Kernel/drvutil.c

   1 /*
   2  * Acess2 Kernel
   3  * - By John Hodge
   4  *
   5  * drvutil.c
   6  * - Common Driver/Filesystem Helper Functions
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <api_drv_disk.h>
  11 #include <api_drv_video.h>
  12
  13 // === TYPES ===
  14
  15 // === PROTOTYPES ===
  16 //int   DrvUtil_Video_2DStream(void *Ent, void *Buffer, int Length, tDrvUtil_Video_2DHandlers *Handlers, int SizeofHandlers);
  17 //size_t        DrvUtil_Video_WriteLFB(int Mode, tDrvUtil_Video_BufInfo *FBInfo, size_t Offset, size_t Length, void *Src);
  18 //void  DrvUtil_Video_SetCursor(tDrvUtil_Video_BufInfo *Buf, tVideo_IOCtl_Bitmap *Bitmap);
  19 //void  DrvUtil_Video_DrawCursor(tDrvUtil_Video_BufInfo *Buf, int X, int Y);
  20 void    DrvUtil_Video_RenderCursor(tDrvUtil_Video_BufInfo *Buf);
  21 //void  DrvUtil_Video_RemoveCursor(tDrvUtil_Video_BufInfo *Buf);
  22 void    DrvUtil_Video_2D_Fill(void *Ent, Uint16 X, Uint16 Y, Uint16 W, Uint16 H, Uint32 Colour);
  23 void    DrvUtil_Video_2D_Blit(void *Ent, Uint16 DstX, Uint16 DstY, Uint16 SrcX, Uint16 SrcY, Uint16 W, Uint16 H);
  24
  25 // === GLOBALS ===
  26 tDrvUtil_Video_2DHandlers       gDrvUtil_Stub_2DFunctions = {
  27         NULL,
  28         DrvUtil_Video_2D_Fill,
  29         DrvUtil_Video_2D_Blit
  30 };
  31 tVideo_IOCtl_Bitmap     gDrvUtil_TextModeCursor = {
  32         8, 16,
  33         0, 0,
  34         {
  35                 0, 0, 0         , 0, 0, 0, 0, 0,
  36                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  37                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  38                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  39                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  40                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  41                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  42                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  43                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  44                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  45                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  46                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  47                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  48                 0,-1, 0xFF000000, 0, 0, 0, 0, 0,
  49                 0, 0, 0         , 0, 0, 0, 0, 0,
  50                 0, 0, 0         , 0, 0, 0, 0, 0
  51         }
  52 };
  53
  54 // === CODE ===
  55 // --- Video Driver Helpers ---
  56 int DrvUtil_Video_2DStream(void *Ent, void *Buffer, int Length,
  57         tDrvUtil_Video_2DHandlers *Handlers, int SizeofHandlers)
  58 {
  59         void    *stream = Buffer;
  60          int    rem = Length;
  61          int    op;
  62         while( rem )
  63         {
  64                 rem --;
  65                 op = *(Uint8*)stream;
  66                 stream = (void*)((tVAddr)stream + 1);
  67
  68                 if(op > NUM_VIDEO_2DOPS) {
  69                         Log_Warning("DrvUtil",
  70                                 "DrvUtil_Video_2DStream: Unknown operation %i",
  71                                 op);
  72                         return Length-rem;
  73                 }
  74
  75                 if(op*sizeof(void*) > SizeofHandlers) {
  76                         Log_Warning("DrvUtil",
  77                                 "DrvUtil_Video_2DStream: Driver does not support op %i",
  78                                 op);
  79                         return Length-rem;
  80                 }
  81
  82                 switch(op)
  83                 {
  84                 case VIDEO_2DOP_NOP:    break;
  85
  86                 case VIDEO_2DOP_FILL:
  87                         if(rem < 12)    return Length-rem;
  88
  89                         if(!Handlers->Fill) {
  90                                 Log_Warning("DrvUtil", "DrvUtil_Video_2DStream: Driver"
  91                                         " does not support VIDEO_2DOP_FILL");
  92                                 return Length-rem;
  93                         }
  94
  95                         Handlers->Fill(
  96                                 Ent,
  97                                 ((Uint16*)stream)[0], ((Uint16*)stream)[1],
  98                                 ((Uint16*)stream)[2], ((Uint16*)stream)[3],
  99                                 ((Uint32*)stream)[2]
