init commit

vendor/nelexa/zip/src/Model/Extra/Fields/ApkAlignmentExtraField.php

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+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the nelexa/zip package.
+ * (c) Ne-Lexa <https://github.com/Ne-Lexa/php-zip>
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+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
+ */
+final 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.
+     */
+    public const HEADER_ID = 0xD935;
+
+    /** @var int */
+    public const ALIGNMENT_BYTES = 4;
+
+    /** @var int */
+    public const COMMON_PAGE_ALIGNMENT_BYTES = 4096;
+
+    private int $multiple;
+
+    private int $padding;
+
+    public function __construct(int $multiple, int $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.
+     */
+    public function getHeaderId(): int
+    {
+        return self::HEADER_ID;
+    }
+
+    public function getMultiple(): int
+    {
+        return $this->multiple;
+    }
+
+    public function getPadding(): int
+    {
+        return $this->padding;
+    }
+
+    public function setMultiple(int $multiple): void
+    {
+        $this->multiple = $multiple;
+    }
+
+    public function setPadding(int $padding): void
+    {
+        $this->padding = $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  optional zip entry
+     *
+     * @throws ZipException
+     *
+     * @return ApkAlignmentExtraField
+     */
+    public static function unpackLocalFileData(string $buffer, ?ZipEntry $entry = null): self
+    {
+        $length = \strlen($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  optional zip entry
+     *
+     * @throws ZipException on error
+     *
+     * @return ApkAlignmentExtraField
+     */
+    public static function unpackCentralDirData(string $buffer, ?ZipEntry $entry = null): self
+    {
+        return self::unpackLocalFileData($buffer, $entry);
+    }
+
+    /**
+     * The actual data to put into local file data - without Header-ID
+     * or length specifier.
+     *
+     * @return string the data
+     */
+    public function packLocalFileData(): string
+    {
+        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(): string
+    {
+        return $this->packLocalFileData();
+    }
+
+    public function __toString(): string
+    {
+        return sprintf(
+            '0x%04x APK Alignment: Multiple=%d Padding=%d',
+            self::HEADER_ID,
+            $this->multiple,
+            $this->padding
+        );
+    }
+}