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#import "CSBzip2Handle.h"
NSString *CSBzip2Exception=@"CSBzip2Exception";
@implementation CSBzip2Handle
+(CSBzip2Handle *)bzip2HandleWithHandle:(CSHandle *)handle
{
return [[[self alloc] initWithHandle:handle length:CSHandleMaxLength name:[handle name]] autorelease];
}
+(CSBzip2Handle *)bzip2HandleWithHandle:(CSHandle *)handle length:(off_t)length
{
return [[[self alloc] initWithHandle:handle length:length name:[handle name]] autorelease];
}
-(id)initWithHandle:(CSHandle *)handle length:(off_t)length name:(NSString *)descname
{
if((self=[super initWithName:descname]))
{
parent=[handle retain];
startoffs=[parent offsetInFile];
inited=NO;
checksumcorrect=YES;
}
return self;
}
-(void)dealloc
{
if(inited) BZ2_bzDecompressEnd(&bzs);
[parent release];
[super dealloc];
}
-(void)resetStream
{
[parent seekToFileOffset:startoffs];
if(inited) BZ2_bzDecompressEnd(&bzs);
memset(&bzs,0,sizeof(bzs));
BZ2_bzDecompressInit(&bzs,0,0);
checksumcorrect=YES;
}
-(int)streamAtMost:(int)num toBuffer:(void *)buffer
{
bzs.next_out=buffer;
bzs.avail_out=num;
while(bzs.avail_out)
{
if(!bzs.avail_in)
{
bzs.avail_in=[parent readAtMost:sizeof(inbuffer) toBuffer:inbuffer];
bzs.next_in=(void *)inbuffer;
if(!bzs.avail_in) [parent _raiseEOF];
}
int err=BZ2_bzDecompress(&bzs);
if(err==BZ_STREAM_END)
{
// Attempt to find another concaternated bzip2 stream.
// Move any remaining data to start of buffer.
memmove(inbuffer,bzs.next_in,bzs.avail_in);
bzs.next_in=(void *)inbuffer;
// Fill up buffer.
int spaceleft=sizeof(inbuffer)-bzs.avail_in;
int more=[parent readAtMost:spaceleft toBuffer:inbuffer+bzs.avail_in];
bzs.avail_in+=more;
// Check for another stream header.
if(bzs.avail_in<20||inbuffer[0]!='B'||inbuffer[1]!='Z'||inbuffer[2]!='h'
||inbuffer[3]<'0'||inbuffer[3]>'9'||inbuffer[4]!=0x31||inbuffer[5]!=0x41
||inbuffer[6]!=0x59||inbuffer[7]!=0x26||inbuffer[8]!=0x53||inbuffer[9]!=0x59)
{
// No other stream available, stop.
[self endStream];
break;
}
BZ2_bzDecompressEnd(&bzs);
BZ2_bzDecompressInit(&bzs,0,0);
}
else if(err!=BZ_OK)
{
if(err==BZ_DATA_ERROR) checksumcorrect=NO;
[self _raiseBzip2:err];
}
}
return num-bzs.avail_out;
}
-(BOOL)hasChecksum { return YES; }
-(BOOL)isChecksumCorrect { return checksumcorrect; }
-(void)_raiseBzip2:(int)error
{
[NSException raise:CSBzip2Exception
format:@"Bzlib error while attepting to read from \"%@\": %d.",name,error];
}
@end
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