Add stbi_load_16() variants to load from memory or callbacks

stb_image.h

@@ -370,7 +370,8 @@ STBIDEF stbi_us *stbi_load_16(char const *filename, int *x, int *y, int *channel
 #ifndef STBI_NO_STDIO
 STBIDEF stbi_us *stbi_load_from_file_16(FILE *f, int *x, int *y, int *channels_in_file, int desired_channels);
 #endif
-// @TODO the other variants
+STBIDEF stbi_us *stbi_load_16_from_memory   (stbi_uc const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels);
+STBIDEF stbi_us *stbi_load_16_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *channels_in_file, int desired_channels);
 
 ////////////////////////////////////
 //
@@ -1191,6 +1192,20 @@ STBIDEF stbi_us *stbi_load_16(char const *filename, int *x, int *y, int *comp, i
 
 #endif //!STBI_NO_STDIO
 
+STBIDEF stbi_us *stbi_load_16_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels)
+{
+    stbi__context s;
+    stbi__start_mem(&s, buffer, len);
+    return stbi__load_and_postprocess_16bit(&s, x, y, channels_in_file, desired_channels);
+}
+
+STBIDEF stbi_us *stbi_load_16_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *channels_in_file, int desired_channels)
+{
+    stbi__context s;
+    stbi__start_callbacks(&s, (stbi_io_callbacks *)clbk, user);
+    return stbi__load_and_postprocess_16bit(&s, x, y, channels_in_file, desired_channels);
+}
+
 STBIDEF stbi_uc *stbi_load_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
 {
    stbi__context s;