[arrow-rs] branch master updated: Add set_bit to BooleanBufferBuilder to allow mutating bit in index (#383)

[dh...@apache.org]

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dheres pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/arrow-rs.git


The following commit(s) were added to refs/heads/master by this push:
     new 18c804a  Add set_bit to BooleanBufferBuilder to allow mutating bit in index (#383)
18c804a is described below

commit 18c804a8f80ada6577d16a6f0fab4b2e262e314d
Author: Boaz <be...@gmail.com>
AuthorDate: Tue Jun 8 10:13:39 2021 +0300

    Add set_bit to BooleanBufferBuilder to allow mutating bit in index (#383)
    
    * Add set_bit to BooleanBufferBuilder to allow mutating bits in the builder
    
    * Fix tests
    
    * Update builder.rs
    
    * Update builder.rs
    
    * Fix clippy failures
    
    Co-authored-by: Boaz Berman <bo...@codota.com>
---
 arrow/src/array/builder.rs | 88 +++++++++++++++++++++++++++++++++++++++++++++-
 arrow/src/util/bit_util.rs |  2 +-
 2 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/arrow/src/array/builder.rs b/arrow/src/array/builder.rs
index a9e7fe2..71fd9a9 100644
--- a/arrow/src/array/builder.rs
+++ b/arrow/src/array/builder.rs
@@ -303,6 +303,15 @@ impl BooleanBufferBuilder {
     }
 
     #[inline]
+    pub fn set_bit(&mut self, index: usize, v: bool) {
+        if v {
+            bit_util::set_bit(self.buffer.as_mut(), index);
+        } else {
+            bit_util::unset_bit(self.buffer.as_mut(), index);
+        }
+    }
+
+    #[inline]
     pub fn is_empty(&self) -> bool {
         self.len == 0
     }
@@ -2266,7 +2275,7 @@ mod tests {
     }
 
     #[test]
-    fn test_write_bytes() {
+    fn test_boolean_buffer_builder_write_bytes() {
         let mut b = BooleanBufferBuilder::new(4);
         b.append(false);
         b.append(true);
@@ -2286,6 +2295,83 @@ mod tests {
     }
 
     #[test]
+    fn test_boolean_buffer_builder_unset_first_bit() {
+        let mut buffer = BooleanBufferBuilder::new(4);
+        buffer.append(true);
+        buffer.append(true);
+        buffer.append(false);
+        buffer.append(true);
+        buffer.set_bit(0, false);
+        assert_eq!(buffer.len(), 4);
+        assert_eq!(buffer.finish().as_slice(), &[0b1010_u8]);
+    }
+
+    #[test]
+    fn test_boolean_buffer_builder_unset_last_bit() {
+        let mut buffer = BooleanBufferBuilder::new(4);
+        buffer.append(true);
+        buffer.append(true);
+        buffer.append(false);
+        buffer.append(true);
+        buffer.set_bit(3, false);
+        assert_eq!(buffer.len(), 4);
+        assert_eq!(buffer.finish().as_slice(), &[0b0011_u8]);
+    }
+
+    #[test]
+    fn test_boolean_buffer_builder_unset_an_inner_bit() {
+        let mut buffer = BooleanBufferBuilder::new(5);
+        buffer.append(true);
+        buffer.append(true);
+        buffer.append(false);
+        buffer.append(true);
+        buffer.set_bit(1, false);
+        assert_eq!(buffer.len(), 4);
+        assert_eq!(buffer.finish().as_slice(), &[0b1001_u8]);
+    }
+
+    #[test]
+    fn test_boolean_buffer_builder_unset_several_bits() {
+        let mut buffer = BooleanBufferBuilder::new(5);
+        buffer.append(true);
+        buffer.append(true);
+        buffer.append(true);
+        buffer.append(false);
+        buffer.append(true);
+        buffer.set_bit(1, false);
+        buffer.set_bit(2, false);
+        assert_eq!(buffer.len(), 5);
+        assert_eq!(buffer.finish().as_slice(), &[0b10001_u8]);
+    }
+
+    #[test]
+    fn test_boolean_buffer_builder_unset_several_bits_bigger_than_one_byte() {
+        let mut buffer = BooleanBufferBuilder::new(16);
+        buffer.append_n(10, true);
+        buffer.set_bit(0, false);
+        buffer.set_bit(3, false);
+        buffer.set_bit(9, false);
+        assert_eq!(buffer.len(), 10);
+        assert_eq!(buffer.finish().as_slice(), &[0b11110110_u8, 0b01_u8]);
+    }
+
+    #[test]
+    fn test_boolean_buffer_builder_flip_several_bits_bigger_than_one_byte() {
+        let mut buffer = BooleanBufferBuilder::new(16);
+        buffer.append_n(5, true);
+        buffer.append_n(5, false);
+        buffer.append_n(5, true);
+        buffer.set_bit(0, false);
+        buffer.set_bit(3, false);
+        buffer.set_bit(9, false);
+        buffer.set_bit(6, true);
+        buffer.set_bit(14, true);
+        buffer.set_bit(13, false);
+        assert_eq!(buffer.len(), 15);
+        assert_eq!(buffer.finish().as_slice(), &[0b01010110_u8, 0b1011100_u8]);
+    }
+
+    #[test]
     fn test_boolean_array_builder_append_slice() {
         let arr1 =
             BooleanArray::from(vec![Some(true), Some(false), None, None, Some(false)]);
diff --git a/arrow/src/util/bit_util.rs b/arrow/src/util/bit_util.rs
index 4cfa816..7298eb3 100644
--- a/arrow/src/util/bit_util.rs
+++ b/arrow/src/util/bit_util.rs
@@ -62,7 +62,7 @@ pub unsafe fn get_bit_raw(data: *const u8, i: usize) -> bool {
     (*data.add(i >> 3) & BIT_MASK[i & 7]) != 0
 }
 
-/// Sets bit at position `i` for `data`
+/// Sets bit at position `i` for `data` to 1
 #[inline]
 pub fn set_bit(data: &mut [u8], i: usize) {
     data[i >> 3] |= BIT_MASK[i & 7];