 100                                 );
 101
 102                         rem -= 12;
 103                         stream = (void*)((tVAddr)stream + 12);
 104                         break;
 105
 106                 case VIDEO_2DOP_BLIT:
 107                         if(rem < 12)    return Length-rem;
 108
 109                         if(!Handlers->Blit) {
 110                                 Log_Warning("DrvUtil", "DrvUtil_Video_2DStream: Driver"
 111                                         " does not support VIDEO_2DOP_BLIT");
 112                                 return Length-rem;
 113                         }
 114
 115                         Handlers->Blit(
 116                                 Ent,
 117                                 ((Uint16*)stream)[0], ((Uint16*)stream)[1],
 118                                 ((Uint16*)stream)[2], ((Uint16*)stream)[3],
 119                                 ((Uint16*)stream)[4], ((Uint16*)stream)[5]
 120                                 );
 121
 122                         rem -= 12;
 123                         stream = (void*)((tVAddr)stream + 12);
 124                         break;
 125
 126                 }
 127         }
 128         return 0;
 129 }
 130
 131 int DrvUtil_Video_WriteLFB(tDrvUtil_Video_BufInfo *FBInfo, size_t Offset, size_t Length, void *Buffer)
 132 {
 133         Uint8   *dest;
 134         Uint32  *src = Buffer;
 135          int    csr_x, csr_y;
 136          int    x, y;
 137          int    bytes_per_px = (FBInfo->Depth + 7) / 8;
 138         ENTER("pFBInfo xOffset xLength pBuffer",
 139                 Mode, FBInfo, Offset, Length, Buffer);
 140
 141         csr_x = FBInfo->CursorX;
 142         csr_y = FBInfo->CursorY;
 143
 144         DrvUtil_Video_RemoveCursor(FBInfo);
 145
 146         switch( FBInfo->BufferFormat )
 147         {
 148         case VIDEO_BUFFMT_TEXT:
 149                 {
 150                 tVT_Char        *chars = Buffer;
 151                  int    widthInChars = FBInfo->Width/giVT_CharWidth;
 152                  int    heightInChars = FBInfo->Height/giVT_CharHeight;
 153                  int    i;
 154
 155                 LOG("bytes_per_px = %i", bytes_per_px);
 156                 LOG("widthInChars = %i, heightInChars = %i", widthInChars, heightInChars);
 157
 158                 Length /= sizeof(tVT_Char);     Offset /= sizeof(tVT_Char);
 159
 160                 x = Offset % widthInChars;      y = Offset / widthInChars;
 161                 LOG("x = %i, y = %i", x, y);
 162
 163                 // Sanity Check
 164                 if(Offset > heightInChars * widthInChars)       LEAVE_RET('i', 0);
 165                 if(y >= heightInChars)  LEAVE_RET('i', 0);
 166
 167                 if( Offset + Length > heightInChars*widthInChars )
 168                 {
 169                         Length = heightInChars*widthInChars - Offset;
 170                 }
 171
 172                 dest = FBInfo->Framebuffer;
 173                 LOG("dest = %p", dest);
 174                 dest += y * giVT_CharHeight * FBInfo->Pitch;
 175                 LOG("dest = %p", dest);
 176
 177                 for( i = 0; i < Length; i++ )
 178                 {
 179                         if( y >= heightInChars )
 180                         {
 181                                 Log_Notice("DrvUtil", "Stopped at %i", i);
 182                                 break;
 183                         }
 184
 185                         VT_Font_Render(
 186                                 chars->Ch,
 187                                 dest + x*giVT_CharWidth*bytes_per_px, FBInfo->Depth, FBInfo->Pitch,
 188                                 VT_Colour12toN(chars->BGCol, FBInfo->Depth),
 189                                 VT_Colour12toN(chars->FGCol, FBInfo->Depth)
 190                                 );
 191
 192                         chars ++;
 193                         x ++;
 194                         if( x >= widthInChars )
 195                         {
 196                                 x = 0;
 197                                 y ++;
 198                                 dest += FBInfo->Pitch*giVT_CharHeight;
 199                                 LOG("dest = %p", dest);
 200                         }
 201                 }
 202                 Length = i * sizeof(tVT_Char);
 203                 }
 204                 break;
 205
 206         case VIDEO_BUFFMT_FRAMEBUFFER:
 207                 if(FBInfo->Width*FBInfo->Height*4 < Offset+Length)
