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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Checked.h>
#include <AK/Types.h>
namespace AK {
class Utf32View;
class Utf32CodepointIterator {
friend class Utf32View;
public:
Utf32CodepointIterator() = default;
~Utf32CodepointIterator() = default;
bool operator==(const Utf32CodepointIterator& other) const
{
return m_ptr == other.m_ptr && m_length == other.m_length;
}
bool operator!=(const Utf32CodepointIterator& other) const
{
return !(*this == other);
}
Utf32CodepointIterator& operator++()
{
VERIFY(m_length > 0);
m_ptr++;
m_length--;
return *this;
}
ssize_t operator-(const Utf32CodepointIterator& other) const
{
return m_ptr - other.m_ptr;
}
u32 operator*() const
{
VERIFY(m_length > 0);
return *m_ptr;
}
constexpr int code_point_length_in_bytes() const { return sizeof(u32); }
bool done() const { return !m_length; }
private:
Utf32CodepointIterator(const u32* ptr, size_t length)
: m_ptr(ptr)
, m_length((ssize_t)length)
{
}
const u32* m_ptr { nullptr };
ssize_t m_length { -1 };
};
class Utf32View {
public:
using Iterator = Utf32CodepointIterator;
Utf32View() = default;
Utf32View(const u32* code_points, size_t length)
: m_code_points(code_points)
, m_length(length)
{
VERIFY(code_points || length == 0);
}
Utf32CodepointIterator begin() const
{
return { begin_ptr(), m_length };
}
Utf32CodepointIterator end() const
{
return { end_ptr(), 0 };
}
const u32* code_points() const { return m_code_points; }
bool is_empty() const { return m_length == 0; }
size_t length() const { return m_length; }
size_t iterator_offset(const Utf32CodepointIterator& it) const
{
VERIFY(it.m_ptr >= m_code_points);
VERIFY(it.m_ptr < m_code_points + m_length);
return ((ptrdiff_t)it.m_ptr - (ptrdiff_t)m_code_points) / sizeof(u32);
}
Utf32View substring_view(size_t offset, size_t length) const
{
if (length == 0)
return {};
VERIFY(offset < m_length);
VERIFY(!Checked<size_t>::addition_would_overflow(offset, length));
VERIFY((offset + length) <= m_length);
return Utf32View(m_code_points + offset, length);
}
private:
const u32* begin_ptr() const
{
return m_code_points;
}
const u32* end_ptr() const
{
return m_code_points + m_length;
}
const u32* m_code_points { nullptr };
size_t m_length { 0 };
};
}
using AK::Utf32View;
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