dlls/windowscodecs/gifformat.c

   1 /*
   2  * Copyright 2009 Vincent Povirk for CodeWeavers
   3  * Copyright 2012 Dmitry Timoshkov
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  18  */
  19
  20 #include "config.h"
  21
  22 #include <stdarg.h>
  23
  24 #define COBJMACROS
  25 #define NONAMELESSUNION
  26
  27 #include "windef.h"
  28 #include "winbase.h"
  29 #include "objbase.h"
  30 #include "wincodec.h"
  31 #include "wincodecsdk.h"
  32
  33 #include "ungif.h"
  34
  35 #include "wincodecs_private.h"
  36
  37 #include "wine/debug.h"
  38
  39 WINE_DEFAULT_DEBUG_CHANNEL(wincodecs);
  40
  41 static LPWSTR strdupAtoW(const char *src)
  42 {
  43     int len = MultiByteToWideChar(CP_ACP, 0, src, -1, NULL, 0);
  44     LPWSTR dst = HeapAlloc(GetProcessHeap(), 0, len * sizeof(WCHAR));
  45     if (dst) MultiByteToWideChar(CP_ACP, 0, src, -1, dst, len);
  46     return dst;
  47 }
  48
  49 static HRESULT load_LSD_metadata(IStream *stream, const GUID *vendor, DWORD options,
  50                                  MetadataItem **items, DWORD *count)
  51 {
  52 #include "pshpack1.h"
  53     struct logical_screen_descriptor
  54     {
  55         char signature[6];
  56         USHORT width;
  57         USHORT height;
  58         BYTE packed;
  59         /* global_color_table_flag : 1;
  60          * color_resolution : 3;
  61          * sort_flag : 1;
  62          * global_color_table_size : 3;
  63          */
  64         BYTE background_color_index;
  65         BYTE pixel_aspect_ratio;
  66     } lsd_data;
  67 #include "poppack.h"
  68     HRESULT hr;
  69     ULONG bytesread, i;
  70     MetadataItem *result;
  71
  72     *items = NULL;
  73     *count = 0;
  74
  75     hr = IStream_Read(stream, &lsd_data, sizeof(lsd_data), &bytesread);
  76     if (FAILED(hr) || bytesread != sizeof(lsd_data)) return S_OK;
  77
  78     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 9);
  79     if (!result) return E_OUTOFMEMORY;
  80
  81     for (i = 0; i < 9; i++)
  82     {
  83         PropVariantInit(&result[i].schema);
  84         PropVariantInit(&result[i].id);
  85         PropVariantInit(&result[i].value);
  86     }
  87
  88     result[0].id.vt = VT_LPWSTR;
  89     result[0].id.u.pwszVal = strdupAtoW("Signature");
  90     result[0].value.vt = VT_UI1|VT_VECTOR;
  91     result[0].value.u.caub.cElems = sizeof(lsd_data.signature);
  92     result[0].value.u.caub.pElems = HeapAlloc(GetProcessHeap(), 0, sizeof(lsd_data.signature));
  93     memcpy(result[0].value.u.caub.pElems, lsd_data.signature, sizeof(lsd_data.signature));
  94
  95     result[1].id.vt = VT_LPWSTR;
  96     result[1].id.u.pwszVal = strdupAtoW("Width");
  97     result[1].value.vt = VT_UI2;
  98     result[1].value.u.uiVal = lsd_data.width;
  99
 100     result[2].id.vt = VT_LPWSTR;
 101     result[2].id.u.pwszVal = strdupAtoW("Height");
 102     result[2].value.vt = VT_UI2;
 103     result[2].value.u.uiVal = lsd_data.height;
 104
 105     result[3].id.vt = VT_LPWSTR;
 106     result[3].id.u.pwszVal = strdupAtoW("GlobalColorTableFlag");
 107     result[3].value.vt = VT_BOOL;
 108     result[3].value.u.boolVal = (lsd_data.packed >> 7) & 1;
 109
 110     result[4].id.vt = VT_LPWSTR;
 111     result[4].id.u.pwszVal = strdupAtoW("ColorResolution");
 112     result[4].value.vt = VT_UI1;
 113     result[4].value.u.bVal = (lsd_data.packed >> 4) & 7;
 114
 115     result[5].id.vt = VT_LPWSTR;
 116     result[5].id.u.pwszVal = strdupAtoW("SortFlag");
 117     result[5].value.vt = VT_BOOL;
 118     result[5].value.u.boolVal = (lsd_data.packed >> 3) & 1;
 119
 120     result[6].id.vt = VT_LPWSTR;
 121     result[6].id.u.pwszVal = strdupAtoW("GlobalColorTableSize");
 122     result[6].value.vt = VT_UI1;
 123     result[6].value.u.bVal = lsd_data.packed & 7;
 124
 125     result[7].id.vt = VT_LPWSTR;
 126     result[7].id.u.pwszVal = strdupAtoW("BackgroundColorIndex");
 127     result[7].value.vt = VT_UI1;
 128     result[7].value.u.bVal = lsd_data.background_color_index;
 129
 130     result[8].id.vt = VT_LPWSTR;
 131     result[8].id.u.pwszVal = strdupAtoW("PixelAspectRatio");
 132     result[8].value.vt = VT_UI1;
 133     result[8].value.u.bVal = lsd_data.pixel_aspect_ratio;
 134
 135     *items = result;
 136     *count = 9;
 137
 138     return S_OK;
 139 }
 140
 141 static const MetadataHandlerVtbl LSDReader_Vtbl = {
 142     0,
 143     &CLSID_WICLSDMetadataReader,
 144     load_LSD_metadata
 145 };
 146
 147 HRESULT LSDReader_CreateInstance(REFIID iid, void **ppv)
 148 {
 149     return MetadataReader_Create(&LSDReader_Vtbl, iid, ppv);
 150 }
 151
 152 #include "pshpack1.h"
 153 struct image_descriptor
 154 {
 155     USHORT left;
 156     USHORT top;
 157     USHORT width;
 158     USHORT height;
 159     BYTE packed;
 160     /* local_color_table_flag : 1;
 161      * interlace_flag : 1;
 162      * sort_flag : 1;
 163      * reserved : 2;
 164      * local_color_table_size : 3;
 165      */
 166 };
 167 #include "poppack.h"
 168
 169 static HRESULT load_IMD_metadata(IStream *stream, const GUID *vendor, DWORD options,
 170                                  MetadataItem **items, DWORD *count)
 171 {
 172     struct image_descriptor imd_data;
 173     HRESULT hr;
 174     ULONG bytesread, i;
 175     MetadataItem *result;
 176
 177     *items = NULL;
 178     *count = 0;
 179
 180     hr = IStream_Read(stream, &imd_data, sizeof(imd_data), &bytesread);
 181     if (FAILED(hr) || bytesread != sizeof(imd_data)) return S_OK;
 182
 183     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 8);
 184     if (!result) return E_OUTOFMEMORY;
 185
 186     for (i = 0; i < 8; i++)
 187     {
 188         PropVariantInit(&result[i].schema);
 189         PropVariantInit(&result[i].id);
 190         PropVariantInit(&result[i].value);
 191     }
 192
 193     result[0].id.vt = VT_LPWSTR;
 194     result[0].id.u.pwszVal = strdupAtoW("Left");
 195     result[0].value.vt = VT_UI2;
 196     result[0].value.u.uiVal = imd_data.left;
 197
 198     result[1].id.vt = VT_LPWSTR;
 199     result[1].id.u.pwszVal = strdupAtoW("Top");