 208                 {
 209                         Log_Warning("DrvUtil", "DrvUtil_Video_WriteLFB - Framebuffer Overflow");
 210                         return 0;
 211                 }
 212
 213                 switch(FBInfo->Depth)
 214                 {
 215                 case 15:
 216                 case 16:
 217                         Log_Warning("DrvUtil", "TODO: Support 15/16 bpp modes in LFB write");
 218                         break;
 219                 case 24:
 220                         x = Offset % FBInfo->Width;
 221                         y = Offset / FBInfo->Width;
 222                         dest = (Uint8*)FBInfo->Framebuffer + y*FBInfo->Pitch;
 223                         for( ; Length >= 4; Length -= 4 )
 224                         {
 225                                 dest[x*3+0] = *src & 0xFF;
 226                                 dest[x*3+1] = (*src >> 8) & 0xFF;
 227                                 dest[x*3+2] = (*src >> 16) & 0xFF;
 228                                 x ++;
 229                                 if(x == FBInfo->Width) {
 230                                         dest += FBInfo->Pitch;
 231                                         x = 0;
 232                                 }
 233                         }
 234                         break;
 235                 case 32:
 236                         // Copy to Frambuffer
 237                         if( FBInfo->Pitch != FBInfo->Width*4 )
 238                         {
 239                                 // Pitch isn't 4*Width
 240                                 x = Offset % FBInfo->Width;
 241                                 y = Offset / FBInfo->Height;
 242
 243                                 dest = (Uint8*)FBInfo->Framebuffer + y*FBInfo->Pitch;
 244
 245                                 for( ; Length >= 4; Length -= 4, x )
 246                                 {
 247                                         ((Uint32*)dest)[x++] = *src ++;
 248                                         if( x == FBInfo->Width ) {
 249                                                 x = 0;
 250                                                 dest += FBInfo->Pitch;
 251                                         }
 252                                 }
 253                         }
 254                         else
 255                         {
 256                                 dest = (Uint8 *)FBInfo->Framebuffer + Offset;
 257                                 memcpy(dest, Buffer, Length);
 258                         }
 259                         break;
 260                 default:
 261                         Log_Warning("DrvUtil", "DrvUtil_Video_WriteLFB - Unknown bit depthn %i", FBInfo->Depth);
 262                         break;
 263                 }
 264                 break;
 265
 266         case VIDEO_BUFFMT_2DSTREAM:
 267                 Length = DrvUtil_Video_2DStream(
 268                         FBInfo, Buffer, Length,
 269                         &gDrvUtil_Stub_2DFunctions, sizeof(gDrvUtil_Stub_2DFunctions)
 270                         );
 271                 break;
 272
 273         default:
 274                 LEAVE('i', -1);
 275                 return -1;
 276         }
 277
 278         DrvUtil_Video_DrawCursor(FBInfo, csr_x, csr_y);
 279
 280         LEAVE('x', Length);
 281         return Length;
 282 }
 283
 284 int DrvUtil_Video_SetCursor(tDrvUtil_Video_BufInfo *Buf, tVideo_IOCtl_Bitmap *Bitmap)
 285 {
 286          int    csrX = Buf->CursorX, csrY = Buf->CursorY;
 287         size_t  size;
 288
 289         // Clear old bitmap
 290         if( Buf->CursorBitmap )
 291         {
 292                 DrvUtil_Video_RemoveCursor(Buf);
 293                 if( !Bitmap || Bitmap->W != Buf->CursorBitmap->W || Bitmap->H != Buf->CursorBitmap->H )
 294                 {
 295                         free( Buf->CursorSaveBuf );
 296                         Buf->CursorSaveBuf = NULL;
 297                 }
 298                 if( Buf->CursorBitmap != &gDrvUtil_TextModeCursor)
 299                         free(Buf->CursorBitmap);
 300                 Buf->CursorBitmap = NULL;
 301         }
 302
 303         // If the new bitmap is null, disable drawing
 304         if( !Bitmap )
 305         {
 306                 Buf->CursorX = -1;
 307                 Buf->CursorY = -1;
 308                 return 0;
 309         }
 310
 311         // Sanity check the bitmap
