/* FILE: crctst.c */

#include <stdio.h>
#include <stdlib.h>
#include "crc.h"
#include "crctst.h"

//#define CRC8
//#define CRC10
//#define X25
//#define CRC16
//#define XMODEM
//#define AUTODINII
//#define MILSTD188

/* local prototypes */
void crcInit( void );
void displayTbl( unsigned char *tbl );
CRC_TYPE crcUpdate( unsigned char c );
CRC_TYPE crcRead( void );



#ifdef CRC8
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0xa0 };
unsigned char str0[] = { 0x03, 0x73, 0x61, 0x00 };
unsigned char str1[] = { 0x01, 0x3f, 0xa8, 0x00 };
#endif

#ifdef CRC10
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0x01, 0x1f };
#ifdef CRC10x
unsigned char str0[] = { 
         0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x00, 0x00, 
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };  /* CRC10 = 0x01f6 */ 
#else
unsigned char str0[] = { 0x03, 0x73, 0x01, 0x2d };
#endif
unsigned char str1[] = { 0x01, 0x3f, 0x00, 0x45 };
#endif

#ifdef XMODEM
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0x1e, 0x0a };
unsigned char str0[] = { 0x03, 0x73, 0x1b, 0xa7 };
unsigned char str1[] = { 0x01, 0x3f, 0xf4, 0x8d };
#endif

#ifdef X25
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0x41, 0xbb };
unsigned char str0[] = { 0x03, 0x73, 0x33, 0x64 }; // X.25 std test case
unsigned char str1[] = { 0x01, 0x3f, 0xeb, 0xdf }; // X.25 std test case
#endif

#ifdef CRC16
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0xb6, 0x23 };
unsigned char str0[] = { 0x03, 0x73, 0x41, 0x15 };
unsigned char str1[] = { 0x01, 0x3f, 0x80, 0x41 };
#endif

#ifdef MILSTD188
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0x65, 0x98, 0x9b };
unsigned char str0[] = { 0x03, 0x73, 0x7e, 0xa5, 0x8a };
unsigned char str1[] = { 0x01, 0x3f, 0x1a, 0x7d, 0xca };
#endif

#ifdef AUTODINII
unsigned char str[LEN] = { 0x54, 0x48, 0x45, 0x93, 0xd0, 0x1d, 0x55 };
unsigned char str0[] = { 0x03, 0x73, 0xa3, 0xf8, 0x86, 0xba };
unsigned char str1[] = { 0x01, 0x3f, 0xee, 0xa4, 0x0e, 0x83 };
#endif

                         //                                   |     X.25
                         // CRC16  XMODEM AUTODINII  MIL188   |residual   CRC
char *str2 = "CatMouse987654321";             
                         // 0x38a6 0xe556 0x084bff58 0x9261ec |0xf56e =>0x910a
char *str3 = "THE,QUICK,BROWN,FOX,0123456789";
                         // 0xb96e 0x0498 0x0c0e7bd9 0xbcbe4f |0xdf91 =>0x6e20
char *str4 = "123456789";                     
                         // 0xbb3d 0x31c3 0xcbf43926 0x9aac54 |0x6f91 =>0x6e90


static int tblInitialized = 0;
static CRC_TYPE crcReg;
static CRC_TYPE crcTbl[ 256 ];


int main( void )
{
int i, j;
CRC_TYPE tmp;

   printf( "Compiled to support %s CRC\n", CRC_ID );
   printf( "CRC initialized to 0x" CRC_PRN "\n", CRC_INIT );
   printf( "CRC polynomial is  0x" CRC_PRN "\n", POLY );


   crcInit();
   for( i=0; i<LEN; i++ ){
      tmp = crcUpdate( str[i] );
      printf( "str[%d]=%2.2x CRC=0x" CRC_PRN " residual=0x" CRC_PRN "\n", 
         i, (unsigned char)str[i], crcRead(), tmp );
   }

