mirror of
https://github.com/samsonjs/arq_restore.git
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74 lines
2.9 KiB
Objective-C
74 lines
2.9 KiB
Objective-C
/*
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Copyright (c) 2009-2017, Haystack Software LLC https://www.arqbackup.com
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the names of PhotoMinds LLC or Haystack Software, nor the names of
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their contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#import "SHA256TreeHash.h"
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#import "SHA256Hash.h"
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#import "NSString_extra.h"
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#define ONE_MB (1024 * 1024)
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@implementation SHA256TreeHash
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+ (NSData *)treeHashOfData:(NSData *)data {
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if ([data length] == 0) {
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return [SHA256Hash hashData:data];
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}
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NSMutableArray *hashes = [NSMutableArray array];
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const unsigned char *bytes = (const unsigned char *)[data bytes];
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NSUInteger length = [data length];
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NSUInteger index = 0;
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while (index < length) {
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NSUInteger toRead = (index + ONE_MB) > length ? (length - index) : ONE_MB;
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NSData *hash = [SHA256Hash hashBytes:(bytes + index) length:toRead];
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[hashes addObject:hash];
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index += toRead;
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}
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while ([hashes count] > 1) {
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NSMutableArray *condensed = [NSMutableArray array];
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for (NSUInteger index = 0; index < [hashes count] / 2; index++) {
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NSMutableData *combined = [NSMutableData dataWithData:[hashes objectAtIndex:(index * 2)]];
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[combined appendData:[hashes objectAtIndex:(index * 2 + 1)]];
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[condensed addObject:[SHA256Hash hashData:combined]];
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}
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if ([hashes count] % 2 == 1) {
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[condensed addObject:[hashes objectAtIndex:([hashes count] - 1)]];
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}
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[hashes setArray:condensed];
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}
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return [hashes objectAtIndex:0];
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}
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@end
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