1 files changed, 181 insertions, 0 deletions
diff --git a/src/command_buffer/validity/update_buffer.rs b/src/command_buffer/validity/update_buffer.rs
new file mode 100644
index 0000000..39f60be
--- /dev/null
+++ b/src/command_buffer/validity/update_buffer.rs
@@ -0,0 +1,181 @@
+// Copyright (c) 2017 The vulkano developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
+// license <LICENSE-MIT or https://opensource.org/licenses/MIT>,
+// at your option. All files in the project carrying such
+// notice may not be copied, modified, or distributed except
+// according to those terms.
+
+use crate::buffer::TypedBufferAccess;
+use crate::device::Device;
+use crate::device::DeviceOwned;
+use crate::DeviceSize;
+use crate::VulkanObject;
+use std::cmp;
+use std::error;
+use std::fmt;
+use std::mem;
+
+/// Checks whether an update buffer command is valid.
+///
+/// # Panic
+///
+/// - Panics if the buffer not created with `device`.
+///
+pub fn check_update_buffer<B, D>(
+    device: &Device,
+    buffer: &B,
+    data: &D,
+) -> Result<(), CheckUpdateBufferError>
+where
+    B: ?Sized + TypedBufferAccess<Content = D>,
+    D: ?Sized,
+{
+    assert_eq!(
+        buffer.inner().buffer.device().internal_object(),
+        device.internal_object()
+    );
+
+    if !buffer.inner().buffer.usage().transfer_destination {
+        return Err(CheckUpdateBufferError::BufferMissingUsage);
+    }
+
+    if buffer.inner().offset % 4 != 0 {
+        return Err(CheckUpdateBufferError::WrongAlignment);
+    }
+
+    let size = cmp::min(buffer.size(), mem::size_of_val(data) as DeviceSize);
+
+    if size % 4 != 0 {
+        return Err(CheckUpdateBufferError::WrongAlignment);
+    }
+
+    if size > 65536 {
+        return Err(CheckUpdateBufferError::DataTooLarge);
+    }
+
+    Ok(())
+}
+
+/// Error that can happen when attempting to add an `update_buffer` command.
+#[derive(Debug, Copy, Clone)]
+pub enum CheckUpdateBufferError {
+    /// The "transfer destination" usage must be enabled on the buffer.
+    BufferMissingUsage,
+    /// The data or size must be 4-bytes aligned.
+    WrongAlignment,
+    /// The data must not be larger than 64k bytes.
+    DataTooLarge,
+}
+
+impl error::Error for CheckUpdateBufferError {}
+
+impl fmt::Display for CheckUpdateBufferError {
+    #[inline]
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(
+            fmt,
+            "{}",
+            match *self {
+                CheckUpdateBufferError::BufferMissingUsage => {
+                    "the transfer destination usage must be enabled on the buffer"
+                }
+                CheckUpdateBufferError::WrongAlignment => {
+                    "the offset or size are not aligned to 4 bytes"
+                }
+                CheckUpdateBufferError::DataTooLarge => "data is too large",
+            }
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::buffer::BufferAccess;
+    use crate::buffer::BufferUsage;
+    use crate::buffer::CpuAccessibleBuffer;
+
+    #[test]
+    fn missing_usage() {
+        let (device, queue) = gfx_dev_and_queue!();
+        let buffer = CpuAccessibleBuffer::from_data(
+            device.clone(),
+            BufferUsage::vertex_buffer(),
+            false,
+            0u32,
+        )
+        .unwrap();
+
+        match check_update_buffer(&device, &buffer, &0) {
+            Err(CheckUpdateBufferError::BufferMissingUsage) => (),
+            _ => panic!(),
+        }
+    }
+
+    #[test]
+    fn data_too_large() {
+        let (device, queue) = gfx_dev_and_queue!();
+        let buffer = CpuAccessibleBuffer::from_iter(
+            device.clone(),
+            BufferUsage::transfer_destination(),
+            false,
+            0..65536,
+        )
+        .unwrap();
+        let data = (0..65536).collect::<Vec<u32>>();
+
+        match check_update_buffer(&device, &buffer, &data[..]) {
+            Err(CheckUpdateBufferError::DataTooLarge) => (),
+            _ => panic!(),
+        }
+    }
+
+    #[test]
+    fn data_just_large_enough() {
+        let (device, queue) = gfx_dev_and_queue!();
+        let buffer = CpuAccessibleBuffer::from_iter(
+            device.clone(),
+            BufferUsage::transfer_destination(),
+            false,
+            (0..100000).map(|_| 0),
+        )
+        .unwrap();
+        let data = (0..65536).map(|_| 0).collect::<Vec<u8>>();
+
+        match check_update_buffer(&device, &buffer, &data[..]) {
+            Ok(_) => (),
+            _ => panic!(),
+        }
+    }
+
+    #[test]
+    fn wrong_alignment() {
+        let (device, queue) = gfx_dev_and_queue!();
+        let buffer = CpuAccessibleBuffer::from_iter(
+            device.clone(),
+            BufferUsage::transfer_destination(),
+            false,
+            0..100,
+        )
+        .unwrap();
+        let data = (0..30).collect::<Vec<u8>>();
+
+        match check_update_buffer(&device, &buffer.slice(1..50).unwrap(), &data[..]) {
+            Err(CheckUpdateBufferError::WrongAlignment) => (),
+            _ => panic!(),
+        }
+    }
+
+    #[test]
+    fn wrong_device() {
+        let (dev1, queue) = gfx_dev_and_queue!();
+        let (dev2, _) = gfx_dev_and_queue!();
+        let buffer = CpuAccessibleBuffer::from_data(dev1, BufferUsage::all(), false, 0u32).unwrap();
+
+        assert_should_panic!({
+            let _ = check_update_buffer(&dev2, &buffer, &0);
+        });
+    }
+}