 200     result[1].value.vt = VT_UI2;
 201     result[1].value.u.uiVal = imd_data.top;
 202
 203     result[2].id.vt = VT_LPWSTR;
 204     result[2].id.u.pwszVal = strdupAtoW("Width");
 205     result[2].value.vt = VT_UI2;
 206     result[2].value.u.uiVal = imd_data.width;
 207
 208     result[3].id.vt = VT_LPWSTR;
 209     result[3].id.u.pwszVal = strdupAtoW("Height");
 210     result[3].value.vt = VT_UI2;
 211     result[3].value.u.uiVal = imd_data.height;
 212
 213     result[4].id.vt = VT_LPWSTR;
 214     result[4].id.u.pwszVal = strdupAtoW("LocalColorTableFlag");
 215     result[4].value.vt = VT_BOOL;
 216     result[4].value.u.boolVal = (imd_data.packed >> 7) & 1;
 217
 218     result[5].id.vt = VT_LPWSTR;
 219     result[5].id.u.pwszVal = strdupAtoW("InterlaceFlag");
 220     result[5].value.vt = VT_BOOL;
 221     result[5].value.u.boolVal = (imd_data.packed >> 6) & 1;
 222
 223     result[6].id.vt = VT_LPWSTR;
 224     result[6].id.u.pwszVal = strdupAtoW("SortFlag");
 225     result[6].value.vt = VT_BOOL;
 226     result[6].value.u.boolVal = (imd_data.packed >> 5) & 1;
 227
 228     result[7].id.vt = VT_LPWSTR;
 229     result[7].id.u.pwszVal = strdupAtoW("LocalColorTableSize");
 230     result[7].value.vt = VT_UI1;
 231     result[7].value.u.bVal = imd_data.packed & 7;
 232
 233     *items = result;
 234     *count = 8;
 235
 236     return S_OK;
 237 }
 238
 239 static const MetadataHandlerVtbl IMDReader_Vtbl = {
 240     0,
 241     &CLSID_WICIMDMetadataReader,
 242     load_IMD_metadata
 243 };
 244
 245 HRESULT IMDReader_CreateInstance(REFIID iid, void **ppv)
 246 {
 247     return MetadataReader_Create(&IMDReader_Vtbl, iid, ppv);
 248 }
 249
 250 static HRESULT load_GCE_metadata(IStream *stream, const GUID *vendor, DWORD options,
 251                                  MetadataItem **items, DWORD *count)
 252 {
 253 #include "pshpack1.h"
 254     struct graphic_control_extenstion
 255     {
 256         BYTE packed;
 257         /* reservred: 3;
 258          * disposal : 3;
 259          * user_input_flag : 1;
 260          * transparency_flag : 1;
 261          */
 262          USHORT delay;
 263          BYTE transparent_color_index;
 264     } gce_data;
 265 #include "poppack.h"
 266     HRESULT hr;
 267     ULONG bytesread, i;
 268     MetadataItem *result;
 269
 270     *items = NULL;
 271     *count = 0;
 272
 273     hr = IStream_Read(stream, &gce_data, sizeof(gce_data), &bytesread);
 274     if (FAILED(hr) || bytesread != sizeof(gce_data)) return S_OK;
 275
 276     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 5);
 277     if (!result) return E_OUTOFMEMORY;
 278
 279     for (i = 0; i < 5; i++)
 280     {
 281         PropVariantInit(&result[i].schema);
 282         PropVariantInit(&result[i].id);
 283         PropVariantInit(&result[i].value);
 284     }
 285
 286     result[0].id.vt = VT_LPWSTR;
 287     result[0].id.u.pwszVal = strdupAtoW("Disposal");
 288     result[0].value.vt = VT_UI1;
 289     result[0].value.u.bVal = (gce_data.packed >> 2) & 7;
 290
 291     result[1].id.vt = VT_LPWSTR;
 292     result[1].id.u.pwszVal = strdupAtoW("UserInputFlag");
 293     result[1].value.vt = VT_BOOL;
 294     result[1].value.u.boolVal = (gce_data.packed >> 1) & 1;
 295
 296     result[2].id.vt = VT_LPWSTR;
 297     result[2].id.u.pwszVal = strdupAtoW("TransparencyFlag");
 298     result[2].value.vt = VT_BOOL;
 299     result[2].value.u.boolVal = gce_data.packed & 1;
 300
 301     result[3].id.vt = VT_LPWSTR;
 302     result[3].id.u.pwszVal = strdupAtoW("Delay");
 303     result[3].value.vt = VT_UI2;
 304     result[3].value.u.uiVal = gce_data.delay;
 305
 306     result[4].id.vt = VT_LPWSTR;
 307     result[4].id.u.pwszVal = strdupAtoW("TransparentColorIndex");
 308     result[4].value.vt = VT_UI1;
 309     result[4].value.u.bVal = gce_data.transparent_color_index;
 310
 311     *items = result;
 312     *count = 5;
 313
 314     return S_OK;
 315 }
 316
 317 static const MetadataHandlerVtbl GCEReader_Vtbl = {
 318     0,
 319     &CLSID_WICGCEMetadataReader,
 320     load_GCE_metadata
 321 };
 322
 323 HRESULT GCEReader_CreateInstance(REFIID iid, void **ppv)
 324 {
 325     return MetadataReader_Create(&GCEReader_Vtbl, iid, ppv);
 326 }
 327
 328 static HRESULT load_APE_metadata(IStream *stream, const GUID *vendor, DWORD options,
 329                                  MetadataItem **items, DWORD *count)
 330 {
 331 #include "pshpack1.h"
 332     struct application_extenstion
 333     {
 334         BYTE extension_introducer;
 335         BYTE extension_label;
 336         BYTE block_size;
 337         BYTE application[11];
 338     } ape_data;
 339 #include "poppack.h"
 340     HRESULT hr;
 341     ULONG bytesread, data_size, i;
 342     MetadataItem *result;
 343     BYTE subblock_size;
 344     BYTE *data;
 345
 346     *items = NULL;
 347     *count = 0;
 348
 349     hr = IStream_Read(stream, &ape_data, sizeof(ape_data), &bytesread);
 350     if (FAILED(hr) || bytesread != sizeof(ape_data)) return S_OK;
 351     if (ape_data.extension_introducer != 0x21 ||
 352         ape_data.extension_label != APPLICATION_EXT_FUNC_CODE ||
 353         ape_data.block_size != 11)
 354         return S_OK;
 355
 356     data = NULL;
 357     data_size = 0;
 358
 359     for (;;)
 360     {
 361         hr = IStream_Read(stream, &subblock_size, sizeof(subblock_size), &bytesread);
 362         if (FAILED(hr) || bytesread != sizeof(subblock_size))
 363         {
 364             HeapFree(GetProcessHeap(), 0, data);
 365             return S_OK;
 366         }
 367         if (!subblock_size) break;
 368
 369         if (!data)
 370             data = HeapAlloc(GetProcessHeap(), 0, subblock_size + 1);
 371         else
 372         {
 373             BYTE *new_data = HeapReAlloc(GetProcessHeap(), 0, data, data_size + subblock_size + 1);
 374             if (!new_data)
 375             {
 376                 HeapFree(GetProcessHeap(), 0, data);
 377                 return S_OK;
 378             }
 379             data = new_data;
 380         }
 381         data[data_size] = subblock_size;
