pad-input-fix: adding support for pads as attributes (#2195)

* pad-input-fix: adding support for pads as attributes

* fix: making asked changes

* clippy fix

crates/burn-import/src/onnx/op_configuration.rs

@@ -768,9 +768,20 @@ pub fn tile_config(node: &Node) -> TileConfig {
 
 /// Create a PadConfig from the attributes of the node
 pub fn pad_config(node: &Node) -> PadConfig {
+    fn get_pads_input(node: &Node) -> Vec<i64> {
+        // If the input is not provided, return an empty vector
+        if node.inputs.get(1).is_none() {
+            return Vec::new();
+        }
+
+        match &node.inputs[1].value {
+            Some(Data::Int64s(shape)) => shape.clone(),
+            _ => panic!("Tensor data type must be int64"),
+        }
+    }
     fn get_pads(node: &Node) -> Vec<usize> {
-        if node.inputs.len() < 2 {
-            panic!("Pad: must provide at least two inputs")
+        if node.inputs.is_empty() {
+            panic!("Pad: must provide data as input")
         }
         if node.inputs.len() >= 4 {
             panic!("Pad: axes input is not supported")
@@ -781,19 +792,41 @@ pub fn pad_config(node: &Node) -> PadConfig {
             _ => panic!("Pad: Only tensor input is valid"),
         };
 
-        let pads: Vec<usize> = match &node.inputs[1].value {
-            Some(Data::Int64s(shape)) => shape
-                .iter()
-                .map(|&x| {
-                    if x < 0 {
-                        // TODO: support negative pads
-                        panic!("Pad: Negative pad is not supported");
+        //TODO : handle more possible attributes
+        let mut pads: Vec<usize> = get_pads_input(node)
+            .into_iter()
+            .map(|x| x as usize)
+            .collect();
+
+        for (key, value) in node.attrs.iter() {
+            match key.as_str() {
+                "pads" => {
+                    pads = value
+                        .clone()
+                        .into_i64s()
+                        .iter()
+                        .map(|&x| {
+                            if x < 0 {
+                                panic!("Pad: Negative pad is not supported");
+                            }
+                            x as usize
+                        })
+                        .collect()
+                }
+                "mode" => {
+                    let mode = value.clone().into_string();
+                    if mode != "constant" {
+                        panic!("only constant mode is supported, given mode is {}", mode);
                     }
-                    x as usize
-                })
-                .collect(),
-            _ => panic!("Pad: pads data type must be int64"),
-        };
+                }
+
+                _ => {}
+            }
+        }
+
+        if pads.is_empty() {
+            panic!("Pad: pads should be given as attribute or as input");
+        }
 
         if pads.len() != input_dim * 2 {
             panic!("Pad: pads should be a 1D tensor of shape [2 * num_axes]");
@@ -823,7 +856,7 @@ pub fn pad_config(node: &Node) -> PadConfig {
     }
     fn get_constant_value(node: &Node) -> f32 {
         // TODO: support int, boolean
-        node.inputs
+        let mut constant_value = node.inputs
                 .get(2)
                 .and_then(|input| match &input.value {
                     Some(Data::Float16s(constant_value)) => {
@@ -840,7 +873,15 @@ pub fn pad_config(node: &Node) -> PadConfig {
                     Some(Data::Float64(constant_value)) => Some(*constant_value as f32),
                      _ => panic!("Pad: only float values are currently supported for constant value, submit an issue on github"),
                 })
-                .unwrap_or(0.0)
+                .unwrap_or(0.0);
+
+        if node.attrs.contains_key("value") {
+            constant_value = node.attrs.get("value").map(|value| match value {
+                AttributeValue::Float32(value) => *value,
+                _ => panic!("Pad: only float32 values are currently supported for constant value as attribute, submit an issue on github"),
+            }).expect("constant_value should have had a value now");
+        }
+        constant_value
     }
 
     let pads = get_pads(node);