Add StringViewArray and BinaryViewArray (#4253)

arrow-array/src/array/byte_array.rs

@@ -94,7 +94,7 @@ pub struct GenericByteArray<T: ByteArrayType> {
 impl<T: ByteArrayType> Clone for GenericByteArray<T> {
     fn clone(&self) -> Self {
         Self {
-            data_type: self.data_type.clone(),
+            data_type: T::DATA_TYPE,
             value_offsets: self.value_offsets.clone(),
             value_data: self.value_data.clone(),
             nulls: self.nulls.clone(),

arrow-array/src/array/byte_view_array.rs

@@ -0,0 +1,346 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use crate::array::print_long_array;
+use crate::builder::GenericByteViewBuilder;
+use crate::iterator::ArrayIter;
+use crate::types::bytes::ByteArrayNativeType;
+use crate::types::{BinaryViewType, ByteViewType, StringViewType};
+use crate::{Array, ArrayAccessor, ArrayRef};
+use arrow_buffer::{Buffer, NullBuffer, ScalarBuffer};
+use arrow_data::view::View;
+use arrow_data::{ArrayData, ArrayDataBuilder};
+use arrow_schema::{ArrowError, DataType};
+use std::any::Any;
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+/// An array of variable length byte view arrays
+pub struct GenericByteViewArray<T: ByteViewType> {
+    data_type: DataType,
+    views: ScalarBuffer<u128>,
+    buffers: Vec<Buffer>,
+    nulls: Option<NullBuffer>,
+    phantom: PhantomData<T>,
+}
+
+impl<T: ByteViewType> Clone for GenericByteViewArray<T> {
+    fn clone(&self) -> Self {
+        Self {
+            data_type: T::DATA_TYPE,
+            views: self.views.clone(),
+            buffers: self.buffers.clone(),
+            nulls: self.nulls.clone(),
+            phantom: Default::default(),
+        }
+    }
+}
+
+impl<T: ByteViewType> GenericByteViewArray<T> {
+    /// Create a new [`GenericByteViewArray`] from the provided parts, panicking on failure
+    ///
+    /// # Panics
+    ///
+    /// Panics if [`GenericByteViewArray::try_new`] returns an error
+    pub fn new(
+        views: ScalarBuffer<u128>,
+        buffers: Vec<Buffer>,
+        nulls: Option<NullBuffer>,
+    ) -> Self {
+        Self::try_new(views, buffers, nulls).unwrap()
+    }
+
+    /// Create a new [`GenericByteViewArray`] from the provided parts, returning an error on failure
+    ///
+    /// # Errors
+    ///
+    /// * `views.len() != nulls.len()`
+    /// * [ByteViewType::validate] fails
+    pub fn try_new(
+        views: ScalarBuffer<u128>,
+        buffers: Vec<Buffer>,
+        nulls: Option<NullBuffer>,
+    ) -> Result<Self, ArrowError> {
+        // Verify data is valid
+        T::validate(&views, &buffers)?;
+
+        if let Some(n) = nulls.as_ref() {
+            if n.len() != views.len() {
+                return Err(ArrowError::InvalidArgumentError(format!(
+                    "Incorrect length of null buffer for {}ViewArray, expected {} got {}",
+                    T::PREFIX,
+                    views.len(),
+                    n.len(),
+                )));
+            }
+        }
+
+        Ok(Self {
+            data_type: T::DATA_TYPE,
+            phantom: Default::default(),
+            views,
+            buffers,
+            nulls,
+        })
+    }
+
+    /// Create a new [`GenericByteViewArray`] from the provided parts, without validation
+    ///
+    /// # Safety
+    ///
+    /// Safe if [`Self::try_new`] would not error
+    pub unsafe fn new_unchecked(
+        views: ScalarBuffer<u128>,
+        buffers: Vec<Buffer>,
+        nulls: Option<NullBuffer>,
+    ) -> Self {
+        Self {
+            data_type: T::DATA_TYPE,
+            phantom: Default::default(),
+            views,
