iOS zlib 压缩解压

最近需要压缩解压问题，查找了一些资料

ZipArchive库,实现对文件的压缩解压缩，网上有资源，可以下载研究一下，对于一些冗余代码可以修改一下。资源链接http://download.csdn.net/detail/deskisme/4440505
iOS zlib文件主要有deflate算法压缩

3.在我所需要的项目中需要解压缩从服务器中请求到的NSData数据(根据自己的情况选择)，所有创建了一个NSData类extension 实现对请求到的data的解压缩，此demo代码中有压缩和解压缩两种方法。
可以比较一下zlib 和gzip的区别，压缩率等。(PS在我们查询资源的时候，对于一些东西，更重要的要自己验证一下。fighting^_^)


#import <Foundation/Foundation.h>@interface NSData (STUnzipArchive)
// ZLIB
- (NSData *) zlibInflate;
- (NSData *) zlibDeflate;// GZIP
- (NSData *) gzipInflate;
- (NSData *) gzipDeflate;@end#import "NSData+STUnzipArchive.h"
#include <zlib.h>
@implementation NSData (STUnzipArchive)- (NSData *)zlibInflate
{if ([self length] == 0) return self;NSUInteger full_length = [self length];NSUInteger 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 = (unsigned)[self length];strm.total_out = 0;strm.zalloc = Z_NULL;strm.zfree = Z_NULL;if (inflateInit (&strm) != 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 = (uint)([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 *)zlibDeflate
{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 = (uint)[self length];// Compresssion Levels://   Z_NO_COMPRESSION//   Z_BEST_SPEED//   Z_BEST_COMPRESSION//   Z_DEFAULT_COMPRESSIONif (deflateInit(&strm, Z_DEFAULT_COMPRESSION) != Z_OK) return nil;NSMutableData *compressed = [NSMutableData dataWithLength:16384];  // 16K chuncks for expansiondo {if (strm.total_out >= [compressed length])[compressed increaseLengthBy: 16384];strm.next_out = [compressed mutableBytes] + strm.total_out;strm.avail_out = (uint)([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];
}- (NSData *)gzipInflate
{if ([self length] == 0) return self;NSInteger full_length = [self length];NSInteger 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 = (uint)[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 = (uint)([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 = (uint)[self length];// Compresssion Levels://   Z_NO_COMPRESSION//   Z_BEST_SPEED//   Z_BEST_COMPRESSION//   Z_DEFAULT_COMPRESSIONif (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 expansiondo {if (strm.total_out >= [compressed length])[compressed increaseLengthBy: 16384];strm.next_out = [compressed mutableBytes] + strm.total_out;strm.avail_out = (uint)([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

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iOS zlib 压缩解压

最近需要压缩解压问题，查找了一些资料

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