dechex - PHP code example

How to Use the PHP Function Dechex to Convert Hexadecimal Into Decimal

In php, you can perform various mathematical functions to convert numbers into other representations. For example, decimal can be converted into binary and octal. Similarly, hexadecimal can be converted into decimal and even back into binary. The dechex function is one of these built-in functions that allows you to do the conversion.

Hexadecimal is a base 16 number system that uses the letters A to F. As a result, it has 6 more unique digits than the decimal system. It also has a zero-based system like the decimal system but unlike decimal, it does not include a digit for 1.

To use the dechex function, all you need to do is pass in a decimal number as the argument and you will get back a string that is the hexadecimal representation of that number. This will help you in displaying hexadecimal values to users or storing them in your database.

The dechex() function is simple to use and can be used in many different applications. For instance, if you are storing colours in your database, it will be easier to work with these in hexadecimal rather than in decimal as it is how browsers render them. Likewise, you may be working with CSS and need to convert the colour code into hex to display it. In such cases, the dechex function would be an essential tool to have at hand. It can be used in all versions of PHP.

dechex example

else {
                    $time = substr_replace($time, str_pad(++$mtime, 9, '0', \STR_PAD_LEFT), -9);
                }

                goto randomize;
            }

            $time = self::$time;
        }

        if (\PHP_INT_SIZE >= 8) {
            $time = dechex($time);
        } else {
            $time = bin2hex(BinaryUtil::fromBase($time, BinaryUtil::BASE10));
        }

        return substr_replace(sprintf('%012s-%04x-%04x-%04x%04x%04x',
            $time,
            0x7000 | (self::$rand[1] << 2) | (self::$rand[2] >> 14),
            0x8000 | (self::$rand[2] & 0x3FFF),
            self::$rand[3],
            self::$rand[4],
            self::$rand[5],
        ),

    protected function loadResource(string $resource): array
    {
        $stream = fopen($resource, 'r');

        $stat = fstat($stream);

        if ($stat['size'] < self::MO_HEADER_SIZE) {
            throw new InvalidResourceException('MO stream content has an invalid format.');
        }
        $magic = unpack('V1', fread($stream, 4));
        $magic = hexdec(substr(dechex(current($magic)), -8));

        if (self::MO_LITTLE_ENDIAN_MAGIC == $magic) {
            $isBigEndian = false;
        } elseif (self::MO_BIG_ENDIAN_MAGIC == $magic) {
            $isBigEndian = true;
        } else {
            throw new InvalidResourceException('MO stream content has an invalid format.');
        }

        // formatRevision         $this->readLong($stream, $isBigEndian);

do {
                $s .= $map[$c[$i]] ?? sprintf('\x%02X', \ord($c[$i]));
            } while (isset($c[++$i]));

            return $s.$endCchr;
        }, $value, -1, $cchrCount);

        if (!($attr['binary'] ?? false)) {
            $value = preg_replace_callback(static::$unicodeCharsRx, function D$c) use (&$cchrCount, $startCchr, $endCchr) {
                ++$cchrCount;

                return $startCchr.'\u{'.strtoupper(dechex(mb_ord($c[0]))).'}'.$endCchr;
            }, $value);
        }

        if ($this->colors && '' !== $value) {
            if ($cchrCount && "\033" === $value[0]) {
                $value = substr($value, \strlen($startCchr));
            } else {
                $value = "\033[{$this->styles[$style]}m".$value;
            }
            if ($cchrCount && str_ends_with($value, $endCchr)) {
                $value = substr($value, 0, -\strlen($endCchr));
            }

$s .= '">';
                }

                $s .= $map[$c[$i]] ?? sprintf('\x%02X', \ord($c[$i]));
            } while (isset($c[++$i]));

            return $s.'</span>';
        }, $v).'</span>';

        if (!($attr['binary'] ?? false)) {
            $v = preg_replace_callback(static::$unicodeCharsRx, function D$c) {
                return '<span class=sf-dump-default>\u{'.strtoupper(dechex(mb_ord($c[0]))).'}</span>';
            }, $v);
        }

        if (isset($attr['file']) && $href = $this->getSourceLink($attr['file'], $attr['line'] ?? 0)) {
            $attr['href'] = $href;
        }
        if (isset($attr['href'])) {
            if ('label' === $style) {
                $v .= '^';
            }
            $target = isset($attr['file']) ? '' : ' target="_blank"';

