iOS compression decompression

#import <zlib.h>

Compression

-(NSData *) Compressdata: (NSData *) uncompresseddata{if ([uncompresseddata length] = = 0) return uncompresseddata;        Z_stream STRM;    Strm.zalloc = Z_null;    Strm.zfree = Z_null;    Strm.opaque = Z_null;    strm.total_out = 0;    strm.next_in= (BYTEF *) [uncompresseddata bytes];        strm.avail_in = (unsigned int) [uncompresseddata length];        if (DeflateInit2 (&STRM, Z_default_compression, z_deflated, (15+16), 8, z_default_strategy)! = Z_OK) return nil;  Nsmutabledata *compressed = [Nsmutabledata datawithlength:16384]; 16K chunks for expansion do {if (strm.total_out >= [Compressed length]) [Compresse                D increaselengthby:16384];        Strm.next_out = [Compressed mutablebytes] + strm.total_out;                Strm.avail_out = (unsigned int) ([compressed length]-strm.total_out);            Deflate (&STRM, z_finish);        } while (strm.avail_out = = 0);        Deflateend (&STRM); [Compressed SETLENGTH:STRM.total_out]; return [NSData datawithdata:compressed];}

Unzip

-(NSData *) Uncompresszippeddata: (NSData *) Compresseddata {if ([compresseddata length] = = 0) return Compressedd         Ata         unsigned full_length = [compresseddata length];        unsigned half_length = [Compresseddata length]/2;        Nsmutabledata *decompressed = [Nsmutabledata datawithlength:full_length + half_length];        BOOL done = NO;        int status;        Z_stream STRM;        strm.next_in = (BYTEF *) [compresseddata bytes];        strm.avail_in = [Compresseddata length];        strm.total_out = 0;        Strm.zalloc = Z_null;        Strm.zfree = Z_null;        if (InflateInit2 (&STRM, (15+32)) = Z_OK) return nil;            while (!done) {//Do sure we have enough and reset the lengths.            if (strm.total_out >= [decompressed length]) {[decompressed increaselengthby:half_length];            } strm.next_out = [decompressed mutablebytes] + strm.total_out; Strm.avail_out = [decompressed length]-strm.total_out;            Inflate another chunk.            Status = Inflate (&STRM, Z_sync_flush);            if (status = = Z_stream_end) {done = YES;            } else if (status! = Z_OK) {break;        }} if (Inflateend (&STRM)! = Z_OK) return nil;        Set real length.            if (done) {[decompressed setLength:strm.total_out];        return [NSData datawithdata:decompressed];        } else {return nil;   }    }

iOS compression decompression