Re-enable several MSVC warnings

core/fxcodec/jbig2/JBig2_TrdProc.cpp

 // Copyright 2015 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 "core/fxcodec/jbig2/JBig2_TrdProc.h"
 
 #include <memory>
 
 #include "core/fxcodec/jbig2/JBig2_ArithDecoder.h"
 #include "core/fxcodec/jbig2/JBig2_ArithIntDecoder.h"
 #include "core/fxcodec/jbig2/JBig2_GrrdProc.h"
 #include "core/fxcodec/jbig2/JBig2_HuffmanDecoder.h"
 
 CJBig2_Image* CJBig2_TRDProc::decode_Huffman(CJBig2_BitStream* pStream,
                                              JBig2ArithCtx* grContext) {
-  int32_t STRIPT, FIRSTS;
-  FX_DWORD NINSTANCES;
-  int32_t DT, DFS, CURS;
-  int32_t SI, TI;
-  CJBig2_Image* IBI;
-  FX_DWORD WI, HI;
-  int32_t IDS;
-  FX_BOOL RI;
-  int32_t RDWI, RDHI, RDXI, RDYI;
-  CJBig2_Image* IBOI;
-  FX_DWORD WOI, HOI;
-  FX_BOOL bFirst;
-  FX_DWORD nTmp;
-  int32_t nVal, nBits;
+  int32_t STRIPT = 0;
+  int32_t DT = 0, DFS = 0;
+  int32_t CURS = 0;
+  CJBig2_Image* IBI = nullptr;
+  int32_t IDS = 0;
+  FX_BOOL RI = 0;
+  int32_t RDWI = 0, RDHI = 0, RDXI = 0, RDYI = 0;

[dsinclair, 2016/03/16 13:23:32]

ditto

[Wei Li, 2016/03/16 17:51:31]

Done.

+  FX_DWORD nTmp = 0;
+  int32_t nVal = 0, nBits = 0;

[Tom Sepez, 2016/03/16 18:34:59]

These are probably OK since the compiler can't prove that a value will be set
when passing these by &STRIPT to decodeAsValue().  

This would benefit from declaring these right before they get clobbered by the
decode calls.

[Wei Li, 2016/03/17 02:24:05]

Very good idea. :)

   std::unique_ptr<CJBig2_HuffmanDecoder> pHuffmanDecoder(
       new CJBig2_HuffmanDecoder(pStream));
   std::unique_ptr<CJBig2_Image> SBREG(new CJBig2_Image(SBW, SBH));
   SBREG->fill(SBDEFPIXEL);
   if (pHuffmanDecoder->decodeAValue(SBHUFFDT, &STRIPT) != 0)
     return nullptr;
 
   STRIPT *= SBSTRIPS;
   STRIPT = -STRIPT;
-  FIRSTS = 0;
-  NINSTANCES = 0;
+  int32_t FIRSTS = 0;
+  FX_DWORD NINSTANCES = 0;
   while (NINSTANCES < SBNUMINSTANCES) {
     if (pHuffmanDecoder->decodeAValue(SBHUFFDT, &DT) != 0)
       return nullptr;
 
     DT *= SBSTRIPS;
     STRIPT = STRIPT + DT;
-    bFirst = TRUE;
+    FX_BOOL bFirst = TRUE;

[dsinclair, 2016/03/16 13:23:32]

nit: bool

[Wei Li, 2016/03/16 17:51:31]

Done.

     for (;;) {
       if (bFirst) {
         if (pHuffmanDecoder->decodeAValue(SBHUFFFS, &DFS) != 0)
           return nullptr;
 
         FIRSTS = FIRSTS + DFS;
         CURS = FIRSTS;
         bFirst = FALSE;
       } else {
         nVal = pHuffmanDecoder->decodeAValue(SBHUFFDS, &IDS);
         if (nVal == JBIG2_OOB) {
           break;
         } else if (nVal != 0) {
           return nullptr;
         } else {
           CURS = CURS + IDS + SBDSOFFSET;
         }
       }
       uint8_t CURT = 0;
       if (SBSTRIPS != 1) {
         nTmp = 1;
         while ((FX_DWORD)(1 << nTmp) < SBSTRIPS) {
           nTmp++;
         }
         if (pStream->readNBits(nTmp, &nVal) != 0)
           return nullptr;
 