 382         hr = IStream_Read(stream, data + data_size + 1, subblock_size, &bytesread);
 383         if (FAILED(hr) || bytesread != subblock_size)
 384         {
 385             HeapFree(GetProcessHeap(), 0, data);
 386             return S_OK;
 387         }
 388         data_size += subblock_size + 1;
 389     }
 390
 391     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 2);
 392     if (!result)
 393     {
 394         HeapFree(GetProcessHeap(), 0, data);
 395         return E_OUTOFMEMORY;
 396     }
 397
 398     for (i = 0; i < 2; i++)
 399     {
 400         PropVariantInit(&result[i].schema);
 401         PropVariantInit(&result[i].id);
 402         PropVariantInit(&result[i].value);
 403     }
 404
 405     result[0].id.vt = VT_LPWSTR;
 406     result[0].id.u.pwszVal = strdupAtoW("Application");
 407     result[0].value.vt = VT_UI1|VT_VECTOR;
 408     result[0].value.u.caub.cElems = sizeof(ape_data.application);
 409     result[0].value.u.caub.pElems = HeapAlloc(GetProcessHeap(), 0, sizeof(ape_data.application));
 410     memcpy(result[0].value.u.caub.pElems, ape_data.application, sizeof(ape_data.application));
 411
 412     result[1].id.vt = VT_LPWSTR;
 413     result[1].id.u.pwszVal = strdupAtoW("Data");
 414     result[1].value.vt = VT_UI1|VT_VECTOR;
 415     result[1].value.u.caub.cElems = data_size;
 416     result[1].value.u.caub.pElems = data;
 417
 418     *items = result;
 419     *count = 2;
 420
 421     return S_OK;
 422 }
 423
 424 static const MetadataHandlerVtbl APEReader_Vtbl = {
 425     0,
 426     &CLSID_WICAPEMetadataReader,
 427     load_APE_metadata
 428 };
 429
 430 HRESULT APEReader_CreateInstance(REFIID iid, void **ppv)
 431 {
 432     return MetadataReader_Create(&APEReader_Vtbl, iid, ppv);
 433 }
 434
 435 static HRESULT load_GifComment_metadata(IStream *stream, const GUID *vendor, DWORD options,
 436                                         MetadataItem **items, DWORD *count)
 437 {
 438 #include "pshpack1.h"
 439     struct gif_extenstion
 440     {
 441         BYTE extension_introducer;
 442         BYTE extension_label;
 443     } ext_data;
 444 #include "poppack.h"
 445     HRESULT hr;
 446     ULONG bytesread, data_size;
 447     MetadataItem *result;
 448     BYTE subblock_size;
 449     char *data;
 450
 451     *items = NULL;
 452     *count = 0;
 453
 454     hr = IStream_Read(stream, &ext_data, sizeof(ext_data), &bytesread);
 455     if (FAILED(hr) || bytesread != sizeof(ext_data)) return S_OK;
 456     if (ext_data.extension_introducer != 0x21 ||
 457         ext_data.extension_label != COMMENT_EXT_FUNC_CODE)
 458         return S_OK;
 459
 460     data = NULL;
 461     data_size = 0;
 462
 463     for (;;)
 464     {
 465         hr = IStream_Read(stream, &subblock_size, sizeof(subblock_size), &bytesread);
 466         if (FAILED(hr) || bytesread != sizeof(subblock_size))
 467         {
 468             HeapFree(GetProcessHeap(), 0, data);
 469             return S_OK;
 470         }
 471         if (!subblock_size) break;
 472
 473         if (!data)
 474             data = HeapAlloc(GetProcessHeap(), 0, subblock_size + 1);
 475         else
 476         {
 477             char *new_data = HeapReAlloc(GetProcessHeap(), 0, data, data_size + subblock_size + 1);
 478             if (!new_data)
 479             {
 480                 HeapFree(GetProcessHeap(), 0, data);
 481                 return S_OK;
 482             }
 483             data = new_data;
 484         }
 485         hr = IStream_Read(stream, data + data_size, subblock_size, &bytesread);
 486         if (FAILED(hr) || bytesread != subblock_size)
 487         {
 488             HeapFree(GetProcessHeap(), 0, data);
 489             return S_OK;
 490         }
 491         data_size += subblock_size;
 492     }
 493
 494     data[data_size] = 0;
 495
 496     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem));
 497     if (!result)
 498     {
 499         HeapFree(GetProcessHeap(), 0, data);
 500         return E_OUTOFMEMORY;
 501     }
 502
 503     PropVariantInit(&result->schema);
 504     PropVariantInit(&result->id);
 505     PropVariantInit(&result->value);
 506
 507     result->id.vt = VT_LPWSTR;
 508     result->id.u.pwszVal = strdupAtoW("TextEntry");
 509     result->value.vt = VT_LPSTR;
 510     result->value.u.pszVal = data;
 511
 512     *items = result;
 513     *count = 1;
 514
 515     return S_OK;
 516 }
 517
 518 static const MetadataHandlerVtbl GifCommentReader_Vtbl = {
 519     0,
 520     &CLSID_WICGifCommentMetadataReader,
 521     load_GifComment_metadata
 522 };
 523
 524 HRESULT GifCommentReader_CreateInstance(REFIID iid, void **ppv)
 525 {
 526     return MetadataReader_Create(&GifCommentReader_Vtbl, iid, ppv);
 527 }
 528
 529 static IStream *create_stream(const void *data, int data_size)
 530 {
 531     HRESULT hr;
 532     IStream *stream;
 533     HGLOBAL hdata;
 534     void *locked_data;
 535
 536     hdata = GlobalAlloc(GMEM_MOVEABLE, data_size);
 537     if (!hdata) return NULL;
 538
 539     locked_data = GlobalLock(hdata);
 540     memcpy(locked_data, data, data_size);
 541     GlobalUnlock(hdata);
 542
 543     hr = CreateStreamOnHGlobal(hdata, TRUE, &stream);
 544     return FAILED(hr) ? NULL : stream;
 545 }
 546
 547 static HRESULT create_metadata_reader(const void *data, int data_size,
 548                                       class_constructor constructor,
 549                                       IWICMetadataReader **reader)
 550 {
 551     HRESULT hr;
 552     IWICMetadataReader *metadata_reader;
 553     IWICPersistStream *persist;
 554     IStream *stream;
 555
 556     /* FIXME: Use IWICComponentFactory_CreateMetadataReader once it's implemented */
 557
 558     hr = constructor(&IID_IWICMetadataReader, (void**)&metadata_reader);
 559     if (FAILED(hr)) return hr;
 560
 561     hr = IWICMetadataReader_QueryInterface(metadata_reader, &IID_IWICPersistStream, (void **)&persist);
 562     if (FAILED(hr))
 563     {
 564         IWICMetadataReader_Release(metadata_reader);
 565         return hr;
 566     }
 567
