Support > 4GB of chained arenas

src/arena.h

@@ -17,7 +17,7 @@ struct MemoryBlock {
     U32 size;           // Block size, page aligned
     U32 pos;            // start of next allocation
     U64 base_pos;       // absolute position of base relative to the first linked arena
-    U32 committed_pos;  // end of committed region. Will be page aligned
+    U32 committed_end;  // end of committed region. Will be page aligned
     MemoryBlock *prev;
 };
 
@@ -34,7 +34,7 @@ struct Arena {
 typedef struct ArenaCheckpoint ArenaCheckpoint;
 struct ArenaCheckpoint {
     Arena *arena;
-    U32 absolute_pos;
+    U64 absolute_pos;
 };
 #ifndef ArenaParams_Default
 #define ArenaParams_Default { .size = MB(32), .commit_size = KB(64) }
@@ -49,11 +49,12 @@ void arena_free(Arena *arena);
 void *arena_push(Arena *arena, U32 size, U32 align);
 
 #define arena_push_type(arena, type) arena_push(arena, (U32)sizeof(type), alignof(type))
+// Invalid for arrays > U32
 #define arena_push_array_of(arena, type, len) arena_push(arena, (U32) (sizeof(type) * (len)), alignof(type))
 
 ArenaCheckpoint arena_temp_begin(Arena *arena);
 void arena_temp_end(ArenaCheckpoint *checkpoint);
-void arena_pop_to(Arena *arena, U32 abs_pos);
+void arena_pop_to(Arena *arena, U64 abs_pos);
 void arena_reset(Arena *arena);
 
 static INLINE U32 memoryblock_available(const MemoryBlock *block)
@@ -61,7 +62,7 @@ static INLINE U32 memoryblock_available(const MemoryBlock *block)
     return block->size - block->pos;
 }
 
-static INLINE U32 arena_used(const Arena *arena)
+static INLINE U64 arena_used(const Arena *arena)
 {
     const MemoryBlock *block = arena->current;
     return block->base_pos + block->pos;