Re-enable several MSVC warnings

core/fxcodec/codec/fx_codec_jpx_opj.cpp

Index: core/fxcodec/codec/fx_codec_jpx_opj.cpp
diff --git a/core/fxcodec/codec/fx_codec_jpx_opj.cpp b/core/fxcodec/codec/fx_codec_jpx_opj.cpp
index aaa89388b806b8d7ba46d3cf076835b4aa7abc36..b45ee2b2090b8e1e4523e4b34d3d72ca33160fe5 100644
--- a/core/fxcodec/codec/fx_codec_jpx_opj.cpp
+++ b/core/fxcodec/codec/fx_codec_jpx_opj.cpp
@@ -29,11 +29,11 @@ OPJ_SIZE_T opj_read_from_memory(void* p_buffer,
                                 void* p_user_data) {
   DecodeData* srcData = static_cast<DecodeData*>(p_user_data);
   if (!srcData || !srcData->src_data || srcData->src_size == 0) {
-    return -1;
+    return static_cast<OPJ_SIZE_T>(-1);

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

Can you add a TODO, this seems broken. OPJ_SIZE is a typedef for size_t. size_t
is a unsigned data type. We probably shouldn't be using -1 as a sentinal value
in that case.

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

Done.

[Tom Sepez, 2016/03/16 18:34:58]

Probably ok along the lines of std::string::npos's usage of the same technique.

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

Ack. I digged deeper and found that this is required/used by libopenjpeg code.

[Tom Sepez, 2016/03/17 16:40:05]

Acknowledged.

   }
   // Reads at EOF return an error code.
   if (srcData->offset >= srcData->src_size) {
-    return -1;
+    return static_cast<OPJ_SIZE_T>(-1);
   }
   OPJ_SIZE_T bufferLength = srcData->src_size - srcData->offset;
   OPJ_SIZE_T readlength = nb_bytes < bufferLength ? nb_bytes : bufferLength;
@@ -46,11 +46,11 @@ OPJ_SIZE_T opj_write_from_memory(void* p_buffer,
                                  void* p_user_data) {
   DecodeData* srcData = static_cast<DecodeData*>(p_user_data);
   if (!srcData || !srcData->src_data || srcData->src_size == 0) {
-    return -1;
+    return static_cast<OPJ_SIZE_T>(-1);
   }
   // Writes at EOF return an error code.
   if (srcData->offset >= srcData->src_size) {
-    return -1;
+    return static_cast<OPJ_SIZE_T>(-1);
   }
   OPJ_SIZE_T bufferLength = srcData->src_size - srcData->offset;
   OPJ_SIZE_T writeLength = nb_bytes < bufferLength ? nb_bytes : bufferLength;
@@ -61,14 +61,14 @@ OPJ_SIZE_T opj_write_from_memory(void* p_buffer,
 OPJ_OFF_T opj_skip_from_memory(OPJ_OFF_T nb_bytes, void* p_user_data) {
   DecodeData* srcData = static_cast<DecodeData*>(p_user_data);
   if (!srcData || !srcData->src_data || srcData->src_size == 0) {
-    return -1;
+    return static_cast<OPJ_OFF_T>(-1);
   }
   // Offsets are signed and may indicate a negative skip. Do not support this
   // because of the strange return convention where either bytes skipped or
   // -1 is returned. Following that convention, a successful relative seek of
   // -1 bytes would be required to to give the same result as the error case.
   if (nb_bytes < 0) {
-    return -1;
+    return static_cast<OPJ_OFF_T>(-1);
   }
   // FIXME: use std::make_unsigned<OPJ_OFF_T>::type once c++11 lib is OK'd.
   uint64_t unsignedNbBytes = static_cast<uint64_t>(nb_bytes);