Re-enable several MSVC warnings

core/fxcodec/jbig2/JBig2_Image.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 "core/fxcodec/jbig2/JBig2_Image.h"
 #include "core/include/fxcrt/fx_coordinates.h"
@@ skipping 647 matching lines @@
       }
     }
   }
   return 1;
 }
 FX_BOOL CJBig2_Image::composeTo_opt2(CJBig2_Image* pDst,
                                      int32_t x,
                                      int32_t y,
                                      JBig2ComposeOp op,
                                      const FX_RECT* pSrcRect) {
-  int32_t xs0, ys0, xs1, ys1, xd0, yd0, xd1, yd1, xx, yy, w, h, middleDwords,
-      lineLeft;
-  FX_DWORD s1, d1, d2, shift, shift1, shift2, tmp, tmp1, tmp2, maskL, maskR,
-      maskM;
-  uint8_t *lineSrc, *lineDst, *sp, *dp;
-  int32_t sw, sh;
+  int32_t xs0 = 0, ys0 = 0, xs1 = 0, ys1 = 0;

[dsinclair, 2016/03/16 13:23:31]

nit: one per line.

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

Done.

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

I didn't see how these could be used uninitialized.  Also, can we move these
down to right before they are used? eg. declare ys0 at 683?

These might clean up if we combined declaration and initialization using the ?
operator.

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

Done.

+  int32_t xd0 = 0, yd0 = 0, xx = 0, yy = 0;
+  FX_DWORD shift = 0, shift1 = 0, shift2 = 0;
+  FX_DWORD tmp1 = 0, tmp2 = 0;
+  uint8_t* sp = nullptr;
+  uint8_t* dp = nullptr;
+  FX_DWORD tmp = 0;
   if (!m_pData) {
     return FALSE;
   }
   if (x < -1048576 || x > 1048576 || y < -1048576 || y > 1048576) {

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

nit: they probably mean >= 1048576, since x wont fit in 20 bits if it is
1048576.

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

Ack. I am not certain about the code here, will defer behavior changes from this
CL.

     return FALSE;
   }
-  sw = pSrcRect->Width();
-  sh = pSrcRect->Height();
+  int32_t sw = pSrcRect->Width();
+  int32_t sh = pSrcRect->Height();
   if (y < 0) {
     ys0 = -y;
   } else {
     ys0 = 0;
   }
   if (y + sh > pDst->m_nHeight) {
     ys1 = pDst->m_nHeight - y;
   } else {
     ys1 = sh;
   }
   if (x < 0) {
     xs0 = -x;
   } else {
     xs0 = 0;
   }
   if (x + sw > pDst->m_nWidth) {
     xs1 = pDst->m_nWidth - x;
   } else {
     xs1 = sw;
   }
   if ((ys0 >= ys1) || (xs0 >= xs1)) {
     return 0;
   }
-  w = xs1 - xs0;
-  h = ys1 - ys0;
+  int32_t w = xs1 - xs0;
+  int32_t h = ys1 - ys0;
   if (y < 0) {
     yd0 = 0;
   } else {
     yd0 = y;
   }
   if (x < 0) {
     xd0 = 0;
   } else {
     xd0 = x;
   }
-  xd1 = xd0 + w;
-  yd1 = yd0 + h;
-  d1 = xd0 & 31;
-  d2 = xd1 & 31;
-  s1 = xs0 & 31;
-  maskL = 0xffffffff >> d1;
-  maskR = 0xffffffff << ((32 - (xd1 & 31)) % 32);
-  maskM = maskL & maskR;
-  lineSrc = m_pData + (pSrcRect->top + ys0) * m_nStride +
-            (((xs0 + pSrcRect->left) >> 5) << 2);
-  lineLeft = m_nStride - ((xs0 >> 5) << 2);
-  lineDst = pDst->m_pData + yd0 * pDst->m_nStride + ((xd0 >> 5) << 2);
+  int32_t xd1 = xd0 + w;
+  int32_t yd1 = yd0 + h;
+  int32_t d1 = xd0 & 31;
+  int32_t d2 = xd1 & 31;
+  int32_t s1 = xs0 & 31;
+  int32_t maskL = 0xffffffff >> d1;
+  int32_t maskR = 0xffffffff << ((32 - (xd1 & 31)) % 32);
+  int32_t maskM = maskL & maskR;
+  uint8_t* lineSrc = m_pData + (pSrcRect->top + ys0) * m_nStride +
+                     (((xs0 + pSrcRect->left) >> 5) << 2);
+  int32_t lineLeft = m_nStride - ((xs0 >> 5) << 2);
+  uint8_t* lineDst = pDst->m_pData + yd0 * pDst->m_nStride + ((xd0 >> 5) << 2);
   if ((xd0 & ~31) == ((xd1 - 1) & ~31)) {
     if ((xs0 & ~31) == ((xs1 - 1) & ~31)) {
       if (s1 > d1) {
         shift = s1 - d1;
         for (yy = yd0; yy < yd1; yy++) {
           tmp1 = JBIG2_GETDWORD(lineSrc) << shift;
           tmp2 = JBIG2_GETDWORD(lineDst);
           switch (op) {
             case JBIG2_COMPOSE_OR:
               tmp = (tmp2 & ~maskM) | ((tmp1 | tmp2) & maskM);
@@ skipping 74 matching lines @@
         }
         lineDst[0] = (uint8_t)(tmp >> 24);
         lineDst[1] = (uint8_t)(tmp >> 16);
         lineDst[2] = (uint8_t)(tmp >> 8);
         lineDst[3] = (uint8_t)tmp;
         lineSrc += m_nStride;
         lineDst += pDst->m_nStride;
       }
     }
   } else {
+    int32_t middleDwords = 0;

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

I don't think this needs to persist between blocks, since we initialize it each
time.  Maybe use N decls of this at line 828, 920, etc.

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

Done.

     if (s1 > d1) {
       shift1 = s1 - d1;
       shift2 = 32 - shift1;
       middleDwords = (xd1 >> 5) - ((xd0 + 31) >> 5);
       for (yy = yd0; yy < yd1; yy++) {
         sp = lineSrc;
         dp = lineDst;
         if (d1 != 0) {
           tmp1 = (JBIG2_GETDWORD(sp) << shift1) |
                  (JBIG2_GETDWORD(sp + 4) >> shift2);
@@ skipping 257 matching lines @@
           dp[2] = (uint8_t)(tmp >> 8);
           dp[3] = (uint8_t)tmp;
         }
         lineSrc += m_nStride;
         lineDst += pDst->m_nStride;
       }
     }
   }
   return 1;
 }