Make mmap() scalable

It's now possible to create thousands of thousands of sparse independent
memory mappings, without any slowdown. The memory manager is better with
tracking memory protection now, particularly on Windows in a precise way
that can be restored during fork(). You now have the highest quality mem
manager possible. It's even better than some OSes like XNU, where mmap()
is implemented as an O(n) operation which means sadly things aren't much
improved over there. With this change the llamafile HTTP server endpoint
at /tokenize with a prompt of 50 tokens is now able to handle 2.6m r/sec

test/libc/intrin/tree_test.c

@@ -0,0 +1,139 @@
+// Copyright 2024 Justine Alexandra Roberts Tunney
+//
+// Permission to use, copy, modify, and/or distribute this software for
+// any purpose with or without fee is hereby granted, provided that the
+// above copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+// WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+// AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+// DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+// PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+// TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include "libc/intrin/tree.h"
+#include "libc/intrin/kprintf.h"
+#include "libc/intrin/maps.h"
+#include "libc/macros.internal.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/rand.h"
+
+#define NUMBER_CONTAINER(e) TREE_CONTAINER(struct number, elem, e)
+
+void tree_checker(const struct Tree *node, const struct Tree *parent,
+                  int black_count, int *black_height, tree_cmp_f *cmp) {
+  if (!node) {
+    // Leaf nodes are considered black
+    if (*black_height == -1) {
+      *black_height = black_count;
+    } else if (black_count != *black_height) {
+      // ILLEGAL TREE: Black height mismatch
+      __builtin_trap();
+    }
+    return;
+  }
+  if (node->parent != parent)
+    // ILLEGAL TREE: Parent link is incorrect
+    __builtin_trap();
+  if (parent) {
+    if (tree_get_left(parent) == node && cmp(parent, node) < 0)
+      // ILLEGAL TREE: Binary search property violated on left child
+      __builtin_trap();
+    if (parent->right == node && cmp(node, parent) < 0)
+      // ILLEGAL TREE: Binary search property violated on right child
+      __builtin_trap();
+  }
+  if (!tree_get_red(node)) {
+    black_count++;
+  } else if (parent && tree_get_red(parent)) {
+    // ILLEGAL TREE: Red node has red child
+    __builtin_trap();
+  }
+  tree_checker(tree_get_left(node), node, black_count, black_height, cmp);
+  tree_checker(node->right, node, black_count, black_height, cmp);
+}
+
+void tree_check(struct Tree *root, tree_cmp_f *cmp) {
+  if (root) {
+    if (tree_get_red(root))
+      // ILLEGAL TREE: root node must be black
+      __builtin_trap();
+    int black_height = -1;
+    tree_checker(root, 0, 0, &black_height, cmp);
+  }
+}
+
+struct number {
+  long number;
+  struct Tree elem;
+};
+
+int number_search(const void *ra, const struct Tree *rb) {
+  long a = (long)ra;
+  const struct number *b = NUMBER_CONTAINER(rb);
+  return (a > b->number) - (a < b->number);
+}
+
+int number_compare(const struct Tree *ra, const struct Tree *rb) {
+  const struct number *a = NUMBER_CONTAINER(ra);
+  const struct number *b = NUMBER_CONTAINER(rb);
+  return (a->number > b->number) - (a->number < b->number);
+}
+
+struct number *number_new(int number) {
+  struct number *res;
+  if ((res = malloc(sizeof(struct number))))
+    res->number = number;
+  return res;
+}
+
+struct Tree *tree = 0;
+
+void print(void) {
+  for (struct Tree *e = tree_first(tree); e; e = tree_next(e))
+    kprintf("%3d", NUMBER_CONTAINER(e)->number);
+  kprintf("\n");
+}
+
+void print_reversed(void) {
+  for (struct Tree *e = tree_last(tree); e; e = tree_prev(e))
+    kprintf("%3d", NUMBER_CONTAINER(e)->number);
+  kprintf("\n");
+}
+
+void simple_test(void) {
+  static const long kNumba[] = {74, 53, 96, 70, 34, 95, 30, 2,  96, 46,
+                                23, 2,  52, 0,  34, 94, 90, 95, 32, 65};
+  for (int i = 0; i < 20; ++i) {
+    int number = kNumba[i];
+    kprintf("%3d", number);
+    tree_insert(&tree, &number_new(number)->elem, number_compare);
+    tree_check(tree, number_compare);
+  }
+  kprintf("\n");
+  print();
+  print_reversed();
+  for (int i = 0; i < 20; ++i) {
+    tree_remove(&tree, tree_get(tree, (void *)kNumba[i], number_search));
+    tree_check(tree, number_compare);
+    print();
+  }
+}
+
+int main() {
+  ShowCrashReports();
+  tree_check(__maps.maps, __maps_compare);
+  kprintf("\n");
+  __print_maps(15);
+  kprintf("\n");
+  simple_test();
+  tree_check(__maps.maps, __maps_compare);
+  for (int i = 0; i < 100000; ++i)
+    tree_insert(&tree, &number_new(rand())->elem, number_compare);
+  tree_check(tree, number_compare);
+  tree_check(__maps.maps, __maps_compare);
+  __print_maps(15);
+}