dlls/windowscodecs/gifformat.c

   1 /*
   2  * Copyright 2009 Vincent Povirk for CodeWeavers
   3  * Copyright 2012,2016 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 <stdarg.h>
  21
  22 #define COBJMACROS
  23 #define NONAMELESSUNION
  24
  25 #include "windef.h"
  26 #include "winbase.h"
  27 #include "objbase.h"
  28
  29 #include "ungif.h"
  30
  31 #include "wincodecs_private.h"
  32
  33 #include "wine/debug.h"
  34
  35 WINE_DEFAULT_DEBUG_CHANNEL(wincodecs);
  36
  37 #include "pshpack1.h"
  38
  39 struct logical_screen_descriptor
  40 {
  41     char signature[6];
  42     USHORT width;
  43     USHORT height;
  44     BYTE packed;
  45     /* global_color_table_flag : 1;
  46      * color_resolution : 3;
  47      * sort_flag : 1;
  48      * global_color_table_size : 3;
  49      */
  50     BYTE background_color_index;
  51     BYTE pixel_aspect_ratio;
  52 };
  53
  54 struct image_descriptor
  55 {
  56     USHORT left;
  57     USHORT top;
  58     USHORT width;
  59     USHORT height;
  60     BYTE packed;
  61     /* local_color_table_flag : 1;
  62      * interlace_flag : 1;
  63      * sort_flag : 1;
  64      * reserved : 2;
  65      * local_color_table_size : 3;
  66      */
  67 };
  68
  69 #include "poppack.h"
  70
  71 static LPWSTR strdupAtoW(const char *src)
  72 {
  73     int len = MultiByteToWideChar(CP_ACP, 0, src, -1, NULL, 0);
  74     LPWSTR dst = HeapAlloc(GetProcessHeap(), 0, len * sizeof(WCHAR));
  75     if (dst) MultiByteToWideChar(CP_ACP, 0, src, -1, dst, len);
  76     return dst;
  77 }
  78
  79 static HRESULT load_LSD_metadata(IStream *stream, const GUID *vendor, DWORD options,
  80                                  MetadataItem **items, DWORD *count)
  81 {
  82     struct logical_screen_descriptor lsd_data;
  83     HRESULT hr;
  84     ULONG bytesread, i;
  85     MetadataItem *result;
  86
  87     *items = NULL;
  88     *count = 0;
  89
  90     hr = IStream_Read(stream, &lsd_data, sizeof(lsd_data), &bytesread);
  91     if (FAILED(hr) || bytesread != sizeof(lsd_data)) return S_OK;
  92
  93     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 9);
  94     if (!result) return E_OUTOFMEMORY;
  95
  96     for (i = 0; i < 9; i++)
  97     {
  98         PropVariantInit(&result[i].schema);
  99         PropVariantInit(&result[i].id);
 100         PropVariantInit(&result[i].value);
 101     }
 102
 103     result[0].id.vt = VT_LPWSTR;
 104     result[0].id.u.pwszVal = strdupAtoW("Signature");
 105     result[0].value.vt = VT_UI1|VT_VECTOR;
 106     result[0].value.u.caub.cElems = sizeof(lsd_data.signature);
 107     result[0].value.u.caub.pElems = HeapAlloc(GetProcessHeap(), 0, sizeof(lsd_data.signature));
 108     memcpy(result[0].value.u.caub.pElems, lsd_data.signature, sizeof(lsd_data.signature));
 109
 110     result[1].id.vt = VT_LPWSTR;
 111     result[1].id.u.pwszVal = strdupAtoW("Width");
 112     result[1].value.vt = VT_UI2;
 113     result[1].value.u.uiVal = lsd_data.width;
 114
 115     result[2].id.vt = VT_LPWSTR;
 116     result[2].id.u.pwszVal = strdupAtoW("Height");
 117     result[2].value.vt = VT_UI2;
 118     result[2].value.u.uiVal = lsd_data.height;
 119
 120     result[3].id.vt = VT_LPWSTR;
 121     result[3].id.u.pwszVal = strdupAtoW("GlobalColorTableFlag");
 122     result[3].value.vt = VT_BOOL;
 123     result[3].value.u.boolVal = (lsd_data.packed >> 7) & 1;
 124
 125     result[4].id.vt = VT_LPWSTR;
 126     result[4].id.u.pwszVal = strdupAtoW("ColorResolution");
 127     result[4].value.vt = VT_UI1;
 128     result[4].value.u.bVal = (lsd_data.packed >> 4) & 7;
 129
 130     result[5].id.vt = VT_LPWSTR;
 131     result[5].id.u.pwszVal = strdupAtoW("SortFlag");
 132     result[5].value.vt = VT_BOOL;
 133     result[5].value.u.boolVal = (lsd_data.packed >> 3) & 1;
 134
 135     result[6].id.vt = VT_LPWSTR;
 136     result[6].id.u.pwszVal = strdupAtoW("GlobalColorTableSize");
 137     result[6].value.vt = VT_UI1;
 138     result[6].value.u.bVal = lsd_data.packed & 7;
 139
 140     result[7].id.vt = VT_LPWSTR;
 141     result[7].id.u.pwszVal = strdupAtoW("BackgroundColorIndex");
 142     result[7].value.vt = VT_UI1;
 143     result[7].value.u.bVal = lsd_data.background_color_index;
 144
 145     result[8].id.vt = VT_LPWSTR;
 146     result[8].id.u.pwszVal = strdupAtoW("PixelAspectRatio");
 147     result[8].value.vt = VT_UI1;
 148     result[8].value.u.bVal = lsd_data.pixel_aspect_ratio;
 149
 150     *items = result;
 151     *count = 9;
 152
 153     return S_OK;
 154 }
 155
 156 static const MetadataHandlerVtbl LSDReader_Vtbl = {
 157     0,
 158     &CLSID_WICLSDMetadataReader,
 159     load_LSD_metadata
 160 };
 161
 162 HRESULT LSDReader_CreateInstance(REFIID iid, void **ppv)
 163 {
 164     return MetadataReader_Create(&LSDReader_Vtbl, iid, ppv);
 165 }
 166
 167 static HRESULT load_IMD_metadata(IStream *stream, const GUID *vendor, DWORD options,
 168                                  MetadataItem **items, DWORD *count)
 169 {
 170     struct image_descriptor imd_data;
 171     HRESULT hr;
 172     ULONG bytesread, i;
 173     MetadataItem *result;
 174
 175     *items = NULL;
 176     *count = 0;
 177
 178     hr = IStream_Read(stream, &imd_data, sizeof(imd_data), &bytesread);
 179     if (FAILED(hr) || bytesread != sizeof(imd_data)) return S_OK;
 180
 181     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 8);
 182     if (!result) return E_OUTOFMEMORY;
 183
 184     for (i = 0; i < 8; i++)
 185     {
 186         PropVariantInit(&result[i].schema);
 187         PropVariantInit(&result[i].id);
 188         PropVariantInit(&result[i].value);
 189     }
 190
 191     result[0].id.vt = VT_LPWSTR;
 192     result[0].id.u.pwszVal = strdupAtoW("Left");
 193     result[0].value.vt = VT_UI2;
 194     result[0].value.u.uiVal = imd_data.left;
 195
 196     result[1].id.vt = VT_LPWSTR;
 197     result[1].id.u.pwszVal = strdupAtoW("Top");
 198     result[1].value.vt = VT_UI2;
 199     result[1].value.u.uiVal = imd_data.top;
 200
 201     result[2].id.vt = VT_LPWSTR;
 202     result[2].id.u.pwszVal = strdupAtoW("Width");
 203     result[2].value.vt = VT_UI2;
 204     result[2].value.u.uiVal = imd_data.width;
 205
 206     result[3].id.vt = VT_LPWSTR;
 207     result[3].id.u.pwszVal = strdupAtoW("Height");
 208     result[3].value.vt = VT_UI2;
 209     result[3].value.u.uiVal = imd_data.height;
 210
 211     result[4].id.vt = VT_LPWSTR;
 212     result[4].id.u.pwszVal = strdupAtoW("LocalColorTableFlag");
 213     result[4].value.vt = VT_BOOL;
 214     result[4].value.u.boolVal = (imd_data.packed >> 7) & 1;
 215
 216     result[5].id.vt = VT_LPWSTR;
 217     result[5].id.u.pwszVal = strdupAtoW("InterlaceFlag");
 218     result[5].value.vt = VT_BOOL;
 219     result[5].value.u.boolVal = (imd_data.packed >> 6) & 1;
 220
 221     result[6].id.vt = VT_LPWSTR;
 222     result[6].id.u.pwszVal = strdupAtoW("SortFlag");
 223     result[6].value.vt = VT_BOOL;
 224     result[6].value.u.boolVal = (imd_data.packed >> 5) & 1;
 225
 226     result[7].id.vt = VT_LPWSTR;
 227     result[7].id.u.pwszVal = strdupAtoW("LocalColorTableSize");
 228     result[7].value.vt = VT_UI1;
 229     result[7].value.u.bVal = imd_data.packed & 7;
 230
 231     *items = result;
 232     *count = 8;
 233
 234     return S_OK;
 235 }
 236
 237 static const MetadataHandlerVtbl IMDReader_Vtbl = {
 238     0,
 239     &CLSID_WICIMDMetadataReader,
 240     load_IMD_metadata
 241 };
 242
 243 HRESULT IMDReader_CreateInstance(REFIID iid, void **ppv)
 244 {
 245     return MetadataReader_Create(&IMDReader_Vtbl, iid, ppv);
 246 }
 247
 248 static HRESULT load_GCE_metadata(IStream *stream, const GUID *vendor, DWORD options,
 249                                  MetadataItem **items, DWORD *count)
 250 {
 251 #include "pshpack1.h"
 252     struct graphic_control_extension
 253     {
 254         BYTE packed;
 255         /* reservred: 3;
 256          * disposal : 3;
 257          * user_input_flag : 1;
 258          * transparency_flag : 1;
 259          */
 260          USHORT delay;
 261          BYTE transparent_color_index;
 262     } gce_data;
 263 #include "poppack.h"
 264     HRESULT hr;
 265     ULONG bytesread, i;
 266     MetadataItem *result;
 267
 268     *items = NULL;
 269     *count = 0;
 270
 271     hr = IStream_Read(stream, &gce_data, sizeof(gce_data), &bytesread);
 272     if (FAILED(hr) || bytesread != sizeof(gce_data)) return S_OK;
 273
 274     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 5);
 275     if (!result) return E_OUTOFMEMORY;
 276
 277     for (i = 0; i < 5; i++)
 278     {
 279         PropVariantInit(&result[i].schema);
 280         PropVariantInit(&result[i].id);
 281         PropVariantInit(&result[i].value);
 282     }
 283
 284     result[0].id.vt = VT_LPWSTR;
 285     result[0].id.u.pwszVal = strdupAtoW("Disposal");
 286     result[0].value.vt = VT_UI1;
 287     result[0].value.u.bVal = (gce_data.packed >> 2) & 7;
 288
 289     result[1].id.vt = VT_LPWSTR;
 290     result[1].id.u.pwszVal = strdupAtoW("UserInputFlag");
 291     result[1].value.vt = VT_BOOL;
 292     result[1].value.u.boolVal = (gce_data.packed >> 1) & 1;
 293
 294     result[2].id.vt = VT_LPWSTR;
 295     result[2].id.u.pwszVal = strdupAtoW("TransparencyFlag");
 296     result[2].value.vt = VT_BOOL;
 297     result[2].value.u.boolVal = gce_data.packed & 1;
 298
 299     result[3].id.vt = VT_LPWSTR;
 300     result[3].id.u.pwszVal = strdupAtoW("Delay");
 301     result[3].value.vt = VT_UI2;
 302     result[3].value.u.uiVal = gce_data.delay;
 303
 304     result[4].id.vt = VT_LPWSTR;
 305     result[4].id.u.pwszVal = strdupAtoW("TransparentColorIndex");
 306     result[4].value.vt = VT_UI1;
 307     result[4].value.u.bVal = gce_data.transparent_color_index;
 308
 309     *items = result;
 310     *count = 5;
 311
 312     return S_OK;
 313 }
 314
 315 static const MetadataHandlerVtbl GCEReader_Vtbl = {
 316     0,
 317     &CLSID_WICGCEMetadataReader,
 318     load_GCE_metadata
 319 };
 320
 321 HRESULT GCEReader_CreateInstance(REFIID iid, void **ppv)
 322 {
 323     return MetadataReader_Create(&GCEReader_Vtbl, iid, ppv);
 324 }
 325
 326 static HRESULT load_APE_metadata(IStream *stream, const GUID *vendor, DWORD options,
 327                                  MetadataItem **items, DWORD *count)
 328 {
 329 #include "pshpack1.h"
 330     struct application_extension
 331     {
