Merge to XFA: Change |CCodec_ScanlineDecoder::m_Pitch| to FX_DWORD

core/src/fxcodec/codec/fx_codec_fax.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 "codec_int.h"
 #include "core/include/fxcodec/fx_codec.h"
 
 namespace {
@@ skipping 638 matching lines @@
   m_bByteAlign = EncodedByteAlign;
   m_bBlack = BlackIs1;
   m_OrigWidth = Columns;
   m_OrigHeight = Rows;
   if (m_OrigWidth == 0) {
     m_OrigWidth = width;
   }
   if (m_OrigHeight == 0) {
     m_OrigHeight = height;
   }
-  m_Pitch = (m_OrigWidth + 31) / 32 * 4;
+  // Should not overflow. Checked by FPDFAPI_CreateFaxDecoder.
+  m_Pitch = (static_cast<FX_DWORD>(m_OrigWidth) + 31) / 32 * 4;
   m_OutputWidth = m_OrigWidth;
   m_OutputHeight = m_OrigHeight;
   m_pScanlineBuf = FX_Alloc(uint8_t, m_Pitch);
   m_pRefBuf = FX_Alloc(uint8_t, m_Pitch);
   m_pSrcBuf = src_buf;
   m_SrcSize = src_size;
   m_nComps = 1;
   m_bpc = 1;
   m_bColorTransformed = FALSE;
   return TRUE;
@@ skipping 39 matching lines @@
         m_bByteAlign = FALSE;
       } else {
         bitpos0++;
       }
     }
     if (m_bByteAlign) {
       bitpos = bitpos1;
     }
   }
   if (m_bBlack) {
-    for (int i = 0; i < m_Pitch; i++) {
+    for (FX_DWORD i = 0; i < m_Pitch; i++) {
       m_pScanlineBuf[i] = ~m_pScanlineBuf[i];
     }
   }
   return m_pScanlineBuf;
 }
 FX_DWORD CCodec_FaxDecoder::GetSrcOffset() {
   FX_DWORD ret = (bitpos + 7) / 8;
   if (ret > m_SrcSize) {
     ret = m_SrcSize;
   }
@@ skipping 91 matching lines @@
     FX_BOOL EndOfLine,
     FX_BOOL EncodedByteAlign,
     FX_BOOL BlackIs1,
     int Columns,
     int Rows) {
   CCodec_FaxDecoder* pDecoder = new CCodec_FaxDecoder;
   pDecoder->Create(src_buf, src_size, width, height, K, EndOfLine,
                    EncodedByteAlign, BlackIs1, Columns, Rows);
   return pDecoder;
 }