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authororivej <orivej@yandex-team.ru>2022-02-10 16:45:01 +0300
committerDaniil Cherednik <dcherednik@yandex-team.ru>2022-02-10 16:45:01 +0300
commit2d37894b1b037cf24231090eda8589bbb44fb6fc (patch)
treebe835aa92c6248212e705f25388ebafcf84bc7a1 /contrib/tools/python3/src/Modules/rotatingtree.c
parent718c552901d703c502ccbefdfc3c9028d608b947 (diff)
downloadydb-2d37894b1b037cf24231090eda8589bbb44fb6fc.tar.gz
Restoring authorship annotation for <orivej@yandex-team.ru>. Commit 2 of 2.
Diffstat (limited to 'contrib/tools/python3/src/Modules/rotatingtree.c')
-rw-r--r--contrib/tools/python3/src/Modules/rotatingtree.c242
1 files changed, 121 insertions, 121 deletions
diff --git a/contrib/tools/python3/src/Modules/rotatingtree.c b/contrib/tools/python3/src/Modules/rotatingtree.c
index 6d31a2ec90..07e08bc316 100644
--- a/contrib/tools/python3/src/Modules/rotatingtree.c
+++ b/contrib/tools/python3/src/Modules/rotatingtree.c
@@ -1,121 +1,121 @@
-#include "rotatingtree.h"
-
-#define KEY_LOWER_THAN(key1, key2) ((char*)(key1) < (char*)(key2))
-
-/* The randombits() function below is a fast-and-dirty generator that
- * is probably irregular enough for our purposes. Note that it's biased:
- * I think that ones are slightly more probable than zeroes. It's not
- * important here, though.
- */
-
-static unsigned int random_value = 1;
-static unsigned int random_stream = 0;
-
-static int
-randombits(int bits)
-{
- int result;
- if (random_stream < (1U << bits)) {
- random_value *= 1082527;
- random_stream = random_value;
- }
- result = random_stream & ((1<<bits)-1);
- random_stream >>= bits;
- return result;
-}
-
-
-/* Insert a new node into the tree.
- (*root) is modified to point to the new root. */
-void
-RotatingTree_Add(rotating_node_t **root, rotating_node_t *node)
-{
- while (*root != NULL) {
- if (KEY_LOWER_THAN(node->key, (*root)->key))
- root = &((*root)->left);
- else
- root = &((*root)->right);
- }
- node->left = NULL;
- node->right = NULL;
- *root = node;
-}
-
-/* Locate the node with the given key. This is the most complicated
- function because it occasionally rebalances the tree to move the
- resulting node closer to the root. */
-rotating_node_t *
-RotatingTree_Get(rotating_node_t **root, void *key)
-{
- if (randombits(3) != 4) {
- /* Fast path, no rebalancing */
- rotating_node_t *node = *root;
- while (node != NULL) {
- if (node->key == key)
- return node;
- if (KEY_LOWER_THAN(key, node->key))
- node = node->left;
- else
- node = node->right;
- }
- return NULL;
- }
- else {
- rotating_node_t **pnode = root;
- rotating_node_t *node = *pnode;
- rotating_node_t *next;
- int rotate;
- if (node == NULL)
- return NULL;
- while (1) {
- if (node->key == key)
- return node;
- rotate = !randombits(1);
- if (KEY_LOWER_THAN(key, node->key)) {
- next = node->left;
- if (next == NULL)
- return NULL;
- if (rotate) {
- node->left = next->right;
- next->right = node;
- *pnode = next;
- }
- else
- pnode = &(node->left);
- }
- else {
- next = node->right;
- if (next == NULL)
- return NULL;
- if (rotate) {
- node->right = next->left;
- next->left = node;
- *pnode = next;
- }
- else
- pnode = &(node->right);
- }
- node = next;
- }
- }
-}
-
-/* Enumerate all nodes in the tree. The callback enumfn() should return
- zero to continue the enumeration, or non-zero to interrupt it.