 332         BYTE extension_introducer;
 333         BYTE extension_label;
 334         BYTE block_size;
 335         BYTE application[11];
 336     } ape_data;
 337 #include "poppack.h"
 338     HRESULT hr;
 339     ULONG bytesread, data_size, i;
 340     MetadataItem *result;
 341     BYTE subblock_size;
 342     BYTE *data;
 343
 344     *items = NULL;
 345     *count = 0;
 346
 347     hr = IStream_Read(stream, &ape_data, sizeof(ape_data), &bytesread);
 348     if (FAILED(hr) || bytesread != sizeof(ape_data)) return S_OK;
 349     if (ape_data.extension_introducer != 0x21 ||
 350         ape_data.extension_label != APPLICATION_EXT_FUNC_CODE ||
 351         ape_data.block_size != 11)
 352         return S_OK;
 353
 354     data = NULL;
 355     data_size = 0;
 356
 357     for (;;)
 358     {
 359         hr = IStream_Read(stream, &subblock_size, sizeof(subblock_size), &bytesread);
 360         if (FAILED(hr) || bytesread != sizeof(subblock_size))
 361         {
 362             HeapFree(GetProcessHeap(), 0, data);
 363             return S_OK;
 364         }
 365         if (!subblock_size) break;
 366
 367         if (!data)
 368             data = HeapAlloc(GetProcessHeap(), 0, subblock_size + 1);
 369         else
 370         {
 371             BYTE *new_data = HeapReAlloc(GetProcessHeap(), 0, data, data_size + subblock_size + 1);
 372             if (!new_data)
 373             {
 374                 HeapFree(GetProcessHeap(), 0, data);
 375                 return S_OK;
 376             }
 377             data = new_data;
 378         }
 379         data[data_size] = subblock_size;
 380         hr = IStream_Read(stream, data + data_size + 1, subblock_size, &bytesread);
 381         if (FAILED(hr) || bytesread != subblock_size)
 382         {
 383             HeapFree(GetProcessHeap(), 0, data);
 384             return S_OK;
 385         }
 386         data_size += subblock_size + 1;
 387     }
 388
 389     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem) * 2);
 390     if (!result)
 391     {
 392         HeapFree(GetProcessHeap(), 0, data);
 393         return E_OUTOFMEMORY;
 394     }
 395
 396     for (i = 0; i < 2; i++)
 397     {
 398         PropVariantInit(&result[i].schema);
 399         PropVariantInit(&result[i].id);
 400         PropVariantInit(&result[i].value);
 401     }
 402
 403     result[0].id.vt = VT_LPWSTR;
 404     result[0].id.u.pwszVal = strdupAtoW("Application");
 405     result[0].value.vt = VT_UI1|VT_VECTOR;
 406     result[0].value.u.caub.cElems = sizeof(ape_data.application);
 407     result[0].value.u.caub.pElems = HeapAlloc(GetProcessHeap(), 0, sizeof(ape_data.application));
 408     memcpy(result[0].value.u.caub.pElems, ape_data.application, sizeof(ape_data.application));
 409
 410     result[1].id.vt = VT_LPWSTR;
 411     result[1].id.u.pwszVal = strdupAtoW("Data");
 412     result[1].value.vt = VT_UI1|VT_VECTOR;
 413     result[1].value.u.caub.cElems = data_size;
 414     result[1].value.u.caub.pElems = data;
 415
 416     *items = result;
 417     *count = 2;
 418
 419     return S_OK;
 420 }
 421
 422 static const MetadataHandlerVtbl APEReader_Vtbl = {
 423     0,
 424     &CLSID_WICAPEMetadataReader,
 425     load_APE_metadata
 426 };
 427
 428 HRESULT APEReader_CreateInstance(REFIID iid, void **ppv)
 429 {
 430     return MetadataReader_Create(&APEReader_Vtbl, iid, ppv);
 431 }
 432
 433 static HRESULT load_GifComment_metadata(IStream *stream, const GUID *vendor, DWORD options,
 434                                         MetadataItem **items, DWORD *count)
 435 {
 436 #include "pshpack1.h"
 437     struct gif_extension
 438     {
 439         BYTE extension_introducer;
 440         BYTE extension_label;
 441     } ext_data;
 442 #include "poppack.h"
 443     HRESULT hr;
 444     ULONG bytesread, data_size;
 445     MetadataItem *result;
 446     BYTE subblock_size;
 447     char *data;
 448
 449     *items = NULL;
 450     *count = 0;
 451
 452     hr = IStream_Read(stream, &ext_data, sizeof(ext_data), &bytesread);
 453     if (FAILED(hr) || bytesread != sizeof(ext_data)) return S_OK;
 454     if (ext_data.extension_introducer != 0x21 ||
 455         ext_data.extension_label != COMMENT_EXT_FUNC_CODE)
 456         return S_OK;
 457
 458     data = NULL;
 459     data_size = 0;
 460
 461     for (;;)
 462     {
 463         hr = IStream_Read(stream, &subblock_size, sizeof(subblock_size), &bytesread);
 464         if (FAILED(hr) || bytesread != sizeof(subblock_size))
 465         {
 466             HeapFree(GetProcessHeap(), 0, data);
 467             return S_OK;
 468         }
 469         if (!subblock_size) break;
 470
 471         if (!data)
 472             data = HeapAlloc(GetProcessHeap(), 0, subblock_size + 1);
 473         else
 474         {
 475             char *new_data = HeapReAlloc(GetProcessHeap(), 0, data, data_size + subblock_size + 1);
 476             if (!new_data)
 477             {
 478                 HeapFree(GetProcessHeap(), 0, data);
 479                 return S_OK;
 480             }
 481             data = new_data;
 482         }
 483         hr = IStream_Read(stream, data + data_size, subblock_size, &bytesread);
 484         if (FAILED(hr) || bytesread != subblock_size)
 485         {
 486             HeapFree(GetProcessHeap(), 0, data);
 487             return S_OK;
 488         }
 489         data_size += subblock_size;
 490     }
 491
 492     data[data_size] = 0;
 493
 494     result = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(MetadataItem));
 495     if (!result)
 496     {
 497         HeapFree(GetProcessHeap(), 0, data);
 498         return E_OUTOFMEMORY;
 499     }
 500
 501     PropVariantInit(&result->schema);
 502     PropVariantInit(&result->id);
 503     PropVariantInit(&result->value);
 504
 505     result->id.vt = VT_LPWSTR;
 506     result->id.u.pwszVal = strdupAtoW("TextEntry");
 507     result->value.vt = VT_LPSTR;
 508     result->value.u.pszVal = data;
 509
 510     *items = result;
 511     *count = 1;
 512
 513     return S_OK;
 514 }
 515
 516 static const MetadataHandlerVtbl GifCommentReader_Vtbl = {
 517     0,
 518     &CLSID_WICGifCommentMetadataReader,
 519     load_GifComment_metadata
 520 };
 521
 522 HRESULT GifCommentReader_CreateInstance(REFIID iid, void **ppv)
 523 {
 524     return MetadataReader_Create(&GifCommentReader_Vtbl, iid, ppv);
 525 }
 526
 527 static IStream *create_stream(const void *data, int data_size)
 528 {
 529     HRESULT hr;
 530     IStream *stream;
 531     HGLOBAL hdata;
 532     void *locked_data;
 533
 534     hdata = GlobalAlloc(GMEM_MOVEABLE, data_size);
 535     if (!hdata) return NULL;
 536
 537     locked_data = GlobalLock(hdata);
 538     memcpy(locked_data, data, data_size);
 539     GlobalUnlock(hdata);
 540
 541     hr = CreateStreamOnHGlobal(hdata, TRUE, &stream);
 542     return FAILED(hr) ? NULL : stream;
 543 }
 544
 545 static HRESULT create_metadata_reader(const void *data, int data_size,
 546                                       class_constructor constructor,
 547                                       IWICMetadataReader **reader)
 548 {
 549     HRESULT hr;
 550     IWICMetadataReader *metadata_reader;
 551     IWICPersistStream *persist;
 552     IStream *stream;
 553
 554     /* FIXME: Use IWICComponentFactory_CreateMetadataReader once it's implemented */
 555
 556     hr = constructor(&IID_IWICMetadataReader, (void**)&metadata_reader);
 557     if (FAILED(hr)) return hr;
 558
 559     hr = IWICMetadataReader_QueryInterface(metadata_reader, &IID_IWICPersistStream, (void **)&persist);
 560     if (FAILED(hr))
 561     {
 562         IWICMetadataReader_Release(metadata_reader);
 563         return hr;
 564     }
 565
 566     stream = create_stream(data, data_size);
 567     IWICPersistStream_LoadEx(persist, stream, NULL, WICPersistOptionDefault);
 568     IStream_Release(stream);
 569
 570     IWICPersistStream_Release(persist);
 571
 572     *reader = metadata_reader;
 573     return S_OK;
 574 }
 575
 576 typedef struct {
 577     IWICBitmapDecoder IWICBitmapDecoder_iface;
 578     IWICMetadataBlockReader IWICMetadataBlockReader_iface;
 579     IStream *stream;
 580     BYTE LSD_data[13]; /* Logical Screen Descriptor */
 581     LONG ref;
 582     BOOL initialized;
 583     GifFileType *gif;
 584     UINT current_frame;
 585     CRITICAL_SECTION lock;
 586 } GifDecoder;
 587
 588 typedef struct {
 589     IWICBitmapFrameDecode IWICBitmapFrameDecode_iface;
 590     IWICMetadataBlockReader IWICMetadataBlockReader_iface;
 591     LONG ref;
 592     SavedImage *frame;
 593     GifDecoder *parent;
 594 } GifFrameDecode;
 595
 596 static inline GifDecoder *impl_from_IWICBitmapDecoder(IWICBitmapDecoder *iface)
 597 {
 598     return CONTAINING_RECORD(iface, GifDecoder, IWICBitmapDecoder_iface);
 599 }
 600
 601 static inline GifDecoder *impl_from_IWICMetadataBlockReader(IWICMetadataBlockReader *iface)
 602 {
 603     return CONTAINING_RECORD(iface, GifDecoder, IWICMetadataBlockReader_iface);
 604 }
 605
 606 static inline GifFrameDecode *impl_from_IWICBitmapFrameDecode(IWICBitmapFrameDecode *iface)
 607 {
 608     return CONTAINING_RECORD(iface, GifFrameDecode, IWICBitmapFrameDecode_iface);
 609 }
 610
 611 static inline GifFrameDecode *frame_from_IWICMetadataBlockReader(IWICMetadataBlockReader *iface)
 612 {
 613     return CONTAINING_RECORD(iface, GifFrameDecode, IWICMetadataBlockReader_iface);
 614 }
 615
 616 static HRESULT WINAPI GifFrameDecode_QueryInterface(IWICBitmapFrameDecode *iface, REFIID iid,
 617     void **ppv)
 618 {
 619     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 620     TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
 621
 622     if (!ppv) return E_INVALIDARG;
 623
 624     if (IsEqualIID(&IID_IUnknown, iid) ||
 625         IsEqualIID(&IID_IWICBitmapSource, iid) ||
 626         IsEqualIID(&IID_IWICBitmapFrameDecode, iid))
 627     {
 628         *ppv = &This->IWICBitmapFrameDecode_iface;
 629     }
 630     else if (IsEqualIID(&IID_IWICMetadataBlockReader, iid))
 631     {
 632         *ppv = &This->IWICMetadataBlockReader_iface;
 633     }
 634     else
 635     {
 636         *ppv = NULL;
 637         return E_NOINTERFACE;
 638     }
 639
 640     IUnknown_AddRef((IUnknown*)*ppv);
 641     return S_OK;
 642 }
 643
 644 static ULONG WINAPI GifFrameDecode_AddRef(IWICBitmapFrameDecode *iface)
 645 {
