Re-enable several MSVC warnings

core/fxcodec/jbig2/JBig2_Image.cpp

Index: core/fxcodec/jbig2/JBig2_Image.cpp
diff --git a/core/fxcodec/jbig2/JBig2_Image.cpp b/core/fxcodec/jbig2/JBig2_Image.cpp
index 311c38270ee940b0103752e6fe838c49ba2755a5..e4520d8b1ee12e35a4ca84a075a727e31da86b72 100644
--- a/core/fxcodec/jbig2/JBig2_Image.cpp
+++ b/core/fxcodec/jbig2/JBig2_Image.cpp
@@ -665,20 +665,21 @@ FX_BOOL CJBig2_Image::composeTo_opt2(CJBig2_Image* pDst,
                                      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 {
@@ -702,8 +703,8 @@ FX_BOOL CJBig2_Image::composeTo_opt2(CJBig2_Image* pDst,
   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 {
@@ -714,18 +715,18 @@ FX_BOOL CJBig2_Image::composeTo_opt2(CJBig2_Image* pDst,
   } 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) {
@@ -820,6 +821,7 @@ FX_BOOL CJBig2_Image::composeTo_opt2(CJBig2_Image* pDst,
       }
     }
   } 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;