THUAI6/CAPI/cpp/grpc/include/upb/internal/upb.h

/*
 * Copyright (c) 2009-2021, Google LLC
 * All rights reserved.
 *
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 * modification, are permitted provided that the following conditions are met:
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 *       derived from this software without specific prior written permission.
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#ifndef UPB_INTERNAL_UPB_H_
#define UPB_INTERNAL_UPB_H_

#include "upb/upb.h"

struct mem_block;
typedef struct mem_block mem_block;

struct upb_Arena
{
    _upb_ArenaHead head;
    /* Stores cleanup metadata for this arena.
     * - a pointer to the current cleanup counter.
     * - a boolean indicating if there is an unowned initial block.  */
    uintptr_t cleanup_metadata;

    /* Allocator to allocate arena blocks.  We are responsible for freeing these
     * when we are destroyed. */
    upb_alloc* block_alloc;
    uint32_t last_size;

    /* When multiple arenas are fused together, each arena points to a parent
     * arena (root points to itself). The root tracks how many live arenas
     * reference it. */
    uint32_t refcount; /* Only used when a->parent == a */
    struct upb_Arena* parent;

    /* Linked list of blocks to free/cleanup. */
    mem_block *freelist, *freelist_tail;
};

// Encodes a float or double that is round-trippable, but as short as possible.
// These routines are not fully optimal (not guaranteed to be shortest), but are
// short-ish and match the implementation that has been used in protobuf since
// the beginning.
//
// The given buffer size must be at least kUpb_RoundTripBufferSize.
enum
{
    kUpb_RoundTripBufferSize = 32
};
void _upb_EncodeRoundTripDouble(double val, char* buf, size_t size);
void _upb_EncodeRoundTripFloat(float val, char* buf, size_t size);

#endif /* UPB_INTERNAL_UPB_H_ */