 646     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 647     ULONG ref = InterlockedIncrement(&This->ref);
 648
 649     TRACE("(%p) refcount=%u\n", iface, ref);
 650
 651     return ref;
 652 }
 653
 654 static ULONG WINAPI GifFrameDecode_Release(IWICBitmapFrameDecode *iface)
 655 {
 656     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 657     ULONG ref = InterlockedDecrement(&This->ref);
 658
 659     TRACE("(%p) refcount=%u\n", iface, ref);
 660
 661     if (ref == 0)
 662     {
 663         IWICBitmapDecoder_Release(&This->parent->IWICBitmapDecoder_iface);
 664         HeapFree(GetProcessHeap(), 0, This);
 665     }
 666
 667     return ref;
 668 }
 669
 670 static HRESULT WINAPI GifFrameDecode_GetSize(IWICBitmapFrameDecode *iface,
 671     UINT *puiWidth, UINT *puiHeight)
 672 {
 673     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 674     TRACE("(%p,%p,%p)\n", iface, puiWidth, puiHeight);
 675
 676     *puiWidth = This->frame->ImageDesc.Width;
 677     *puiHeight = This->frame->ImageDesc.Height;
 678
 679     return S_OK;
 680 }
 681
 682 static HRESULT WINAPI GifFrameDecode_GetPixelFormat(IWICBitmapFrameDecode *iface,
 683     WICPixelFormatGUID *pPixelFormat)
 684 {
 685     memcpy(pPixelFormat, &GUID_WICPixelFormat8bppIndexed, sizeof(GUID));
 686
 687     return S_OK;
 688 }
 689
 690 static HRESULT WINAPI GifFrameDecode_GetResolution(IWICBitmapFrameDecode *iface,
 691     double *pDpiX, double *pDpiY)
 692 {
 693     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 694     const GifWord aspect_word = This->parent->gif->SAspectRatio;
 695     const double aspect = (aspect_word > 0) ? ((aspect_word + 15.0) / 64.0) : 1.0;
 696     TRACE("(%p,%p,%p)\n", iface, pDpiX, pDpiY);
 697
 698     *pDpiX = 96.0 / aspect;
 699     *pDpiY = 96.0;
 700
 701     return S_OK;
 702 }
 703
 704 static HRESULT WINAPI GifFrameDecode_CopyPalette(IWICBitmapFrameDecode *iface,
 705     IWICPalette *pIPalette)
 706 {
 707     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 708     WICColor colors[256];
 709     ColorMapObject *cm = This->frame->ImageDesc.ColorMap;
 710     int i, trans;
 711     ExtensionBlock *eb;
 712     TRACE("(%p,%p)\n", iface, pIPalette);
 713
 714     if (!cm) cm = This->parent->gif->SColorMap;
 715
 716     if (cm->ColorCount > 256)
 717     {
 718         ERR("GIF contains %i colors???\n", cm->ColorCount);
 719         return E_FAIL;
 720     }
 721
 722     for (i = 0; i < cm->ColorCount; i++) {
 723         colors[i] = 0xff000000| /* alpha */
 724                     cm->Colors[i].Red << 16|
 725                     cm->Colors[i].Green << 8|
 726                     cm->Colors[i].Blue;
 727     }
 728
 729     /* look for the transparent color extension */
 730     for (i = 0; i < This->frame->Extensions.ExtensionBlockCount; ++i) {
 731         eb = This->frame->Extensions.ExtensionBlocks + i;
 732         if (eb->Function == GRAPHICS_EXT_FUNC_CODE && eb->ByteCount == 8) {
 733             if (eb->Bytes[3] & 1) {
 734                 trans = (unsigned char)eb->Bytes[6];
 735                 colors[trans] &= 0xffffff; /* set alpha to 0 */
 736                 break;
 737             }
 738         }
 739     }
 740
 741     return IWICPalette_InitializeCustom(pIPalette, colors, cm->ColorCount);
 742 }
 743
 744 static HRESULT copy_interlaced_pixels(const BYTE *srcbuffer,
 745     UINT srcwidth, UINT srcheight, INT srcstride, const WICRect *rc,
 746     UINT dststride, UINT dstbuffersize, BYTE *dstbuffer)
 747 {
 748     UINT row_offset; /* number of bytes into the source rows where the data starts */
 749     const BYTE *src;
 750     BYTE *dst;
 751     UINT y;
 752     WICRect rect;
 753
 754     if (!rc)
 755     {
 756         rect.X = 0;
 757         rect.Y = 0;
 758         rect.Width = srcwidth;
 759         rect.Height = srcheight;
 760         rc = &rect;
 761     }
 762     else
 763     {
 764         if (rc->X < 0 || rc->Y < 0 || rc->X+rc->Width > srcwidth || rc->Y+rc->Height > srcheight)
 765             return E_INVALIDARG;
 766     }
 767
 768     if (dststride < rc->Width)
 769         return E_INVALIDARG;
 770
 771     if ((dststride * rc->Height) > dstbuffersize)
 772         return E_INVALIDARG;
 773
 774     row_offset = rc->X;
 775
 776     dst = dstbuffer;
 777     for (y=rc->Y; y-rc->Y < rc->Height; y++)
 778     {
 779         if (y%8 == 0)
 780             src = srcbuffer + srcstride * (y/8);
 781         else if (y%4 == 0)
 782             src = srcbuffer + srcstride * ((srcheight+7)/8 + y/8);
 783         else if (y%2 == 0)
 784             src = srcbuffer + srcstride * ((srcheight+3)/4 + y/4);
 785         else /* y%2 == 1 */
 786             src = srcbuffer + srcstride * ((srcheight+1)/2 + y/2);
 787         src += row_offset;
 788         memcpy(dst, src, rc->Width);
 789         dst += dststride;
 790     }
 791     return S_OK;
 792 }
 793
 794 static HRESULT WINAPI GifFrameDecode_CopyPixels(IWICBitmapFrameDecode *iface,
 795     const WICRect *prc, UINT cbStride, UINT cbBufferSize, BYTE *pbBuffer)
 796 {
 797     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 798     TRACE("(%p,%s,%u,%u,%p)\n", iface, debug_wic_rect(prc), cbStride, cbBufferSize, pbBuffer);
 799
 800     if (This->frame->ImageDesc.Interlace)
 801     {
 802         return copy_interlaced_pixels(This->frame->RasterBits, This->frame->ImageDesc.Width,
 803             This->frame->ImageDesc.Height, This->frame->ImageDesc.Width,
 804             prc, cbStride, cbBufferSize, pbBuffer);
 805     }
 806     else
 807     {
 808         return copy_pixels(8, This->frame->RasterBits, This->frame->ImageDesc.Width,
 809             This->frame->ImageDesc.Height, This->frame->ImageDesc.Width,
 810             prc, cbStride, cbBufferSize, pbBuffer);
 811     }
 812 }
 813
 814 static HRESULT WINAPI GifFrameDecode_GetMetadataQueryReader(IWICBitmapFrameDecode *iface,
 815     IWICMetadataQueryReader **ppIMetadataQueryReader)
 816 {
 817     GifFrameDecode *This = impl_from_IWICBitmapFrameDecode(iface);
 818
 819     TRACE("(%p,%p)\n", iface, ppIMetadataQueryReader);
 820
 821     if (!ppIMetadataQueryReader)
 822         return E_INVALIDARG;
 823
 824     return MetadataQueryReader_CreateInstance(&This->IWICMetadataBlockReader_iface, NULL, ppIMetadataQueryReader);
 825 }
 826
 827 static HRESULT WINAPI GifFrameDecode_GetColorContexts(IWICBitmapFrameDecode *iface,
 828     UINT cCount, IWICColorContext **ppIColorContexts, UINT *pcActualCount)
 829 {
 830     TRACE("(%p,%u,%p,%p)\n", iface, cCount, ppIColorContexts, pcActualCount);
 831     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
 832 }
 833
 834 static HRESULT WINAPI GifFrameDecode_GetThumbnail(IWICBitmapFrameDecode *iface,
 835     IWICBitmapSource **ppIThumbnail)
 836 {
 837     TRACE("(%p,%p)\n", iface, ppIThumbnail);
 838     return WINCODEC_ERR_CODECNOTHUMBNAIL;
 839 }
 840
 841 static const IWICBitmapFrameDecodeVtbl GifFrameDecode_Vtbl = {
 842     GifFrameDecode_QueryInterface,
 843     GifFrameDecode_AddRef,
 844     GifFrameDecode_Release,
 845     GifFrameDecode_GetSize,
 846     GifFrameDecode_GetPixelFormat,
 847     GifFrameDecode_GetResolution,
 848     GifFrameDecode_CopyPalette,
 849     GifFrameDecode_CopyPixels,
 850     GifFrameDecode_GetMetadataQueryReader,
 851     GifFrameDecode_GetColorContexts,
 852     GifFrameDecode_GetThumbnail
 853 };
 854
 855 static HRESULT WINAPI GifFrameDecode_Block_QueryInterface(IWICMetadataBlockReader *iface,
 856     REFIID iid, void **ppv)
 857 {
 858     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 859     return IWICBitmapFrameDecode_QueryInterface(&This->IWICBitmapFrameDecode_iface, iid, ppv);
 860 }
 861
 862 static ULONG WINAPI GifFrameDecode_Block_AddRef(IWICMetadataBlockReader *iface)
 863 {
 864     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 865     return IWICBitmapFrameDecode_AddRef(&This->IWICBitmapFrameDecode_iface);
 866 }
 867
 868 static ULONG WINAPI GifFrameDecode_Block_Release(IWICMetadataBlockReader *iface)
 869 {
 870     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 871     return IWICBitmapFrameDecode_Release(&This->IWICBitmapFrameDecode_iface);
 872 }
 873
 874 static HRESULT WINAPI GifFrameDecode_Block_GetContainerFormat(IWICMetadataBlockReader *iface,
 875     GUID *guid)
 876 {
 877     TRACE("(%p,%p)\n", iface, guid);
 878
 879     if (!guid) return E_INVALIDARG;
 880
 881     *guid = GUID_ContainerFormatGif;
 882     return S_OK;
 883 }
 884
 885 static HRESULT WINAPI GifFrameDecode_Block_GetCount(IWICMetadataBlockReader *iface,
 886     UINT *count)
 887 {
 888     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 889
 890     TRACE("%p,%p\n", iface, count);
 891
 892     if (!count) return E_INVALIDARG;
 893
 894     *count = This->frame->Extensions.ExtensionBlockCount + 1;
 895     return S_OK;
 896 }
 897
 898 static HRESULT create_IMD_metadata_reader(GifFrameDecode *This, IWICMetadataReader **reader)
 899 {
 900     HRESULT hr;
 901     IWICMetadataReader *metadata_reader;
 902     IWICPersistStream *persist;
 903     IStream *stream;
 904     struct image_descriptor IMD_data;
 905
 906     /* FIXME: Use IWICComponentFactory_CreateMetadataReader once it's implemented */
 907
 908     hr = IMDReader_CreateInstance(&IID_IWICMetadataReader, (void **)&metadata_reader);
 909     if (FAILED(hr)) return hr;
 910
 911     hr = IWICMetadataReader_QueryInterface(metadata_reader, &IID_IWICPersistStream, (void **)&persist);
 912     if (FAILED(hr))
 913     {
 914         IWICMetadataReader_Release(metadata_reader);
 915         return hr;
 916     }
 917
 918     /* recreate IMD structure from GIF decoder data */
 919     IMD_data.left = This->frame->ImageDesc.Left;
 920     IMD_data.top = This->frame->ImageDesc.Top;
 921     IMD_data.width = This->frame->ImageDesc.Width;
 922     IMD_data.height = This->frame->ImageDesc.Height;
 923     IMD_data.packed = 0;
 924     /* interlace_flag */
 925     IMD_data.packed |= This->frame->ImageDesc.Interlace ? (1 << 6) : 0;
 926     if (This->frame->ImageDesc.ColorMap)
 927     {
 928         /* local_color_table_flag */
 929         IMD_data.packed |= 1 << 7;
 930         /* local_color_table_size */
 931         IMD_data.packed |= This->frame->ImageDesc.ColorMap->BitsPerPixel - 1;
 932         /* sort_flag */
 933         IMD_data.packed |= This->frame->ImageDesc.ColorMap->SortFlag ? 0x20 : 0;