 312         if( !CheckMem(Bitmap, sizeof(*Bitmap)) || !CheckMem(Bitmap->Data, Bitmap->W*Bitmap->H*sizeof(Uint32)) )
 313         {
 314                 Log_Warning("DrvUtil", "DrvUtil_Video_SetCursor: Bitmap (%p) is in invalid memory", Bitmap);
 315                 errno = -EINVAL;
 316                 return -1;
 317         }
 318
 319         // Don't take a copy of the DrvUtil provided cursor
 320         if( Bitmap == &gDrvUtil_TextModeCursor )
 321         {
 322                 Buf->CursorBitmap = Bitmap;
 323         }
 324         else
 325         {
 326                 size = sizeof(tVideo_IOCtl_Bitmap) + Bitmap->W*Bitmap->H*4;
 327
 328                 // Take a copy
 329                 Buf->CursorBitmap = malloc( size );
 330                 memcpy(Buf->CursorBitmap, Bitmap, size);
 331         }
 332
 333         // Restore cursor position
 334         DrvUtil_Video_DrawCursor(Buf, csrX, csrY);
 335         return 0;
 336 }
 337
 338 void DrvUtil_Video_DrawCursor(tDrvUtil_Video_BufInfo *Buf, int X, int Y)
 339 {
 340          int    render_ox=0, render_oy=0, render_w, render_h;
 341
 342         DrvUtil_Video_RemoveCursor(Buf);
 343
 344         // X < 0 disables the cursor
 345         if( X < 0 ) {
 346                 Buf->CursorX = -1;
 347                 return ;
 348         }
 349
 350         // Sanity checking
 351         if( X < 0 || Y < 0 )    return;
 352         if( X >= Buf->Width || Y >= Buf->Height )       return;
 353
 354         // Ensure the cursor is enabled
 355         if( !Buf->CursorBitmap )        return ;
 356
 357         // Save cursor position (for changing the bitmap)
 358         Buf->CursorX = X;       Buf->CursorY = Y;
 359
 360         // Apply cursor's center offset
 361         X -= Buf->CursorBitmap->XOfs;
 362         Y -= Buf->CursorBitmap->YOfs;
 363
 364         // Get the width of the cursor on screen (clipping to right/bottom edges)
 365         render_w = X > Buf->Width  - Buf->CursorBitmap->W ? Buf->Width  - X : Buf->CursorBitmap->W;
 366         render_h = Y > Buf->Height - Buf->CursorBitmap->H ? Buf->Height - Y : Buf->CursorBitmap->H;
 367
 368         // Clipp to left/top edges
 369         if(X < 0) {     render_ox = -X; X = 0;  }
 370         if(Y < 0) {     render_oy = -Y; Y = 0;  }
 371
 372         // Save values
 373         Buf->CursorRenderW = render_w;  Buf->CursorRenderH = render_h;
 374         Buf->CursorDestX   = X;         Buf->CursorDestY = Y;
 375         Buf->CursorReadX   = render_ox; Buf->CursorReadY = render_oy;
 376
 377         // Call render routine
 378         DrvUtil_Video_RenderCursor(Buf);
 379 }
 380
 381 void DrvUtil_Video_RenderCursor(tDrvUtil_Video_BufInfo *Buf)
 382 {
 383          int    src_x = Buf->CursorReadX, src_y = Buf->CursorReadY;
 384          int    render_w = Buf->CursorRenderW, render_h = Buf->CursorRenderH;
 385          int    dest_x = Buf->CursorDestX, dest_y = Buf->CursorDestY;
 386          int    bytes_per_px = (Buf->Depth + 7) / 8;
 387          int    save_pitch = Buf->CursorBitmap->W * bytes_per_px;
 388         void    *dest;
 389         Uint32  *src;
 390          int    x, y;
 391
 392         dest = (Uint8*)Buf->Framebuffer + dest_y*Buf->Pitch + dest_x*bytes_per_px;
 393         src = Buf->CursorBitmap->Data + src_y * Buf->CursorBitmap->W + src_x;
 394
 395         // Allocate save buffer if not already
 396         if( !Buf->CursorSaveBuf )
 397                 Buf->CursorSaveBuf = malloc( Buf->CursorBitmap->W*Buf->CursorBitmap->H*bytes_per_px );
 398
 399         // Save behind the cursor
 400         for( y = 0; y < render_h; y ++ )
 401                 memcpy(
 402                         (Uint8*)Buf->CursorSaveBuf + y*save_pitch,
 403                         (Uint8*)dest + y*Buf->Pitch,
 404                         render_w*bytes_per_px
 405                         );
 406
 407         // Draw the cursor
 408         switch(Buf->Depth)
 409         {
 410         case 15:
 411         case 16:
 412                 Log_Warning("DrvUtil", "TODO: Support 15/16 bpp modes in cursor draw");
 413                 break;
 414         case 24:
 415                 for( y = 0; y < render_h; y ++ )
 416                 {
 417                         Uint8   *px;
 418                         px = dest;
 419                         for(x = 0; x < render_w; x ++, px += 3)
 420                         {
 421                                 Uint32  value = src[x];
 422                                 // TODO: Should I implement alpha blending?