 568     stream = create_stream(data, data_size);
 569     IWICPersistStream_LoadEx(persist, stream, NULL, WICPersistOptionsDefault);
 570     IStream_Release(stream);
 571
 572     IWICPersistStream_Release(persist);
 573
 574     *reader = metadata_reader;
 575     return S_OK;
 576 }
 577
 578 typedef struct {
 579     IWICBitmapDecoder IWICBitmapDecoder_iface;
 580     IWICMetadataBlockReader IWICMetadataBlockReader_iface;
 581     IStream *stream;
 582     BYTE LSD_data[13]; /* Logical Screen Descriptor */
 583     LONG ref;
 584     BOOL initialized;
 585     GifFileType *gif;
 586     UINT current_frame;
 587     CRITICAL_SECTION lock;
 588 } GifDecoder;
 589
 590 typedef struct {
 591     IWICBitmapFrameDecode IWICBitmapFrameDecode_iface;
 592     IWICMetadataBlockReader IWICMetadataBlockReader_iface;
 593     LONG ref;
 594     SavedImage *frame;
 595     GifDecoder *parent;
 596 } GifFrameDecode;
 597
 598 static inline GifDecoder *impl_from_IWICBitmapDecoder(IWICBitmapDecoder *iface)
 599 {
 600     return CONTAINING_RECORD(iface, GifDecoder, IWICBitmapDecoder_iface);
 601 }
 602
 603 static inline GifDecoder *impl_from_IWICMetadataBlockReader(IWICMetadataBlockReader *iface)
 604 {
 605     return CONTAINING_RECORD(iface, GifDecoder, IWICMetadataBlockReader_iface);
 606 }
 607
 608 static inline GifFrameDecode *impl_from_IWICBitmapFrameDecode(IWICBitmapFrameDecode *iface)
 609 {
 610     return CONTAINING_RECORD(iface, GifFrameDecode, IWICBitmapFrameDecode_iface);
 611 }
 612
 613 static inline GifFrameDecode *frame_from_IWICMetadataBlockReader(IWICMetadataBlockReader *iface)
 614 {
 615     return CONTAINING_RECORD(iface, GifFrameDecode, IWICMetadataBlockReader_iface);
 616 }
 617
 618 static HRESULT WINAPI GifFrameDecode_QueryInterface(IWICBitmapFrameDecode *iface, REFIID iid,
 619     void **ppv)
 620 {
 621     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 622     TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
 623
 624     if (!ppv) return E_INVALIDARG;
 625
 626     if (IsEqualIID(&IID_IUnknown, iid) ||
 627         IsEqualIID(&IID_IWICBitmapSource, iid) ||
 628         IsEqualIID(&IID_IWICBitmapFrameDecode, iid))
 629     {
 630         *ppv = &This->IWICBitmapFrameDecode_iface;
 631     }
 632     else if (IsEqualIID(&IID_IWICMetadataBlockReader, iid))
 633     {
 634         *ppv = &This->IWICMetadataBlockReader_iface;
 635     }
 636     else
 637     {
 638         *ppv = NULL;
 639         return E_NOINTERFACE;
 640     }
 641
 642     IUnknown_AddRef((IUnknown*)*ppv);
 643     return S_OK;
 644 }
 645
 646 static ULONG WINAPI GifFrameDecode_AddRef(IWICBitmapFrameDecode *iface)
 647 {
 648     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 649     ULONG ref = InterlockedIncrement(&This->ref);
 650
 651     TRACE("(%p) refcount=%u\n", iface, ref);
 652
 653     return ref;
 654 }
 655
 656 static ULONG WINAPI GifFrameDecode_Release(IWICBitmapFrameDecode *iface)
 657 {
 658     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 659     ULONG ref = InterlockedDecrement(&This->ref);
 660
 661     TRACE("(%p) refcount=%u\n", iface, ref);
 662
 663     if (ref == 0)
 664     {
 665         IWICBitmapDecoder_Release(&This->parent->IWICBitmapDecoder_iface);
 666         HeapFree(GetProcessHeap(), 0, This);
 667     }
 668
 669     return ref;
 670 }
 671
 672 static HRESULT WINAPI GifFrameDecode_GetSize(IWICBitmapFrameDecode *iface,
 673     UINT *puiWidth, UINT *puiHeight)
 674 {
 675     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 676     TRACE("(%p,%p,%p)\n", iface, puiWidth, puiHeight);
 677
 678     *puiWidth = This->frame->ImageDesc.Width;
 679     *puiHeight = This->frame->ImageDesc.Height;
 680
 681     return S_OK;
 682 }
 683
 684 static HRESULT WINAPI GifFrameDecode_GetPixelFormat(IWICBitmapFrameDecode *iface,
 685     WICPixelFormatGUID *pPixelFormat)
 686 {
 687     memcpy(pPixelFormat, &GUID_WICPixelFormat8bppIndexed, sizeof(GUID));
 688
 689     return S_OK;
 690 }
 691
 692 static HRESULT WINAPI GifFrameDecode_GetResolution(IWICBitmapFrameDecode *iface,
 693     double *pDpiX, double *pDpiY)
 694 {
 695     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 696     const GifWord aspect_word = This->parent->gif->SAspectRatio;
 697     const double aspect = (aspect_word > 0) ? ((aspect_word + 15.0) / 64.0) : 1.0;
 698     TRACE("(%p,%p,%p)\n", iface, pDpiX, pDpiY);
 699
 700     *pDpiX = 96.0 / aspect;
 701     *pDpiY = 96.0;
 702
 703     return S_OK;
 704 }
 705
 706 static HRESULT WINAPI GifFrameDecode_CopyPalette(IWICBitmapFrameDecode *iface,
 707     IWICPalette *pIPalette)
 708 {
 709     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 710     WICColor colors[256];
 711     ColorMapObject *cm = This->frame->ImageDesc.ColorMap;
 712     int i, trans;
 713     ExtensionBlock *eb;
 714     TRACE("(%p,%p)\n", iface, pIPalette);
 715
 716     if (!cm) cm = This->parent->gif->SColorMap;
 717
 718     if (cm->ColorCount > 256)
 719     {
 720         ERR("GIF contains %i colors???\n", cm->ColorCount);
 721         return E_FAIL;
 722     }
 723
 724     for (i = 0; i < cm->ColorCount; i++) {
 725         colors[i] = 0xff000000| /* alpha */
 726                     cm->Colors[i].Red << 16|
 727                     cm->Colors[i].Green << 8|
 728                     cm->Colors[i].Blue;
 729     }
 730
 731     /* look for the transparent color extension */
 732     for (i = 0; i < This->frame->Extensions.ExtensionBlockCount; ++i) {
 733         eb = This->frame->Extensions.ExtensionBlocks + i;
 734         if (eb->Function == GRAPHICS_EXT_FUNC_CODE && eb->ByteCount == 8) {
 735             if (eb->Bytes[3] & 1) {
 736                 trans = (unsigned char)eb->Bytes[6];
 737                 colors[trans] &= 0xffffff; /* set alpha to 0 */
 738                 break;
 739             }
 740         }
 741     }
 742
 743     return IWICPalette_InitializeCustom(pIPalette, colors, cm->ColorCount);
 744 }
 745
 746 static HRESULT copy_interlaced_pixels(const BYTE *srcbuffer,
 747     UINT srcwidth, UINT srcheight, INT srcstride, const WICRect *rc,
