/
arena.h
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/
arena.h
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// Protocol Buffers - Google's data interchange format
// Copyright 2023 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
/* upb_Arena is a specific allocator implementation that uses arena allocation.
* The user provides an allocator that will be used to allocate the underlying
* arena blocks. Arenas by nature do not require the individual allocations
* to be freed. However the Arena does allow users to register cleanup
* functions that will run when the arena is destroyed.
*
* A upb_Arena is *not* thread-safe.
*
* You could write a thread-safe arena allocator that satisfies the
* upb_alloc interface, but it would not be as efficient for the
* single-threaded case. */
#ifndef UPB_MEM_ARENA_H_
#define UPB_MEM_ARENA_H_
#include <stddef.h>
#include <stdint.h>
#include "upb/mem/alloc.h"
#include "upb/mem/internal/arena.h"
// Must be last.
#include "upb/port/def.inc"
typedef struct upb_Arena upb_Arena;
#ifdef __cplusplus
extern "C" {
#endif
// Creates an arena from the given initial block (if any -- n may be 0).
// Additional blocks will be allocated from |alloc|. If |alloc| is NULL, this
// is a fixed-size arena and cannot grow.
UPB_API upb_Arena* upb_Arena_Init(void* mem, size_t n, upb_alloc* alloc);
UPB_API void upb_Arena_Free(upb_Arena* a);
UPB_API bool upb_Arena_Fuse(upb_Arena* a, upb_Arena* b);
bool upb_Arena_IncRefFor(upb_Arena* a, const void* owner);
void upb_Arena_DecRefFor(upb_Arena* a, const void* owner);
size_t upb_Arena_SpaceAllocated(upb_Arena* a, size_t* fused_count);
uint32_t upb_Arena_DebugRefCount(upb_Arena* a);
UPB_API_INLINE upb_Arena* upb_Arena_New(void) {
return upb_Arena_Init(NULL, 0, &upb_alloc_global);
}
UPB_API_INLINE void* upb_Arena_Malloc(struct upb_Arena* a, size_t size) {
return UPB_PRIVATE(_upb_Arena_Malloc)(a, size);
}
UPB_API_INLINE void* upb_Arena_Realloc(upb_Arena* a, void* ptr, size_t oldsize,
size_t size) {
return UPB_PRIVATE(_upb_Arena_Realloc)(a, ptr, oldsize, size);
}
// Shrinks the last alloc from arena.
// REQUIRES: (ptr, oldsize) was the last malloc/realloc from this arena.
// We could also add a upb_Arena_TryShrinkLast() which is simply a no-op if
// this was not the last alloc.
UPB_API_INLINE void upb_Arena_ShrinkLast(upb_Arena* a, void* ptr,
size_t oldsize, size_t size) {
UPB_PRIVATE(_upb_Arena_ShrinkLast)(a, ptr, oldsize, size);
}
#ifdef __cplusplus
} /* extern "C" */
#endif
#include "upb/port/undef.inc"
#endif /* UPB_MEM_ARENA_H_ */