tustvold commented on code in PR #37877:
URL: https://github.com/apache/arrow/pull/37877#discussion_r1343251727


##########
docs/source/format/Columnar.rst:
##########
@@ -487,6 +499,102 @@ will be represented as follows: ::
           |-------------------------------|-----------------------|
           | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 | unspecified (padding) |
 
+ListView Layout
+~~~~~~~~~~~~~~~
+
+The ListView layout is defined by three buffers: a validity bitmap, an offsets
+buffer, and an additional sizes buffer. Sizes and offsets have the identical 
bit
+width and both 32-bit and 64-bit signed integer options are supported.
+
+As in the List layout, the offsets encode the start position of each slot in 
the
+child array. In contrast to the List layout, list lengths are stored explicitly
+in the sizes buffer instead of inferred. This allows offsets to be out of 
order.
+Elements of the child array do not have to be stored in the same order they
+logically appear in the list elements of the parent array.
+
+When a value is null, the corresponding offset and size can have arbitrary
+values. When size is 0, the corresponding offset can have an arbitrary value.

Review Comment:
   >  Being stricter on producers of list-views doesn't make the consumers 
protected from malicious or bogus producers.
   
   > So it seems to me that being stricter at the edge helps safety more than 
making the format more lenient
   
   FWIW this is the approach of arrow-rs, and Rust in general, all data is 
either validated or constructed in such a way as to statically guarantee the 
necessary invariants.



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