Objective c 如何解压缩使用zlib压缩的NSString
我有一个Objective c 如何解压缩使用zlib压缩的NSString,objective-c,zlib,compression,Objective C,Zlib,Compression,我有一个NSString（例如enolycgsvgchvilseows1iopqbfzgb4），我从一个web服务器上获得，它只是一个使用zlib压缩的普通字符串。如何在Objective-C中解压？我发现了一些库，但它们只接受完整的文件，而不是简单的字符串。好的，根据上面的内容，您似乎不知道格式是什么，但它似乎是ZLibdeflate，Base64编码的。不知羞耻地抄袭其他StackOverflow答案，这里有一段代码可以解压您的数据： #import <Foundation/Found
NSStringenolycgsvgchvilseows1iopqbfzgb4zlibdeflate#import <Foundation/Foundation.h>
#import <zlib.h>
int main( int argc, const char * argv[] )
{
@autoreleasepool
{
NSLog( @"Starting..." );
NSString * base64String = @"eJwLycgsVgChvILSEoWS1IoSPQBFZgb4";
NSData * compressedData = [ [ NSData alloc ] initWithBase64EncodedString: base64String options: 0 ];
NSUInteger full_length = [ compressedData length ];
NSUInteger half_length = [ compressedData length ] / 2;
NSMutableData * decompressedData = [ NSMutableData dataWithLength: full_length + half_length ];
BOOL done = NO;
int status;
z_stream strm;
strm.next_in = ( Bytef * )[ compressedData bytes ];
strm.avail_in = ( unsigned int ) full_length;
strm.total_out = 0;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
if ( inflateInit2( &strm, ( 15 + 32 ) ) != Z_OK )
{
NSLog( @"Could not initialise ZLib" );
return EXIT_FAILURE;
}
while ( done == NO )
{
// Make sure we have enough room and reset the lengths.
if ( strm.total_out >= [ decompressedData length ] )
{
[ decompressedData increaseLengthBy: half_length ];
}
strm.next_out = [ decompressedData mutableBytes ] + strm.total_out;
strm.avail_out = ( unsigned int )( [ decompressedData 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 )
{
NSLog( @"Decompression failed with status %i", status );
break;
}
}
if ( inflateEnd( &strm ) != Z_OK )
{
NSLog( @"Could not complete decompression" );
return EXIT_FAILURE;
}
// Set real length.
if ( done )
{
[ decompressedData setLength: strm.total_out ];
NSString * string = [ [ NSString alloc ] initWithData: decompressedData
encoding: NSUTF8StringEncoding ];
NSLog( @"String: %@", string );
}
else
{
return EXIT_FAILURE;
}
}
NSLog( @"...Success" );
return EXIT_SUCCESS;
}
你需要确保你链接到ZLib。从XCode中项目的构建阶段部分，在“链接二进制文件与库”下，“+”按钮提供一个可搜索的弹出窗口；寻找“libz”。这可能在iOS上不存在；它存在于OSXSDK中；这超出了这个答案的范围，毫无疑问，如果您遇到问题，谷歌会迅速给出答案。好的，基于上述内容，您似乎不知道该格式是什么，但它似乎是ZLib
deflate#import <Foundation/Foundation.h>
#import <zlib.h>
int main( int argc, const char * argv[] )
{
@autoreleasepool
{
NSLog( @"Starting..." );
NSString * base64String = @"eJwLycgsVgChvILSEoWS1IoSPQBFZgb4";
NSData * compressedData = [ [ NSData alloc ] initWithBase64EncodedString: base64String options: 0 ];
NSUInteger full_length = [ compressedData length ];
NSUInteger half_length = [ compressedData length ] / 2;
NSMutableData * decompressedData = [ NSMutableData dataWithLength: full_length + half_length ];
BOOL done = NO;
int status;
z_stream strm;
strm.next_in = ( Bytef * )[ compressedData bytes ];
strm.avail_in = ( unsigned int ) full_length;
strm.total_out = 0;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
if ( inflateInit2( &strm, ( 15 + 32 ) ) != Z_OK )
{
NSLog( @"Could not initialise ZLib" );
return EXIT_FAILURE;
}
while ( done == NO )
{
// Make sure we have enough room and reset the lengths.
if ( strm.total_out >= [ decompressedData length ] )
{
[ decompressedData increaseLengthBy: half_length ];
}
strm.next_out = [ decompressedData mutableBytes ] + strm.total_out;
strm.avail_out = ( unsigned int )( [ decompressedData 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 )
{
NSLog( @"Decompression failed with status %i", status );
break;
}
}
if ( inflateEnd( &strm ) != Z_OK )
{
NSLog( @"Could not complete decompression" );
return EXIT_FAILURE;
}
// Set real length.
if ( done )
{
[ decompressedData setLength: strm.total_out ];
NSString * string = [ [ NSString alloc ] initWithData: decompressedData
encoding: NSUTF8StringEncoding ];
NSLog( @"String: %@", string );
}
else
{
return EXIT_FAILURE;
}
}
NSLog( @"...Success" );
return EXIT_SUCCESS;
}
你需要确保你链接到ZLib。从XCode中项目的构建阶段部分，在“链接二进制文件与库”下，“+”按钮提供一个可搜索的弹出窗口；寻找“libz”。这可能在iOS上不存在；它存在于OSXSDK中；这超出了这个答案的范围，如果您遇到问题，谷歌无疑会迅速给出答案。您所说的“压缩”是什么意思？所讨论的字符串不是二进制压缩的，因为它使用ASCII字符，但它看起来也不像Base64。您给出的示例使用了什么样的GLib方法以及原始输入字符串是什么？@Andrewodgkinson这里有一个示例网站展示了这一点：您可以输入文本来缩小或扩大现有文本。这个网站正确地解压了我从服务器API收到的文本，所以我想我只是好奇我会怎么做locally@AndrewHodgkinson类似地，这个站点将对deflate执行相同的操作。示例数据是用Base64编码的zlib（而不是“glib”）流。它解压缩为
，这是输入文本。，这是输入文本。