 748     UINT dststride, UINT dstbuffersize, BYTE *dstbuffer)
 749 {
 750     UINT row_offset; /* number of bytes into the source rows where the data starts */
 751     const BYTE *src;
 752     BYTE *dst;
 753     UINT y;
 754     WICRect rect;
 755
 756     if (!rc)
 757     {
 758         rect.X = 0;
 759         rect.Y = 0;
 760         rect.Width = srcwidth;
 761         rect.Height = srcheight;
 762         rc = &rect;
 763     }
 764     else
 765     {
 766         if (rc->X < 0 || rc->Y < 0 || rc->X+rc->Width > srcwidth || rc->Y+rc->Height > srcheight)
 767             return E_INVALIDARG;
 768     }
 769
 770     if (dststride < rc->Width)
 771         return E_INVALIDARG;
 772
 773     if ((dststride * rc->Height) > dstbuffersize)
 774         return E_INVALIDARG;
 775
 776     row_offset = rc->X;
 777
 778     dst = dstbuffer;
 779     for (y=rc->Y; y-rc->Y < rc->Height; y++)
 780     {
 781         if (y%8 == 0)
 782             src = srcbuffer + srcstride * (y/8);
 783         else if (y%4 == 0)
 784             src = srcbuffer + srcstride * ((srcheight+7)/8 + y/8);
 785         else if (y%2 == 0)
 786             src = srcbuffer + srcstride * ((srcheight+3)/4 + y/4);
 787         else /* y%2 == 1 */
 788             src = srcbuffer + srcstride * ((srcheight+1)/2 + y/2);
 789         src += row_offset;
 790         memcpy(dst, src, rc->Width);
 791         dst += dststride;
 792     }
 793     return S_OK;
 794 }
 795
 796 static HRESULT WINAPI GifFrameDecode_CopyPixels(IWICBitmapFrameDecode *iface,
 797     const WICRect *prc, UINT cbStride, UINT cbBufferSize, BYTE *pbBuffer)
 798 {
 799     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 800     TRACE("(%p,%p,%u,%u,%p)\n", iface, prc, cbStride, cbBufferSize, pbBuffer);
 801
 802     if (This->frame->ImageDesc.Interlace)
 803     {
 804         return copy_interlaced_pixels(This->frame->RasterBits, This->frame->ImageDesc.Width,
 805             This->frame->ImageDesc.Height, This->frame->ImageDesc.Width,
 806             prc, cbStride, cbBufferSize, pbBuffer);
 807     }
 808     else
 809     {
 810         return copy_pixels(8, This->frame->RasterBits, This->frame->ImageDesc.Width,
 811             This->frame->ImageDesc.Height, This->frame->ImageDesc.Width,
 812             prc, cbStride, cbBufferSize, pbBuffer);
 813     }
 814 }
 815
 816 static HRESULT WINAPI GifFrameDecode_GetMetadataQueryReader(IWICBitmapFrameDecode *iface,
 817     IWICMetadataQueryReader **ppIMetadataQueryReader)
 818 {
 819     TRACE("(%p,%p)\n", iface, ppIMetadataQueryReader);
 820     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
 821 }
 822
 823 static HRESULT WINAPI GifFrameDecode_GetColorContexts(IWICBitmapFrameDecode *iface,
 824     UINT cCount, IWICColorContext **ppIColorContexts, UINT *pcActualCount)
 825 {
 826     TRACE("(%p,%u,%p,%p)\n", iface, cCount, ppIColorContexts, pcActualCount);
 827     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
 828 }
 829
 830 static HRESULT WINAPI GifFrameDecode_GetThumbnail(IWICBitmapFrameDecode *iface,
 831     IWICBitmapSource **ppIThumbnail)
 832 {
 833     TRACE("(%p,%p)\n", iface, ppIThumbnail);
 834     return WINCODEC_ERR_CODECNOTHUMBNAIL;
 835 }
 836
 837 static const IWICBitmapFrameDecodeVtbl GifFrameDecode_Vtbl = {
 838     GifFrameDecode_QueryInterface,
 839     GifFrameDecode_AddRef,
 840     GifFrameDecode_Release,
 841     GifFrameDecode_GetSize,
 842     GifFrameDecode_GetPixelFormat,
 843     GifFrameDecode_GetResolution,
 844     GifFrameDecode_CopyPalette,
 845     GifFrameDecode_CopyPixels,
 846     GifFrameDecode_GetMetadataQueryReader,
 847     GifFrameDecode_GetColorContexts,
 848     GifFrameDecode_GetThumbnail
 849 };
 850
 851 static HRESULT WINAPI GifFrameDecode_Block_QueryInterface(IWICMetadataBlockReader *iface,
 852     REFIID iid, void **ppv)
 853 {
 854     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 855     return IWICBitmapFrameDecode_QueryInterface(&This->IWICBitmapFrameDecode_iface, iid, ppv);
 856 }
 857
 858 static ULONG WINAPI GifFrameDecode_Block_AddRef(IWICMetadataBlockReader *iface)
 859 {
 860     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 861     return IWICBitmapFrameDecode_AddRef(&This->IWICBitmapFrameDecode_iface);
 862 }
 863
 864 static ULONG WINAPI GifFrameDecode_Block_Release(IWICMetadataBlockReader *iface)
 865 {
 866     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 867     return IWICBitmapFrameDecode_Release(&This->IWICBitmapFrameDecode_iface);
 868 }
 869
 870 static HRESULT WINAPI GifFrameDecode_Block_GetContainerFormat(IWICMetadataBlockReader *iface,
 871     GUID *guid)
 872 {
 873     TRACE("(%p,%p)\n", iface, guid);
 874
 875     if (!guid) return E_INVALIDARG;
 876
 877     *guid = GUID_ContainerFormatGif;
 878     return S_OK;
 879 }
 880
 881 static HRESULT WINAPI GifFrameDecode_Block_GetCount(IWICMetadataBlockReader *iface,
 882     UINT *count)
 883 {
 884     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 885
 886     TRACE("%p,%p\n", iface, count);
 887
 888     if (!count) return E_INVALIDARG;
 889
 890     *count = This->frame->Extensions.ExtensionBlockCount + 1;
 891     return S_OK;
 892 }
 893
 894 static HRESULT create_IMD_metadata_reader(GifFrameDecode *This, IWICMetadataReader **reader)
 895 {
 896     HRESULT hr;
 897     IWICMetadataReader *metadata_reader;
 898     IWICPersistStream *persist;
 899     IStream *stream;
 900     struct image_descriptor IMD_data;
 901
 902     /* FIXME: Use IWICComponentFactory_CreateMetadataReader once it's implemented */
 903
 904     hr = IMDReader_CreateInstance(&IID_IWICMetadataReader, (void **)&metadata_reader);
 905     if (FAILED(hr)) return hr;
 906
 907     hr = IWICMetadataReader_QueryInterface(metadata_reader, &IID_IWICPersistStream, (void **)&persist);
 908     if (FAILED(hr))
 909     {
 910         IWICMetadataReader_Release(metadata_reader);
 911         return hr;
 912     }
 913
 914     /* recreate IMD structure from GIF decoder data */
 915     IMD_data.left = This->frame->ImageDesc.Left;
 916     IMD_data.top = This->frame->ImageDesc.Top;
