XADMaster/XADLZMAAloneParser.m

106 lines
3.7 KiB
Objective-C

/*
* XADLZMAAloneParser.m
*
* Copyright (c) 2017-present, MacPaw Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
#import "XADLZMAAloneParser.h"
#import "XADLZMAHandle.h"
@implementation XADLZMAAloneParser
+(int)requiredHeaderSize { return 13; }
+(BOOL)recognizeFileWithHandle:(CSHandle *)handle firstBytes:(NSData *)data name:(NSString *)name;
{
// Geez, put some magic bytes in your file formats, people!
const uint8_t *bytes=[data bytes];
int length=[data length];
if(length<13) return NO;
// Reject invalid settings bytes
if(bytes[0]>=9*5*5) return NO;
// Accept only power-of-two or three-times-power-of-two dictionary sizes
uint32_t dictsize=CSUInt32LE(&bytes[1]);
uint32_t div3=dictsize*0xaaaaaaab; // Multiplicative inverse of three
if((dictsize&dictsize-1)!=0 && (div3&div3-1)!=0) return NO;
// Reject all-0 size fields.
if(CSUInt64LE(&bytes[5])==0) return NO;
// Reject huge sizes
if(!(bytes[11]==0x00&&bytes[12]==0x00)&&!(bytes[11]==0xff&&bytes[12]==0xff)) return NO;
return YES;
// if([name rangeOfString:@".lzma" options:NSAnchoredSearch|NSCaseInsensitiveSearch|NSBackwardsSearch].location!=NSNotFound) return YES;
// if([name rangeOfString:@".tlz" options:NSAnchoredSearch|NSCaseInsensitiveSearch|NSBackwardsSearch].location!=NSNotFound) return YES;
// return NO;
}
-(void)parse
{
CSHandle *handle=[self handle];
NSString *name=[self name];
NSString *extension=[[name pathExtension] lowercaseString];
NSString *contentname;
if([extension isEqual:@"tlz"]) contentname=[[name stringByDeletingPathExtension] stringByAppendingPathExtension:@"tar"];
else contentname=[name stringByDeletingPathExtension];
NSData *props=[handle readDataOfLength:5];
// TODO: set no filename flag
NSMutableDictionary *dict=[NSMutableDictionary dictionaryWithObjectsAndKeys:
[self XADPathWithUnseparatedString:contentname],XADFileNameKey,
[self XADStringWithString:@"LZMA"],XADCompressionNameKey,
props,@"LZMAProperties",
nil];
if([contentname matchedByPattern:@"\\.(tar|cpio|pax|warc)$" options:REG_ICASE])
[dict setObject:[NSNumber numberWithBool:YES] forKey:XADIsArchiveKey];
uint64_t size=[handle readUInt64LE];
if(size!=0xffffffffffffffff)
[dict setObject:[NSNumber numberWithUnsignedLongLong:size] forKey:XADFileSizeKey];
off_t filesize=[[self handle] fileSize];
if(filesize!=CSHandleMaxLength)
[dict setObject:[NSNumber numberWithUnsignedLongLong:filesize-13] forKey:XADCompressedSizeKey];
[self addEntryWithDictionary:dict];
}
-(CSHandle *)handleForEntryWithDictionary:(NSDictionary *)dictionary wantChecksum:(BOOL)checksum
{
CSHandle *handle=[self handle];
NSNumber *size=[dictionary objectForKey:XADFileSizeKey];
[handle seekToFileOffset:13];
if(size) return [[[XADLZMAHandle alloc] initWithHandle:handle length:[size unsignedLongLongValue]
propertyData:[dictionary objectForKey:@"LZMAProperties"]] autorelease];
else return [[[XADLZMAHandle alloc] initWithHandle:handle
propertyData:[dictionary objectForKey:@"LZMAProperties"]] autorelease];
}
-(NSString *)formatName { return @"LZMA_Alone"; }
@end