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#include <bits/ensure.h>
#include <search.h>
#include <stddef.h>
#include <new>
#include <mlibc/allocator.hpp>
#include <frg/stack.hpp>
#include <stdlib.h>
struct node {
const void *key;
void *a[2];
int h;
};
namespace {
int height(struct node *node) {
return node ? node->h : 0;
}
int rotate(struct node **nodep, int side) {
struct node *node = *nodep;
struct node *x = static_cast<struct node *>(node->a[side]);
struct node *y = static_cast<struct node *>(x->a[!side]);
struct node *z = static_cast<struct node *>(x->a[side]);
int height_node = node->h;
int height_y = height(y);
if (height_y > height(z)) {
// Perform double rotation
node->a[side] = y->a[!side];
x->a[!side] = y->a[side];
y->a[!side] = node;
y->a[side] = x;
node->h = height_y;
x->h = height_y;
y->h = height_y + 1;
} else {
// Perform single rotation
node->a[side] = y;
x->a[!side] = node;
node->h = height_y + 1;
x->h = height_y + 2;
y = x;
}
*nodep = y;
return y->h - height_node;
}
int balance_tree(struct node **nodep) {
struct node *node = *nodep;
int height_a = height(static_cast<struct node *>(node->a[0]));
int height_b = height(static_cast<struct node *>(node->a[1]));
if (height_a - height_b < 2) {
int old = node->h;
node->h = height_a < height_b ? height_b + 1 : height_a + 1;
return node->h - old;
}
return rotate(nodep, height_a < height_b);
}
}
void *tsearch(const void *key, void **rootp, int(*compar)(const void *, const void *)) {
if (!rootp)
return NULL;
struct node *n = static_cast<struct node *>(*rootp);
frg::stack<struct node **, MemoryAllocator> nodes(getAllocator());
nodes.push(reinterpret_cast<struct node **>(rootp));
int c = 0;
for (;;) {
if (!n)
break;
c = compar(key, n->key);
if (!c)
return n;
nodes.push(reinterpret_cast<struct node **>(&n->a[c > 0]));
n = static_cast<struct node *>(n->a[c > 0]);
}
struct node *insert = static_cast<struct node*>(malloc(sizeof(struct node)));
if (!insert)
return NULL;
insert->key = key;
insert->a[0] = insert->a[1] = NULL;
insert->h = 1;
(*nodes.top()) = insert;
nodes.pop();
while(nodes.size() && balance_tree(nodes.top())) nodes.pop();
return insert;
}
// This implementation is taken from musl
void *tfind(const void *key, void *const *rootp, int (*compar)(const void *, const void *)) {
if(!rootp)
return 0;
struct node *n = (struct node *)*rootp;
for(;;) {
if(!n)
break;
int c = compar(key, n->key);
if(!c)
break;
n = (struct node *)n->a[c > 0];
}
return n;
}
void *tdelete(const void *, void **, int(*compar)(const void *, const void *)) {
(void)compar;
__ensure(!"Not implemented");
__builtin_unreachable();
}
void twalk(const void *, void (*action)(const void *, VISIT, int)) {
(void)action;
__ensure(!"Not implemented");
__builtin_unreachable();
}
void tdestroy(void *, void (*free_node)(void *)) {
(void)free_node;
__ensure(!"Not implemented");
__builtin_unreachable();
}
void *lsearch(const void *key, void *base, size_t *nelp, size_t width,
int (*compar)(const void *, const void *)) {
(void)key;
(void)base;
(void)nelp;
(void)width;
(void)compar;
__ensure(!"Not implemented");
__builtin_unreachable();
}
void *lfind(const void *key, const void *base, size_t *nelp,
size_t width, int (*compar)(const void *, const void *)) {
(void)key;
(void)base;
(void)nelp;
(void)width;
(void)compar;
__ensure(!"Not implemented");
__builtin_unreachable();
}
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