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#include "cnn1986_treap_cache.h"
// ===================================================================
// Types
// ===================================================================
typedef struct treap_node_s {
uint64_t key;
uint32_t weight;
struct treap_node_s *left, *right, *parent;
/*
* colour_stack_t colours[25];
* data_t celldat[25];
* uint8_t white_count, black_count;
*/
float result;
} * TreapNode;
// ===================================================================
// Variables
// ===================================================================
uint32_t cnn1986_num_cached;
static TreapNode root;
// ===================================================================
// Helper declarations
// ===================================================================
void recurse_tree(const TreapNode n);
TreapNode new_treap_node(const float in_result, const uint64_t key);
void bubble_up(const TreapNode n);
// ===================================================================
// Exported functions
// ===================================================================
int cnn1986_cache_init(void) {
root = NULL;
cnn1986_num_cached = 0;
return EXIT_SUCCESS;
}
void cnn1986_cache_free(void) {
recurse_tree(root);
return;
}
int cnn1986_cache_seek(const uint64_t key, float *out_result) {
if (root == NULL) return EXIT_FAILURE;
TreapNode n = root;
while (n != NULL && n->key != key) {
if (n->key > key) n = n->right;
else n = n->left;
}
if (n == NULL) return EXIT_FAILURE;
*out_result = n->result;
return EXIT_SUCCESS;
}
int cnn1986_cache_insert(const uint64_t key, const float in_result) {
if (root == NULL) {
root = new_treap_node(in_result, key);
cnn1986_num_cached = 1;
return EXIT_SUCCESS;
}
TreapNode s = root, n = root,
m = new_treap_node(in_result, key);
// Find the correct position by doing a BST traversal
while (n!=NULL) {
s = n;
if (n->key >= key) n = n->right;
else n = n->left;
}
// Make it a leaf
if (s->key > key) s->right = m;
else s->left = m;
m->parent = s;
// Now bubble upward to satisfy the heap property
bubble_up(m);
cnn1986_num_cached++;
return EXIT_SUCCESS;
}
// ===================================================================
// Helper implementations
// ===================================================================
void recurse_tree(TreapNode n) {
if (n==NULL) return;
if (n->left != NULL) recurse_tree(n->left);
if (n->right != NULL) recurse_tree(n->right);
free(n);
}
TreapNode new_treap_node(const float in_result, const uint64_t key) {
TreapNode n = malloc(sizeof(struct treap_node_s));
// TODO: trap
n->key = key;
n->left = NULL;
n->right = NULL;
n->parent = NULL;
XORSHIFT64; n->weight = RANDOM32;
// Set value
n->result = in_result;
return n;
}
void rotate_left(TreapNode n) {
TreapNode a = n->parent, b = a->left, c = n->left;
/*
We are the right child, so do this
a n
/ \ / \
b n --> a d
/ \ / \
c d b c
*/
n->parent = a->parent;
// We may have to repair one level up as well
if (a->parent!=NULL) {
if (a->parent->left == a) a->parent->left = n;
else a->parent->right = n;
}
a->parent = n;
n->left = a; a->parent = n;
a->left = b; if (b!=NULL) b->parent = a;
a->right = c; if (c!=NULL) c->parent = a;
}
void rotate_right(TreapNode n) {
TreapNode a = n->parent, b = a->right, d = n->right;
/*
We are the left child, so do this
a n
/ \ / \
n b --> c a
/ \ / \
c d d b
*/
n->parent = a->parent;
// We may have to repair one level up as well
if (a->parent!=NULL) {
if (a->parent->left == a) a->parent->left = n;
else a->parent->right = n;
}
a->parent = n;
n->right = a; a->parent = n;
a->left = d; if (d!=NULL) d->parent = a;
a->right = b; if (b!=NULL) b->parent = a;
}
//This preserves the BST quality of the treap
void bubble_up(TreapNode n) {
// Nothing to be done in this case
if (n==NULL || n->parent == NULL) return;
// Bubble until the treap invariants are satisfied
while (n->parent != NULL && n->weight < n->parent->weight) {
if (n->parent->left == n) rotate_right(n);
else rotate_left(n);
}
if (n->parent == NULL) root = n;
}
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