XADMaster/XADRARInputHandle.m

107 lines
2.8 KiB
Objective-C

/*
* XADRARInputHandle.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 "XADRARInputHandle.h"
#import "XADException.h"
#import "CRC.h"
@implementation XADRARInputHandle
-(id)initWithHandle:(CSHandle *)handle parts:(NSArray *)partarray
{
off_t totallength=0;
NSEnumerator *enumerator=[partarray objectEnumerator];
NSDictionary *dict;
while((dict=[enumerator nextObject]))
{
totallength+=[[dict objectForKey:@"InputLength"] longLongValue];
}
if((self=[super initWithParentHandle:handle length:totallength]))
{
parts=[partarray retain];
}
return self;
}
-(void)dealloc
{
[parts release];
[super dealloc];
}
-(void)resetStream
{
part=0;
partend=0;
[self startNextPart];
}
-(int)streamAtMost:(int)num toBuffer:(void *)buffer
{
uint8_t *bytebuf=buffer;
int total=0;
while(total<num)
{
if(streampos+total>=partend) [self startNextPart];
int numbytes=num-total;
if(streampos+total+numbytes>=partend) numbytes=(int)(partend-streampos-total);
[parent readBytes:numbytes toBuffer:&bytebuf[total]];
crc=XADCalculateCRCFast(crc,&bytebuf[total],numbytes,XADCRCTable_sliced16_edb88320);
total+=numbytes;
// RAR CRCs are for compressed and encrypted data for all parts
// except the last one, where it is for descrypted and uncompressed data.
// Check the CRC on all parts but the last.
// TODO: Add blake2sp
if(streampos+total>=partend) // If at the end a block,
if(partend!=streamlength) // but not the end of the file,
if(correctcrc!=0xffffffff) // and there is a correct CRC available,
if(~crc!=correctcrc) [XADException raiseChecksumException]; // check it.
}
return num;
}
-(void)startNextPart
{
if(part>=[parts count]) [XADException raiseInputException];
NSDictionary *dict=[parts objectAtIndex:part];
part++;
off_t offset=[[dict objectForKey:@"Offset"] longLongValue];
off_t length=[[dict objectForKey:@"InputLength"] longLongValue];
[parent seekToFileOffset:offset];
partend+=length;
crc=0xffffffff;
NSNumber *crcnum=[dict objectForKey:@"CRC32"];
if(crcnum) correctcrc=[crcnum unsignedIntValue];
else correctcrc=0xffffffff;
}
@end