File size: 4.25Kb
- <?php
-
- namespace PhpZip\Model\Extra\Fields;
-
- use PhpZip\Exception\ZipException;
- use PhpZip\Model\Extra\ZipExtraField;
- use PhpZip\Model\ZipEntry;
-
- /**
- * Apk Alignment Extra Field.
- *
- * @see https://android.googlesource.com/platform/tools/apksig/+/master/src/main/java/com/android/apksig/ApkSigner.java
- * @see https://developer.android.com/studio/command-line/zipalign
- */
- class ApkAlignmentExtraField implements ZipExtraField
- {
- /**
- * @var int Extensible data block/field header ID used for storing
- * information about alignment of uncompressed entries as
- * well as for aligning the entries's data. See ZIP
- * appnote.txt section 4.5 Extensible data fields.
- */
- const HEADER_ID = 0xd935;
-
- /**
- * @var int minimum size (in bytes) of the extensible data block/field used
- * for alignment of uncompressed entries
- */
- const MIN_SIZE = 6;
-
- /** @var int */
- const ALIGNMENT_BYTES = 4;
-
- /** @var int */
- const COMMON_PAGE_ALIGNMENT_BYTES = 4096;
-
- /** @var int */
- private $multiple;
-
- /** @var int */
- private $padding;
-
- /**
- * @param int $multiple
- * @param int $padding
- */
- public function __construct($multiple, $padding)
- {
- $this->multiple = $multiple;
- $this->padding = $padding;
- }
-
- /**
- * Returns the Header ID (type) of this Extra Field.
- * The Header ID is an unsigned short integer (two bytes)
- * which must be constant during the life cycle of this object.
- *
- * @return int
- */
- public function getHeaderId()
- {
- return self::HEADER_ID;
- }
-
- /**
- * @return int
- */
- public function getMultiple()
- {
- return $this->multiple;
- }
-
- /**
- * @return int
- */
- public function getPadding()
- {
- return $this->padding;
- }
-
- /**
- * @param int $multiple
- */
- public function setMultiple($multiple)
- {
- $this->multiple = (int) $multiple;
- }
-
- /**
- * @param int $padding
- */
- public function setPadding($padding)
- {
- $this->padding = (int) $padding;
- }
-
- /**
- * Populate data from this array as if it was in local file data.
- *
- * @param string $buffer the buffer to read data from
- * @param ZipEntry|null $entry
- *
- * @throws ZipException
- *
- * @return ApkAlignmentExtraField
- */
- public static function unpackLocalFileData($buffer, ZipEntry $entry = null)
- {
- $length = \strlen($buffer);
-
- if ($length < 2) {
- // This is APK alignment field.
- // FORMAT:
- // * uint16 alignment multiple (in bytes)
- // * remaining bytes -- padding to achieve alignment of data which starts after
- // the extra field
- throw new ZipException(
- 'Minimum 6 bytes of the extensible data block/field used for alignment of uncompressed entries.'
- );
- }
- $multiple = unpack('v', $buffer)[1];
- $padding = $length - 2;
-
- return new self($multiple, $padding);
- }
-
- /**
- * Populate data from this array as if it was in central directory data.
- *
- * @param string $buffer the buffer to read data from
- * @param ZipEntry|null $entry
- *
- * @throws ZipException on error
- *
- * @return ApkAlignmentExtraField
- */
- public static function unpackCentralDirData($buffer, ZipEntry $entry = null)
- {
- return self::unpackLocalFileData($buffer, $entry);
- }
-
- /**
- * The actual data to put into local file data - without Header-ID
- * or length specifier.
- *
- * @return string the data
- */
- public function packLocalFileData()
- {
- return pack('vx' . $this->padding, $this->multiple);
- }
-
- /**
- * The actual data to put into central directory - without Header-ID or
- * length specifier.
- *
- * @return string the data
- */
- public function packCentralDirData()
- {
- return $this->packLocalFileData();
- }
-
- /**
- * @return string
- */
- public function __toString()
- {
- return sprintf(
- '0x%04x APK Alignment: Multiple=%d Padding=%d',
- self::HEADER_ID,
- $this->multiple,
- $this->padding
- );
- }
- }