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#pragma once
#include "base/string_utils.hpp"
#include "std/cstdint.hpp"
#include "std/string.hpp"
#include "std/vector.hpp"
namespace search
{
class StringSliceBase
{
public:
using TString = strings::UniString;
virtual ~StringSliceBase() = default;
virtual TString const & Get(size_t i) const = 0;
virtual size_t Size() const = 0;
};
class StringSlice : public StringSliceBase
{
public:
StringSlice(vector<TString> const & strings) : m_strings(strings) {}
virtual TString const & Get(size_t i) const override { return m_strings[i]; }
virtual size_t Size() const override { return m_strings.size(); }
private:
vector<TString> const & m_strings;
};
// Allows to iterate over space-separated strings in StringSliceBase.
class JoinIterator
{
public:
using difference_type = ptrdiff_t;
using value_type = strings::UniChar;
using pointer = strings::UniChar *;
using reference = strings::UniChar &;
using iterator_category = std::forward_iterator_tag;
static JoinIterator Begin(StringSliceBase const & slice);
static JoinIterator End(StringSliceBase const & slice);
inline bool operator==(JoinIterator const & rhs) const
{
return &m_slice == &rhs.m_slice && m_string == rhs.m_string && m_offset == rhs.m_offset;
}
inline bool operator!=(JoinIterator const & rhs) const { return !(*this == rhs); }
inline value_type operator*() const { return GetChar(m_string, m_offset); }
JoinIterator & operator++();
private:
enum class Position
{
Begin,
End
};
JoinIterator(StringSliceBase const & slice, Position position);
// Normalizes current position, i.e. moves to the next valid
// character if current position is invalid, or to the end of the
// whole sequence if there are no valid positions.
void Normalize();
size_t GetSize(size_t string) const;
inline size_t GetMaxSize() const { return m_slice.Size() == 0 ? 0 : m_slice.Size() * 2 - 1; }
value_type GetChar(size_t string, size_t offset) const;
StringSliceBase const & m_slice;
// Denotes the current string the iterator points to. Even values
// of |m_string| divided by two correspond to indices in
// |m_slice|. Odd values correspond to intermediate space
// characters.
size_t m_string;
// An index of the current character in the current string.
size_t m_offset;
};
} // namespace search
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