little size compeitino

1 files changed, 17 insertions, 0 deletions

diff --git a/examples/wasm-png/src/lib.rs b/examples/wasm-png/src/lib.rs
new file mode 100644
index 0000000..1c3c150
--- /dev/null
+++ b/examples/wasm-png/src/lib.rs
@@ -0,0 +1,17 @@
+#[no_mangle]
+pub unsafe fn decode_png(input: *const u8, input_len: usize, output: *mut u8, output_len: usize) -> usize {
+	let input = core::slice::from_raw_parts(input, input_len);
+	let output = core::slice::from_raw_parts_mut(output, output_len);
+	
+	let decoder = png::Decoder::new(input);
+	let Ok(mut reader) = decoder.read_info() else {
+		return 0;
+	};
+	let required_bytes = reader.output_buffer_size();
+	if output_len >= required_bytes {
+		if reader.next_frame(output).is_err() {
+			return 0;
+		}
+	}
+	required_bytes
+}