We update ECC in blocks by applying every data block to all ECC blocks. This function applies one data block to one ECC block.
| 259 | // We update ECC in blocks by applying every data block to all ECC blocks. |
| 260 | // This function applies one data block to one ECC block. |
| 261 | void RSCoder16::UpdateECC(uint DataNum, uint ECCNum, const byte *Data, byte *ECC, size_t BlockSize) |
| 262 | { |
| 263 | if (DataNum==0) // Init ECC data. |
| 264 | memset(ECC, 0, BlockSize); |
| 265 | |
| 266 | bool DirectAccess; |
| 267 | #ifdef LITTLE_ENDIAN |
| 268 | // We can access data and ECC directly if we have little endian 16 bit uint. |
| 269 | DirectAccess=sizeof(ushort)==2; |
| 270 | #else |
| 271 | DirectAccess=false; |
| 272 | #endif |
| 273 | |
| 274 | #ifdef USE_SSE |
| 275 | if (DirectAccess && SSE_UpdateECC(DataNum,ECCNum,Data,ECC,BlockSize)) |
| 276 | return; |
| 277 | #endif |
| 278 | |
| 279 | if (ECCNum==0) |
| 280 | { |
| 281 | if (DataLogSize!=BlockSize) |
| 282 | { |
| 283 | delete[] DataLog; |
| 284 | DataLog=new uint[BlockSize]; |
| 285 | DataLogSize=BlockSize; |
| 286 | |
| 287 | } |
| 288 | if (DirectAccess) |
| 289 | for (size_t I=0; I<BlockSize; I+=2) |
| 290 | DataLog[I] = gfLog[ *(ushort*)(Data+I) ]; |
| 291 | else |
| 292 | for (size_t I=0; I<BlockSize; I+=2) |
| 293 | { |
| 294 | uint D=Data[I]+Data[I+1]*256; |
| 295 | DataLog[I] = gfLog[ D ]; |
| 296 | } |
| 297 | } |
| 298 | |
| 299 | uint ML = gfLog[ MX[ECCNum * ND + DataNum] ]; |
| 300 | |
| 301 | if (DirectAccess) |
| 302 | for (size_t I=0; I<BlockSize; I+=2) |
| 303 | *(ushort*)(ECC+I) ^= gfExp[ ML + DataLog[I] ]; |
| 304 | else |
| 305 | for (size_t I=0; I<BlockSize; I+=2) |
| 306 | { |
| 307 | uint R=gfExp[ ML + DataLog[I] ]; |
| 308 | ECC[I]^=byte(R); |
| 309 | ECC[I+1]^=byte(R/256); |
| 310 | } |
| 311 | } |
| 312 | |
| 313 | |
| 314 | #ifdef USE_SSE |