 423                                 if(value & 0xFF000000)
 424                                 {
 425                                         px[0] = value & 0xFF;
 426                                         px[1] = (value >> 8) & 0xFF;
 427                                         px[2] = (value >> 16) & 0xFF;
 428                                 }
 429                                 else
 430                                         ;
 431                         }
 432                         src += Buf->CursorBitmap->W;
 433                         dest = (Uint8*)dest + Buf->Pitch;
 434                 }
 435                 break;
 436         case 32:
 437                 for( y = 0; y < render_h; y ++ )
 438                 {
 439                         Uint32  *px;
 440                         px = dest;
 441                         for(x = 0; x < render_w; x ++, px ++)
 442                         {
 443                                 Uint32  value = src[x];
 444                                 // TODO: Should I implement alpha blending?
 445                                 if(value & 0xFF000000)
 446                                         *px = value;
 447                                 else
 448                                         ;       // NOP, completely transparent
 449                         }
 450                         src += Buf->CursorBitmap->W;
 451                         dest = (Uint8*)dest + Buf->Pitch;
 452                 }
 453                 break;
 454         default:
 455                 Log_Error("DrvUtil", "RenderCursor - Unknown bit depth %i", Buf->Depth);
 456                 Buf->CursorX = -1;
 457                 break;
 458         }
 459 }
 460
 461 void DrvUtil_Video_RemoveCursor(tDrvUtil_Video_BufInfo *Buf)
 462 {
 463          int    bytes_per_px = (Buf->Depth + 7) / 8;
 464          int    y, save_pitch;
 465         Uint8   *dest, *src;
 466
 467         // Just a little sanity
 468         if( !Buf->CursorBitmap || Buf->CursorX == -1 )  return ;
 469         if( !Buf->CursorSaveBuf )       return ;
 470
 471 //      Debug("DrvUtil_Video_RemoveCursor: (Buf=%p) dest_x=%i, dest_y=%i", Buf, Buf->CursorDestX, Buf->CursorDestY);
 472
 473         // Set up
 474         save_pitch = Buf->CursorBitmap->W * bytes_per_px;
 475         dest = (Uint8*)Buf->Framebuffer + Buf->CursorDestY * Buf->Pitch + Buf->CursorDestX*bytes_per_px;
 476         src = Buf->CursorSaveBuf;
 477
 478         // Copy each line back
 479         for( y = 0; y < Buf->CursorRenderH; y ++ )
 480         {
 481                 memcpy( dest, src, Buf->CursorRenderW * bytes_per_px );
 482                 src += save_pitch;
 483                 dest += Buf->Pitch;
 484         }
 485
 486         // Set the cursor as removed
 487         Buf->CursorX = -1;
 488 }
 489
 490 void DrvUtil_Video_2D_Fill(void *Ent, Uint16 X, Uint16 Y, Uint16 W, Uint16 H, Uint32 Colour)
 491 {
 492         tDrvUtil_Video_BufInfo  *FBInfo = Ent;
 493
 494         // TODO: Handle non-32bit modes