+            buffers,
+            nulls,
+        }
+    }
+
+    /// Create a new [`GenericByteViewArray`] of length `len` where all values are null
+    pub fn new_null(len: usize) -> Self {
+        Self {
+            data_type: T::DATA_TYPE,
+            views: vec![0; len].into(),
+            buffers: vec![],
+            nulls: Some(NullBuffer::new_null(len)),
+            phantom: Default::default(),
+        }
+    }
+
+    /// Creates a [`GenericByteViewArray`] based on an iterator of values without nulls
+    pub fn from_iter_values<Ptr, I>(iter: I) -> Self
+    where
+        Ptr: AsRef<T::Native>,
+        I: IntoIterator<Item = Ptr>,
+    {
+        let iter = iter.into_iter();
+        let mut builder = GenericByteViewBuilder::<T>::with_capacity(iter.size_hint().0);
+        for v in iter {
+            builder.append_value(v);
+        }
+        builder.finish()
+    }
+
+    /// Deconstruct this array into its constituent parts
+    pub fn into_parts(self) -> (ScalarBuffer<u128>, Vec<Buffer>, Option<NullBuffer>) {
+        (self.views, self.buffers, self.nulls)
+    }
+
+    /// Returns the views buffer
+    #[inline]
+    pub fn views(&self) -> &ScalarBuffer<u128> {
+        &self.views
+    }
+
+    /// Returns the buffers storing string data
+    #[inline]
+    pub fn data_buffers(&self) -> &[Buffer] {
+        &self.buffers
+    }
+
+    /// Returns the element at index `i`
+    /// # Panics
+    /// Panics if index `i` is out of bounds.
+    pub fn value(&self, i: usize) -> &T::Native {
+        assert!(
+            i < self.len(),
+            "Trying to access an element at index {} from a {}ViewArray of length {}",
+            i,
+            T::PREFIX,
+            self.len()
+        );
+
+        assert!(i < self.views.len());
+        unsafe { self.value_unchecked(i) }
+    }
+
+    /// Returns the element at index `i`
+    /// # Safety
+    /// Caller is responsible for ensuring that the index is within the bounds of the array
+    pub unsafe fn value_unchecked(&self, idx: usize) -> &T::Native {
+        let v = self.views.get_unchecked(idx);
+        let len = *v as u32;
+        let b = if len <= 12 {
+            let ptr = self.views.as_ptr() as *const u8;
+            std::slice::from_raw_parts(ptr.add(idx * 16 + 4), len as usize)
+        } else {
+            let view = View::from(*v);
+            let data = self.buffers.get_unchecked(view.buffer_index as usize);
+            let offset = view.offset as usize;
+            data.get_unchecked(offset..offset + len as usize)
+        };
+        T::Native::from_bytes_unchecked(b)
+    }
+
+    /// constructs a new iterator
+    pub fn iter(&self) -> ArrayIter<&Self> {
+        ArrayIter::new(self)
+    }
+
+    /// Returns a zero-copy slice of this array with the indicated offset and length.
+    pub fn slice(&self, offset: usize, length: usize) -> Self {
+        Self {
+            data_type: T::DATA_TYPE,
+            views: self.views.slice(offset, length),
+            buffers: self.buffers.clone(),
+            nulls: self.nulls.as_ref().map(|n| n.slice(offset, length)),
+            phantom: Default::default(),
+        }
+    }
+}
+
+impl<T: ByteViewType> std::fmt::Debug for GenericByteViewArray<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(f, "{}ViewArray\n[\n", T::PREFIX)?;
+        print_long_array(self, f, |array, index, f| {
+            std::fmt::Debug::fmt(&array.value(index), f)
+        })?;
+        write!(f, "]")
+    }
+}
+
+impl<T: ByteViewType> Array for GenericByteViewArray<T> {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn to_data(&self) -> ArrayData {