 934     }
 935
 936     stream = create_stream(&IMD_data, sizeof(IMD_data));
 937     IWICPersistStream_LoadEx(persist, stream, NULL, WICPersistOptionDefault);
 938     IStream_Release(stream);
 939
 940     IWICPersistStream_Release(persist);
 941
 942     *reader = metadata_reader;
 943     return S_OK;
 944 }
 945
 946 static HRESULT WINAPI GifFrameDecode_Block_GetReaderByIndex(IWICMetadataBlockReader *iface,
 947     UINT index, IWICMetadataReader **reader)
 948 {
 949     GifFrameDecode *This = frame_from_IWICMetadataBlockReader(iface);
 950     int i, gce_index = -1, gce_skipped = 0;
 951
 952     TRACE("(%p,%u,%p)\n", iface, index, reader);
 953
 954     if (!reader) return E_INVALIDARG;
 955
 956     if (index == 0)
 957         return create_IMD_metadata_reader(This, reader);
 958
 959     if (index >= This->frame->Extensions.ExtensionBlockCount + 1)
 960         return E_INVALIDARG;
 961
 962     for (i = 0; i < This->frame->Extensions.ExtensionBlockCount; i++)
 963     {
 964         class_constructor constructor;
 965         const void *data;
 966         int data_size;
 967
 968         if (index != i + 1 - gce_skipped) continue;
 969
 970         if (This->frame->Extensions.ExtensionBlocks[i].Function == GRAPHICS_EXT_FUNC_CODE)
 971         {
 972             gce_index = i;
 973             gce_skipped = 1;
 974             continue;
 975         }
 976         else if (This->frame->Extensions.ExtensionBlocks[i].Function == COMMENT_EXT_FUNC_CODE)
 977         {
 978             constructor = GifCommentReader_CreateInstance;
 979             data = This->frame->Extensions.ExtensionBlocks[i].Bytes;
 980             data_size = This->frame->Extensions.ExtensionBlocks[i].ByteCount;
 981         }
 982         else
 983         {
 984             constructor = UnknownMetadataReader_CreateInstance;
 985             data = This->frame->Extensions.ExtensionBlocks[i].Bytes;
 986             data_size = This->frame->Extensions.ExtensionBlocks[i].ByteCount;
 987         }
 988         return create_metadata_reader(data, data_size, constructor, reader);
 989     }
 990
 991     if (gce_index == -1) return E_INVALIDARG;
 992
 993     return create_metadata_reader(This->frame->Extensions.ExtensionBlocks[gce_index].Bytes + 3,
 994                                   This->frame->Extensions.ExtensionBlocks[gce_index].ByteCount - 4,
 995                                   GCEReader_CreateInstance, reader);
 996 }
 997
 998 static HRESULT WINAPI GifFrameDecode_Block_GetEnumerator(IWICMetadataBlockReader *iface,
 999     IEnumUnknown **enumerator)
1000 {
1001     FIXME("(%p,%p): stub\n", iface, enumerator);
1002     return E_NOTIMPL;
1003 }
1004
1005 static const IWICMetadataBlockReaderVtbl GifFrameDecode_BlockVtbl =
1006 {
1007     GifFrameDecode_Block_QueryInterface,
1008     GifFrameDecode_Block_AddRef,
1009     GifFrameDecode_Block_Release,
1010     GifFrameDecode_Block_GetContainerFormat,
1011     GifFrameDecode_Block_GetCount,
1012     GifFrameDecode_Block_GetReaderByIndex,
1013     GifFrameDecode_Block_GetEnumerator
1014 };
1015
1016 static HRESULT WINAPI GifDecoder_QueryInterface(IWICBitmapDecoder *iface, REFIID iid,
1017     void **ppv)
1018 {
1019     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1020     TRACE("(%p,%s,%p)\n", iface, debugstr_guid(iid), ppv);
1021
1022     if (!ppv) return E_INVALIDARG;
1023
1024     if (IsEqualIID(&IID_IUnknown, iid) ||
1025         IsEqualIID(&IID_IWICBitmapDecoder, iid))
1026     {
1027         *ppv = &This->IWICBitmapDecoder_iface;
1028     }
1029     else if (IsEqualIID(&IID_IWICMetadataBlockReader, iid))
1030     {
1031         *ppv = &This->IWICMetadataBlockReader_iface;
1032     }
1033     else
1034     {
1035         *ppv = NULL;
1036         return E_NOINTERFACE;
1037     }
1038
1039     IUnknown_AddRef((IUnknown*)*ppv);
1040     return S_OK;
1041 }
1042
1043 static ULONG WINAPI GifDecoder_AddRef(IWICBitmapDecoder *iface)
1044 {
1045     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1046     ULONG ref = InterlockedIncrement(&This->ref);
1047
1048     TRACE("(%p) refcount=%u\n", iface, ref);
1049
1050     return ref;
1051 }
1052
1053 static ULONG WINAPI GifDecoder_Release(IWICBitmapDecoder *iface)
1054 {
1055     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1056     ULONG ref = InterlockedDecrement(&This->ref);
1057
1058     TRACE("(%p) refcount=%u\n", iface, ref);
1059
1060     if (ref == 0)
1061     {
1062         if (This->stream)
1063         {
1064             IStream_Release(This->stream);
1065             DGifCloseFile(This->gif);
1066         }
1067         This->lock.DebugInfo->Spare[0] = 0;
1068         DeleteCriticalSection(&This->lock);
1069         HeapFree(GetProcessHeap(), 0, This);
1070     }
1071
1072     return ref;
1073 }
1074
1075 static HRESULT WINAPI GifDecoder_QueryCapability(IWICBitmapDecoder *iface, IStream *stream,
1076     DWORD *capability)
1077 {
1078     HRESULT hr;
1079
1080     TRACE("(%p,%p,%p)\n", iface, stream, capability);
1081
1082     if (!stream || !capability) return E_INVALIDARG;
1083
1084     hr = IWICBitmapDecoder_Initialize(iface, stream, WICDecodeMetadataCacheOnDemand);
1085     if (hr != S_OK) return hr;
1086
1087     *capability = WICBitmapDecoderCapabilityCanDecodeAllImages |
1088                   WICBitmapDecoderCapabilityCanDecodeSomeImages |
1089                   WICBitmapDecoderCapabilityCanEnumerateMetadata;
1090     return S_OK;
1091 }
1092
1093 static int _gif_inputfunc(GifFileType *gif, GifByteType *data, int len) {
1094     IStream *stream = gif->UserData;
1095     ULONG bytesread;
1096     HRESULT hr;
1097
1098     if (!stream)
1099     {
1100         ERR("attempting to read file after initialization\n");
1101         return 0;
1102     }
1103
1104     hr = IStream_Read(stream, data, len, &bytesread);
1105     if (FAILED(hr)) bytesread = 0;
1106     return bytesread;
1107 }
1108
1109 static HRESULT WINAPI GifDecoder_Initialize(IWICBitmapDecoder *iface, IStream *pIStream,
1110     WICDecodeOptions cacheOptions)
1111 {
1112     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1113     LARGE_INTEGER seek;
1114     int ret;
1115
1116     TRACE("(%p,%p,%x)\n", iface, pIStream, cacheOptions);
1117
1118     EnterCriticalSection(&This->lock);
1119
1120     if (This->initialized || This->gif)
1121     {
1122         WARN("already initialized\n");
1123         LeaveCriticalSection(&This->lock);
1124         return WINCODEC_ERR_WRONGSTATE;
1125     }
1126
1127     /* seek to start of stream */
1128     seek.QuadPart = 0;
1129     IStream_Seek(pIStream, seek, STREAM_SEEK_SET, NULL);
1130
1131     /* read all data from the stream */
1132     This->gif = DGifOpen((void*)pIStream, _gif_inputfunc);
1133     if (!This->gif)
1134     {
1135         LeaveCriticalSection(&This->lock);
1136         return E_FAIL;
1137     }
1138
1139     ret = DGifSlurp(This->gif);
1140     if (ret == GIF_ERROR)
1141     {
1142         LeaveCriticalSection(&This->lock);
1143         return E_FAIL;
1144     }
1145
1146     /* make sure we don't use the stream after this method returns */
1147     This->gif->UserData = NULL;
1148
1149     seek.QuadPart = 0;
1150     IStream_Seek(pIStream, seek, STREAM_SEEK_SET, NULL);
1151     IStream_Read(pIStream, This->LSD_data, sizeof(This->LSD_data), NULL);
1152
1153     This->stream = pIStream;
1154     IStream_AddRef(This->stream);
1155
1156     This->initialized = TRUE;
1157
1158     LeaveCriticalSection(&This->lock);
1159
1160     return S_OK;
1161 }
1162
1163 static HRESULT WINAPI GifDecoder_GetContainerFormat(IWICBitmapDecoder *iface,
1164     GUID *pguidContainerFormat)
1165 {
1166     memcpy(pguidContainerFormat, &GUID_ContainerFormatGif, sizeof(GUID));
1167     return S_OK;
1168 }
1169
1170 static HRESULT WINAPI GifDecoder_GetDecoderInfo(IWICBitmapDecoder *iface,
1171     IWICBitmapDecoderInfo **ppIDecoderInfo)
1172 {
1173     TRACE("(%p,%p)\n", iface, ppIDecoderInfo);
1174
1175     return get_decoder_info(&CLSID_WICGifDecoder, ppIDecoderInfo);
1176 }
1177
1178 static HRESULT WINAPI GifDecoder_CopyPalette(IWICBitmapDecoder *iface, IWICPalette *palette)
1179 {
1180     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1181     WICColor colors[256];
1182     ColorMapObject *cm;
1183     int i, trans, count;
1184     ExtensionBlock *eb;
1185
1186     TRACE("(%p,%p)\n", iface, palette);
1187
1188     if (!This->gif)
1189         return WINCODEC_ERR_WRONGSTATE;
1190
1191     cm = This->gif->SColorMap;
1192     if (cm)
1193     {
1194         if (cm->ColorCount > 256)
1195         {
1196             ERR("GIF contains invalid number of colors: %d\n", cm->ColorCount);
1197             return E_FAIL;
1198         }
1199
1200         for (i = 0; i < cm->ColorCount; i++)
1201         {
1202             colors[i] = 0xff000000 | /* alpha */
1203                         cm->Colors[i].Red << 16 |
1204                         cm->Colors[i].Green << 8 |
1205                         cm->Colors[i].Blue;
1206         }
1207
1208         count = cm->ColorCount;
1209     }
1210     else
1211     {
1212         colors[0] = 0xff000000;
1213         colors[1] = 0xffffffff;
1214
1215         for (i = 2; i < 256; i++)
1216             colors[i] = 0xff000000;
1217
1218         count = 256;
1219     }
1220
1221     /* look for the transparent color extension */
1222     for (i = 0; i < This->gif->SavedImages[This->current_frame].Extensions.ExtensionBlockCount; i++)
1223     {
1224         eb = This->gif->SavedImages[This->current_frame].Extensions.ExtensionBlocks + i;
1225         if (eb->Function == GRAPHICS_EXT_FUNC_CODE && eb->ByteCount == 8)
1226         {
1227             if (eb->Bytes[3] & 1)
1228             {
1229                 trans = (unsigned char)eb->Bytes[6];
1230                 colors[trans] &= 0xffffff; /* set alpha to 0 */
1231                 break;
1232             }
1233         }
1234     }
1235
1236     return IWICPalette_InitializeCustom(palette, colors, count);
1237 }
1238
1239 static HRESULT WINAPI GifDecoder_GetMetadataQueryReader(IWICBitmapDecoder *iface,
1240     IWICMetadataQueryReader **ppIMetadataQueryReader)
1241 {
1242     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1243
1244     TRACE("(%p,%p)\n", iface, ppIMetadataQueryReader);
1245
1246     if (!ppIMetadataQueryReader) return E_INVALIDARG;
1247
1248     return MetadataQueryReader_CreateInstance(&This->IWICMetadataBlockReader_iface, NULL, ppIMetadataQueryReader);
