Method CopyString

Unrar4iOS/unrar/unpack.cpp:81–124

_forceinline void Unpack::CopyString(uint Length,uint Distance)
{
  uint SrcPtr=UnpPtr-Distance;
  if (SrcPtr<MAXWINSIZE-MAX_LZ_MATCH && UnpPtr<MAXWINSIZE-MAX_LZ_MATCH)
  {
    // If we are not close to end of window, we do not need to waste time
    // to "& MAXWINMASK" pointer protection.

    byte *Src=Window+SrcPtr;
    byte *Dest=Window+UnpPtr;
    UnpPtr+=Length;

    while (Length>=8)
    {
      // Unroll the loop for 8 byte and longer strings.
      Dest[0]=Src[0];
      Dest[1]=Src[1];
      Dest[2]=Src[2];
      Dest[3]=Src[3];
      Dest[4]=Src[4];
      Dest[5]=Src[5];
      Dest[6]=Src[6];
      Dest[7]=Src[7];
      Src+=8;
      Dest+=8;
      Length-=8;
    }

    // Unroll the loop for 0 - 7 bytes left. Note that we use nested "if"s.
    if (Length>0) { Dest[0]=Src[0];
    if (Length>1) { Dest[1]=Src[1];
    if (Length>2) { Dest[2]=Src[2];
    if (Length>3) { Dest[3]=Src[3];
    if (Length>4) { Dest[4]=Src[4];
    if (Length>5) { Dest[5]=Src[5];
    if (Length>6) { Dest[6]=Src[6]; } } } } } } } // Close all nested "if"s.
  }
  else
    while (Length--) // Slow copying with all possible precautions.
    {
      Window[UnpPtr]=Window[SrcPtr++ & MAXWINMASK];
      UnpPtr=(UnpPtr+1) & MAXWINMASK;
    }
}


_forceinline uint Unpack::DecodeNumber(DecodeTable *Dec)