nextcloud/apps/files_external/3rdparty/aws-sdk-php/Aws/Common/Hash/TreeHash.php

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<?php
/**
* Copyright 2010-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
namespace Aws\Common\Hash;
use Aws\Common\Enum\Size;
use Aws\Common\Exception\InvalidArgumentException;
use Aws\Common\Exception\LogicException;
use Guzzle\Http\EntityBody;
/**
* Encapsulates the creation of a tree hash from streamed chunks of data
*/
class TreeHash implements ChunkHashInterface
{
/**
* @var string The algorithm used for hashing
*/
protected $algorithm;
/**
* @var array Set of binary checksums from which the tree hash is derived
*/
protected $checksums = array();
/**
* @var string The resulting hash in hex form
*/
protected $hash;
/**
* @var string The resulting hash in binary form
*/
protected $hashRaw;
/**
* Create a tree hash from an array of existing tree hash checksums
*
* @param array $checksums Set of checksums
* @param bool $inBinaryForm Whether or not the checksums are already in binary form
* @param string $algorithm A valid hash algorithm name as returned by `hash_algos()`
*
* @return TreeHash
*/
public static function fromChecksums(array $checksums, $inBinaryForm = false, $algorithm = self::DEFAULT_ALGORITHM)
{
$treeHash = new self($algorithm);
// Convert checksums to binary form if provided in hex form and add them to the tree hash
$treeHash->checksums = $inBinaryForm ? $checksums : array_map('Aws\Common\Hash\HashUtils::hexToBin', $checksums);
// Pre-calculate hash
$treeHash->getHash();
return $treeHash;
}
/**
* Create a tree hash from a content body
*
* @param string|resource|EntityBody $content Content to create a tree hash for
* @param string $algorithm A valid hash algorithm name as returned by `hash_algos()`
*
* @return TreeHash
*/
public static function fromContent($content, $algorithm = self::DEFAULT_ALGORITHM)
{
$treeHash = new self($algorithm);
// Read the data in 1MB chunks and add to tree hash
$content = EntityBody::factory($content);
while ($data = $content->read(Size::MB)) {
$treeHash->addData($data);
}
// Pre-calculate hash
$treeHash->getHash();
return $treeHash;
}
/**
* Validates an entity body with a tree hash checksum
*
* @param string|resource|EntityBody $content Content to create a tree hash for
* @param string $checksum The checksum to use for validation
* @param string $algorithm A valid hash algorithm name as returned by `hash_algos()`
*
* @return bool
*/
public static function validateChecksum($content, $checksum, $algorithm = self::DEFAULT_ALGORITHM)
{
$treeHash = self::fromContent($content, $algorithm);
return ($checksum === $treeHash->getHash());
}
/**
* {@inheritdoc}
*/
public function __construct($algorithm = self::DEFAULT_ALGORITHM)
{
HashUtils::validateAlgorithm($algorithm);
$this->algorithm = $algorithm;
}
/**
* {@inheritdoc}
* @throws LogicException if the root tree hash is already calculated
* @throws InvalidArgumentException if the data is larger than 1MB
*/
public function addData($data)
{
// Error if hash is already calculated
if ($this->hash) {
throw new LogicException('You may not add more data to a finalized tree hash.');
}
// Make sure that only 1MB chunks or smaller get passed in
if (strlen($data) > Size::MB) {
throw new InvalidArgumentException('The chunk of data added is too large for tree hashing.');
}
// Store the raw hash of this data segment
$this->checksums[] = hash($this->algorithm, $data, true);
return $this;
}
/**
* Add a checksum to the tree hash directly
*
* @param string $checksum The checksum to add
* @param bool $inBinaryForm Whether or not the checksum is already in binary form
*
* @return self
* @throws LogicException if the root tree hash is already calculated
*/
public function addChecksum($checksum, $inBinaryForm = false)
{
// Error if hash is already calculated
if ($this->hash) {
throw new LogicException('You may not add more checksums to a finalized tree hash.');
}
// Convert the checksum to binary form if necessary
$this->checksums[] = $inBinaryForm ? $checksum : HashUtils::hexToBin($checksum);
return $this;
}
/**
* {@inheritdoc}
*/
public function getHash($returnBinaryForm = false)
{
if (!$this->hash) {
// Perform hashes up the tree to arrive at the root checksum of the tree hash
$hashes = $this->checksums;
while (count($hashes) > 1) {
$sets = array_chunk($hashes, 2);
$hashes = array();
foreach ($sets as $set) {
$hashes[] = (count($set) === 1) ? $set[0] : hash($this->algorithm, $set[0] . $set[1], true);
}
}
$this->hashRaw = $hashes[0];
$this->hash = HashUtils::binToHex($this->hashRaw);
}
return $returnBinaryForm ? $this->hashRaw : $this->hash;
}
/**
* @return array Array of raw checksums composing the tree hash
*/
public function getChecksums()
{
return $this->checksums;
}
}