From c88bd10b73b4bea456a3b19a135de061a85b6060 Mon Sep 17 00:00:00 2001
From: Richard Thier <magosit@outlook.hu>
Date: Sat, 7 Sep 2024 21:25:03 +0200
Subject: [PATCH] add missing arena.h

---
 arena.h     | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 main.cpp    |   5 ++-
 turbolist.h |   7 +++-
 3 files changed, 112 insertions(+), 3 deletions(-)
 create mode 100644 arena.h

diff --git a/arena.h b/arena.h
new file mode 100644
index 0000000..f71396a
--- /dev/null
+++ b/arena.h
@@ -0,0 +1,103 @@
+// Gradual-commit arena demonstration
+// This is free and unencumbered software released into the public domain.
+/* Usage:
+ * 
+ *    arena a = newarena((ptrdiff_t)1 << 33);
+ *    if (!alloc(a, size, align, count)) {
+ *      break;
+ *    }
+ *    total += size * count;
+ */
+#ifndef ARENA_H
+#define ARENA_H
+
+#include <stddef.h>
+#include <string.h>
+
+static void *os_reserve(ptrdiff_t);
+static char os_commit(void *, ptrdiff_t);
+
+#define ARENA_PAGESIZE ((ptrdiff_t)1<<26)
+
+typedef struct {
+    char *begin;
+    char *commit;
+    char *end;
+} arena;
+
+static arena newarena(ptrdiff_t cap)
+{
+    arena a = {0};
+    cap += -cap & (ARENA_PAGESIZE - 1);
+    a.begin = a.commit = a.end = (char*) os_reserve(cap);
+    if (a.begin) {
+        a.end += cap;
+    }
+    return a;
+}
+
+static void *alloc(arena *a, ptrdiff_t size, ptrdiff_t align, ptrdiff_t count)
+{
+    ptrdiff_t padding   = -(size_t)a->begin & (align - 1);
+    ptrdiff_t committed = a->commit - a->begin;
+    if (count > (committed-padding)/size) {
+        ptrdiff_t reserved = a->end - a->begin;
+        if (count > (reserved-padding)/size) {
+            return 0;
+        }
+
+        ptrdiff_t needed = size*count + padding - committed;
+        needed += -needed & (ARENA_PAGESIZE - 1);
+        if (!os_commit(a->commit, needed)) {
+            return 0;
+        }
+        a->commit += needed;
+    }
+
+    void *ptr = a->begin + padding;
+    a->begin += padding + size*count;
+
+	// Change to this instead if you want zero-inited (but this gets slow with many arenas)
+    //return memset(ptr, 0, size*count);
+	return ptr;
+}
+
+#ifdef _WIN32
+// $ cc -g3 -nostartfiles -o arena.exe arena.c
+// $ cl /Z7 arena.c /link /subsystem:console kernel32.lib libvcruntime.lib
+#define W32(r) __declspec(dllimport) r __stdcall
+W32(void)   ExitProcess(int);
+W32(void *) VirtualAlloc(void *, ptrdiff_t, int, int);
+
+#define MEM_COMMIT     0x1000
+#define MEM_RESERVE    0x2000
+#define PAGE_NOACCESS  0x0001
+#define PAGE_READWRITE 0x0004
+
+static void *os_reserve(ptrdiff_t cap)
+{
+    return VirtualAlloc(0, cap, MEM_RESERVE, PAGE_NOACCESS);
+}
+
+static char os_commit(void *ptr, ptrdiff_t len)
+{
+    return VirtualAlloc(ptr, len, MEM_COMMIT, PAGE_READWRITE);
+}
+
+#else  // POSIX
+// $ cc -g3 -o arena arena.c
+#include <sys/mman.h>
+
+static void *os_reserve(ptrdiff_t cap)
+{
+    void *r = mmap(0, cap, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
+    return r==MAP_FAILED ? 0 : r;
+}
+
+static char os_commit(void *ptr, ptrdiff_t len)
+{
+    return !mprotect(ptr, len, PROT_READ|PROT_WRITE);
+}
+#endif // POSIX
+
+#endif /* ARENA_H */
diff --git a/main.cpp b/main.cpp
index 3d79b10..8a302c7 100644
--- a/main.cpp
+++ b/main.cpp
@@ -6,7 +6,10 @@
 #include<vector>
 #include<stdlib.h>
 #include"TurboList.hpp"
-#include"turbolist.h"
+
+#define TLT int
+#include "turbolist.h"
+
 #include"arena.h"
 
 // #define PRINT_DBG
diff --git a/turbolist.h b/turbolist.h
index 92d29eb..2c523f8 100644
--- a/turbolist.h
+++ b/turbolist.h
@@ -1,6 +1,9 @@
 #ifndef TURBO_LIST_H
 #define TURBO_LIST_H
 
+#ifndef TL_NO_CSTDLIB
+#include<cstdlib>
+#endif /* TL_NO_CSTDLIB */
 #include<stdint.h>
 #include<assert.h>
 
@@ -56,11 +59,11 @@ static inline turbolist turbolist_create_adv(void* (*malloc_like)(size_t size),
 	return tl;
 }
 
-#ifndef NO_CSTDLIB
+#ifndef TL_NO_CSTDLIB
 static inline turbolist turbolist_create() {
 	return turbolist_create_adv(malloc, free, 0, 16);
 }
-#endif /* NO_CSTDLIB */
+#endif /* TL_NO_CSTDLIB */
 
 static inline void turbolist_delete(turbolist *tl) {
 	if(tl->nex) tl->free(tl->nex);