libragephoto: add opt-in C++17 support

- RagePhoto(A): add jpeg_view() function
- CMakeLists.txt: move C++17 and WebAssembly stuff inside include files

src/RagePhoto.cpp

@@ -602,6 +602,16 @@ const std::string RagePhoto::jpeg() const
         return std::string();
 }
 
+#if (RAGEPHOTO_CXX_STD >= 17) && (__cplusplus >= 201703L)
+const std::string_view RagePhoto::jpeg_view() const
+{
+    if (m_data->jpeg)
+        return std::string_view(m_data->jpeg, m_data->jpegSize);
+    else
+        return std::string_view();
+}
+#endif
+
 const char* RagePhoto::jpegData() const
 {
     return m_data->jpeg;

src/RagePhoto.h

@@ -115,6 +115,9 @@ public:
     int32_t error() const; /**< Returns the last error occurred. */
     uint32_t format() const; /**< Returns the Photo Format (GTA V or RDR 2). */
     const std::string jpeg() const; /**< Returns the Photo JPEG data. */
+#if (RAGEPHOTO_CXX_STD >= 17) && (__cplusplus >= 201703L)
+    const std::string_view jpeg_view() const; /**< Returns the Photo JPEG data. */
+#endif
     const char* jpegData() const; /**< Returns the Photo JPEG data. */
     uint32_t jpegSize() const; /**< Returns the Photo JPEG data size. */
     const char* description() const; /**< Returns the Photo description. */

src/RagePhotoA.h

@@ -147,8 +147,22 @@ public:
     }
     /** Returns the Photo JPEG data. */
     const std::string jpeg() const {
-        return std::string(ragephoto_getphotojpeg(instance), ragephoto_getphotosize(instance));
+        const char *jpegData = ragephoto_getphotojpeg(instance);
+        if (jpegData)
+            return std::string(jpegData, ragephoto_getphotosize(instance));
+        else
+            return std::string();
     }
+#if (__cplusplus >= 201703L)
+    /** Returns the Photo JPEG data. */
+    const std::string_view jpeg_view() const {
+        const char *jpegData = ragephoto_getphotojpeg(instance);
+        if (jpegData)
+            return std::string_view(jpegData, ragephoto_getphotosize(instance));
+        else
+            return std::string_view();
+    }
+#endif
     /** Returns the Photo JPEG data. */
     const char* jpegData() const {
         return ragephoto_getphotojpeg(instance);
@@ -308,6 +322,8 @@ public:
 private:
     ragephoto_t instance;
 };
+#else
+#include "RagePhotoC.h"
 #endif // __cplusplus
 
 #endif // RAGEPHOTOA_H

src/RagePhotoConfig.h.in

@@ -22,6 +22,7 @@
 /* CMAKE CONFIG BEGIN */
 #define @LIBRAGEPHOTO_API@
 #define @LIBRAGEPHOTO_LIBTYPE@
+#define RAGEPHOTO_CXX_STD @CMAKE_CXX_STANDARD@
 #define RAGEPHOTO_VERSION "@ragephoto_VERSION@"
 #define RAGEPHOTO_VERSION_MAJOR @ragephoto_VERSION_MAJOR@
 #define RAGEPHOTO_VERSION_MINOR @ragephoto_VERSION_MINOR@