Some warnings fixed

lodepng.cpp

@@ -37,6 +37,7 @@ Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for
 #if defined(_MSC_VER) && (_MSC_VER >= 1310) /*Visual Studio: A few warning types are not desired here.*/
 #pragma warning( disable : 4244 ) /*implicit conversions: not warned by gcc -Wall -Wextra and requires too much casts*/
 #pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/
+#pragma warning( disable : 4334 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/
 #endif /*_MSC_VER */
 
 const char* LODEPNG_VERSION_STRING = "20161127";
@@ -1455,11 +1456,11 @@ static void updateHashChain(Hash* hash, size_t wpos, unsigned hashval, unsigned
 {
   hash->val[wpos] = (int)hashval;
   if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval];
-  hash->head[hashval] = wpos;
+  hash->head[hashval] = (int)wpos;
 
   hash->zeros[wpos] = numzeros;
   if(hash->headz[numzeros] != -1) hash->chainz[wpos] = hash->headz[numzeros];
-  hash->headz[numzeros] = wpos;
+  hash->headz[numzeros] = (int)wpos;
 }
 
 /*
@@ -1531,7 +1532,7 @@ static unsigned encodeLZ77(uivector* out, Hash* hash,
     for(;;)
     {
       if(chainlength++ >= maxchainlength) break;
-      current_offset = hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize;
+      current_offset = hashpos <= wpos ? (unsigned int)wpos - hashpos : (unsigned int)wpos - hashpos + windowsize;
 
       if(current_offset < prev_offset) break; /*stop when went completely around the circular buffer*/
       prev_offset = current_offset;
@@ -3489,7 +3490,7 @@ unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
     for(i = 0; i != palsize; ++i)
     {
       const unsigned char* p = &palette[i * 4];
-      color_tree_add(&tree, p[0], p[1], p[2], p[3], i);
+      color_tree_add(&tree, p[0], p[1], p[2], p[3], (unsigned int)i);
     }
   }
 
@@ -4329,7 +4330,7 @@ static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, siz
 
     string2_begin = length + 1; /*skip keyword null terminator*/
 
-    length = chunkLength < string2_begin ? 0 : chunkLength - string2_begin;
+    length = chunkLength < string2_begin ? 0 : (unsigned int)chunkLength - string2_begin;
     str = (char*)lodepng_malloc(length + 1);
     if(!str) CERROR_BREAK(error, 83); /*alloc fail*/
 
@@ -4377,7 +4378,7 @@ static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecompressSetting
     string2_begin = length + 2;
     if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
 
-    length = chunkLength - string2_begin;
+    length = (unsigned int)chunkLength - string2_begin;
     /*will fail if zlib error, e.g. if length is too small*/
     error = zlib_decompress(&decoded.data, &decoded.size,
                             (unsigned char*)(&data[string2_begin]),
@@ -4457,7 +4458,7 @@ static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecompressSetting
     /*read the actual text*/
     begin += length + 1;
 
-    length = chunkLength < begin ? 0 : chunkLength - begin;
+    length = chunkLength < begin ? 0 : (unsigned int)chunkLength - begin;
 
     if(compressed)
     {
@@ -5400,7 +5401,7 @@ static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w,
     {
       for(type = 0; type != 5; ++type)
       {
-        unsigned testsize = linebytes;
+        unsigned testsize = (unsigned)linebytes;
         /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/
 
         filterScanline(attempt[type], &in[y * linebytes], prevline, linebytes, bytewidth, type);