[PATCH v5 02/12] box: introduce key_def_parts_are_sequential

[Kirill Shcherbatov <kshcherbatov@tarantool.org>]

Introduced a new key_def_parts_are_sequential routine that test,
does specified key_def have sequential fields. This would be
useful with introducing JSON path as there would be another
complex criteria as fields with JSONs can't be 'sequential' in
this meaning.

Need for #1012
---
 src/box/tuple_extract_key.cc | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/box/tuple_extract_key.cc b/src/box/tuple_extract_key.cc
index e493c3b..e9d7cac 100644
--- a/src/box/tuple_extract_key.cc
+++ b/src/box/tuple_extract_key.cc
@@ -4,12 +4,21 @@
 
 enum { MSGPACK_NULL = 0xc0 };
 
+/** True if key part i and i+1 are sequential. */
+static inline bool
+key_def_parts_are_sequential(const struct key_def *def, int i)
+{
+	uint32_t fieldno1 = def->parts[i].fieldno + 1;
+	uint32_t fieldno2 = def->parts[i + 1].fieldno;
+	return fieldno1 == fieldno2;
+}
+
 /** True, if a key con contain two or more parts in sequence. */
 static bool
 key_def_contains_sequential_parts(const struct key_def *def)
 {
 	for (uint32_t i = 0; i < def->part_count - 1; ++i) {
-		if (def->parts[i].fieldno + 1 == def->parts[i + 1].fieldno)
+		if (key_def_parts_are_sequential(def, i))
 			return true;
 	}
 	return false;
@@ -123,8 +132,7 @@ tuple_extract_key_slowpath(const struct tuple *tuple,
 			 * minimize tuple_field_raw() calls.
 			 */
 			for (; i < part_count - 1; i++) {
-				if (key_def->parts[i].fieldno + 1 !=
-				    key_def->parts[i + 1].fieldno) {
+				if (!key_def_parts_are_sequential(key_def, i)) {
 					/*
 					 * End of sequential part.
 					 */
@@ -165,8 +173,7 @@ tuple_extract_key_slowpath(const struct tuple *tuple,
 			 * minimize tuple_field_raw() calls.
 			 */
 			for (; i < part_count - 1; i++) {
-				if (key_def->parts[i].fieldno + 1 !=
-				    key_def->parts[i + 1].fieldno) {
+				if (!key_def_parts_are_sequential(key_def, i)) {
 					/*
 					 * End of sequential part.
 					 */
@@ -231,8 +238,7 @@ tuple_extract_key_slowpath_raw(const char *data, const char *data_end,
 		uint32_t fieldno = key_def->parts[i].fieldno;
 		uint32_t null_count = 0;
 		for (; i < key_def->part_count - 1; i++) {
-			if (key_def->parts[i].fieldno + 1 !=
-			    key_def->parts[i + 1].fieldno)
+			if (!key_def_parts_are_sequential(key_def, i))
 				break;
 		}
 		uint32_t end_fieldno = key_def->parts[i].fieldno;
-- 
2.7.4