1249 }
1250
1251 static HRESULT WINAPI GifDecoder_GetPreview(IWICBitmapDecoder *iface,
1252     IWICBitmapSource **ppIBitmapSource)
1253 {
1254     TRACE("(%p,%p)\n", iface, ppIBitmapSource);
1255     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
1256 }
1257
1258 static HRESULT WINAPI GifDecoder_GetColorContexts(IWICBitmapDecoder *iface,
1259     UINT cCount, IWICColorContext **ppIColorContexts, UINT *pcActualCount)
1260 {
1261     TRACE("(%p,%u,%p,%p)\n", iface, cCount, ppIColorContexts, pcActualCount);
1262     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
1263 }
1264
1265 static HRESULT WINAPI GifDecoder_GetThumbnail(IWICBitmapDecoder *iface,
1266     IWICBitmapSource **ppIThumbnail)
1267 {
1268     TRACE("(%p,%p)\n", iface, ppIThumbnail);
1269     return WINCODEC_ERR_CODECNOTHUMBNAIL;
1270 }
1271
1272 static HRESULT WINAPI GifDecoder_GetFrameCount(IWICBitmapDecoder *iface,
1273     UINT *pCount)
1274 {
1275     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1276
1277     if (!pCount) return E_INVALIDARG;
1278
1279     EnterCriticalSection(&This->lock);
1280     *pCount = This->gif ? This->gif->ImageCount : 0;
1281     LeaveCriticalSection(&This->lock);
1282
1283     TRACE("(%p) <-- %d\n", iface, *pCount);
1284
1285     return S_OK;
1286 }
1287
1288 static HRESULT WINAPI GifDecoder_GetFrame(IWICBitmapDecoder *iface,
1289     UINT index, IWICBitmapFrameDecode **ppIBitmapFrame)
1290 {
1291     GifDecoder *This = impl_from_IWICBitmapDecoder(iface);
1292     GifFrameDecode *result;
1293     TRACE("(%p,%u,%p)\n", iface, index, ppIBitmapFrame);
1294
1295     if (!This->initialized) return WINCODEC_ERR_FRAMEMISSING;
1296
1297     if (index >= This->gif->ImageCount) return E_INVALIDARG;
1298
1299     result = HeapAlloc(GetProcessHeap(), 0, sizeof(GifFrameDecode));
1300     if (!result) return E_OUTOFMEMORY;
1301
1302     result->IWICBitmapFrameDecode_iface.lpVtbl = &GifFrameDecode_Vtbl;
1303     result->IWICMetadataBlockReader_iface.lpVtbl = &GifFrameDecode_BlockVtbl;
1304     result->ref = 1;
1305     result->frame = &This->gif->SavedImages[index];
1306     IWICBitmapDecoder_AddRef(iface);
1307     result->parent = This;
1308     This->current_frame = index;
1309
1310     *ppIBitmapFrame = &result->IWICBitmapFrameDecode_iface;
1311
1312     return S_OK;
1313 }
1314
1315 static const IWICBitmapDecoderVtbl GifDecoder_Vtbl = {
1316     GifDecoder_QueryInterface,
1317     GifDecoder_AddRef,
1318     GifDecoder_Release,
1319     GifDecoder_QueryCapability,
1320     GifDecoder_Initialize,
1321     GifDecoder_GetContainerFormat,
1322     GifDecoder_GetDecoderInfo,
1323     GifDecoder_CopyPalette,
1324     GifDecoder_GetMetadataQueryReader,
1325     GifDecoder_GetPreview,
1326     GifDecoder_GetColorContexts,
1327     GifDecoder_GetThumbnail,
1328     GifDecoder_GetFrameCount,
1329     GifDecoder_GetFrame
1330 };
1331
1332 static HRESULT WINAPI GifDecoder_Block_QueryInterface(IWICMetadataBlockReader *iface,
1333     REFIID iid, void **ppv)
1334 {
1335     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1336     return IWICBitmapDecoder_QueryInterface(&This->IWICBitmapDecoder_iface, iid, ppv);
1337 }
1338
1339 static ULONG WINAPI GifDecoder_Block_AddRef(IWICMetadataBlockReader *iface)
1340 {
1341     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1342     return IWICBitmapDecoder_AddRef(&This->IWICBitmapDecoder_iface);
1343 }
1344
1345 static ULONG WINAPI GifDecoder_Block_Release(IWICMetadataBlockReader *iface)
1346 {
1347     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1348     return IWICBitmapDecoder_Release(&This->IWICBitmapDecoder_iface);
1349 }
1350
1351 static HRESULT WINAPI GifDecoder_Block_GetContainerFormat(IWICMetadataBlockReader *iface,
1352     GUID *guid)
1353 {
1354     TRACE("(%p,%p)\n", iface, guid);
1355
1356     if (!guid) return E_INVALIDARG;
1357
1358     *guid = GUID_ContainerFormatGif;
1359     return S_OK;
1360 }
1361
1362 static HRESULT WINAPI GifDecoder_Block_GetCount(IWICMetadataBlockReader *iface,
1363     UINT *count)
1364 {
1365     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1366
1367     TRACE("%p,%p\n", iface, count);
1368
1369     if (!count) return E_INVALIDARG;
1370
1371     *count = This->gif->Extensions.ExtensionBlockCount + 1;
1372     return S_OK;
1373 }
1374
1375 static HRESULT WINAPI GifDecoder_Block_GetReaderByIndex(IWICMetadataBlockReader *iface,
1376     UINT index, IWICMetadataReader **reader)
1377 {
1378     GifDecoder *This = impl_from_IWICMetadataBlockReader(iface);
1379     int i;
1380
1381     TRACE("(%p,%u,%p)\n", iface, index, reader);
1382
1383     if (!reader) return E_INVALIDARG;
1384
1385     if (index == 0)
1386         return create_metadata_reader(This->LSD_data, sizeof(This->LSD_data),
1387                                       LSDReader_CreateInstance, reader);
1388
1389     for (i = 0; i < This->gif->Extensions.ExtensionBlockCount; i++)
1390     {
1391         class_constructor constructor;
1392
1393         if (index != i + 1) continue;
1394
1395         if (This->gif->Extensions.ExtensionBlocks[i].Function == APPLICATION_EXT_FUNC_CODE)
1396             constructor = APEReader_CreateInstance;
1397         else if (This->gif->Extensions.ExtensionBlocks[i].Function == COMMENT_EXT_FUNC_CODE)
1398             constructor = GifCommentReader_CreateInstance;
1399         else
1400             constructor = UnknownMetadataReader_CreateInstance;
1401
1402         return create_metadata_reader(This->gif->Extensions.ExtensionBlocks[i].Bytes,
1403                                       This->gif->Extensions.ExtensionBlocks[i].ByteCount,
1404                                       constructor, reader);
1405     }
1406
1407     return E_INVALIDARG;
1408 }
1409
1410 static HRESULT WINAPI GifDecoder_Block_GetEnumerator(IWICMetadataBlockReader *iface,
1411     IEnumUnknown **enumerator)
1412 {
1413     FIXME("(%p,%p): stub\n", iface, enumerator);
1414     return E_NOTIMPL;
1415 }
1416
1417 static const IWICMetadataBlockReaderVtbl GifDecoder_BlockVtbl =
1418 {
1419     GifDecoder_Block_QueryInterface,
1420     GifDecoder_Block_AddRef,
1421     GifDecoder_Block_Release,
1422     GifDecoder_Block_GetContainerFormat,
1423     GifDecoder_Block_GetCount,
1424     GifDecoder_Block_GetReaderByIndex,
1425     GifDecoder_Block_GetEnumerator
1426 };
1427
1428 HRESULT GifDecoder_CreateInstance(REFIID iid, void** ppv)
1429 {
1430     GifDecoder *This;
1431     HRESULT ret;
1432
1433     TRACE("(%s,%p)\n", debugstr_guid(iid), ppv);
1434
1435     *ppv = NULL;
1436
1437     This = HeapAlloc(GetProcessHeap(), 0, sizeof(GifDecoder));
1438     if (!This) return E_OUTOFMEMORY;
1439
1440     This->IWICBitmapDecoder_iface.lpVtbl = &GifDecoder_Vtbl;
1441     This->IWICMetadataBlockReader_iface.lpVtbl = &GifDecoder_BlockVtbl;
1442     This->stream = NULL;
1443     This->ref = 1;
1444     This->initialized = FALSE;
1445     This->gif = NULL;
1446     This->current_frame = 0;
1447     InitializeCriticalSection(&This->lock);
1448     This->lock.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": GifDecoder.lock");
1449
1450     ret = IWICBitmapDecoder_QueryInterface(&This->IWICBitmapDecoder_iface, iid, ppv);
1451     IWICBitmapDecoder_Release(&This->IWICBitmapDecoder_iface);
1452
1453     return ret;
1454 }
1455
1456 typedef struct GifEncoder
1457 {
1458     IWICBitmapEncoder IWICBitmapEncoder_iface;
1459     LONG ref;
1460     IStream *stream;
1461     CRITICAL_SECTION lock;
1462     BOOL initialized, info_written, committed;
1463     UINT n_frames;
1464     WICColor palette[256];
1465     UINT colors;
1466 } GifEncoder;
1467
1468 static inline GifEncoder *impl_from_IWICBitmapEncoder(IWICBitmapEncoder *iface)
1469 {
1470     return CONTAINING_RECORD(iface, GifEncoder, IWICBitmapEncoder_iface);
1471 }
1472
1473 typedef struct GifFrameEncode
1474 {
1475     IWICBitmapFrameEncode IWICBitmapFrameEncode_iface;
1476     IWICMetadataBlockWriter IWICMetadataBlockWriter_iface;
1477     LONG ref;
1478     GifEncoder *encoder;
1479     BOOL initialized, interlace, committed;
1480     UINT width, height, lines;
1481     double xres, yres;
1482     WICColor palette[256];
1483     UINT colors;
1484     BYTE *image_data;
1485 } GifFrameEncode;
1486
1487 static inline GifFrameEncode *impl_from_IWICBitmapFrameEncode(IWICBitmapFrameEncode *iface)
1488 {
1489     return CONTAINING_RECORD(iface, GifFrameEncode, IWICBitmapFrameEncode_iface);
1490 }
1491
1492 static inline GifFrameEncode *impl_from_IWICMetadataBlockWriter(IWICMetadataBlockWriter *iface)
1493 {
1494     return CONTAINING_RECORD(iface, GifFrameEncode, IWICMetadataBlockWriter_iface);
1495 }
1496
1497 static HRESULT WINAPI GifFrameEncode_QueryInterface(IWICBitmapFrameEncode *iface, REFIID iid, void **ppv)
1498 {
1499     GifFrameEncode *encoder = impl_from_IWICBitmapFrameEncode(iface);
1500
1501     TRACE("%p,%s,%p\n", iface, debugstr_guid(iid), ppv);
1502
1503     if (!ppv) return E_INVALIDARG;
1504
1505     if (IsEqualIID(&IID_IUnknown, iid) ||
1506         IsEqualIID(&IID_IWICBitmapFrameEncode, iid))
1507     {
1508         *ppv = iface;
1509     }
1510     else if (IsEqualIID(&IID_IWICMetadataBlockWriter, iid))
1511     {
1512         *ppv = &encoder->IWICMetadataBlockWriter_iface;
1513     }
1514     else
1515     {
1516         *ppv = NULL;
1517         return E_NOINTERFACE;
1518     }
1519
1520     IUnknown_AddRef((IUnknown *)*ppv);
1521     return S_OK;
1522 }
1523
1524 static ULONG WINAPI GifFrameEncode_AddRef(IWICBitmapFrameEncode *iface)
1525 {
1526     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1527     ULONG ref = InterlockedIncrement(&This->ref);
1528
1529     TRACE("%p -> %u\n", iface, ref);
1530     return ref;
1531 }
1532
1533 static ULONG WINAPI GifFrameEncode_Release(IWICBitmapFrameEncode *iface)
1534 {
1535     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1536     ULONG ref = InterlockedDecrement(&This->ref);
1537
1538     TRACE("%p -> %u\n", iface, ref);
1539
1540     if (!ref)
1541     {
1542         IWICBitmapEncoder_Release(&This->encoder->IWICBitmapEncoder_iface);
1543         HeapFree(GetProcessHeap(), 0, This->image_data);
1544         HeapFree(GetProcessHeap(), 0, This);
1545     }
1546
1547     return ref;
1548 }
1549
1550 static HRESULT WINAPI GifFrameEncode_Initialize(IWICBitmapFrameEncode *iface, IPropertyBag2 *options)
