sql: allow get_bit() and set_bit() builtin functions to support byte …

…array.

Fixes #45851

This commit modified get_bit and set_bit to allow them to support
byte array along with their respective testcases.
And modified doc and info of get_bit() and set_bit() for bit Array.

Release justification: low-risk change to existing functionality.

Release note (sql change): This PR is modified get_bits()
and set_bit() functions to allow them support byte array.

docs/generated/sql/functions.md

@@ -871,7 +871,9 @@ has no relationship with the commit order of concurrent transactions.</p>
 </span></td></tr>
 <tr><td><a name="from_uuid"></a><code>from_uuid(val: <a href="bytes.html">bytes</a>) &rarr; <a href="string.html">string</a></code></td><td><span class="funcdesc"><p>Converts the byte string representation of a UUID to its character string representation.</p>
 </span></td></tr>
-<tr><td><a name="get_bit"></a><code>get_bit(bit_string: varbit, index: <a href="int.html">int</a>) &rarr; <a href="int.html">int</a></code></td><td><span class="funcdesc"><p>Extracts a bit at given index in the bit array</p>
+<tr><td><a name="get_bit"></a><code>get_bit(bit_string: varbit, index: <a href="int.html">int</a>) &rarr; <a href="int.html">int</a></code></td><td><span class="funcdesc"><p>Extracts a bit at given index in the bit array.</p>
+</span></td></tr>
+<tr><td><a name="get_bit"></a><code>get_bit(byte_string: <a href="bytes.html">bytes</a>, index: <a href="int.html">int</a>) &rarr; <a href="int.html">int</a></code></td><td><span class="funcdesc"><p>Extracts a bit at given index in the byte array.</p>
 </span></td></tr>
 <tr><td><a name="initcap"></a><code>initcap(val: <a href="string.html">string</a>) &rarr; <a href="string.html">string</a></code></td><td><span class="funcdesc"><p>Capitalizes the first letter of <code>val</code>.</p>
 </span></td></tr>
@@ -1015,7 +1017,9 @@ has no relationship with the commit order of concurrent transactions.</p>
 </span></td></tr>
 <tr><td><a name="rtrim"></a><code>rtrim(val: <a href="string.html">string</a>) &rarr; <a href="string.html">string</a></code></td><td><span class="funcdesc"><p>Removes all spaces from the end (right-hand side) of <code>val</code>.</p>
 </span></td></tr>
-<tr><td><a name="set_bit"></a><code>set_bit(bit_string: varbit, index: <a href="int.html">int</a>, to_set: <a href="int.html">int</a>) &rarr; varbit</code></td><td><span class="funcdesc"><p>Updates a bit at given index in the bit array</p>
+<tr><td><a name="set_bit"></a><code>set_bit(bit_string: varbit, index: <a href="int.html">int</a>, to_set: <a href="int.html">int</a>) &rarr; varbit</code></td><td><span class="funcdesc"><p>Updates a bit at given index in the bit array.</p>
+</span></td></tr>
+<tr><td><a name="set_bit"></a><code>set_bit(byte_string: <a href="bytes.html">bytes</a>, index: <a href="int.html">int</a>, to_set: <a href="int.html">int</a>) &rarr; <a href="bytes.html">bytes</a></code></td><td><span class="funcdesc"><p>Updates a bit at given index in the byte array.</p>
 </span></td></tr>
 <tr><td><a name="sha1"></a><code>sha1(<a href="bytes.html">bytes</a>...) &rarr; <a href="string.html">string</a></code></td><td><span class="funcdesc"><p>Calculates the SHA1 hash value of a set of values.</p>
 </span></td></tr>

pkg/sql/logictest/testdata/logic_test/builtin_function

@@ -2584,6 +2584,34 @@ SELECT get_bit(B'10110', 10)
 query error get_bit\(\): GetBitAtIndex: bit index 0 out of valid range \(0..-1\)
 SELECT get_bit(B'', 0);
 
+# Binary representation of 'l' is 01101100
+# Binary representation of \o145 is 01100101
+# Binary representation of \x61\x62\x6C are 01100001 01100010 01101100
+
+query I rowsort
+SELECT get_bit(b'\145\x6C\l', 0) UNION SELECT get_bit(b'\145\x6C\l', 13)
+----
+0
+1
+
+query I rowsort
+SELECT get_bit(b'\145', 7) UNION SELECT get_bit(b'\145', 0)
+----
+1
+0
+
+query I rowsort
+SELECT get_bit('\x6162'::bytea, 7) UNION SELECT get_bit('\x6162'::bytea, 12)
+----
+1
+0
+
+query error get_bit\(\): bit index 8 out of valid range \(0..7\)
+SELECT get_bit(b'\x61', 8)
+
+query error get_bit\(\): bit index 0 out of valid range \(0..-1\)
+SELECT get_bit(b'', 0)
+
 subtest set_bit
 
