padded_string_view.h

#ifndef SIMDJSON_PADDED_STRING_VIEW_H
#define SIMDJSON_PADDED_STRING_VIEW_H

#include "simdjson/portability.h"
#include "simdjson/base.h" // for SIMDJSON_PADDING
#include "simdjson/error.h"

#include <cstring>
#include <memory>
#include <string>
#include <ostream>

namespace simdjson {

/**
 * User-provided string that promises it has extra padded bytes at the end for use with parser::parse().
 */
class padded_string_view : public std::string_view {
private:
  size_t _capacity;

public:
  /** Create an empty padded_string_view. */
  inline padded_string_view() noexcept = default;

  /**
   * Promise the given buffer has at least SIMDJSON_PADDING extra bytes allocated to it.
   *
   * @param s The string.
   * @param len The length of the string (not including padding).
   * @param capacity The allocated length of the string, including padding. If the capacity is less
   *       than the length, the capacity will be set to the length.
   */
  explicit inline padded_string_view(const char* s, size_t len, size_t capacity) noexcept;
  /** overload explicit inline padded_string_view(const char* s, size_t len) noexcept */
  explicit inline padded_string_view(const uint8_t* s, size_t len, size_t capacity) noexcept;

  /**
   * Promise the given string has at least SIMDJSON_PADDING extra bytes allocated to it.
   *
   * The capacity of the string will be used to determine its padding.
   *
   * @param s The string.
   */
  explicit inline padded_string_view(const std::string &s) noexcept;

  /**
   * Promise the given string_view has at least SIMDJSON_PADDING extra bytes allocated to it.
   *
   * @param s The string.
   * @param capacity The allocated length of the string, including padding. If the capacity is less
   *      than the length, the capacity will be set to the length.
   */
  explicit inline padded_string_view(std::string_view s, size_t capacity) noexcept;

  /** The number of allocated bytes. */
  inline size_t capacity() const noexcept;

  /**
   * Remove the UTF-8 Byte Order Mark (BOM) if it exists.
   *
   * @return whether a BOM was found and removed
   */
  inline bool remove_utf8_bom() noexcept;

  /** The amount of padding on the string (capacity() - length()) */
  inline size_t padding() const noexcept;

}; // padded_string_view

#if SIMDJSON_EXCEPTIONS
/**
 * Send padded_string instance to an output stream.
 *
 * @param out The output stream.
 * @param s The padded_string_view.
 * @throw simdjson_error if the result being printed has an error. If there is an error with the
 *        underlying output stream, that error will be propagated (simdjson_error will not be
 *        thrown).
 */
inline std::ostream& operator<<(std::ostream& out, simdjson_result<padded_string_view> &s) noexcept(false);
#endif

} // namespace simdjson

#endif // SIMDJSON_PADDED_STRING_VIEW_H