1551 {
1552     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1553     HRESULT hr;
1554
1555     TRACE("%p,%p\n", iface, options);
1556
1557     EnterCriticalSection(&This->encoder->lock);
1558
1559     if (!This->initialized)
1560     {
1561         This->initialized = TRUE;
1562         hr = S_OK;
1563     }
1564     else
1565         hr = WINCODEC_ERR_WRONGSTATE;
1566
1567     LeaveCriticalSection(&This->encoder->lock);
1568
1569     return hr;
1570 }
1571
1572 static HRESULT WINAPI GifFrameEncode_SetSize(IWICBitmapFrameEncode *iface, UINT width, UINT height)
1573 {
1574     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1575     HRESULT hr;
1576
1577     TRACE("%p,%u,%u\n", iface, width, height);
1578
1579     if (!width || !height) return E_INVALIDARG;
1580
1581     EnterCriticalSection(&This->encoder->lock);
1582
1583     if (This->initialized)
1584     {
1585         HeapFree(GetProcessHeap(), 0, This->image_data);
1586
1587         This->image_data = HeapAlloc(GetProcessHeap(), 0, width * height);
1588         if (This->image_data)
1589         {
1590             This->width = width;
1591             This->height = height;
1592             hr = S_OK;
1593         }
1594         else
1595             hr = E_OUTOFMEMORY;
1596     }
1597     else
1598         hr = WINCODEC_ERR_WRONGSTATE;
1599
1600     LeaveCriticalSection(&This->encoder->lock);
1601
1602     return hr;
1603 }
1604
1605 static HRESULT WINAPI GifFrameEncode_SetResolution(IWICBitmapFrameEncode *iface, double xres, double yres)
1606 {
1607     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1608     HRESULT hr;
1609
1610     TRACE("%p,%f,%f\n", iface, xres, yres);
1611
1612     EnterCriticalSection(&This->encoder->lock);
1613
1614     if (This->initialized)
1615     {
1616         This->xres = xres;
1617         This->yres = yres;
1618         hr = S_OK;
1619     }
1620     else
1621         hr = WINCODEC_ERR_WRONGSTATE;
1622
1623     LeaveCriticalSection(&This->encoder->lock);
1624
1625     return hr;
1626 }
1627
1628 static HRESULT WINAPI GifFrameEncode_SetPixelFormat(IWICBitmapFrameEncode *iface, WICPixelFormatGUID *format)
1629 {
1630     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1631     HRESULT hr;
1632
1633     TRACE("%p,%s\n", iface, debugstr_guid(format));
1634
1635     if (!format) return E_INVALIDARG;
1636
1637     EnterCriticalSection(&This->encoder->lock);
1638
1639     if (This->initialized)
1640     {
1641         *format = GUID_WICPixelFormat8bppIndexed;
1642         hr = S_OK;
1643     }
1644     else
1645         hr = WINCODEC_ERR_WRONGSTATE;
1646
1647     LeaveCriticalSection(&This->encoder->lock);
1648
1649     return hr;
1650 }
1651
1652 static HRESULT WINAPI GifFrameEncode_SetColorContexts(IWICBitmapFrameEncode *iface, UINT count, IWICColorContext **context)
1653 {
1654     FIXME("%p,%u,%p: stub\n", iface, count, context);
1655     return E_NOTIMPL;
1656 }
1657
1658 static HRESULT WINAPI GifFrameEncode_SetPalette(IWICBitmapFrameEncode *iface, IWICPalette *palette)
1659 {
1660     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1661     HRESULT hr;
1662
1663     TRACE("%p,%p\n", iface, palette);
1664
1665     if (!palette) return E_INVALIDARG;
1666
1667     EnterCriticalSection(&This->encoder->lock);
1668
1669     if (This->initialized)
1670         hr = IWICPalette_GetColors(palette, 256, This->palette, &This->colors);
1671     else
1672         hr = WINCODEC_ERR_NOTINITIALIZED;
1673
1674     LeaveCriticalSection(&This->encoder->lock);
1675     return hr;
1676 }
1677
1678 static HRESULT WINAPI GifFrameEncode_SetThumbnail(IWICBitmapFrameEncode *iface, IWICBitmapSource *thumbnail)
1679 {
1680     FIXME("%p,%p: stub\n", iface, thumbnail);
1681     return E_NOTIMPL;
1682 }
1683
1684 static HRESULT WINAPI GifFrameEncode_WritePixels(IWICBitmapFrameEncode *iface, UINT lines, UINT stride, UINT size, BYTE *pixels)
1685 {
1686     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1687     HRESULT hr;
1688
1689     TRACE("%p,%u,%u,%u,%p\n", iface, lines, stride, size, pixels);
1690
1691     if (!pixels) return E_INVALIDARG;
1692
1693     EnterCriticalSection(&This->encoder->lock);
1694
1695     if (This->initialized && This->image_data)
1696     {
1697         if (This->lines + lines <= This->height)
1698         {
1699             UINT i;
1700             BYTE *src, *dst;
1701
1702             src = pixels;
1703             dst = This->image_data + This->lines * This->width;
1704
1705             for (i = 0; i < lines; i++)
1706             {
1707                 memcpy(dst, src, This->width);
1708                 src += stride;
1709                 dst += This->width;
1710             }
1711
1712             This->lines += lines;
1713             hr = S_OK;
1714         }
1715         else
1716             hr = E_INVALIDARG;
1717     }
1718     else
1719         hr = WINCODEC_ERR_WRONGSTATE;
1720
1721     LeaveCriticalSection(&This->encoder->lock);
1722     return hr;
1723 }
1724
1725 static HRESULT WINAPI GifFrameEncode_WriteSource(IWICBitmapFrameEncode *iface, IWICBitmapSource *source, WICRect *rc)
1726 {
1727     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
1728     HRESULT hr;
1729
1730     TRACE("%p,%p,%p\n", iface, source, rc);
1731
1732     if (!source) return E_INVALIDARG;
1733
1734     EnterCriticalSection(&This->encoder->lock);
1735
1736     if (This->initialized)
1737     {
1738         const GUID *format = &GUID_WICPixelFormat8bppIndexed;
1739
1740         hr = configure_write_source(iface, source, rc, format,
1741                                     This->width, This->height, This->xres, This->yres);
1742         if (hr == S_OK)
1743             hr = write_source(iface, source, rc, format, 8, !This->colors, This->width, This->height);
1744     }
1745     else
1746         hr = WINCODEC_ERR_WRONGSTATE;
1747
1748     LeaveCriticalSection(&This->encoder->lock);
1749     return hr;
1750 }
1751
1752 #define LZW_DICT_SIZE (1 << 12)
1753
1754 struct lzw_dict
1755 {
1756     short prefix[LZW_DICT_SIZE];
1757     unsigned char suffix[LZW_DICT_SIZE];
1758 };
1759
1760 struct lzw_state
1761 {
1762     struct lzw_dict dict;
1763     short init_code_bits, code_bits, next_code, clear_code, eof_code;
1764     unsigned bits_buf;
1765     int bits_count;
1766     int (*user_write_data)(void *user_ptr, void *data, int length);
1767     void *user_ptr;
1768 };
1769
1770 struct input_stream
1771 {
1772     unsigned len;
1773     const BYTE *in;
1774 };
1775
1776 struct output_stream
1777 {
1778     struct
1779     {
1780         unsigned char len;
1781         char data[255];
1782     } gif_block;
1783     IStream *out;
1784 };
1785
1786 static int lzw_output_code(struct lzw_state *state, short code)
1787 {
1788     state->bits_buf |= code << state->bits_count;
1789     state->bits_count += state->code_bits;
1790
1791     while (state->bits_count >= 8)
1792     {
1793         unsigned char byte = (unsigned char)state->bits_buf;
1794         if (state->user_write_data(state->user_ptr, &byte, 1) != 1)
1795             return 0;
1796         state->bits_buf >>= 8;
1797         state->bits_count -= 8;
1798     }
1799
1800     return 1;
1801 }
1802
1803 static inline int lzw_output_clear_code(struct lzw_state *state)
1804 {
1805     return lzw_output_code(state, state->clear_code);
1806 }
1807
1808 static inline int lzw_output_eof_code(struct lzw_state *state)
1809 {
1810     return lzw_output_code(state, state->eof_code);
1811 }
1812
1813 static int lzw_flush_bits(struct lzw_state *state)
1814 {
1815     unsigned char byte;
1816
1817     while (state->bits_count >= 8)
1818     {
1819         byte = (unsigned char)state->bits_buf;
1820         if (state->user_write_data(state->user_ptr, &byte, 1) != 1)
1821             return 0;
1822         state->bits_buf >>= 8;
1823         state->bits_count -= 8;
1824     }
1825
1826     if (state->bits_count)
1827     {
1828         static const char mask[8] = { 0x00,0x01,0x03,0x07,0x0f,0x1f,0x3f,0x7f };
1829
1830         byte = (unsigned char)state->bits_buf & mask[state->bits_count];
1831         if (state->user_write_data(state->user_ptr, &byte, 1) != 1)
1832             return 0;
1833     }
1834
1835     state->bits_buf = 0;
1836     state->bits_count = 0;
1837
1838     return 1;
1839 }
1840
1841 static void lzw_dict_reset(struct lzw_state *state)
1842 {
1843     int i;
1844
1845     state->code_bits = state->init_code_bits + 1;
1846     state->next_code = (1 << state->init_code_bits) + 2;
1847
1848     for(i = 0; i < LZW_DICT_SIZE; i++)
1849     {
1850         state->dict.prefix[i] = 1 << 12; /* impossible LZW code value */
1851         state->dict.suffix[i] = 0;
1852     }
1853 }
1854
1855 static void lzw_state_init(struct lzw_state *state, short init_code_bits, void *user_write_data, void *user_ptr)
1856 {
1857     state->init_code_bits = init_code_bits;
1858     state->clear_code = 1 << init_code_bits;
1859     state->eof_code = state->clear_code + 1;
1860     state->bits_buf = 0;
1861     state->bits_count = 0;
1862     state->user_write_data = user_write_data;
1863     state->user_ptr = user_ptr;
1864
1865     lzw_dict_reset(state);
1866 }
1867
1868 static int lzw_dict_add(struct lzw_state *state, short prefix, unsigned char suffix)
1869 {
1870     if (state->next_code < LZW_DICT_SIZE)
1871     {
1872         state->dict.prefix[state->next_code] = prefix;
1873         state->dict.suffix[state->next_code] = suffix;
1874
1875         if ((state->next_code & (state->next_code - 1)) == 0)
1876             state->code_bits++;
1877
1878         state->next_code++;
1879         return state->next_code;
1880     }
1881
1882     return -1;
1883 }
1884
1885 static short lzw_dict_lookup(const struct lzw_state *state, short prefix, unsigned char suffix)
1886 {
1887     short i;
1888
1889     for (i = 0; i < state->next_code; i++)
1890     {
1891         if (state->dict.prefix[i] == prefix && state->dict.suffix[i] == suffix)
1892             return i;
1893     }
1894
1895     return -1;
1896 }
1897
1898 static inline int write_byte(struct output_stream *out, char byte)
1899 {
1900     if (out->gif_block.len == 255)
1901     {
1902         if (IStream_Write(out->out, &out->gif_block, sizeof(out->gif_block), NULL) != S_OK)
1903             return 0;
1904
1905         out->gif_block.len = 0;
1906     }
1907
1908     out->gif_block.data[out->gif_block.len++] = byte;
1909
