Safe casting to int (WIP)

SafeCast.php

<?php

final class SafeCast
{
    /**
     * Converts the given variable to an integer.
     *
     * Allowed types are int, float and string.
     *
     * - int values are returned as is;
     * - floats must have an exact int equivalent;
     * - strings must have digits only, and an optional minus sign, and must not overflow an integer.
     *
     * All other types throw an exception.
     *
     * @param mixed $value
     *
     * @return int
     *
     * @throws SafeCastException
     */
    public static function toInt($value): int
    {
        if (is_int($value)) {
            return $value;
        }

        if (is_float($value)) {
            $int = (int) $value;

            if ($value !== (float) $int) {
                throw new SafeCastException(sprintf(
                    'The given floating-point value (%s) does not have an exact integer equivalent.',
                    (string) $value
                ));
            }

            return $int;
        }

        if (is_string($value)) {
            if (preg_match('/^-?[0-9]+$/', $value) !== 1) {
                throw new SafeCastException(sprintf(
                    'The given string %s does not represent a valid integer value.',
                    var_export($value, true)
                ));
            }

            $int = (int) $value;

            if ($value !== (string) $int) {
                throw new SafeCastException(sprintf(
                    'The given string %s overflows an integer.',
                    var_export($value, true)
                ));
            }

            return $int;
        }

        throw new SafeCastException(sprintf(
            'The type %s cannot be converted to an integer.',
            gettype($value)
        ));
    }
}

SafeCastException.php

<?php

final class SafeCastException extends Exception
{
}