 495         if( FBInfo->Depth != 32 )       return;
 496
 497         // TODO: Be less hacky
 498          int    pitch = FBInfo->Pitch/4;
 499         Uint32  *buf = (Uint32*)FBInfo->Framebuffer + Y*pitch + X;
 500         while( H -- ) {
 501                 Uint32 *tmp;
 502                  int    i;
 503                 tmp = buf;
 504                 for(i=W;i--;tmp++)      *tmp = Colour;
 505                 buf += pitch;
 506         }
 507 }
 508
 509 void DrvUtil_Video_2D_Blit(void *Ent, Uint16 DstX, Uint16 DstY, Uint16 SrcX, Uint16 SrcY, Uint16 W, Uint16 H)
 510 {
 511         tDrvUtil_Video_BufInfo  *FBInfo = Ent;
 512          int    scrnpitch = FBInfo->Pitch;
 513          int    bytes_per_px = (FBInfo->Depth + 7) / 8;
 514          int    dst = DstY*scrnpitch + DstX;
 515          int    src = SrcY*scrnpitch + SrcX;
 516          int    tmp;
 517
 518         //Log("Vesa_2D_Blit: (Ent=%p, DstX=%i, DstY=%i, SrcX=%i, SrcY=%i, W=%i, H=%i)",
 519         //      Ent, DstX, DstY, SrcX, SrcY, W, H);
 520
 521         if(SrcX + W > FBInfo->Width)    W = FBInfo->Width - SrcX;
 522         if(DstX + W > FBInfo->Width)    W = FBInfo->Width - DstX;
 523         if(SrcY + H > FBInfo->Height)   H = FBInfo->Height - SrcY;
 524         if(DstY + H > FBInfo->Height)   H = FBInfo->Height - DstY;
 525
 526         //Debug("W = %i, H = %i", W, H);
 527
 528         if( dst > src ) {
 529                 // Reverse copy
 530                 dst += H*scrnpitch;
 531                 src += H*scrnpitch;
 532                 while( H -- ) {
 533                         dst -= scrnpitch;
 534                         src -= scrnpitch;
 535                         tmp = W*bytes_per_px;
 536                         for( tmp = W; tmp --; ) {
 537                                 *((Uint8*)FBInfo->Framebuffer + dst + tmp) = *((Uint8*)FBInfo->Framebuffer + src + tmp);
 538                         }
 539                 }
 540         }
 541         else {
 542                 // Normal copy is OK
 543                 while( H -- ) {
 544                         memcpy((Uint8*)FBInfo->Framebuffer + dst, (Uint8*)FBInfo->Framebuffer + src, W*bytes_per_px);
 545                         dst += scrnpitch;
 546                         src += scrnpitch;
 547                 }
 548         }
 549         //Log("Vesa_2D_Blit: RETURN");
 550 }
 551
 552
 553 // --- Disk Driver Helpers ---
 554 Uint64 DrvUtil_ReadBlock(Uint64 Start, Uint64 Length, void *Buffer,
 555         tDrvUtil_Callback ReadBlocks, Uint64 BlockSize, Uint Argument)
 556 {
 557         Uint8   tmp[BlockSize]; // C99
 558         Uint64  block = Start / BlockSize;
 559          int    offset = Start - block * BlockSize;
 560          int    leading = BlockSize - offset;
 561         Uint64  num;
 562          int    tailings;
 563         Uint64  ret;
 564
 565         ENTER("XStart XLength pBuffer pReadBlocks XBlockSize xArgument",
 566                 Start, Length, Buffer, ReadBlocks, BlockSize, Argument);
 567
 568         // Non aligned start, let's fix that!
