// ArduinoJson - https://arduinojson.org

// Copyright © 2014-2026, Benoit BLANCHON

// MIT License

#pragma once

#include <ArduinoJson/Memory/Allocator.hpp>

#include <ArduinoJson/Namespace.hpp>

#include <ArduinoJson/Polyfills/assert.hpp>

#include <ArduinoJson/Polyfills/integer.hpp>

#include <ArduinoJson/Polyfills/limits.hpp>

#include <stddef.h>  // offsetof

ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE

struct StringNode {

  // Use the same type as SlotId to store the reference count

  // (there can never be more references than slots)

  using references_type = uint_t<ARDUINOJSON_SLOT_ID_SIZE * 8>;

  using length_type = uint_t<ARDUINOJSON_STRING_LENGTH_SIZE * 8>;

  struct StringNode* next;

  references_type references;

  length_type length;

  char data[1];

  static constexpr size_t maxLength = numeric_limits<length_type>::highest();

  static constexpr size_t sizeForLength(size_t n) {

    return n + 1 + offsetof(StringNode, data);

  }

  static StringNode* create(size_t length, Allocator* allocator) {

    if (length > maxLength)

      return nullptr;

    auto size = sizeForLength(length);

    if (size < length)  // integer overflow

      return nullptr;   // (not testable on 64-bit)

    auto node = reinterpret_cast<StringNode*>(allocator->allocate(size));

    if (node) {

      node->length = length_type(length);

      node->references = 1;

    }

    return node;

  }

  static StringNode* resize(StringNode* node, size_t length,

                            Allocator* allocator) {

    ARDUINOJSON_ASSERT(node != nullptr);

    StringNode* newNode;

    if (length <= maxLength)

      newNode = reinterpret_cast<StringNode*>(

          allocator->reallocate(node, sizeForLength(length)));

    else

      newNode = nullptr;

    if (newNode)

      newNode->length = length_type(length);

    else

      allocator->deallocate(node);

    return newNode;

  }

  static void destroy(StringNode* node, Allocator* allocator) {

    allocator->deallocate(node);

  }

};

// Returns the size (in bytes) of an string with n characters.

constexpr size_t sizeofString(size_t n) {

  return StringNode::sizeForLength(n);

}

ARDUINOJSON_END_PRIVATE_NAMESPACE