 917     IMD_data.width = This->frame->ImageDesc.Width;
 918     IMD_data.height = This->frame->ImageDesc.Height;
 919     IMD_data.packed = 0;
 920     /* interlace_flag */
 921     IMD_data.packed |= This->frame->ImageDesc.Interlace ? (1 << 6) : 0;
 922     if (This->frame->ImageDesc.ColorMap)
 923     {
 924         /* local_color_table_flag */
 925         IMD_data.packed |= 1 << 7;
 926         /* local_color_table_size */
 927         IMD_data.packed |= This->frame->ImageDesc.ColorMap->BitsPerPixel - 1;
 928         /* sort_flag */
 929         IMD_data.packed |= This->frame->ImageDesc.ColorMap->SortFlag ? 0x20 : 0;
 930     }
 931
 932     stream = create_stream(&IMD_data, sizeof(IMD_data));
 933     IWICPersistStream_LoadEx(persist, stream, NULL, WICPersistOptionsDefault);
 934     IStream_Release(stream);
 935
 936     IWICPersistStream_Release(persist);
 937
 938     *reader = metadata_reader;
 939     return S_OK;
 940 }
 941
 942 static HRESULT WINAPI GifFrameDecode_Block_GetReaderByIndex(IWICMetadataBlockReader *iface,
 943     UINT index, IWICMetadataReader **reader)
 944 {
 945     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 946     int i, gce_index = -1, gce_skipped = 0;
 947
 948     TRACE("(%p,%u,%p)\n", iface, index, reader);
 949
 950     if (!reader) return E_INVALIDARG;
 951
 952     if (index == 0)
 953         return create_IMD_metadata_reader(This, reader);
 954
 955     if (index >= This->frame->Extensions.ExtensionBlockCount + 1)
 956         return E_INVALIDARG;
 957
 958     for (i = 0; i < This->frame->Extensions.ExtensionBlockCount; i++)
 959     {
 960         class_constructor constructor;
 961         const void *data;
 962         int data_size;
 963
 964         if (index != i + 1 - gce_skipped) continue;
 965
 966         if (This->frame->Extensions.ExtensionBlocks[i].Function == GRAPHICS_EXT_FUNC_CODE)
 967         {
 968             gce_index = i;
 969             gce_skipped = 1;
 970             continue;
 971         }
 972         else if (This->frame->Extensions.ExtensionBlocks[i].Function == COMMENT_EXT_FUNC_CODE)
 973         {
 974             constructor = GifCommentReader_CreateInstance;
 975             data = This->frame->Extensions.ExtensionBlocks[i].Bytes;
 976             data_size = This->frame->Extensions.ExtensionBlocks[i].ByteCount;
 977         }
 978         else
 979         {
 980             constructor = UnknownMetadataReader_CreateInstance;
 981             data = This->frame->Extensions.ExtensionBlocks[i].Bytes;
 982             data_size = This->frame->Extensions.ExtensionBlocks[i].ByteCount;
 983         }
 984         return create_metadata_reader(data, data_size, constructor, reader);
 985     }
 986
 987     if (gce_index == -1) return E_INVALIDARG;
 988
 989     return create_metadata_reader(This->frame->Extensions.ExtensionBlocks[gce_index].Bytes + 3,
 990                                   This->frame->Extensions.ExtensionBlocks[gce_index].ByteCount - 4,
 991                                   GCEReader_CreateInstance, reader);
 992 }
 993
 994 static HRESULT WINAPI GifFrameDecode_Block_GetEnumerator(IWICMetadataBlockReader *iface,
 995     IEnumUnknown **enumerator)
 996 {
 997     FIXME("(%p,%p): stub\n", iface, enumerator);
 998     return E_NOTIMPL;
 999 }
1000
1001 static const IWICMetadataBlockReaderVtbl GifFrameDecode_BlockVtbl =
1002 {
1003     GifFrameDecode_Block_QueryInterface,
1004     GifFrameDecode_Block_AddRef,
1005     GifFrameDecode_Block_Release,
1006     GifFrameDecode_Block_GetContainerFormat,
1007     GifFrameDecode_Block_GetCount,
1008     GifFrameDecode_Block_GetReaderByIndex,
1009     GifFrameDecode_Block_GetEnumerator
1010 };
1011
1012 static HRESULT WINAPI GifDecoder_QueryInterface(IWICBitmapDecoder *iface, REFIID iid,
1013     void **ppv)
1014 {
1015     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1016     TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
1017
1018     if (!ppv) return E_INVALIDARG;
1019
1020     if (IsEqualIID(&IID_IUnknown, iid) ||
1021         IsEqualIID(&IID_IWICBitmapDecoder, iid))
1022     {
1023         *ppv = &This->IWICBitmapDecoder_iface;
1024     }
1025     else if (IsEqualIID(&IID_IWICMetadataBlockReader, iid))
1026     {
1027         *ppv = &This->IWICMetadataBlockReader_iface;
1028     }
1029     else
1030     {
1031         *ppv = NULL;
1032         return E_NOINTERFACE;
1033     }
1034
1035     IUnknown_AddRef((IUnknown*)*ppv);
1036     return S_OK;
1037 }
1038
1039 static ULONG WINAPI GifDecoder_AddRef(IWICBitmapDecoder *iface)
1040 {
1041     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1042     ULONG ref = InterlockedIncrement(&This->ref);
1043
1044     TRACE("(%p) refcount=%u\n", iface, ref);
1045
1046     return ref;
1047 }
1048
1049 static ULONG WINAPI GifDecoder_Release(IWICBitmapDecoder *iface)
1050 {
1051     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1052     ULONG ref = InterlockedDecrement(&This->ref);
1053
1054     TRACE("(%p) refcount=%u\n", iface, ref);
1055
1056     if (ref == 0)
1057     {
1058         IStream_Release(This->stream);
1059         This->lock.DebugInfo->Spare[0] = 0;
1060         DeleteCriticalSection(&This->lock);
1061         DGifCloseFile(This->gif);
1062         HeapFree(GetProcessHeap(), 0, This);
1063     }
1064
1065     return ref;
1066 }
1067
1068 static HRESULT WINAPI GifDecoder_QueryCapability(IWICBitmapDecoder *iface, IStream *stream,
1069     DWORD *capability)
1070 {
1071     HRESULT hr;
1072
1073     TRACE("(%p,%p,%p)\n", iface, stream, capability);
1074
1075     if (!stream || !capability) return E_INVALIDARG;
1076
1077     hr = IWICBitmapDecoder_Initialize(iface, stream, WICDecodeMetadataCacheOnDemand);
1078     if (hr != S_OK) return hr;
1079
1080     *capability = WICBitmapDecoderCapabilityCanDecodeAllImages |
1081                   WICBitmapDecoderCapabilityCanDecodeSomeImages |
1082                   WICBitmapDecoderCapabilityCanEnumerateMetadata;
1083     return S_OK;
1084 }
1085
1086 static int _gif_inputfunc(GifFileType *gif, GifByteType *data, int len) {