1910     return 1;
1911 }
1912
1913 static int write_data(void *user_ptr, void *user_data, int length)
1914 {
1915     unsigned char *data = user_data;
1916     struct output_stream *out = user_ptr;
1917     int len = length;
1918
1919     while (len-- > 0)
1920     {
1921         if (!write_byte(out, *data++)) return 0;
1922     }
1923
1924     return length;
1925 }
1926
1927 static int flush_output_data(void *user_ptr)
1928 {
1929     struct output_stream *out = user_ptr;
1930
1931     if (out->gif_block.len)
1932     {
1933         if (IStream_Write(out->out, &out->gif_block, out->gif_block.len + sizeof(out->gif_block.len), NULL) != S_OK)
1934             return 0;
1935     }
1936
1937     /* write GIF block terminator */
1938     out->gif_block.len = 0;
1939     return IStream_Write(out->out, &out->gif_block, sizeof(out->gif_block.len), NULL) == S_OK;
1940 }
1941
1942 static inline int read_byte(struct input_stream *in, unsigned char *byte)
1943 {
1944     if (in->len)
1945     {
1946         in->len--;
1947         *byte = *in->in++;
1948         return 1;
1949     }
1950
1951     return 0;
1952 }
1953
1954 static HRESULT gif_compress(IStream *out_stream, const BYTE *in_data, ULONG in_size)
1955 {
1956     struct input_stream in;
1957     struct output_stream out;
1958     struct lzw_state state;
1959     short init_code_bits, prefix, code;
1960     unsigned char suffix;
1961
1962     in.in = in_data;
1963     in.len = in_size;
1964
1965     out.gif_block.len = 0;
1966     out.out = out_stream;
1967
1968     init_code_bits = suffix = 8;
1969     if (IStream_Write(out.out, &suffix, sizeof(suffix), NULL) != S_OK)
1970         return E_FAIL;
1971
1972     lzw_state_init(&state, init_code_bits, write_data, &out);
1973
1974     if (!lzw_output_clear_code(&state))
1975         return E_FAIL;
1976
1977     if (read_byte(&in, &suffix))
1978     {
1979         prefix = suffix;
1980
1981         while (read_byte(&in, &suffix))
1982         {
1983             code = lzw_dict_lookup(&state, prefix, suffix);
1984             if (code == -1)
1985             {
1986                 if (!lzw_output_code(&state, prefix))
1987                     return E_FAIL;
1988
1989                 if (lzw_dict_add(&state, prefix, suffix) == -1)
1990                 {
1991                     if (!lzw_output_clear_code(&state))
1992                         return E_FAIL;
1993                     lzw_dict_reset(&state);
1994                 }
1995
1996                 prefix = suffix;
1997             }
1998             else
1999                 prefix = code;
2000         }
2001
2002         if (!lzw_output_code(&state, prefix))
2003             return E_FAIL;
2004         if (!lzw_output_eof_code(&state))
2005             return E_FAIL;
2006         if (!lzw_flush_bits(&state))
2007             return E_FAIL;
2008     }
2009
2010     return flush_output_data(&out) ? S_OK : E_FAIL;
2011 }
2012
2013 static HRESULT WINAPI GifFrameEncode_Commit(IWICBitmapFrameEncode *iface)
2014 {
2015     GifFrameEncode *This = impl_from_IWICBitmapFrameEncode(iface);
2016     HRESULT hr;
2017
2018     TRACE("%p\n", iface);
2019
2020     EnterCriticalSection(&This->encoder->lock);
2021
2022     if (This->image_data && This->lines == This->height && !This->committed)
2023     {
2024         BYTE gif_palette[256][3];
2025
2026         hr = S_OK;
2027
2028         if (!This->encoder->info_written)
2029         {
2030             struct logical_screen_descriptor lsd;
2031
2032             /* Logical Screen Descriptor */
2033             memcpy(lsd.signature, "GIF89a", 6);
2034             lsd.width = This->width;
2035             lsd.height = This->height;
2036             lsd.packed = 0;
2037             if (This->encoder->colors)
2038                 lsd.packed |= 0x80; /* global color table flag */
2039             lsd.packed |= 0x07 << 4; /* color resolution */
2040             lsd.packed |= 0x07; /* global color table size */
2041             lsd.background_color_index = 0; /* FIXME */
2042             lsd.pixel_aspect_ratio = 0;
2043             hr = IStream_Write(This->encoder->stream, &lsd, sizeof(lsd), NULL);
2044             if (hr == S_OK && This->encoder->colors)
2045             {
2046                 UINT i;
2047
2048                 /* Global Color Table */
2049                 memset(gif_palette, 0, sizeof(gif_palette));
2050                 for (i = 0; i < This->encoder->colors; i++)
2051                 {
2052                     gif_palette[i][0] = (This->encoder->palette[i] >> 16) & 0xff;
2053                     gif_palette[i][1] = (This->encoder->palette[i] >> 8) & 0xff;
2054                     gif_palette[i][2] = This->encoder->palette[i] & 0xff;
2055                 }
2056                 hr = IStream_Write(This->encoder->stream, gif_palette, sizeof(gif_palette), NULL);
2057             }
2058
2059             /* FIXME: write GCE, APE, etc. GIF extensions */
2060
2061             if (hr == S_OK)
2062                 This->encoder->info_written = TRUE;
2063         }
2064
2065         if (hr == S_OK)
2066         {
2067             char image_separator = 0x2c;
2068
2069             hr = IStream_Write(This->encoder->stream, &image_separator, sizeof(image_separator), NULL);
2070             if (hr == S_OK)
2071             {
2072                 struct image_descriptor imd;
2073
2074                 /* Image Descriptor */
2075                 imd.left = 0;
2076                 imd.top = 0;
2077                 imd.width = This->width;
2078                 imd.height = This->height;
2079                 imd.packed = 0;
2080                 if (This->colors)
2081                 {
2082                     imd.packed |= 0x80; /* local color table flag */
2083                     imd.packed |= 0x07; /* local color table size */
2084                 }
2085                 /* FIXME: interlace flag */
2086                 hr = IStream_Write(This->encoder->stream, &imd, sizeof(imd), NULL);
2087                 if (hr == S_OK && This->colors)
2088                 {
2089                     UINT i;
2090
2091                     /* Local Color Table */
2092                     memset(gif_palette, 0, sizeof(gif_palette));
2093                     for (i = 0; i < This->colors; i++)
2094                     {
2095                         gif_palette[i][0] = (This->palette[i] >> 16) & 0xff;
2096                         gif_palette[i][1] = (This->palette[i] >> 8) & 0xff;
2097                         gif_palette[i][2] = This->palette[i] & 0xff;
2098                     }
2099                     hr = IStream_Write(This->encoder->stream, gif_palette, sizeof(gif_palette), NULL);
2100                     if (hr == S_OK)
2101                     {
2102                         /* Image Data */
2103                         hr = gif_compress(This->encoder->stream, This->image_data, This->width * This->height);
2104                         if (hr == S_OK)
2105                             This->committed = TRUE;
2106                     }
2107                 }
2108             }
2109         }
2110     }
2111     else
2112         hr = WINCODEC_ERR_WRONGSTATE;
2113
2114     LeaveCriticalSection(&This->encoder->lock);
2115     return hr;
2116 }
2117
2118 static HRESULT WINAPI GifFrameEncode_GetMetadataQueryWriter(IWICBitmapFrameEncode *iface, IWICMetadataQueryWriter **writer)
2119 {
2120     GifFrameEncode *encode = impl_from_IWICBitmapFrameEncode(iface);
2121
2122     TRACE("iface, %p, writer %p.\n", iface, writer);
2123
2124     if (!writer)
2125         return E_INVALIDARG;
2126
2127     if (!encode->initialized)
2128         return WINCODEC_ERR_NOTINITIALIZED;
2129
2130     return MetadataQueryWriter_CreateInstance(&encode->IWICMetadataBlockWriter_iface, NULL, writer);
2131 }
2132
2133 static const IWICBitmapFrameEncodeVtbl GifFrameEncode_Vtbl =
2134 {
2135     GifFrameEncode_QueryInterface,
2136     GifFrameEncode_AddRef,
2137     GifFrameEncode_Release,
2138     GifFrameEncode_Initialize,
2139     GifFrameEncode_SetSize,
2140     GifFrameEncode_SetResolution,
2141     GifFrameEncode_SetPixelFormat,
2142     GifFrameEncode_SetColorContexts,
2143     GifFrameEncode_SetPalette,
2144     GifFrameEncode_SetThumbnail,
2145     GifFrameEncode_WritePixels,
2146     GifFrameEncode_WriteSource,
2147     GifFrameEncode_Commit,
2148     GifFrameEncode_GetMetadataQueryWriter
2149 };
2150
2151 static HRESULT WINAPI GifEncoder_QueryInterface(IWICBitmapEncoder *iface, REFIID iid, void **ppv)
2152 {
2153     TRACE("%p,%s,%p\n", iface, debugstr_guid(iid), ppv);
2154
2155     if (!ppv) return E_INVALIDARG;
2156
2157     if (IsEqualIID(&IID_IUnknown, iid) ||
2158         IsEqualIID(&IID_IWICBitmapEncoder, iid))
2159     {
2160         IWICBitmapEncoder_AddRef(iface);
2161         *ppv = iface;
2162         return S_OK;
2163     }
2164
2165     *ppv = NULL;
2166     return E_NOINTERFACE;
2167 }
2168
2169 static ULONG WINAPI GifEncoder_AddRef(IWICBitmapEncoder *iface)
2170 {
2171     GifEncoder *This = impl_from_IWICBitmapEncoder(iface);
2172     ULONG ref = InterlockedIncrement(&This->ref);
2173
2174     TRACE("%p -> %u\n", iface, ref);
2175     return ref;
2176 }
2177
2178 static ULONG WINAPI GifEncoder_Release(IWICBitmapEncoder *iface)
2179 {
2180     GifEncoder *This = impl_from_IWICBitmapEncoder(iface);
2181     ULONG ref = InterlockedDecrement(&This->ref);
2182
2183     TRACE("%p -> %u\n", iface, ref);
2184
2185     if (!ref)
2186     {
2187         if (This->stream) IStream_Release(This->stream);
2188         This->lock.DebugInfo->Spare[0] = 0;
2189         DeleteCriticalSection(&This->lock);
2190         HeapFree(GetProcessHeap(), 0, This);
2191     }
2192
2193     return ref;
2194 }
2195
2196 static HRESULT WINAPI GifEncoder_Initialize(IWICBitmapEncoder *iface, IStream *stream, WICBitmapEncoderCacheOption option)
2197 {
2198     GifEncoder *This = impl_from_IWICBitmapEncoder(iface);
2199     HRESULT hr;
2200
2201     TRACE("%p,%p,%#x\n", iface, stream, option);
2202
2203     if (!stream) return E_INVALIDARG;
2204
2205     EnterCriticalSection(&This->lock);
2206
2207     if (!This->initialized)
2208     {
2209         IStream_AddRef(stream);
2210         This->stream = stream;
2211         This->initialized = TRUE;
2212         hr = S_OK;
2213     }
2214     else
2215         hr = WINCODEC_ERR_WRONGSTATE;
2216
2217     LeaveCriticalSection(&This->lock);
2218
2219     return hr;
2220 }
