From bd5969fc876a10b18613302db7087ef3c40f18e1 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Thu, 7 Mar 2024 17:28:00 -0500
Subject: lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 lib/mlibc/options/posix/generic/search.cpp | 151 +++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 lib/mlibc/options/posix/generic/search.cpp

(limited to 'lib/mlibc/options/posix/generic/search.cpp')

diff --git a/lib/mlibc/options/posix/generic/search.cpp b/lib/mlibc/options/posix/generic/search.cpp
new file mode 100644
index 0000000..e6f8c1d
--- /dev/null
+++ b/lib/mlibc/options/posix/generic/search.cpp
@@ -0,0 +1,151 @@
+
+#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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