         CURT = nVal;
       }
-      TI = STRIPT + CURT;
+      int32_t TI = STRIPT + CURT;
       nVal = 0;
       nBits = 0;
       FX_DWORD IDI;
       for (;;) {
         if (pStream->read1Bit(&nTmp) != 0)
           return nullptr;
 
         nVal = (nVal << 1) | nTmp;
         nBits++;
         for (IDI = 0; IDI < SBNUMSYMS; IDI++) {
@@ skipping 18 matching lines @@
       } else {
         if ((pHuffmanDecoder->decodeAValue(SBHUFFRDW, &RDWI) != 0) ||
             (pHuffmanDecoder->decodeAValue(SBHUFFRDH, &RDHI) != 0) ||
             (pHuffmanDecoder->decodeAValue(SBHUFFRDX, &RDXI) != 0) ||
             (pHuffmanDecoder->decodeAValue(SBHUFFRDY, &RDYI) != 0) ||
             (pHuffmanDecoder->decodeAValue(SBHUFFRSIZE, &nVal) != 0)) {
           return nullptr;
         }
         pStream->alignByte();
         nTmp = pStream->getOffset();
-        IBOI = SBSYMS[IDI];
+        CJBig2_Image* IBOI = SBSYMS[IDI];
         if (!IBOI)
           return nullptr;
 
-        WOI = IBOI->m_nWidth;
-        HOI = IBOI->m_nHeight;
+        FX_DWORD WOI = IBOI->m_nWidth;
+        FX_DWORD HOI = IBOI->m_nHeight;
         if ((int)(WOI + RDWI) < 0 || (int)(HOI + RDHI) < 0)
           return nullptr;
 
         std::unique_ptr<CJBig2_GRRDProc> pGRRD(new CJBig2_GRRDProc());
         pGRRD->GRW = WOI + RDWI;
         pGRRD->GRH = HOI + RDHI;
         pGRRD->GRTEMPLATE = SBRTEMPLATE;
         pGRRD->GRREFERENCE = IBOI;
         pGRRD->GRREFERENCEDX = (RDWI >> 2) + RDXI;
         pGRRD->GRREFERENCEDY = (RDHI >> 2) + RDYI;
@@ skipping 14 matching lines @@
         pStream->alignByte();
         pStream->offset(2);
         if ((FX_DWORD)nVal != (pStream->getOffset() - nTmp)) {
           delete IBI;
           return nullptr;
         }
       }
       if (!IBI) {
         continue;
       }
-      WI = IBI->m_nWidth;
-      HI = IBI->m_nHeight;
+      FX_DWORD WI = IBI->m_nWidth;
+      FX_DWORD HI = IBI->m_nHeight;
       if (TRANSPOSED == 0 && ((REFCORNER == JBIG2_CORNER_TOPRIGHT) ||
                               (REFCORNER == JBIG2_CORNER_BOTTOMRIGHT))) {
         CURS = CURS + WI - 1;
       } else if (TRANSPOSED == 1 && ((REFCORNER == JBIG2_CORNER_BOTTOMLEFT) ||
                                      (REFCORNER == JBIG2_CORNER_BOTTOMRIGHT))) {
         CURS = CURS + HI - 1;
       }
-      SI = CURS;
+      int32_t SI = CURS;
       if (TRANSPOSED == 0) {
         switch (REFCORNER) {
           case JBIG2_CORNER_TOPLEFT:
             SBREG->composeFrom(SI, TI, IBI, SBCOMBOP);
             break;
           case JBIG2_CORNER_TOPRIGHT:
             SBREG->composeFrom(SI - WI + 1, TI, IBI, SBCOMBOP);
             break;
           case JBIG2_CORNER_BOTTOMLEFT:
             SBREG->composeFrom(SI, TI - HI + 1, IBI, SBCOMBOP);
@@ skipping 92 matching lines @@
   }
   std::unique_ptr<CJBig2_Image> SBREG(new CJBig2_Image(SBW, SBH));
   SBREG->fill(SBDEFPIXEL);
   int32_t STRIPT;
   pIADT->decode(pArithDecoder, &STRIPT);
   STRIPT *= SBSTRIPS;
   STRIPT = -STRIPT;
   int32_t FIRSTS = 0;
   FX_DWORD NINSTANCES = 0;
   while (NINSTANCES < SBNUMINSTANCES) {
-    int32_t CURS;
+    int32_t CURS = 0;
     int32_t DT;
     pIADT->decode(pArithDecoder, &DT);
     DT *= SBSTRIPS;
     STRIPT += DT;
     bool bFirst = true;
     for (;;) {
       if (bFirst) {
         int32_t DFS;
         pIAFS->decode(pArithDecoder, &DFS);
         FIRSTS += DFS;
@@ skipping 107 matching lines @@
         CURS += WI - 1;
       } else if (TRANSPOSED == 1 && ((REFCORNER == JBIG2_CORNER_TOPLEFT) ||
                                      (REFCORNER == JBIG2_CORNER_TOPRIGHT))) {
         CURS += HI - 1;
       }
       ++NINSTANCES;
     }
   }
   return SBREG.release();
 }