2221
2222 static HRESULT WINAPI GifEncoder_GetContainerFormat(IWICBitmapEncoder *iface, GUID *format)
2223 {
2224     if (!format) return E_INVALIDARG;
2225
2226     *format = GUID_ContainerFormatGif;
2227     return S_OK;
2228 }
2229
2230 static HRESULT WINAPI GifEncoder_GetEncoderInfo(IWICBitmapEncoder *iface, IWICBitmapEncoderInfo **info)
2231 {
2232     IWICComponentInfo *comp_info;
2233     HRESULT hr;
2234
2235     TRACE("%p,%p\n", iface, info);
2236
2237     if (!info) return E_INVALIDARG;
2238
2239     hr = CreateComponentInfo(&CLSID_WICGifEncoder, &comp_info);
2240     if (hr == S_OK)
2241     {
2242         hr = IWICComponentInfo_QueryInterface(comp_info, &IID_IWICBitmapEncoderInfo, (void **)info);
2243         IWICComponentInfo_Release(comp_info);
2244     }
2245     return hr;
2246 }
2247
2248 static HRESULT WINAPI GifEncoder_SetColorContexts(IWICBitmapEncoder *iface, UINT count, IWICColorContext **context)
2249 {
2250     FIXME("%p,%u,%p: stub\n", iface, count, context);
2251     return E_NOTIMPL;
2252 }
2253
2254 static HRESULT WINAPI GifEncoder_SetPalette(IWICBitmapEncoder *iface, IWICPalette *palette)
2255 {
2256     GifEncoder *This = impl_from_IWICBitmapEncoder(iface);
2257     HRESULT hr;
2258
2259     TRACE("%p,%p\n", iface, palette);
2260
2261     if (!palette) return E_INVALIDARG;
2262
2263     EnterCriticalSection(&This->lock);
2264
2265     if (This->initialized)
2266         hr = IWICPalette_GetColors(palette, 256, This->palette, &This->colors);
2267     else
2268         hr = WINCODEC_ERR_NOTINITIALIZED;
2269
2270     LeaveCriticalSection(&This->lock);
2271     return hr;
2272 }
2273
2274 static HRESULT WINAPI GifEncoder_SetThumbnail(IWICBitmapEncoder *iface, IWICBitmapSource *thumbnail)
2275 {
2276     TRACE("%p,%p\n", iface, thumbnail);
2277     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
2278 }
2279
2280 static HRESULT WINAPI GifEncoder_SetPreview(IWICBitmapEncoder *iface, IWICBitmapSource *preview)
2281 {
2282     TRACE("%p,%p\n", iface, preview);
2283     return WINCODEC_ERR_UNSUPPORTEDOPERATION;
2284 }
2285
2286 static HRESULT WINAPI GifEncoderFrame_Block_QueryInterface(IWICMetadataBlockWriter *iface, REFIID iid, void **ppv)
2287 {
2288     GifFrameEncode *frame_encoder = impl_from_IWICMetadataBlockWriter(iface);
2289
2290     return IWICBitmapFrameEncode_QueryInterface(&frame_encoder->IWICBitmapFrameEncode_iface, iid, ppv);
2291 }
2292
2293 static ULONG WINAPI GifEncoderFrame_Block_AddRef(IWICMetadataBlockWriter *iface)
2294 {
2295     GifFrameEncode *frame_encoder = impl_from_IWICMetadataBlockWriter(iface);
2296
2297     return IWICBitmapFrameEncode_AddRef(&frame_encoder->IWICBitmapFrameEncode_iface);
2298 }
2299
2300 static ULONG WINAPI GifEncoderFrame_Block_Release(IWICMetadataBlockWriter *iface)
2301 {
2302     GifFrameEncode *frame_encoder = impl_from_IWICMetadataBlockWriter(iface);
2303
2304     return IWICBitmapFrameEncode_Release(&frame_encoder->IWICBitmapFrameEncode_iface);
2305 }
2306
2307 static HRESULT WINAPI GifEncoderFrame_Block_GetContainerFormat(IWICMetadataBlockWriter *iface, GUID *container_format)
2308 {
2309     FIXME("iface %p, container_format %p stub.\n", iface, container_format);
2310
2311     return E_NOTIMPL;
2312 }
2313
2314 static HRESULT WINAPI GifEncoderFrame_Block_GetCount(IWICMetadataBlockWriter *iface, UINT *count)
2315 {
2316     FIXME("iface %p, count %p stub.\n", iface, count);
2317
2318     return E_NOTIMPL;
2319 }
2320
2321 static HRESULT WINAPI GifEncoderFrame_Block_GetReaderByIndex(IWICMetadataBlockWriter *iface,
2322         UINT index, IWICMetadataReader **metadata_reader)
2323 {
2324     FIXME("iface %p, index %d, metadata_reader %p stub.\n", iface, index, metadata_reader);
2325
2326     return E_NOTIMPL;
2327 }
2328
2329 static HRESULT WINAPI GifEncoderFrame_Block_GetEnumerator(IWICMetadataBlockWriter *iface, IEnumUnknown **enum_metadata)
2330 {
2331     FIXME("iface %p, enum_metadata %p stub.\n", iface, enum_metadata);
2332
2333     return E_NOTIMPL;
2334 }
2335
2336 static HRESULT WINAPI GifEncoderFrame_Block_InitializeFromBlockReader(IWICMetadataBlockWriter *iface,
2337         IWICMetadataBlockReader *block_reader)
2338 {
2339     FIXME("iface %p, block_reader %p stub.\n", iface, block_reader);
2340
2341     return E_NOTIMPL;
2342 }
2343
2344 static HRESULT WINAPI GifEncoderFrame_Block_GetWriterByIndex(IWICMetadataBlockWriter *iface, UINT index,
2345         IWICMetadataWriter **metadata_writer)
2346 {
2347     FIXME("iface %p, index %u, metadata_writer %p stub.\n", iface, index, metadata_writer);
2348
2349     return E_NOTIMPL;
2350 }
2351
2352 static HRESULT WINAPI GifEncoderFrame_Block_AddWriter(IWICMetadataBlockWriter *iface, IWICMetadataWriter *metadata_writer)
2353 {
2354     FIXME("iface %p, metadata_writer %p stub.\n", iface, metadata_writer);
2355
2356     return E_NOTIMPL;
2357 }
2358
2359 static HRESULT WINAPI GifEncoderFrame_Block_SetWriterByIndex(IWICMetadataBlockWriter *iface, UINT index,
2360         IWICMetadataWriter *metadata_writer)
2361 {
2362     FIXME("iface %p, index %u, metadata_writer %p stub.\n", iface, index, metadata_writer);
2363
2364     return E_NOTIMPL;
2365 }
2366
2367 static HRESULT WINAPI GifEncoderFrame_Block_RemoveWriterByIndex(IWICMetadataBlockWriter *iface, UINT index)
2368 {
2369     FIXME("iface %p, index %u stub.\n", iface, index);
2370
2371     return E_NOTIMPL;
2372 }
2373
2374 static const IWICMetadataBlockWriterVtbl GifFrameEncode_BlockVtbl = {
2375     GifEncoderFrame_Block_QueryInterface,
2376     GifEncoderFrame_Block_AddRef,
2377     GifEncoderFrame_Block_Release,
2378     GifEncoderFrame_Block_GetContainerFormat,
2379     GifEncoderFrame_Block_GetCount,
2380     GifEncoderFrame_Block_GetReaderByIndex,
2381     GifEncoderFrame_Block_GetEnumerator,
2382     GifEncoderFrame_Block_InitializeFromBlockReader,
2383     GifEncoderFrame_Block_GetWriterByIndex,
2384     GifEncoderFrame_Block_AddWriter,
2385     GifEncoderFrame_Block_SetWriterByIndex,
2386     GifEncoderFrame_Block_RemoveWriterByIndex,
2387 };
2388
2389 static HRESULT WINAPI GifEncoder_CreateNewFrame(IWICBitmapEncoder *iface, IWICBitmapFrameEncode **frame, IPropertyBag2 **options)
2390 {
2391     GifEncoder *This = impl_from_IWICBitmapEncoder(iface);
2392     HRESULT hr;
2393
2394     TRACE("%p,%p,%p\n", iface, frame, options);
2395
2396     if (!frame) return E_INVALIDARG;
2397
2398     EnterCriticalSection(&This->lock);
2399
2400     if (This->initialized && !This->committed)
2401     {
2402         GifFrameEncode *ret = HeapAlloc(GetProcessHeap(), 0, sizeof(*ret));
2403         if (ret)
2404         {
2405             This->n_frames++;
2406
2407             ret->IWICBitmapFrameEncode_iface.lpVtbl = &GifFrameEncode_Vtbl;
2408             ret->IWICMetadataBlockWriter_iface.lpVtbl = &GifFrameEncode_BlockVtbl;
2409
2410             ret->ref = 1;
2411             ret->encoder = This;
2412             ret->initialized = FALSE;
2413             ret->interlace = FALSE; /* FIXME: read from the properties */
2414             ret->committed = FALSE;
2415             ret->width = 0;
2416             ret->height = 0;
2417             ret->lines = 0;
2418             ret->xres = 0.0;
2419             ret->yres = 0.0;
2420             ret->colors = 0;
2421             ret->image_data = NULL;
2422             IWICBitmapEncoder_AddRef(iface);
2423             *frame = &ret->IWICBitmapFrameEncode_iface;
2424
2425             hr = S_OK;
2426
2427             if (options)
2428             {
2429                 hr = CreatePropertyBag2(NULL, 0, options);
2430                 if (hr != S_OK)
2431                 {
2432                     IWICBitmapFrameEncode_Release(*frame);
2433                     *frame = NULL;
2434                 }
2435             }
2436         }
2437         else
2438             hr = E_OUTOFMEMORY;
2439     }
2440     else
2441         hr = WINCODEC_ERR_WRONGSTATE;
2442
2443     LeaveCriticalSection(&This->lock);
2444
2445     return hr;
2446
2447 }
2448
2449 static HRESULT WINAPI GifEncoder_Commit(IWICBitmapEncoder *iface)
2450 {
2451     GifEncoder *This = impl_from_IWICBitmapEncoder(iface);
2452     HRESULT hr;
2453
2454     TRACE("%p\n", iface);
2455
2456     EnterCriticalSection(&This->lock);
2457
2458     if (This->initialized && !This->committed)
2459     {
2460         char gif_trailer = 0x3b;
2461
2462         /* FIXME: write text, comment GIF extensions */
2463
2464         hr = IStream_Write(This->stream, &gif_trailer, sizeof(gif_trailer), NULL);
2465         if (hr == S_OK)
2466             This->committed = TRUE;
2467     }
2468     else
2469         hr = WINCODEC_ERR_WRONGSTATE;
2470
2471     LeaveCriticalSection(&This->lock);
2472     return hr;
2473 }
2474
2475 static HRESULT WINAPI GifEncoder_GetMetadataQueryWriter(IWICBitmapEncoder *iface, IWICMetadataQueryWriter **writer)
2476 {
2477     FIXME("%p,%p: stub\n", iface, writer);
2478     return E_NOTIMPL;
2479 }
2480
2481 static const IWICBitmapEncoderVtbl GifEncoder_Vtbl =
2482 {
2483     GifEncoder_QueryInterface,
2484     GifEncoder_AddRef,
2485     GifEncoder_Release,
2486     GifEncoder_Initialize,
2487     GifEncoder_GetContainerFormat,
2488     GifEncoder_GetEncoderInfo,
2489     GifEncoder_SetColorContexts,
2490     GifEncoder_SetPalette,
2491     GifEncoder_SetThumbnail,
2492     GifEncoder_SetPreview,
2493     GifEncoder_CreateNewFrame,
2494     GifEncoder_Commit,
2495     GifEncoder_GetMetadataQueryWriter
2496 };
2497
2498 HRESULT GifEncoder_CreateInstance(REFIID iid, void **ppv)
2499 {
2500     GifEncoder *This;
2501     HRESULT ret;
2502
2503     TRACE("%s,%p\n", debugstr_guid(iid), ppv);
2504
2505     *ppv = NULL;
2506
2507     This = HeapAlloc(GetProcessHeap(), 0, sizeof(*This));
2508     if (!This) return E_OUTOFMEMORY;
2509
2510     This->IWICBitmapEncoder_iface.lpVtbl = &GifEncoder_Vtbl;
2511     This->ref = 1;
2512     This->stream = NULL;
2513     InitializeCriticalSection(&This->lock);
2514     This->lock.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": GifEncoder.lock");
2515     This->initialized = FALSE;
2516     This->info_written = FALSE;
2517     This->committed = FALSE;
2518     This->n_frames = 0;
2519     This->colors = 0;
2520
2521     ret = IWICBitmapEncoder_QueryInterface(&This->IWICBitmapEncoder_iface, iid, ppv);
2522     IWICBitmapEncoder_Release(&This->IWICBitmapEncoder_iface);
2523
2524     return ret;
2525 }