);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
  FG (4);
#else /* !UNROLL_LOOPS */
  for (i = 0; i < 20; ++i) {
    FG (1);
  }
  for (i = 20; i < 40; ++i) {
    FG (2);
  }
  for (i = 40; i < 60; ++i) {
    FG (3);
  }
  for (i = 60; i < 80; ++i) {
    FG (4);
  }
#endif /* !UNROLL_LOOPS */
  sha_info->digest[0] = T32 (sha_info->digest[0] + A);
  sha_info->digest[1] = T32 (sha_info->digest[1] + B);
  sha_info->digest[2] = T32 (sha_info->digest[2] + C);
  sha_info->digest[3] = T32 (sha_info->digest[3] + D);
  sha_info->digest[4] = T32 (sha_info->digest[4] + E);
#endif /* !UNRAVEL */
}

/* initialize the SHA digest */

void
sha_init (SHA_INFO * sha_info)
{
  sha_info->digest[0] = 0x67452301L;
  sha_info->digest[1] = 0xefcdab89L;
  sha_info->digest[2] = 0x98badcfeL;
  sha_info->digest[3] = 0x10325476L;
  sha_info->digest[4] = 0xc3d2e1f0L;
  sha_info->count_lo = 0L;
  sha_info->count_hi = 0L;
  sha_info->local = 0;
}

/* update the SHA digest */

void
sha_update (SHA_INFO * sha_info, SHA_BYTE * buffer, int count)
{
  int i;
  SHA_LONG clo;

  clo = T32 (sha_info->count_lo + ((SHA_LONG) count << 3));
  if (clo < sha_info->count_lo) {
    ++sha_info->count_hi;
  }
  sha_info->count_lo = clo;
  sha_info->count_hi += (SHA_LONG) count >> 29;
  if (sha_info->local) {
    i = SHA_BLOCKSIZE - sha_info->local;
    if (i > count) {
      i = count;
    }
    memcpy (((SHA_BYTE *) sha_info->data) + sha_info->local, buffer, i);
    count -= i;
    buffer += i;
    sha_info->local += i;
    if (sha_info->local == SHA_BLOCKSIZE) {
      sha_transform (sha_info);
    } else {
      return;
    }
  }
  while (count >= SHA_BLOCKSIZE) {
    memcpy (sha_info->data, buffer, SHA_BLOCKSIZE);
    buffer += SHA_BLOCKSIZE;
    count -= SHA_BLOCKSIZE;
    sha_transform (sha_info);
  }
  memcpy (sha_info->data, buffer, count);
  sha_info->local = count;
}

/* finish computing the SHA digest */

void
sha_final (unsigned char digest[20], SHA_INFO * sha_info)
{
  int count;
  SHA_LONG lo_bit_count, hi_bit_count;

  lo_bit_count = sha_info->count_lo;
  hi_bit_count = sha_info->count_hi;
  count = (int) ((lo_bit_count >> 3) & 0x3f);
  ((SHA_BYTE *) sha_info->data)[count++] = 0x80;
  if (count > SHA_BLOCKSIZE - 8) {
    memset (((SHA_BYTE *) sha_info->data) + count, 0, SHA_BLOCKSIZE - count);
    sha_transform (sha_info);
    memset ((SHA_BYTE *) sha_info->data, 0, SHA_BLOCKSIZE - 8);
  } else {
    memset (((SHA_BYTE *) sha_info->data) + count, 0,
        SHA_BLOCKSIZE - 8 - count);
  }
  sha_info->data[56] = (unsigned char) ((hi_bit_count >> 24) & 0xff);
  sha_info->data[57] = (unsigned char) ((hi_bit_count >> 16) & 0xff);
  sha_info->data[58] = (unsigned char) ((hi_bit_count >> 8) & 0xff);
  sha_info->data[59] = (unsigned char) ((hi_bit_count >> 0) & 0xff);
  sha_info->data[60] = (unsigned char) ((lo_bit_count >> 24) & 0xff);
  sha_info->data[61] = (unsigned char) ((lo_bit_count >> 16) & 0xff);
  sha_info->data[62] = (unsigned char) ((lo_bit_count >> 8) & 0xff);
  sha_info->data[63] = (unsigned char) ((lo_bit_count >> 0) & 0xff);
  sha_transform (sha_info);
  digest[0] = (unsigned char) ((sha_info->digest[0] >> 24) & 0xff);
  digest[1] = (unsigned char) ((sha_info->digest[0] >> 16) & 0xff);
  digest[2] = (unsigned char) ((sha_info->digest[0] >> 8) & 0xff);
  digest[3] = (unsigned char) ((sha_info->digest[0]) & 0xff);
  digest[4] = (unsigned char) ((sha_info->digest[1] >> 24) & 0xff);
  digest[5] = (unsigned char) ((sha_info->digest[1] >> 16) & 0xff);
  digest[6] = (unsigned char) ((sha_info->digest[1] >> 8) & 0xff);
  digest[7] = (unsigned char) ((sha_info->digest[1]) & 0xff);
  digest[8] = (unsigned char) ((sha_info->digest[2] >> 24) & 0xff);
  digest[9] = (unsigned char) ((sha_info->digest[2] >> 16) & 0xff);
  digest[10] = (unsigned char) ((sha_info->digest[2] >> 8) & 0xff);
  digest[11] = (unsigned char) ((sha_info->digest[2]) & 0xff);
  digest[12] = (unsigned char) ((sha_info->digest[3] >> 24) & 0xff);
  digest[13] = (unsigned char) ((sha_info->digest[3] >> 16) & 0xff);
  digest[14] = (unsigned char) ((sha_info->digest[3] >> 8) & 0xff);
  digest[15] = (unsigned char) ((sha_info->digest[3]) & 0xff);
  digest[16] = (unsigned char) ((sha_info->digest[4] >> 24) & 0xff);
  digest[17] = (unsigned char) ((sha_info->digest[4] >> 16) & 0xff);
  digest[18] = (unsigned char) ((sha_info->digest[4] >> 8) & 0xff);
  digest[19] = (unsigned char) ((sha_info->digest[4]) & 0xff);
}