#ifdef CRC10
#ifdef CRC10x
   j = 46;
#else
   j = 4;
#endif
#else
   j = 2;
#endif
   crcInit();
   for( i=0; i<j; i++ ){
      crcUpdate( str0[i] );
   }
   printf( "crc for str0 0x%2.2x 0x%2.2x 0x%2.2x 0x%2.2x =0x" CRC_PRN "\n", 
            str0[0], str0[1], str0[2], str0[3], crcRead() );

   j = 2;
   crcInit();
   for( i=0; i<j; i++ ){
      crcUpdate( str1[i] );
   }
   printf( "crc for str1 0x%2.2x 0x%2.2x=0x" CRC_PRN "\n", 
            str1[0], str1[1], crcRead() );

   j = strlen( str2 );
   crcInit();
   for( i=0; i<j; i++ ){
      crcUpdate( str2[i] );
   }
   printf( "str2=\"%s\"\n", str2 );
   printf( "crc for str2=0x" CRC_PRN "\n", crcRead() );

   crcReg = crc( str3, strlen( str3 ) );
   printf( "str3=\"%s\"\n", str3 );
   printf( "crc for str3=0x" CRC_PRN "\n", crcReg );

   crcReg = crc( str4, strlen( str4 ) );
   printf( "str4=\"%s\"\n", str4 );
   printf( "crc for str4=0x" CRC_PRN "\n", crcReg );

//   displayTbl( &crcTbl[0] );

return( 0 );
}



CRC_TYPE crcRead( void )
{

   #ifdef CRC10
CRC_TYPE tmp = crcReg;
int len;
   for( len=2; len--; ){
      tmp = (CRC_TYPE)(((tmp << 8) & 0x3ff) ^
             crcTbl[ ((tmp >> 2) & 0x00ff) ] );
   }
   return( tmp );
   #endif

   #ifdef X25
   /* X.25 swaps bytes (lo byte then hi byte) and complements bits */
   return( ~(((crcReg & 0xff) << 8) | (crcReg >> 8)) );
   #endif
   #if defined AUTODINII
   return( ~crcReg );
   #endif
   #if defined XMODEM || CRC16 || MILSTD188 || CRC8
   return( crcReg );
   #endif

}


CRC_TYPE crcUpdate( unsigned char c )
{
   #if defined CRC8
   crcReg = crcTbl[ crcReg ^ c ];
   #endif
   #if defined CRC10
   crcReg = (CRC_TYPE)(((crcReg << 8) & 0x3ff) ^  
                             crcTbl[ ((crcReg >> 2) & 0x00ff) ] ^ c );
   #endif
   #if defined XMODEM
   crcReg = (CRC_TYPE)((crcReg << 8) ^  
                             crcTbl[ ((crcReg >> 8) & 0x00ff) ^ c ]);
   #endif
   #if defined X25 || CRC16 || MILSTD188 || AUTODINII
   crcReg = (CRC_TYPE)((crcReg >> 8) ^ crcTbl[ (crcReg ^ c) & 0x00ff ]);
   #endif

   return( crcReg );
}


void crcInit( void )
{
unsigned long int i, j, k;

   if( !tblInitialized ){
      #if defined CRC8
      for( j=0; j < 256; j++ ){
         k = j;
         for( i=0; i < 8; i++ ){
            k = k & 0x80? (k << 1) ^ POLY : k << 1;
         }
         crcTbl[ j ] = (CRC_TYPE)k;
      }
      #endif
      #if defined CRC10
      for( j=0; j < 256; j++ ){
         k = j << 2;
         for( i=0; i < 8; i++ ){
            if( (k <<= 1) & 0x0400 ){
               k ^= POLY;
            }
         }
         crcTbl[ j ] = (CRC_TYPE)k;
      }
      #endif
      #ifdef XMODEM
      for( j=0; j < 256; j++ ){
         k = j << 8;
         for( i=0; i < 8; i++ ){
            k = k & 0x8000? (k << 1) ^ POLY : k << 1;
         }
         crcTbl[ j ] = (CRC_TYPE)k;
      }
      #endif
      #if defined X25 || CRC16 || MILSTD188 || AUTODINII
      for( i=0; i < 256; i++ ){
         j = i;
         for( k=8; k--; ){
            j = j & 1? (j >> 1) ^ POLY : j >> 1;
         }
         crcTbl[ i ] = (CRC_TYPE)j;
      }
      #endif
      tblInitialized = 1;
   }
   crcReg = CRC_INIT;
}


void displayTbl( unsigned char *tbl )
{
int i, j;

   for( i=j=0; i < 256; i++ ){
      printf( CRC_PRN " ", (CRC_TYPE)tbl[ i ] );
      if( ++j > 7 ){
         j = 0;
         printf( "\n" );
      }
   }
   printf( "\n" );
}