 569         if(offset != 0)
 570         {
 571                 if(leading > Length)    leading = Length;
 572                 LOG("Reading %i bytes from Block1+%i", leading, offset);
 573                 ret = ReadBlocks(block, 1, tmp, Argument);
 574                 if(ret != 1) {
 575                         LEAVE('i', 0);
 576                         return 0;
 577                 }
 578                 memcpy( Buffer, &tmp[offset], leading );
 579
 580                 if(leading == Length) {
 581                         LEAVE('i', leading);
 582                         return leading;
 583                 }
 584
 585                 Buffer = (Uint8*)Buffer + leading;
 586                 block ++;
 587                 num = ( Length - leading ) / BlockSize;
 588                 tailings = Length - num * BlockSize - leading;
 589         }
 590         else {
 591                 num = Length / BlockSize;
 592                 tailings = Length % BlockSize;
 593         }
 594
 595         // Read central blocks
 596         if(num)
 597         {
 598                 LOG("Reading %i blocks", num);
 599                 ret = ReadBlocks(block, num, Buffer, Argument);
 600                 if(ret != num ) {
 601                         LEAVE('X', leading + ret * BlockSize);
 602                         return leading + ret * BlockSize;
 603                 }
 604         }
 605
 606         // Read last tailing block
 607         if(tailings != 0)
 608         {
 609                 LOG("Reading %i bytes from last block", tailings);
 610                 block += num;
 611                 Buffer = (Uint8*)Buffer + num * BlockSize;
 612                 ret = ReadBlocks(block, 1, tmp, Argument);
 613                 if(ret != 1) {
 614                         LEAVE('X', leading + num * BlockSize);
 615                         return leading + num * BlockSize;
 616                 }
 617                 memcpy( Buffer, tmp, tailings );
 618         }
 619
 620         LEAVE('X', Length);
 621         return Length;
 622 }
 623
 624 Uint64 DrvUtil_WriteBlock(Uint64 Start, Uint64 Length, void *Buffer,
 625         tDrvUtil_Callback ReadBlocks, tDrvUtil_Callback WriteBlocks,
 626         Uint64 BlockSize, Uint Argument)
 627 {
 628         Uint8   tmp[BlockSize]; // C99
 629         Uint64  block = Start / BlockSize;
 630          int    offset = Start - block * BlockSize;
 631          int    leading = BlockSize - offset;
 632         Uint64  num;
 633          int    tailings;
 634         Uint64  ret;
 635
 636         ENTER("XStart XLength pBuffer pReadBlocks pWriteBlocks XBlockSize xArgument",
 637                 Start, Length, Buffer, ReadBlocks, WriteBlocks, BlockSize, Argument);
 638
 639         // Non aligned start, let's fix that!
 640         if(offset != 0)
 641         {
 642                 if(leading > Length)    leading = Length;
 643                 LOG("Writing %i bytes to Block1+%i", leading, offset);
 644                 // Read a copy of the block
 645                 ret = ReadBlocks(block, 1, tmp, Argument);
 646                 if(ret != 1) {
 647                         LEAVE('i', 0);
 648                         return 0;
 649                 }
 650                 // Modify
 651                 memcpy( &tmp[offset], Buffer, leading );
 652                 // Write Back
 653                 ret = WriteBlocks(block, 1, tmp, Argument);
 654                 if(ret != 1) {
 655                         LEAVE('i', 0);
 656                         return 0;
 657                 }
 658
 659                 if(leading == Length) {
 660                         LEAVE('i', leading);
 661                         return leading;
 662                 }
 663
 664                 Buffer = (Uint8*)Buffer + leading;
 665                 block ++;
 666                 num = ( Length - leading ) / BlockSize;
 667                 tailings = Length - num * BlockSize - leading;
 668         }
 669         else {
 670                 num = Length / BlockSize;
 671                 tailings = Length % BlockSize;
 672         }
 673
 674         // Read central blocks
 675         if(num)
 676         {
 677                 LOG("Writing %i blocks", num);
 678                 ret = WriteBlocks(block, num, Buffer, Argument);
 679                 if(ret != num ) {
 680                         LEAVE('X', leading + ret * BlockSize);
 681                         return leading + ret * BlockSize;
 682                 }
 683         }
 684
 685         // Read last tailing block
 686         if(tailings != 0)
 687         {
 688                 LOG("Writing %i bytes to last block", tailings);
 689                 block += num;
 690                 Buffer = (Uint8*)Buffer + num * BlockSize;
 691                 // Read
 692                 ret = ReadBlocks(block, 1, tmp, Argument);
 693                 if(ret != 1) {
 694                         LEAVE('X', leading + num * BlockSize);
 695                         return leading + num * BlockSize;
 696                 }
 697                 // Modify
 698                 memcpy( tmp, Buffer, tailings );
 699                 // Write
 700                 ret = WriteBlocks(block, 1, tmp, Argument);
 701                 if(ret != 1) {
 702                         LEAVE('X', leading + num * BlockSize);
 703                         return leading + num * BlockSize;
 704                 }
 705
 706         }
 707
 708         LEAVE('X', Length);
 709         return Length;
 710 }