1 files changed, 58 insertions, 0 deletions
diff --git a/third_party/rust/spirv-cross-internal/src/ptr_util.rs b/third_party/rust/spirv-cross-internal/src/ptr_util.rs
new file mode 100644
index 0000000000..c4b5312e8d
--- /dev/null
+++ b/third_party/rust/spirv-cross-internal/src/ptr_util.rs
@@ -0,0 +1,58 @@
+//! Pointer utilities to abstract over native pointer access (i.e. `*const T`)
+//! and Emscripten pointer access (i.e. `u32` offset into the Emscripten heap).
+
+use crate::ErrorCode;
+use std::ffi::CStr;
+use std::slice;
+
+#[cfg(target_arch = "wasm32")]
+use crate::emscripten;
+
+pub unsafe fn read_string_from_ptr(ptr: *const std::os::raw::c_char) -> Result<String, ErrorCode> {
+    #[cfg(not(target_arch = "wasm32"))]
+    let string = CStr::from_ptr(ptr)
+        .to_owned()
+        .into_string()
+        .map_err(|_| ErrorCode::Unhandled);
+    #[cfg(target_arch = "wasm32")]
+    let string = {
+        let bytes = emscripten::get_module().read_bytes_into_vec_while(
+            emscripten::Pointer::from_offset(ptr as u32),
+            |byte, _| 0 != byte,
+            false,
+        );
+        String::from_utf8(bytes).map_err(|_| ErrorCode::Unhandled)
+    };
+    string
+}
+
+pub unsafe fn read_from_ptr<T>(ptr: *const T) -> T {
+    #[cfg(not(target_arch = "wasm32"))]
+    let value = ptr.read();
+    #[cfg(target_arch = "wasm32")]
+    let value = {
+        let num_bytes_to_read = std::mem::size_of::<T>();
+        let mut t_val: T = std::mem::uninitialized();
+        let t_ptr = &mut t_val as *mut T as *mut u8;
+        let bytes = emscripten::get_module().read_bytes_into_vec_while(
+            emscripten::Pointer::from_offset(ptr as u32),
+            |_, bytes_read| bytes_read < num_bytes_to_read,
+            false,
+        );
+        for (offset, byte) in bytes.iter().enumerate() {
+            *t_ptr.offset(offset as isize) = *byte;
+        }
+        t_val
+    };
+    value
+}
+
+pub unsafe fn read_into_vec_from_ptr<T: Clone>(ptr: *const T, size: usize) -> Vec<T> {
+    #[cfg(not(target_arch = "wasm32"))]
+    let values = slice::from_raw_parts(ptr, size).to_vec();
+    #[cfg(target_arch = "wasm32")]
+    let values = (0..size)
+        .map(|offset| read_from_ptr(ptr.add(offset)))
+        .collect();
+    values
+}