//----------------------------------------------------------------------------
//
// \file    crc32.cpp
//
// \brief   Calculates crc32 checksums
//
// \date    20160228
// \author  Maximilian Seesslen <mes@seesslen.net>
//
//----------------------------------------------------------------------------


//---Includes-----------------------------------------------------------------


#include <stdint.h>
#include <lepto/log.h>
#include <lepto/lepto.h>      // IS_ENABLED
#include <lepto/crc32.h>


//---Implementation-----------------------------------------------------------

// Runtime-Calculated CRC32 table saves around 1000Bytes in flash :/
// but needs the amount in RAM
#define STATIC_CRC32_TABLE
//#undef STATIC_CRC32_TABLE

const uint32_t *getCrc32Table();

#if defined ( STATIC_CRC32_TABLE )
// Thats one KB
static constexpr uint32_t pCrc32Table[256] = {
    0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
    0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
    0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
    0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
    0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
    0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
    0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
    0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
    0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
    0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
    0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
    0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
    0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
    0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
    0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
    0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
    0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
    0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
    0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
    0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
    0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
    0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
    0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
    0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
    0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
    0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
    0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
    0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
    0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
    0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
    0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
    0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
    0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
    0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
    0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
    0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
    0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
    0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
    0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
    0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
    0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
    0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
    0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
    0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
    0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
    0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
    0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
    0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
    0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
    0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
    0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
    0x2d02ef8dL
};

static constexpr crc32_t pCrc32MpegTable[256] = {
    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
};

#else
static const uint32_t *pCrc32Table=nullptr;
#endif

/// \brief  Calculate table with all CRC32 single-byte values
void createCrc32Table( uint32_t table[] )
{
   uint32_t c;
   int n, k;
   uint32_t poly;
   static const char p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
   
   poly = 0L;
   for (n = 0; n < (int)(sizeof(p)/sizeof(char)); n++)
      poly |= 1L << (31 - p[n]);
   
   for (n = 0; n < 256; n++)
   {
      c = (uint32_t)n;
      for (k = 0; k < 8; k++)
         c = c & 1 ? poly ^ (c >> 1) : c >> 1;
      table[n] = c;
   }
}

const uint32_t *getCrc32Table()
{
#if defined (STATIC_CRC32_TABLE)
   return (const uint32_t *)pCrc32Table;
#else
   if (!pCrc32Table)
   {
      uint32_t *crc32Table;
      crc32Table=new uint32_t[0x100];
      createCrc32Table(crc32Table);
      lAssert( crc32Table != 0 );
      
      pCrc32Table=crc32Table;
   };
   return (const uint32_t *)pCrc32Table;
#endif
}

const uint32_t *getCrc32MpegTable()
{
   return (const uint32_t *)pCrc32MpegTable;
}

uint32_t crc32DefaultInit()
{
   return 0xFFFFFFFF;
}

uint32_t crc32MpegInit()
{
   return 0xFFFFFFFF;
}

uint32_t crc32DefaultFinalize(uint32_t crc)
{
   // XOR / Invert
   return crc ^ 0xFFFFFFFF;
}

uint32_t crc32MpegFinalize(uint32_t crc)
{
   return crc;
}

uint32_t crc32DefaultUpdate( uint32_t crc, const void *_buf, uint32_t len )
{
   const char *buf=(const char *)_buf;
   if (buf == 0) return 0L;
   
   const uint32_t *crc32Table=getCrc32Table();
   
   while ( len )
   {
      crc = crc32Table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
      len--;
   };
   
   return (crc);
}

uint32_t crc32MpegUpdate( uint32_t crc, const void *_buf, uint32_t len )
{
   const char *buf=(const char *)_buf;
   if (buf == 0) return 0L;
   
   const uint32_t *crc32Table=getCrc32MpegTable();
   
   while ( len )
   {
      crc = crc32Table[(( (int)crc >> 24 ) ^ (*buf++)) & 0xff] ^ (crc << 8);
      len--;
   };
   
   return (crc);
}

/*
crc_t crc_update(crc_t crc, const void *data, size_t data_len)
{
    const unsigned char *d = (const unsigned char *)data;
    unsigned int tbl_idx;

    while (data_len--) {
        tbl_idx = ((crc >> 24) ^ *d) & 0xff;
        crc = (crc_table[tbl_idx] ^ (crc << 8)) & 0xffffffff;
        d++;
    }
    return crc & 0xffffffff;
}
*/


crc32_t calcCrc32Default( const void *buf, uint32_t len )
{
   uint32_t crc;
   crc = crc32DefaultInit();
   crc = crc32DefaultUpdate( crc, buf, len);
   return( crc32DefaultFinalize(crc) );
}

crc32_t calcCrc32Mpeg( const void *buf, uint32_t len )
{
   uint32_t crc;
   crc = crc32MpegInit();
   crc = crc32MpegUpdate( crc, buf, len);
   return( crc32MpegFinalize(crc) );
}


//#if defined ( LEPTO_CRC32_MPEG )
//#endif // ? ( LEPTO_CRC32_MPEG )

#if IS_ENABLED( CONFIG_LEPTO_CONFIGURABLE_CRC32 )

crc32_t (*calcCrc32)( const void *buf, uint32_t len ) = calcCrc32Default;
crc32_t (*crc32Init)() = crc32DefaultInit;
crc32_t (*crc32Update)( uint32_t crc, const void *_buf, uint32_t len ) = crc32DefaultUpdate;
crc32_t (*crc32Finalize)(uint32_t crc) = crc32DefaultFinalize;

void configCrc32( ECrc32Mode mode)
{
   switch(mode)
   {
      case(Mpeg):
         calcCrc32  = calcCrc32Mpeg;
         crc32Init = crc32MpegInit;
         crc32Update = crc32MpegUpdate;
         crc32Finalize = crc32MpegFinalize;
         break;
      case(Default):
         calcCrc32  = calcCrc32Default;
         crc32Init = crc32DefaultInit;
         crc32Update = crc32DefaultUpdate;
         crc32Finalize = crc32DefaultFinalize;
         break;
      default:
         lFatal("Unknown CRC");
         break;
   }

}
#elif 1

crc32_t calcCrc32( const void *buf, uint32_t len ) __attribute__((alias("calcCrc32Default")));
crc32_t crc32Init() __attribute__((alias("crc32DefaultInit")));
crc32_t crc32Update( uint32_t crc, const void *_buf, uint32_t len )__attribute__((alias("crc32DefaultUpdate")));
crc32_t crc32Finalize(uint32_t crc)__attribute__((alias("crc32DefaultFinalize")));

#else

crc32_t calcCrc32( const void *buf, uint32_t len ) __attribute__((alias("calcCrc32Mpeg")));
crc32_t crc32Init() __attribute__((alias("crc32MpegInit")));
crc32_t crc32Update( uint32_t crc, const void *_buf, uint32_t len )__attribute__((alias("crc32MpegUpdate")));
crc32_t crc32Finalize(uint32_t crc)__attribute__((alias("crc32MpegFinalize")));

#endif

//----------------------------------------------------------------------------
