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//
// NSData+ZlibAdditions.m
// Spike
//
// Created by Matt Mower on 18/02/2009.
// Copyright 2009 LucidMac Software. All rights reserved.
//
#import "NSData+ZlibAdditions.h"
#import "zlib.h"
@implementation NSData (NSData_ZlibAdditions)
- (NSData *)gzipInflate
{
if ([self length] == 0) return self;
unsigned full_length = [self length];
unsigned half_length = [self length] / 2;
NSMutableData *decompressed = [NSMutableData dataWithLength: full_length + half_length];
BOOL done = NO;
int status;
z_stream strm;
strm.next_in = (Bytef *)[self bytes];
strm.avail_in = [self length];
strm.total_out = 0;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
if (inflateInit2(&strm, (15+32)) != Z_OK) return nil;
while (!done)
{
// Make sure we have enough room 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;
}
- (NSData *)gzipDeflate
{
if ([self length] == 0) return self;
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.total_out = 0;
strm.next_in=(Bytef *)[self bytes];
strm.avail_in = [self length];
// Compresssion Levels:
// Z_NO_COMPRESSION
// Z_BEST_SPEED
// Z_BEST_COMPRESSION
// Z_DEFAULT_COMPRESSION
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])
[compressed increaseLengthBy: 16384];
strm.next_out = [compressed mutableBytes] + strm.total_out;
strm.avail_out = [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];
}
@end