Revert "Revert "Add type cast definitions for CPDF_Dictionary.""

core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <limits.h>
 #include "../../../include/fpdfapi/fpdf_parser.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "../../../include/fxcodec/fx_codec.h"
@@ skipping 265 matching lines @@
     const uint8_t* src_buf,
     FX_DWORD src_size,
     int width,
     int height,
     int nComps,
     int bpc,
     const CPDF_Dictionary* pParams) {
   int predictor = 0;
   int Colors = 0, BitsPerComponent = 0, Columns = 0;
   if (pParams) {
-    predictor = ((CPDF_Dictionary*)pParams)->GetInteger(FX_BSTRC("Predictor"));
+    predictor = pParams->GetInteger(FX_BSTRC("Predictor"));
     Colors = pParams->GetInteger(FX_BSTRC("Colors"), 1);
     BitsPerComponent = pParams->GetInteger(FX_BSTRC("BitsPerComponent"), 8);
     Columns = pParams->GetInteger(FX_BSTRC("Columns"), 1);
     if (!CheckFlateDecodeParams(Colors, BitsPerComponent, Columns)) {
       return NULL;
     }
   }
   return CPDF_ModuleMgr::Get()->GetFlateModule()->CreateDecoder(
       src_buf, src_size, width, height, nComps, bpc, predictor, Colors,
       BitsPerComponent, Columns);
 }
 FX_DWORD FPDFAPI_FlateOrLZWDecode(FX_BOOL bLZW,
                                   const uint8_t* src_buf,
                                   FX_DWORD src_size,
                                   CPDF_Dictionary* pParams,
                                   FX_DWORD estimated_size,
                                   uint8_t*& dest_buf,
                                   FX_DWORD& dest_size) {
   int predictor = 0;
   FX_BOOL bEarlyChange = TRUE;
   int Colors = 0, BitsPerComponent = 0, Columns = 0;
   if (pParams) {
-    predictor = ((CPDF_Dictionary*)pParams)->GetInteger(FX_BSTRC("Predictor"));
-    bEarlyChange =
-        ((CPDF_Dictionary*)pParams)->GetInteger(FX_BSTRC("EarlyChange"), 1);
+    predictor = pParams->GetInteger(FX_BSTRC("Predictor"));
+    bEarlyChange = pParams->GetInteger(FX_BSTRC("EarlyChange"), 1);
     Colors = pParams->GetInteger(FX_BSTRC("Colors"), 1);
     BitsPerComponent = pParams->GetInteger(FX_BSTRC("BitsPerComponent"), 8);
     Columns = pParams->GetInteger(FX_BSTRC("Columns"), 1);
     if (!CheckFlateDecodeParams(Colors, BitsPerComponent, Columns)) {
       return (FX_DWORD)-1;
     }
   }
   return CPDF_ModuleMgr::Get()->GetFlateModule()->FlateOrLZWDecode(
       bLZW, src_buf, src_size, bEarlyChange, predictor, Colors,
       BitsPerComponent, Columns, estimated_size, dest_buf, dest_size);
@@ skipping 36 matching lines @@
   } else {
     DecoderList.Add(pDecoder->GetConstString());
     ParamList.Add(pParams ? pParams->GetDict() : NULL);
   }
   uint8_t* last_buf = (uint8_t*)src_buf;
   FX_DWORD last_size = src_size;
   for (int i = 0; i < DecoderList.GetSize(); i++) {
     int estimated_size =
         i == DecoderList.GetSize() - 1 ? last_estimated_size : 0;
     CFX_ByteString decoder = DecoderList[i];
-    CPDF_Dictionary* pParam = (CPDF_Dictionary*)ParamList[i];
+    // Use ToDictionary here because we can push NULL into the ParamList.
+    CPDF_Dictionary* pParam =
+        ToDictionary(static_cast<CPDF_Object*>(ParamList[i]));
     uint8_t* new_buf = NULL;
     FX_DWORD new_size = (FX_DWORD)-1;
     int offset = -1;
     if (decoder == FX_BSTRC("FlateDecode") || decoder == FX_BSTRC("Fl")) {
       if (bImageAcc && i == DecoderList.GetSize() - 1) {
         ImageEncoding = FX_BSTRC("FlateDecode");
         dest_buf = (uint8_t*)last_buf;
         dest_size = last_size;
         pImageParms = pParam;
         return TRUE;
@@ skipping 198 matching lines @@
                      FX_DWORD src_size,
                      uint8_t*& dest_buf,
                      FX_DWORD& dest_size) {
   CCodec_ModuleMgr* pEncoders = CPDF_ModuleMgr::Get()->GetCodecModule();
   if (pEncoders) {
     return pEncoders->GetFlateModule()->FlateOrLZWDecode(
         FALSE, src_buf, src_size, FALSE, 0, 0, 0, 0, 0, dest_buf, dest_size);
   }
   return 0;
 }