 query T rowsort
@@ -2606,3 +2634,28 @@ SELECT set_bit(B'1001010', 0, 2)
 
 query error set_bit\(\): SetBitAtIndex: bit index 0 out of valid range \(0..-1\)
 SELECT set_bit(B'', 0, 1)
+
+# Binary representation of 'a' 'b' 'c' 'f' 'l'  are 01100001 01100010 01100011 01100110 01101100
+# Binary representation of \o145 is 1100101
+# Binary representation of \x61\x62\x66\x6C are 01100001 01100010 01100110 01101100
+
+query T rowsort
+SELECT set_bit(b'ab', 6, 1) UNION SELECT set_bit(b'\x61\x66', 15, 0)
+----
+cb
+af
+
+query T rowsort
+SELECT set_bit('a'::bytea, 5, 0) UNION SELECT set_bit('\x6162'::bytea, 13, 1)
+----
+a
+af
+
+query error set_bit\(\): bit index 16 out of valid range \(0..15\)
+SELECT set_bit(b'ac', 16, 0)
+
+query error set_bit\(\): bit index 0 out of valid range \(0..-1\)
+SELECT set_bit(b'', 0, 1)
+
+query error set_bit\(\): new bit must be 0 or 1.
+SELECT set_bit(b'\145\x6C\l', 0, 2)

pkg/sql/sem/builtins/builtins.go

@@ -335,7 +335,28 @@ var builtins = map[string]builtinDefinition{
 				}
 				return tree.NewDInt(tree.DInt(bit)), nil
 			},
-			Info: "Extracts a bit at given index in the bit array",
+			Info: "Extracts a bit at given index in the bit array.",
+		},
+		tree.Overload{
+			Types:      tree.ArgTypes{{"byte_string", types.Bytes}, {"index", types.Int}},
+			ReturnType: tree.FixedReturnType(types.Int),
+			Fn: func(_ *tree.EvalContext, args tree.Datums) (tree.Datum, error) {
+				byteString := []byte(*args[0].(*tree.DBytes))
+				index := int(tree.MustBeDInt(args[1]))
+				// Check whether index asked is inside ByteArray.
+				if index < 0 || index >= 8*len(byteString) {
+					return nil, pgerror.Newf(pgcode.ArraySubscript,
+						"bit index %d out of valid range (0..%d)", index, 8*len(byteString)-1)
+				}
+				// To extract a bit at the given index, we have to determine the
+				// position within byte array, i.e. index/8 after that checked
+				// the bit at residual index.
+				if byteString[index/8]&(byte(1)<<(8-1-byte(index)%8)) != 0 {
+					return tree.NewDInt(tree.DInt(1)), nil
+				}
+				return tree.NewDInt(tree.DInt(0)), nil
+			},
+			Info: "Extracts a bit at given index in the byte array.",
 		}),
 
 	// https://www.postgresql.org/docs/9.0/functions-binarystring.html#FUNCTIONS-BINARYSTRING-OTHER
@@ -363,7 +384,39 @@ var builtins = map[string]builtinDefinition{
 				}
 				return &tree.DBitArray{BitArray: updatedBitString}, nil
 			},
-			Info: "Updates a bit at given index in the bit array",
+			Info: "Updates a bit at given index in the bit array.",
+		},
+		tree.Overload{
+			Types: tree.ArgTypes{
+				{"byte_string", types.Bytes},
+				{"index", types.Int},
+				{"to_set", types.Int},
+			},
+			ReturnType: tree.FixedReturnType(types.Bytes),
+			Fn: func(_ *tree.EvalContext, args tree.Datums) (tree.Datum, error) {
+				byteString := []byte(*args[0].(*tree.DBytes))
+				index := int(tree.MustBeDInt(args[1]))
+				toSet := int(tree.MustBeDInt(args[2]))
+				// Value of bit can only be set to 1 or 0.
+				if toSet != 0 && toSet != 1 {
+					return nil, pgerror.Newf(pgcode.InvalidParameterValue,
+						"new bit must be 0 or 1.")
+				}
+				// Check whether index asked is inside ByteArray.
+				if index < 0 || index >= 8*len(byteString) {
+					return nil, pgerror.Newf(pgcode.ArraySubscript,
+						"bit index %d out of valid range (0..%d)", index, 8*len(byteString)-1)
+				}
+				// To update a bit at the given index, we have to determine the
+				// position within byte array, i.e. index/8 after that checked
+				// the bit at residual index.
+				// Forcefully making bit at the index to 0.
+				byteString[index/8] &= ^(byte(1) << (8 - 1 - byte(index)%8))
+				// Updating value at the index to toSet.
+				byteString[index/8] |= byte(toSet) << (8 - 1 - byte(index)%8)
+				return tree.NewDBytes(tree.DBytes(byteString)), nil
+			},
+			Info: "Updates a bit at given index in the byte array.",
 		}),
 
 	"gen_random_uuid": makeBuiltin(