- A non-zero value is directly returned by RotatingTree_Enum(). */
-int
-RotatingTree_Enum(rotating_node_t *root, rotating_tree_enum_fn enumfn,
- void *arg)
-{
- int result;
- rotating_node_t *node;
- while (root != NULL) {
- result = RotatingTree_Enum(root->left, enumfn, arg);
- if (result != 0) return result;
- node = root->right;
- result = enumfn(root, arg);
- if (result != 0) return result;
- root = node;
- }
- return 0;
-}
+#include "rotatingtree.h"
+
+#define KEY_LOWER_THAN(key1, key2) ((char*)(key1) < (char*)(key2))
+
+/* The randombits() function below is a fast-and-dirty generator that
+ * is probably irregular enough for our purposes. Note that it's biased:
+ * I think that ones are slightly more probable than zeroes. It's not
+ * important here, though.
+ */
+
+static unsigned int random_value = 1;
+static unsigned int random_stream = 0;
+
+static int
+randombits(int bits)
+{
+ int result;
+ if (random_stream < (1U << bits)) {
+ random_value *= 1082527;
+ random_stream = random_value;
+ }
+ result = random_stream & ((1<<bits)-1);
+ random_stream >>= bits;
+ return result;
+}
+
+
+/* Insert a new node into the tree.
+ (*root) is modified to point to the new root. */
+void
+RotatingTree_Add(rotating_node_t **root, rotating_node_t *node)
+{
+ while (*root != NULL) {
+ if (KEY_LOWER_THAN(node->key, (*root)->key))
+ root = &((*root)->left);
+ else
+ root = &((*root)->right);
+ }
+ node->left = NULL;
+ node->right = NULL;
+ *root = node;
+}
+
+/* Locate the node with the given key. This is the most complicated
+ function because it occasionally rebalances the tree to move the
+ resulting node closer to the root. */
+rotating_node_t *
+RotatingTree_Get(rotating_node_t **root, void *key)
+{
+ if (randombits(3) != 4) {
+ /* Fast path, no rebalancing */
+ rotating_node_t *node = *root;
+ while (node != NULL) {
+ if (node->key == key)
+ return node;
+ if (KEY_LOWER_THAN(key, node->key))
+ node = node->left;
+ else
+ node = node->right;
+ }
+ return NULL;
+ }
+ else {
+ rotating_node_t **pnode = root;
+ rotating_node_t *node = *pnode;
+ rotating_node_t *next;
+ int rotate;
+ if (node == NULL)
+ return NULL;
+ while (1) {
+ if (node->key == key)
+ return node;
+ rotate = !randombits(1);
+ if (KEY_LOWER_THAN(key, node->key)) {
+ next = node->left;
+ if (next == NULL)
+ return NULL;
+ if (rotate) {
+ node->left = next->right;
+ next->right = node;
+ *pnode = next;
+ }
+ else
+ pnode = &(node->left);
+ }
+ else {
+ next = node->right;
+ if (next == NULL)
+ return NULL;
+ if (rotate) {
+ node->right = next->left;
+ next->left = node;
+ *pnode = next;
+ }
+ else
+ pnode = &(node->right);
+ }
+ node = next;
+ }
+ }
+}
+
+/* Enumerate all nodes in the tree. The callback enumfn() should return
+ zero to continue the enumeration, or non-zero to interrupt it.
+ A non-zero value is directly returned by RotatingTree_Enum(). */
+int
+RotatingTree_Enum(rotating_node_t *root, rotating_tree_enum_fn enumfn,
+ void *arg)
+{
+ int result;
+ rotating_node_t *node;
+ while (root != NULL) {
+ result = RotatingTree_Enum(root->left, enumfn, arg);
+ if (result != 0) return result;
+ node = root->right;
+ result = enumfn(root, arg);
+ if (result != 0) return result;
+ root = node;
+ }
+ return 0;
+}