/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * utils.cpp - Miscellaneous utility functions
 */

#include "utils.h"

#include <stdlib.h>
#include <string.h>
#include <unistd.h>

/**
 * \file utils.h
 * \brief Miscellaneous utility functions
 */

namespace libcamera {

namespace utils {

/**
 * \def ARRAY_SIZE(array)
 * \brief Determine the number of elements in the static array.
 */

/**
 * \brief Strip the directory prefix from the path
 * \param[in] path The path to process
 *
 * basename is implemented differently across different C libraries. This
 * implementation matches the one provided by the GNU libc, and does not
 * modify its input parameter.
 *
 * \return A pointer within the given path without any leading directory
 * components.
 */
const char *basename(const char *path)
{
       const char *base = strrchr(path, '/');
       return base ? base + 1 : path;
}

/**
 * \brief Get an environment variable
 * \param[in] name The name of the variable to return
 *
 * The environment list is searched to find the variable 'name', and the
 * corresponding string is returned.
 *
 * If 'secure execution' is required then this function always returns NULL to
 * avoid vulnerabilities that could occur if set-user-ID or set-group-ID
 * programs accidentally trust the environment.
 *
 * \returns A pointer to the value in the environment or NULL if the requested
 * environment variable doesn't exist or if secure execution is required.
 */
char *secure_getenv(const char *name)
{
#if HAVE_SECURE_GETENV
	return ::secure_getenv(name);
#else
	if (issetugid())
		return NULL;

	return getenv(name);
#endif
}

/**
 * \fn libcamera::utils::make_unique(Args &&... args)
 * \brief Constructs an object of type T and wraps it in a std::unique_ptr.
 */

/**
 * \fn libcamera::utils::set_overlap(InputIt1 first1, InputIt1 last1,
 *				     InputIt2 first2, InputIt2 last2)
 * \brief Count the number of elements in the intersection of two ranges
 *
 * Count the number of elements in the intersection of the sorted ranges [\a
 * first1, \a last1) and [\a first1, \a last2). Elements are compared using
 * operator< and the ranges must be sorted with respect to the same.
 *
 * \return The number of elements in the intersection of the two ranges
 */

/**
 * \fn libcamera::utils::clamp(const T& v, const T& lo, const T& hi)
 * \param[in] v The value to clamp
 * \param[in] lo The lower boundary to clamp v to
 * \param[in] hi The higher boundary to clamp v to
 * \return lo if v is less than lo, hi if v is greater than hi, otherwise v
 */

} /* namespace utils */

} /* namespace libcamera */