1087     IStream *stream = gif->UserData;
1088     ULONG bytesread;
1089     HRESULT hr;
1090
1091     if (!stream)
1092     {
1093         ERR("attempting to read file after initialization\n");
1094         return 0;
1095     }
1096
1097     hr = IStream_Read(stream, data, len, &bytesread);
1098     if (FAILED(hr)) bytesread = 0;
1099     return bytesread;
1100 }
1101
1102 static HRESULT WINAPI GifDecoder_Initialize(IWICBitmapDecoder *iface, IStream *pIStream,
1103     WICDecodeOptions cacheOptions)
1104 {
1105     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1106     LARGE_INTEGER seek;
1107     int ret;
1108
1109     TRACE("(%p,%p,%x)\n", iface, pIStream, cacheOptions);
1110
1111     EnterCriticalSection(&This->lock);
1112
1113     if (This->initialized || This->gif)
1114     {
1115         WARN("already initialized\n");
1116         LeaveCriticalSection(&This->lock);
1117         return WINCODEC_ERR_WRONGSTATE;
1118     }
1119
1120     /* seek to start of stream */
1121     seek.QuadPart = 0;
1122     IStream_Seek(pIStream, seek, STREAM_SEEK_SET, NULL);
1123
1124     /* read all data from the stream */
1125     This->gif = DGifOpen((void*)pIStream, _gif_inputfunc);
1126     if (!This->gif)
1127     {
1128         LeaveCriticalSection(&This->lock);
1129         return E_FAIL;
1130     }
1131
1132     ret = DGifSlurp(This->gif);
1133     if (ret == GIF_ERROR)
1134     {
1135         LeaveCriticalSection(&This->lock);
1136         return E_FAIL;
1137     }
1138
1139     /* make sure we don't use the stream after this method returns */
1140     This->gif->UserData = NULL;
1141
1142     seek.QuadPart = 0;
1143     IStream_Seek(pIStream, seek, STREAM_SEEK_SET, NULL);
1144     IStream_Read(pIStream, This->LSD_data, sizeof(This->LSD_data), NULL);
1145
1146     This->stream = pIStream;
1147     IStream_AddRef(This->stream);
1148
1149     This->initialized = TRUE;
1150
1151     LeaveCriticalSection(&This->lock);
1152
1153     return S_OK;
1154 }
1155
1156 static HRESULT WINAPI GifDecoder_GetContainerFormat(IWICBitmapDecoder *iface,
1157     GUID *pguidContainerFormat)
1158 {
1159     memcpy(pguidContainerFormat, &GUID_ContainerFormatGif, sizeof(GUID));
1160     return S_OK;
1161 }
1162
1163 static HRESULT WINAPI GifDecoder_GetDecoderInfo(IWICBitmapDecoder *iface,
1164     IWICBitmapDecoderInfo **ppIDecoderInfo)
1165 {
1166     HRESULT hr;
1167     IWICComponentInfo *compinfo;
1168
1169     TRACE("(%p,%p)\n", iface, ppIDecoderInfo);
1170
1171     hr = CreateComponentInfo(&CLSID_WICGifDecoder, &compinfo);
1172     if (FAILED(hr)) return hr;
1173
1174     hr = IWICComponentInfo_QueryInterface(compinfo, &IID_IWICBitmapDecoderInfo,
1175         (void**)ppIDecoderInfo);
1176
1177     IWICComponentInfo_Release(compinfo);
1178
1179     return hr;
1180 }
1181
1182 static HRESULT WINAPI GifDecoder_CopyPalette(IWICBitmapDecoder *iface, IWICPalette *palette)
1183 {
1184     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1185     WICColor colors[256];
1186     ColorMapObject *cm;
1187     int i, trans, count;
1188     ExtensionBlock *eb;
1189
1190     TRACE("(%p,%p)\n", iface, palette);
1191
1192     cm = This->gif->SColorMap;
1193     if (cm)
1194     {
1195         if (cm->ColorCount > 256)
1196         {
1197             ERR("GIF contains invalid number of colors: %d\n", cm->ColorCount);
1198             return E_FAIL;
1199         }
1200
1201         for (i = 0; i < cm->ColorCount; i++)
1202         {
1203             colors[i] = 0xff000000 | /* alpha */
1204                         cm->Colors[i].Red << 16 |
1205                         cm->Colors[i].Green << 8 |
1206                         cm->Colors[i].Blue;
1207         }
1208
1209         count = cm->ColorCount;
1210     }
1211     else
1212     {
1213         colors[0] = 0xff000000;
1214         colors[1] = 0xffffffff;
1215
1216         for (i = 2; i < 256; i++)
1217             colors[i] = 0xff000000;
1218
1219         count = 256;
1220     }
1221
1222     /* look for the transparent color extension */
1223     for (i = 0; i < This->gif->SavedImages[This->current_frame].Extensions.ExtensionBlockCount; i++)
1224     {
1225         eb = This->gif->SavedImages[This->current_frame].Extensions.ExtensionBlocks + i;
1226         if (eb->Function == GRAPHICS_EXT_FUNC_CODE && eb->ByteCount == 8)
1227         {
1228             if (eb->Bytes[3] & 1)
1229             {
1230                 trans = (unsigned char)eb->Bytes[6];
1231                 colors[trans] &= 0xffffff; /* set alpha to 0 */
1232                 break;
1233             }
1234         }
1235     }
1236
1237     return IWICPalette_InitializeCustom(palette, colors, count);
1238 }
1239
1240 static HRESULT WINAPI GifDecoder_GetMetadataQueryReader(IWICBitmapDecoder *iface,
1241     IWICMetadataQueryReader **ppIMetadataQueryReader)
1242 {
1243     TRACE("(%p,%p)\n", iface, ppIMetadataQueryReader);
1244     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
1245 }
1246
1247 static HRESULT WINAPI GifDecoder_GetPreview(IWICBitmapDecoder *iface,
1248     IWICBitmapSource **ppIBitmapSource)
1249 {
1250     TRACE("(%p,%p)\n", iface, ppIBitmapSource);
1251     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
1252 }
1253
1254 static HRESULT WINAPI GifDecoder_GetColorContexts(IWICBitmapDecoder *iface,
1255     UINT cCount, IWICColorContext **ppIColorContexts, UINT *pcActualCount)
1256 {
1257     TRACE("(%p,%u,%p,%p)\n", iface, cCount, ppIColorContexts, pcActualCount);
1258     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
1259 }
1260
1261 static HRESULT WINAPI GifDecoder_GetThumbnail(IWICBitmapDecoder *iface,
1262     IWICBitmapSource **ppIThumbnail)
1263 {
1264     TRACE("(%p,%p)\n", iface, ppIThumbnail);
1265     return WINCODEC_ERR_CODECNOTHUMBNAIL;
1266 }
1267
1268 static HRESULT WINAPI GifDecoder_GetFrameCount(IWICBitmapDecoder *iface,
1269     UINT *pCount)
1270 {
1271     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1272
1273     if (!pCount) return E_INVALIDARG;
1274
1275     EnterCriticalSection(&This->lock);
1276     *pCount = This->gif ? This->gif->ImageCount : 0;
