#include <stdlib.h>
/*
#include "crypto_auth.h"
#include "crypto_uint64.h"
#include "crypto_uint32.h"
#include "crypto_uint8.h"

typedef crypto_uint64 u64;
typedef crypto_uint32 u32;
typedef crypto_uint8 u8;
*/

#include <stdio.h>
#include <stdint.h>

#define SIPHASH_ROUNDS 2
#define SIPHASH_FINALROUNDS 4

typedef  uint8_t  u8;
typedef uint32_t u32;
typedef uint64_t u64;

#define rotl64(x, c) ( ((x) << (c)) ^ ((x) >> (64-(c))) )

static u64 siphash(const u8 key[16], const unsigned char *m, const u64 n)
{
    u64 v0, v1, v2, v3;
    u64 k0, k1;
    u64 mi, mask, len;
    size_t i, k;

    k0 = *((u64*)(key + 0));
    k1 = *((u64*)(key + 8));

    v0 = k0 ^ 0x736f6d6570736575ULL;
    v1 = k1 ^ 0x646f72616e646f6dULL;
    v2 = k0 ^ 0x6c7967656e657261ULL;
    v3 = k1 ^ 0x7465646279746573ULL;

#define HALF_ROUND(a,b,c,d,s,t) \
    do \
    { \
        a += b;  c += d; \
        b = rotl64(b, s); d = rotl64(d, t); \
        b ^= a;  d ^= c; \
    } while(0)

#define COMPRESS(v0,v1,v2,v3) \
    do \
    { \
        HALF_ROUND(v0,v1,v2,v3,13,16); \
        v0 = rotl64(v0,32); \
        HALF_ROUND(v2,v1,v0,v3,17,21); \
        v2 = rotl64(v2, 32); \
    } while(0)

    for(i = 0; i < (n-n%8); i += 8)
    {
        mi = *((u64*)(m + i));
        v3 ^= mi;
        for(k = 0; k < SIPHASH_ROUNDS; ++k) COMPRESS(v0,v1,v2,v3);
        v0 ^= mi;
    }


    //mi = *((u64*)(m + i));
    //len = (n&0xff) << 56;
    //mask = n%8 == 0 ? 0 : 0xffffffffffffffffULL >> (8*(8-n%8));
    //mi = (mi&mask) ^ len;
        u8 *p = m + i;
        mi = (n&0xff) << 56;
    switch(n%8)
        {
        case 7: mi |= ( ( u64 )p[ 6] )  << 48;
        case 6: mi |= ( ( u64 )p[ 5] )  << 40;
        case 5: mi |= ( ( u64 )p[ 4] )  << 32;
        case 4: mi |= ( ( u64 )p[ 3] )  << 24;
        case 3: mi |= ( ( u64 )p[ 2] )  << 16;
        case 2: mi |= ( ( u64 )p[ 1] )  <<  8;
        case 1: mi |= ( ( u64 )p[ 0] ); break;
        case 0: break;
        }

    v3 ^= mi;
    for(k = 0; k < SIPHASH_ROUNDS; ++k) COMPRESS(v0,v1,v2,v3);
    v0 ^= mi;

    v2 ^= 0xff;
    for(k = 0; k < SIPHASH_FINALROUNDS; ++k) COMPRESS(v0,v1,v2,v3);

#undef COMPRESS
#undef HALF_ROUND
    return (v0 ^ v1) ^ (v2 ^ v3);
}

int crypto_auth(unsigned char *out,const unsigned char *in,unsigned long long inlen,const unsigned char *k)
{
  int i;
  union
  {
    u8  bytes[8];
    u64 gpr;
  } hash;
  hash.gpr = siphash(k, in, inlen);
  for(i=0; i < 8; ++i) out[i] = hash.bytes[i];
  return 0;
}


static int crypto_verify_8(const unsigned char *x,const unsigned char *y)
{
  unsigned int differentbits = 0;
#define F(i) differentbits |= x[i] ^ y[i];
  F(0)
  F(1)
  F(2)
  F(3)
  F(4)
  F(5)
  F(6)
  F(7)
  return (1 & ((differentbits - 1) >> 8)) - 1;
}


int crypto_auth_verify(const unsigned char *h,const unsigned char *in,unsigned long long inlen,const unsigned char *k)
{
  u8 correct[8];
  crypto_auth(correct,in,inlen,k);
  return crypto_verify_8(h,correct);
}

/*
   SipHash-2-4 output with
   k = 00 01 02 ...
   and
   in = (empty string)
   in = 00 (1 byte)
   in = 00 01 (2 bytes)
   in = 00 01 02 (3 bytes)
   ...
   in = 00 01 02 ... 3e (63 bytes)
*/
u8 vectors[64][8] =
{
  { 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72, },
  { 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74, },
  { 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d, },
  { 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85, },
  { 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf, },
  { 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18, },
  { 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb, },
  { 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab, },
  { 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93, },
  { 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e, },
  { 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a, },
  { 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4, },
  { 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75, },
  { 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14, },
  { 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7, },
  { 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1, },
  { 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f, },
  { 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69, },
  { 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b, },
  { 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb, },
  { 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe, },
  { 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0, },
  { 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93, },
  { 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8, },
  { 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8, },
  { 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc, },
  { 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17, },
  { 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f, },
  { 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde, },
  { 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6, },
  { 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad, },
  { 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32, },
  { 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71, },
  { 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7, },
  { 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12, },
  { 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15, },
  { 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31, },
  { 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02, },
  { 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca, },
  { 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a, },
  { 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e, },
  { 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad, },
  { 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18, },
  { 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4, },
  { 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9, },
  { 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9, },
  { 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb, },
  { 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0, },
  { 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6, },
  { 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7, },
  { 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee, },
  { 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1, },
  { 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a, },
  { 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81, },
  { 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f, },
  { 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24, },
  { 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7, },
  { 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea, },
  { 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60, },
  { 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66, },
  { 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c, },
  { 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f, },
  { 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5, },
  { 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95, }
};


int test_vectors()
{
#define MAXLEN 64
  u8 in[MAXLEN], out[8], k[16];
  int i;
  int ok = 1;

  for( i = 0; i < 16; ++i ) k[i] = i;

  for( i = 0; i < MAXLEN; ++i )
  {
    in[i] = i;
    crypto_auth( out, in, i, k );

    if ( memcmp( out, vectors[i], 8 ) )
    {
      printf( "test vector failed for %d bytes\n", i );
      ok = 0;
    }
  }

  return ok;
}

int main()
{
  u64 hash;
  u8 k[16];
  u8 in2[16];
  int i;
  char *in;

  for( i = 0; i < 16; ++i ) k[i] = i;
  in = malloc(16);
  for( i = 0; i < 16; ++i ) in[i] = i;
  for( i = 0; i < 16; ++i ) in2[i] = i;
  hash = siphash(k, in, 16);
  free(in);
  printf("%llu\n", hash);
  hash = siphash(k, in2, 16);
  printf("%llu\n", hash);

  if ( test_vectors() ) printf( "test vectors ok\n" );

  return 0;
}