/** * @return string Count of 100-nanosecond intervals since the UUID epoch 1582-10-15 00:00:00 in hexadecimal */
    public static function dateTimeToHex(\DateTimeInterface $time): string
    {
        if (\PHP_INT_SIZE >= 8) {
            if (-self::TIME_OFFSET_INT > $time = (int) $time->format('Uu0')) {
                throw new \InvalidArgumentException('The given UUID date cannot be earlier than 1582-10-15.');
            }

            return str_pad(dechex(self::TIME_OFFSET_INT + $time), 16, '0', \STR_PAD_LEFT);
        }

        $time = $time->format('Uu0');
        $negative = '-' === $time[0];
        if ($negative && self::TIME_OFFSET_INT < $time = substr($time, 1)) {
            throw new \InvalidArgumentException('The given UUID date cannot be earlier than 1582-10-15.');
        }
        $time = self::fromBase($time, self::BASE10);
        $time = str_pad($time, 8, "\0", \STR_PAD_LEFT);

        if ($negative) {

// Nor can it be over four characters                 if (strlen($ipv6_part) > 4)
                    return false;

                // Remove leading zeros (this is safe because of the above)                 $ipv6_part = ltrim($ipv6_part, '0');
                if ($ipv6_part === '')
                    $ipv6_part = '0';

                // Check the value is valid                 $value = hexdec($ipv6_part);
                if (dechex($value) !== strtolower($ipv6_part) || $value < 0 || $value > 0xFFFF)
                    return false;
            }
            if (count($ipv4) === 4)
            {
                foreach ($ipv4 as $ipv4_part)
                {
                    $value = (int) $ipv4_part;
                    if ((string) $value !== $ipv4_part || $value < 0 || $value > 0xFF)
                        return false;
                }
            }

    public static function PrintHexBytes($string, $hex=true, $spaces=true, $htmlencoding='UTF-8') {
        $returnstring = '';
        for ($i = 0; $i < strlen($string); $i++) {
            if ($hex) {
                $returnstring .= str_pad(dechex(ord($string[$i])), 2, '0', STR_PAD_LEFT);
            } else {
                $returnstring .= ' '.(preg_match("#[\x20-\x7E]#", $string[$i]) ? $string[$i] : '¤');
            }
            if ($spaces) {
                $returnstring .= ' ';
            }
        }
        if (!empty($htmlencoding)) {
            if ($htmlencoding === true) {
                $htmlencoding = 'UTF-8'; // prior to getID3 v1.9.0 the function's 4th parameter was boolean             }

// Parse string input in CSS notation ('10, 20, 30').     elseif (is_string($input)) {
      preg_match('/(\d+), ?(\d+), ?(\d+)/', $input, $rgb);
      array_shift($rgb);
    }

    $out = 0;
    foreach ($rgb as $k => $v) {
      $out |= $v << (16 - $k * 8);
    }

    return '#' . str_pad(dechex($out), 6, 0, STR_PAD_LEFT);
  }

  /** * Normalize the hex color length to 6 characters for comparison. * * @param string $hex * The hex color to normalize. * * @return string * The 6 character hex color. */

for ($x = 0; $x < $_length; $x++) {
                $return .= '%' . bin2hex($string[$x]);
            }
            return $return;

        case 'hexentity':
            $return = '';
            if (Smarty::$_MBSTRING) {
                require_once(SMARTY_PLUGINS_DIR . 'shared.mb_unicode.php');
                $return = '';
                foreach (smarty_mb_to_unicode($string, Smarty::$_CHARSET) as $unicode) {
                    $return .= '&#x' . strtoupper(dechex($unicode)) . ';';
                }
                return $return;
            }
            // no MBString fallback             $_length = strlen($string);
            for ($x = 0; $x < $_length; $x++) {
                $return .= '&#x' . bin2hex($string[$x]) . ';';
            }
            return $return;

        case 'decentity':

