utils.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2018, Google Inc.
 *
 * Miscellaneous utility functions
 */
 
#pragma once
 
#include <algorithm>
#include <chrono>
#include <functional>
#include <iterator>
#include <ostream>
#include <sstream>
#include <stdint.h>
#include <string.h>
#include <string>
#include <sys/time.h>
#include <type_traits>
#include <utility>
#include <vector>
 
#include <libcamera/base/class.h>
#include <libcamera/base/private.h>
 
#ifndef __DOXYGEN__
 
/* uClibc and uClibc-ng don't provide O_TMPFILE */
#ifndef O_TMPFILE
#define O_TMPFILE (020000000 | O_DIRECTORY)
#endif
 
#endif
 
namespace libcamera {
 
namespace utils {
 
const char *basename(const char *path);
 
char *secure_getenv(const char *name);
std::string dirname(const std::string &path);
 
template<typename T>
std::vector<typename T::key_type> map_keys(const T &map)
{
    std::vector<typename T::key_type> keys;
    std::transform(map.begin(), map.end(), std::back_inserter(keys),
               [](const auto &value) { return value.first; });
    return keys;
}
 
template<class InputIt1, class InputIt2>
unsigned int set_overlap(InputIt1 first1, InputIt1 last1,
             InputIt2 first2, InputIt2 last2)
{
    unsigned int count = 0;
 
    while (first1 != last1 && first2 != last2) {
        if (*first1 < *first2) {
            ++first1;
        } else {
            if (!(*first2 < *first1))
                count++;
            ++first2;
        }
    }
 
    return count;
}
 
using clock = std::chrono::steady_clock;
using duration = std::chrono::steady_clock::duration;
using time_point = std::chrono::steady_clock::time_point;
 
struct timespec duration_to_timespec(const duration &value);
std::string time_point_to_string(const time_point &time);
 
namespace details {
 
struct hex {
    uint64_t v;
    unsigned int w;
};
 
template<typename T>
constexpr unsigned int hex_width()
{
    return sizeof(T) * 2;
}
 
std::basic_ostream<char, std::char_traits<char>> &
operator<<(std::basic_ostream<char, std::char_traits<char>> &stream, const hex &h);
 
} /* namespace details */
 
template<typename T, std::enable_if_t<std::is_integral_v<T>> * = nullptr>
details::hex hex(T value, unsigned int width = details::hex_width<T>())
{
    return { static_cast<std::make_unsigned_t<T>>(value), width };
}
 
size_t strlcpy(char *dst, const char *src, size_t size);
 
#ifndef __DOXYGEN__
template<typename Container, typename UnaryOp>
std::string join(const Container &items, const std::string &sep, UnaryOp op)
{
    std::ostringstream ss;
    bool first = true;
 
    for (auto it = std::begin(items); it != std::end(items); ++it) {
        if (!first)
            ss << sep;
        else
            first = false;
 
        ss << op(*it);
    }
 
    return ss.str();
}
 
template<typename Container>
std::string join(const Container &items, const std::string &sep)
{
    std::ostringstream ss;
    bool first = true;
 
    for (auto it = std::begin(items); it != std::end(items); ++it) {
        if (!first)
            ss << sep;
        else
            first = false;
 
        ss << *it;
    }
 
    return ss.str();
}
#else
template<typename Container, typename UnaryOp>
std::string join(const Container &items, const std::string &sep, UnaryOp op = nullptr);
#endif
 
namespace details {
 
class StringSplitter
{
public:
    StringSplitter(const std::string &str, const std::string &delim);
 
    class iterator
    {
    public:
        using difference_type = std::size_t;
        using value_type = std::string;
        using pointer = value_type *;
        using reference = value_type &;
        using iterator_category = std::input_iterator_tag;
 
        iterator(const StringSplitter *ss, std::string::size_type pos);
 
        iterator &operator++();
        std::string operator*() const;
 
        bool operator==(const iterator &other) const
        {
            return pos_ == other.pos_;
        }
 
        bool operator!=(const iterator &other) const
        {
            return !(*this == other);
        }
 
    private:
        const StringSplitter *ss_;
        std::string::size_type pos_;
        std::string::size_type next_;
    };
 
    iterator begin() const
    {
        return { this, 0 };
    }
 
    iterator end() const
    {
        return { this, std::string::npos };
    }
 
private:
    std::string str_;
    std::string delim_;
};
 
