build.bat

@@ -6,8 +6,6 @@ if not exist ".\build" mkdir ".\build"
 
 pushd .\build
 
-set link= user32.lib
-
-cl /Zi /W4 ..\src\main.c /Feapp.exe /Od /nologo /link %link%
+cl /Zi ..\src\main.c /Feapp.exe /Od /nologo
 
 popd .\build

src/arena.c

@@ -1,43 +1,40 @@
 internal Arena *
-arena_initialize(u64 size, b8 growable)
+arena_initialize(u64 size)
 {
   Arena *result = 0;
-  void *backing_buffer = platform_memory_reserve(size);
+
+  void *backing_buffer = malloc(size);
 
   if (backing_buffer != NULL)
   {
-    platform_memory_commit(backing_buffer, ARENA_INITIAL_COMMIT_SIZE);
-
     result = (Arena*) backing_buffer;
-    result->backing_buffer = backing_buffer;
 
-    // rhjr: immutable arena header
-    result->base_pos = sizeof(Arena);
-    result->commit_pos = sizeof(Arena);
-
-    result->growable = growable;
-    result->size = size;
+    result->buffer = backing_buffer;
+    result->offset = sizeof(Arena);
+    result->size   = sizeof(Arena) + size;
   }
 
-  // rhjr: arenas should be instantiated early on in the programs lifetime, that
-  //       is why this assertion will also be used in production.
-  ASSERT(result != 0);
-  return result;
-}
-
-internal Arena *
-arena_initialize_default()
-{
-  Arena *result = arena_initialize(ARENA_DEFAULT_RESERVE_SIZE, 1);
   return result;
 }
 
 internal void *
 arena_allocate(Arena *arena, u64 size)
 {
+  void *result = 0;
+
+  if (arena->offset + size <= arena->size)
+  {
+    result = (void*)((u64) arena->buffer + (u64) arena->offset);
+    arena->offset += size;
+
+    memset(result, 0, size);
+  }
+
+  return result;
 }
 
 internal void
 arena_release(Arena *arena)
 {
+  arena->offset = 0;
 }

src/arena.h

@@ -1,32 +1,19 @@
 #ifndef ARENA_H
 #define ARENA_H
 
-#define ARENA_INITIAL_COMMIT_SIZE sizeof(struct Arena)
-
-#ifndef ARENA_DEFAULT_RESERVE_SIZE
-#  define ARENA_DEFAULT_RESERVE_SIZE KB(4)
-#endif // ARENA_DEFAULT_RESERVE_SIZE
-
 typedef struct Arena Arena;
 struct Arena {
-  struct Arena *current;
-  struct Arena *prev;
-  u64 *backing_buffer;
-  u64 base_pos;
-  u64 commit_pos;
+  u64 *buffer;
+  u64 offset;
   u64 size;
-  b8 growable;
 };
 
-STATIC_ASSERT(ARENA_INITIAL_COMMIT_SIZE <= ARENA_DEFAULT_RESERVE_SIZE,
-	      arena_default_allocation_size);
+internal Arena * arena_initialize(u64 size);
 
-//= rhjr: arenas
+internal void * arena_allocate(Arena *arena, u64 size);
+internal void   arena_release(Arena *arena);
 
-internal Arena * arena_initialize(u64 size, b8 growable);
-internal Arena * arena_initialize_default();
-
-internal void *  arena_allocate(Arena *arena, u64 size);
+//= rhjr: arena helpers
 
 #define arena_push_array(arena, type, count) \
   (type*) arena_allocate((arena), sizeof(type) * (count))
@@ -34,6 +21,11 @@ internal void *  arena_allocate(Arena *arena, u64 size);
 #define arena_push(arena, type) \
   (type*) arena_allocate((arena), sizeof(type))
 
-internal void arena_release(Arena *arena);
+//= rhjr: memory helpers
+
+#define memory_zero(s,z)       memset((s), 0, (z))
+#define memory_zero_struct(s)  memory_zero((s), sizeof(*(s)))
+
+#define memory_copy(dst, src, length) memmove((dst), (src), (length))
 
 #endif // ARENA_H

src/base.h

@@ -18,26 +18,10 @@ typedef int16_t i16;
 typedef int32_t i32;
 typedef int64_t i64;
 
-typedef uint8_t  b8;
-typedef uint8_t  b16;
-typedef uint8_t  b32;
-typedef uint8_t  b64;
-
 #define KB(b) ((b) << 10)
 #define MB(b) ((b) << 20)
 
-#define Glue_(A,B) A##B
-#define Glue(A,B) Glue_(A,B)
-
 #define STATEMENT(S) do{ S } while(0)
 #define ASSERT(c) STATEMENT( if (!(c)){ (*(volatile int*)0 = 0); } )
-#define STATIC_ASSERT(c,l) typedef u8 Glue(l,__LINE__) [(c)?1:-1]
-
-//= rhjr: memory helpers
-
-#define memory_zero(s,z)       memset((s), 0, (z))
-#define memory_zero_struct(s)  memory_zero((s), sizeof(*(s)))
-
-#define memory_copy(dst, src, length) memmove((dst), (src), (length))
 
 #endif // BASE_H

src/main.c

@@ -1,13 +1,10 @@
 #include "base.h"
 #include "arena.h"
-#include "win32_platform.h"
 
 #include "arena.c"
-#include "win32_platform.c"
 
 int
 main(void)
 {
-  Arena *arena = arena_initialize_default();
   return 0;
 }

src/win32_platform.c

@@ -1,34 +0,0 @@
-
-internal void *
-platform_memory_reserve(u64 size)
-{
-  void *result = VirtualAlloc(0, size, MEM_RESERVE, PAGE_READWRITE);
-  return result;
-}
-
-internal b8
-platform_memory_commit(void *ptr, u64 size)
-{
-  b32 result = (VirtualAlloc(ptr, size, MEM_COMMIT, PAGE_READWRITE) != 0);
-  return result;
-}
-
-internal void
-platform_memory_decommit(void *ptr, u64 size)
-{
-  VirtualFree(ptr, size, MEM_DECOMMIT);
-};
-
-internal void
-platform_memory_release(void *ptr, u64 size)
-{
-  VirtualFree(ptr, 0, MEM_RELEASE);
-}
-
-internal u64
-platform_get_page_size(void)
-{
-  SYSTEM_INFO sysinfo = {0};
-  GetSystemInfo(&sysinfo);
-  return sysinfo.dwPageSize;
-}

src/win32_platform.h

@@ -1,17 +0,0 @@
-#ifndef WIN32_PLATFORM_H
-#define WIN32_PLATFORM_H
-
-#undef internal
-#include <Windows.h>
-#define internal static
-
-//= rhjr: platform memory management
-
-internal void * platform_memory_reserve(u64 size);
-internal b8     platform_memory_commit(void *ptr, u64 size);
-internal void   platform_memory_decommit(void *ptr, u64 size);
-internal void   platform_memory_release(void *ptr, u64 size);
-
-internal u64    platform_get_page_size(void);
-
-#endif // WIN32_PLATFORM_H