1277     LeaveCriticalSection(&This->lock);
1278
1279     TRACE("(%p) <-- %d\n", iface, *pCount);
1280
1281     return S_OK;
1282 }
1283
1284 static HRESULT WINAPI GifDecoder_GetFrame(IWICBitmapDecoder *iface,
1285     UINT index, IWICBitmapFrameDecode **ppIBitmapFrame)
1286 {
1287     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1288     GifFrameDecode *result;
1289     TRACE("(%p,%u,%p)\n", iface, index, ppIBitmapFrame);
1290
1291     if (!This->initialized) return WINCODEC_ERR_FRAMEMISSING;
1292
1293     if (index >= This->gif->ImageCount) return E_INVALIDARG;
1294
1295     result = HeapAlloc(GetProcessHeap(), 0, sizeof(GifFrameDecode));
1296     if (!result) return E_OUTOFMEMORY;
1297
1298     result->IWICBitmapFrameDecode_iface.lpVtbl = &GifFrameDecode_Vtbl;
1299     result->IWICMetadataBlockReader_iface.lpVtbl = &GifFrameDecode_BlockVtbl;
1300     result->ref = 1;
1301     result->frame = &This->gif->SavedImages[index];
1302     IWICBitmapDecoder_AddRef(iface);
1303     result->parent = This;
1304     This->current_frame = index;
1305
1306     *ppIBitmapFrame = &result->IWICBitmapFrameDecode_iface;
1307
1308     return S_OK;
1309 }
1310
1311 static const IWICBitmapDecoderVtbl GifDecoder_Vtbl = {
1312     GifDecoder_QueryInterface,
1313     GifDecoder_AddRef,
1314     GifDecoder_Release,
1315     GifDecoder_QueryCapability,
1316     GifDecoder_Initialize,
1317     GifDecoder_GetContainerFormat,
1318     GifDecoder_GetDecoderInfo,
1319     GifDecoder_CopyPalette,
1320     GifDecoder_GetMetadataQueryReader,
1321     GifDecoder_GetPreview,
1322     GifDecoder_GetColorContexts,
1323     GifDecoder_GetThumbnail,
1324     GifDecoder_GetFrameCount,
1325     GifDecoder_GetFrame
1326 };
1327
1328 static HRESULT WINAPI GifDecoder_Block_QueryInterface(IWICMetadataBlockReader *iface,
1329     REFIID iid, void **ppv)
1330 {
1331     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1332     return IWICBitmapDecoder_QueryInterface(&This->IWICBitmapDecoder_iface, iid, ppv);
1333 }
1334
1335 static ULONG WINAPI GifDecoder_Block_AddRef(IWICMetadataBlockReader *iface)
1336 {
1337     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1338     return IWICBitmapDecoder_AddRef(&This->IWICBitmapDecoder_iface);
1339 }
1340
1341 static ULONG WINAPI GifDecoder_Block_Release(IWICMetadataBlockReader *iface)
1342 {
1343     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1344     return IWICBitmapDecoder_Release(&This->IWICBitmapDecoder_iface);
1345 }
1346
1347 static HRESULT WINAPI GifDecoder_Block_GetContainerFormat(IWICMetadataBlockReader *iface,
1348     GUID *guid)
1349 {
1350     TRACE("(%p,%p)\n", iface, guid);
1351
1352     if (!guid) return E_INVALIDARG;
1353
1354     *guid = GUID_ContainerFormatGif;
1355     return S_OK;
1356 }
1357
1358 static HRESULT WINAPI GifDecoder_Block_GetCount(IWICMetadataBlockReader *iface,
1359     UINT *count)
1360 {
1361     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1362
1363     TRACE("%p,%p\n", iface, count);
1364
1365     if (!count) return E_INVALIDARG;
1366
1367     *count = This->gif->Extensions.ExtensionBlockCount + 1;
1368     return S_OK;
1369 }
1370
1371 static HRESULT WINAPI GifDecoder_Block_GetReaderByIndex(IWICMetadataBlockReader *iface,
1372     UINT index, IWICMetadataReader **reader)
1373 {
1374     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1375     int i;
1376
1377     TRACE("(%p,%u,%p)\n", iface, index, reader);
1378
1379     if (!reader) return E_INVALIDARG;
1380
1381     if (index == 0)
1382         return create_metadata_reader(This->LSD_data, sizeof(This->LSD_data),
1383                                       LSDReader_CreateInstance, reader);
1384
1385     for (i = 0; i < This->gif->Extensions.ExtensionBlockCount; i++)
1386     {
1387         class_constructor constructor;
1388
1389         if (index != i + 1) continue;
1390
1391         if (This->gif->Extensions.ExtensionBlocks[i].Function == APPLICATION_EXT_FUNC_CODE)
1392             constructor = APEReader_CreateInstance;
1393         else if (This->gif->Extensions.ExtensionBlocks[i].Function == COMMENT_EXT_FUNC_CODE)
1394             constructor = GifCommentReader_CreateInstance;
1395         else
1396             constructor = UnknownMetadataReader_CreateInstance;
1397
1398         return create_metadata_reader(This->gif->Extensions.ExtensionBlocks[i].Bytes,
1399                                       This->gif->Extensions.ExtensionBlocks[i].ByteCount,
1400                                       constructor, reader);
1401     }
1402
1403     return E_INVALIDARG;
1404 }
1405
1406 static HRESULT WINAPI GifDecoder_Block_GetEnumerator(IWICMetadataBlockReader *iface,
1407     IEnumUnknown **enumerator)
1408 {
1409     FIXME("(%p,%p): stub\n", iface, enumerator);
1410     return E_NOTIMPL;
1411 }
1412
1413 static const IWICMetadataBlockReaderVtbl GifDecoder_BlockVtbl =
1414 {
1415     GifDecoder_Block_QueryInterface,
1416     GifDecoder_Block_AddRef,
1417     GifDecoder_Block_Release,
1418     GifDecoder_Block_GetContainerFormat,
1419     GifDecoder_Block_GetCount,
1420     GifDecoder_Block_GetReaderByIndex,
1421     GifDecoder_Block_GetEnumerator
1422 };
1423
1424 HRESULT GifDecoder_CreateInstance(REFIID iid, void** ppv)
1425 {
1426     GifDecoder *This;
1427     HRESULT ret;
1428
1429     TRACE("(%s,%p)\n", debugstr_guid(iid), ppv);
1430
1431     *ppv = NULL;
1432
1433     This = HeapAlloc(GetProcessHeap(), 0, sizeof(GifDecoder));
1434     if (!This) return E_OUTOFMEMORY;
1435
1436     This->IWICBitmapDecoder_iface.lpVtbl = &GifDecoder_Vtbl;
1437     This->IWICMetadataBlockReader_iface.lpVtbl = &GifDecoder_BlockVtbl;
1438     This->ref = 1;
1439     This->initialized = FALSE;
1440     This->gif = NULL;
1441     This->current_frame = 0;
1442     InitializeCriticalSection(&This->lock);
1443     This->lock.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": GifDecoder.lock");
1444
1445     ret = IWICBitmapDecoder_QueryInterface(&This->IWICBitmapDecoder_iface, iid, ppv);
1446     IWICBitmapDecoder_Release(&This->IWICBitmapDecoder_iface);
1447
1448     return ret;
1449 }