} /* namespace details */
 
details::StringSplitter split(const std::string &str, const std::string &delim);
 
std::string toAscii(const std::string &str);
 
std::string libcameraBuildPath();
std::string libcameraSourcePath();
 
constexpr unsigned int alignDown(unsigned int value, unsigned int alignment)
{
    return value / alignment * alignment;
}
 
constexpr unsigned int alignUp(unsigned int value, unsigned int alignment)
{
    return (value + alignment - 1) / alignment * alignment;
}
 
namespace details {
 
template<typename T>
struct reverse_adapter {
    T &iterable;
};
 
template<typename T>
auto begin(reverse_adapter<T> r)
{
    return std::rbegin(r.iterable);
}
 
template<typename T>
auto end(reverse_adapter<T> r)
{
    return std::rend(r.iterable);
}
 
} /* namespace details */
 
template<typename T>
details::reverse_adapter<T> reverse(T &&iterable)
{
    return { iterable };
}
 
namespace details {
 
template<typename Base>
class enumerate_iterator
{
private:
    using base_reference = typename std::iterator_traits<Base>::reference;
 
public:
    using difference_type = typename std::iterator_traits<Base>::difference_type;
    using value_type = std::pair<const std::size_t, base_reference>;
    using pointer = value_type *;
    using reference = value_type &;
    using iterator_category = std::input_iterator_tag;
 
    explicit enumerate_iterator(Base iter)
        : current_(iter), pos_(0)
    {
    }
 
    enumerate_iterator &operator++()
    {
        ++current_;
        ++pos_;
        return *this;
    }
 
    bool operator!=(const enumerate_iterator &other) const
    {
        return current_ != other.current_;
    }
 
    value_type operator*() const
    {
        return { pos_, *current_ };
    }
 
private:
    Base current_;
    std::size_t pos_;
};
 
template<typename Base>
class enumerate_adapter
{
public:
    using iterator = enumerate_iterator<Base>;
 
    enumerate_adapter(Base begin, Base end)
        : begin_(begin), end_(end)
    {
    }
 
    iterator begin() const
    {
        return iterator{ begin_ };
    }
 
    iterator end() const
    {
        return iterator{ end_ };
    }
 
private:
    const Base begin_;
    const Base end_;
};
 
} /* namespace details */
 
template<typename T>
auto enumerate(T &iterable)
{
    return details::enumerate_adapter{ std::begin(iterable), std::end(iterable) };
}
 
class Duration : public std::chrono::duration<double, std::nano>
{
    using BaseDuration = std::chrono::duration<double, std::nano>;
 
public:
    Duration() = default;
 
    template<typename Rep>
    constexpr explicit Duration(const Rep &r)
        : BaseDuration(r)
    {
    }
 
    template<typename Rep, typename Period>
    constexpr Duration(const std::chrono::duration<Rep, Period> &d)
        : BaseDuration(d)
    {
    }
 
    template<typename Period>
    double get() const
    {
        auto const c = std::chrono::duration_cast<std::chrono::duration<double, Period>>(*this);
        return c.count();
    }
 
    constexpr Duration operator-() const
    {
        return BaseDuration::operator-();
    }
 
    explicit constexpr operator bool() const
    {
        return *this != BaseDuration::zero();
    }
};
 
template<typename T>
decltype(auto) abs_diff(const T &a, const T &b)
{
    if (a < b)
        return b - a;
    else
        return a - b;
}
 
double strtod(const char *__restrict nptr, char **__restrict endptr);
 
template<class Enum>
constexpr std::underlying_type_t<Enum> to_underlying(Enum e) noexcept
{
    return static_cast<std::underlying_type_t<Enum>>(e);
}
 
class ScopeExitActions
{
public:
    ~ScopeExitActions();
 
    void operator+=(std::function<void()> &&action);
    void release();
 
private:
    std::vector<std::function<void()>> actions_;
};
 
#ifndef __DOXYGEN__
template<typename EF>
class scope_exit
{
public:
    template<typename Fn,
         std::enable_if_t<!std::is_same_v<std::remove_cv_t<std::remove_reference_t<Fn>>, scope_exit> &&
                  std::is_constructible_v<EF, Fn>> * = nullptr>
    explicit scope_exit(Fn &&fn)
        : exitFunction_(std::forward<Fn>(fn))
    {
        static_assert(std::is_nothrow_constructible_v<EF, Fn>);
    }
 
    ~scope_exit()
    {
        if (active_)
            exitFunction_();
    }
 
    void release()
    {
        active_ = false;
    }
 
private:
    LIBCAMERA_DISABLE_COPY_AND_MOVE(scope_exit)
 
    EF exitFunction_;
    bool active_ = true;
};
 
template<typename EF>
scope_exit(EF) -> scope_exit<EF>;
 
#endif /* __DOXYGEN__ */
 
#ifndef __DOXYGEN__
std::ostream &operator<<(std::ostream &os, const Duration &d);
#endif
 
} /* namespace utils */
 
} /* namespace libcamera */