+        self.clone().into()
+    }
+
+    fn into_data(self) -> ArrayData {
+        self.into()
+    }
+
+    fn data_type(&self) -> &DataType {
+        &self.data_type
+    }
+
+    fn slice(&self, offset: usize, length: usize) -> ArrayRef {
+        Arc::new(self.slice(offset, length))
+    }
+
+    fn len(&self) -> usize {
+        self.views.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.views.is_empty()
+    }
+
+    fn offset(&self) -> usize {
+        0
+    }
+
+    fn nulls(&self) -> Option<&NullBuffer> {
+        self.nulls.as_ref()
+    }
+
+    fn get_buffer_memory_size(&self) -> usize {
+        let mut sum = self.buffers.iter().map(|b| b.capacity()).sum::<usize>();
+        sum += self.views.inner().capacity();
+        if let Some(x) = &self.nulls {
+            sum += x.buffer().capacity()
+        }
+        sum
+    }
+
+    fn get_array_memory_size(&self) -> usize {
+        std::mem::size_of::<Self>() + self.get_buffer_memory_size()
+    }
+}
+
+impl<'a, T: ByteViewType> ArrayAccessor for &'a GenericByteViewArray<T> {
+    type Item = &'a T::Native;
+
+    fn value(&self, index: usize) -> Self::Item {
+        GenericByteViewArray::value(self, index)
+    }
+
+    unsafe fn value_unchecked(&self, index: usize) -> Self::Item {
+        GenericByteViewArray::value_unchecked(self, index)
+    }
+}
+
+impl<'a, T: ByteViewType> IntoIterator for &'a GenericByteViewArray<T> {
+    type Item = Option<&'a T::Native>;
+    type IntoIter = ArrayIter<Self>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        ArrayIter::new(self)
+    }
+}
+
+impl<T: ByteViewType> From<ArrayData> for GenericByteViewArray<T> {
+    fn from(value: ArrayData) -> Self {
+        let views = value.buffers()[0].clone();
+        let views = ScalarBuffer::new(views, value.offset(), value.len());
+        let buffers = value.buffers()[1..].to_vec();
+        Self {
+            data_type: T::DATA_TYPE,
+            views,
+            buffers,
+            nulls: value.nulls().cloned(),
+            phantom: Default::default(),
+        }
+    }
+}
+
+impl<T: ByteViewType> From<GenericByteViewArray<T>> for ArrayData {
+    fn from(mut array: GenericByteViewArray<T>) -> Self {
+        let len = array.len();
+        array.buffers.insert(0, array.views.into_inner());
+        let builder = ArrayDataBuilder::new(array.data_type)
+            .len(len)
+            .buffers(array.buffers)
+            .nulls(array.nulls);
+
+        unsafe { builder.build_unchecked() }
+    }
+}
+
+impl<Ptr, T: ByteViewType> FromIterator<Option<Ptr>> for GenericByteViewArray<T>
+where
+    Ptr: AsRef<T::Native>,
+{
+    fn from_iter<I: IntoIterator<Item = Option<Ptr>>>(iter: I) -> Self {
+        let iter = iter.into_iter();
+        let mut builder = GenericByteViewBuilder::<T>::with_capacity(iter.size_hint().0);
+        builder.extend(iter);
+        builder.finish()
+    }
+}
+
+/// A [`GenericByteViewArray`] of `str`
+///
+/// ```
+/// # use arrow_array::StringViewArray;
+/// let array = StringViewArray::from_iter_values(vec!["hello", "world", "foo", "large payload over 12 bytes"]);
+/// assert_eq!(array.value(0), "hello");
+/// assert_eq!(array.value(3), "large payload over 12 bytes");
+/// ```
+pub type StringViewArray = GenericByteViewArray<StringViewType>;
+
+/// A [`GenericByteViewArray`] of `[u8]`
+pub type BinaryViewArray = GenericByteViewArray<BinaryViewType>;

arrow-array/src/array/mod.rs

@@ -34,6 +34,9 @@ pub use boolean_array::*;
 mod byte_array;
 pub use byte_array::*;
 
+mod byte_view_array;
+pub use byte_view_array::*;
+
 mod dictionary_array;
 pub use dictionary_array::*;