static BOOL nsc_rle_decode(const BYTE* in, size_t inSize, BYTE* out, UINT32 outSize,
                           UINT32 originalSize)
{
        UINT32 left = originalSize;
 
        while (left > 4)
        {
                if (inSize < 1)
                        return FALSE;
                inSize--;
 
                const BYTE value = *in++;
                UINT32 len = 0;
 
                if (left == 5)
                {
                        if (outSize < 1)
                                return FALSE;
 
                        outSize--;
                        *out++ = value;
                        left--;
                }
              else if (inSize < 1)
                        return FALSE;
                else if (value == *in)
                {
                        inSize--;
                        in++;
 
                        if (inSize < 1)
                                return FALSE;
                        else if (*in < 0xFF)
                        {
                                inSize--;
                                len = (UINT32)*in++;
                                len += 2;
                        }
                        else
                        {
                                if (inSize < 5)
                                        return FALSE;
                                inSize -= 5;
                                in++;
                                len = ((UINT32)(*in++));
                                len |= ((UINT32)(*in++)) << 8U;
                                len |= ((UINT32)(*in++)) << 16U;
                                len |= ((UINT32)(*in++)) << 24U;
                        }
[1]                        if (outSize < len)
                                return FALSE;
 
                        outSize -= len;
                        FillMemory(out, len, value);
                        out += len;
[2]                        left -= len;
                }
                else
                {
                        if (outSize < 1)
                                return FALSE;

                        outSize--;
                        *out++ = value;
                        left--;
                }
        }
       ...
}