$hexbytecharstring .= chr(hexdec(substr($GUIDstring, 34, 2)));

        return $hexbytecharstring;
    }

    /** * @param string $Bytestring * * @return string */
    public static function BytestringToGUID($Bytestring) {
        $GUIDstring  = str_pad(dechex(ord($Bytestring[3])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= str_pad(dechex(ord($Bytestring[2])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= str_pad(dechex(ord($Bytestring[1])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= str_pad(dechex(ord($Bytestring[0])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= '-';
        $GUIDstring .= str_pad(dechex(ord($Bytestring[5])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= str_pad(dechex(ord($Bytestring[4])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= '-';
        $GUIDstring .= str_pad(dechex(ord($Bytestring[7])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= str_pad(dechex(ord($Bytestring[6])),  2, '0', STR_PAD_LEFT);
        $GUIDstring .= '-';
        $GUIDstring .= str_pad(dechex(ord($Bytestring[8])),  2, '0', STR_PAD_LEFT);

// set md5_data_source - built into flac 0.5+         if (isset($info['flac']['STREAMINFO']['audio_signature'])) {

            if ($info['flac']['STREAMINFO']['audio_signature'] === str_repeat("\x00", 16)) {
                $this->warning('FLAC STREAMINFO.audio_signature is null (known issue with libOggFLAC)');
            }
            else {
                $info['md5_data_source'] = '';
                $md5 = $info['flac']['STREAMINFO']['audio_signature'];
                for ($i = 0; $i < strlen($md5); $i++) {
                    $info['md5_data_source'] .= str_pad(dechex(ord($md5[$i])), 2, '00', STR_PAD_LEFT);
                }
                if (!preg_match('/^[0-9a-f]{32}$/', $info['md5_data_source'])) {
                    unset($info['md5_data_source']);
                }
            }
        }

        if (isset($info['flac']['STREAMINFO']['bits_per_sample'])) {
            $info['audio']['bits_per_sample'] = $info['flac']['STREAMINFO']['bits_per_sample'];
            if ($info['audio']['bits_per_sample'] == 8) {
                // special case

// get name         $element['id_name'] = self::EBMLidName($element['id']);

        // get length         $element['length'] = $this->readEBMLint();

        // get end offset         $element['end'] = $this->current_offset + $element['length'];

        // get raw data         $dont_parse = (in_array($element['id'], $this->unuseful_elements) || $element['id_name'] == dechex($element['id']));
        if (($get_data === true || (is_array($get_data) && !in_array($element['id'], $get_data))) && !$dont_parse) {
            $element['data'] = $this->readEBMLelementData($element['length'], $element);
        }

        return true;
    }

    /** * @param string $type * @param int $line * @param array $element */

    protected function _generateIdentifierName($columnNames, $prefix = '', $maxSize = 30)
    {
        $hash = \implode('', \array_map(static fn ($column) => \dechex(\crc32((string) $column)), $columnNames));

        return \strtoupper(\substr($prefix . '_' . $hash, 0, $maxSize));
    }
}

return false;
                }

                // Remove leading zeros (this is safe because of the above)                 $ipv6_part = ltrim($ipv6_part, '0');
                if ($ipv6_part === '') {
                    $ipv6_part = '0';
                }

                // Check the value is valid                 $value = hexdec($ipv6_part);
                if (dechex($value) !== strtolower($ipv6_part) || $value < 0 || $value > 0xFFFF) {
                    return false;
                }
            }

            if (count($ipv4) === 4) {
                foreach ($ipv4 as $ipv4_part) {
                    $value = (int) $ipv4_part;
                    if ((string) $value !== $ipv4_part || $value < 0 || $value > 0xFF) {
                        return false;
                    }
                }
            }