IOS学习之压缩和解压工具使用

//ZLib压缩
+ (NSData *)zlibCompressData:(NSData *)sourceData {

NSUInteger sourceDataLength = [sourceData length];

if (sourceDataLength == 0) {
return sourceData;
}

z_stream stream;
memset(&stream, 0, sizeof(z_stream));

stream.next_in = (Bytef *)[sourceData bytes];
stream.avail_in = (uInt)sourceDataLength;
stream.total_out = 0;
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;

if (deflateInit(&stream, Z_DEFAULT_COMPRESSION) != Z_OK) {
return nil;
}

const int KBufLen = 1024;
Byte buf[KBufLen];
memset(buf, 0, KBufLen * sizeof(Byte));

BOOL isCompressOK = NO;

NSMutableData *compressedData = [NSMutableData dataWithLength:sourceDataLength];
[compressedData setData:nil]; //必须得加

int res = 0;

while (stream.avail_out == 0) {

memset(buf, 0, KBufLen * sizeof(Byte));
stream.avail_out = KBufLen;
stream.next_out = buf;

res = deflate(&stream, Z_FINISH);
;

switch (res) {
case Z_NEED_DICT:
case Z_DATA_ERROR:
case Z_MEM_ERROR:
case Z_STREAM_ERROR:
case Z_BUF_ERROR: {
isCompressOK = NO;
break;
}

default: {
if (res == Z_OK || res == Z_STREAM_END) {
const int dataLen = KBufLen - stream.avail_out;
isCompressOK = YES;

if (dataLen > 0) {
[compressedData appendBytes:buf length:dataLen];
}
}

break;
}
}

if (!isCompressOK) {
break;
}
}

res = deflateEnd(&stream);
if (res != Z_OK) {
return nil;
}

if (isCompressOK) {
return compressedData;
} else {
return nil;
}
}

//ZLib解压
+ (NSData *)zlibUncompressData:(NSData *)sourceData {

NSUInteger sourceDataLength = [sourceData length];

if (sourceDataLength == 0) {
return sourceData;
}

z_stream stream;
memset(&stream, 0, sizeof(z_stream));

stream.next_in = (Bytef *)[sourceData bytes];
stream.avail_in = (uInt)sourceDataLength;
stream.total_out = 0;
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;

int res = inflateInit(&stream);
// inflateInit2(&strm, (15+32))

if (res != Z_OK) {
return nil;
}

const int KBufLen = 1024;
Byte buf[KBufLen];
memset(buf, 0, KBufLen * sizeof(Byte));

BOOL isUncompressOK = NO;

NSMutableData *decompressed = [NSMutableData dataWithLength:sourceDataLength];
[decompressed setData:nil]; //必须得加

while (stream.avail_out == 0) {

memset(buf, 0, KBufLen * sizeof(Byte));
stream.avail_out = KBufLen;
stream.next_out = buf;

res = inflate(&stream, Z_NO_FLUSH);

switch (res) {
case Z_NEED_DICT:
case Z_DATA_ERROR:
case Z_MEM_ERROR:
case Z_STREAM_ERROR:
case Z_BUF_ERROR: {
isUncompressOK = NO;
break;
}

default: {
if (res == Z_OK || res == Z_STREAM_END) {
const int dataLen = KBufLen - stream.avail_out;
isUncompressOK = YES;

if (dataLen > 0) {
[decompressed appendBytes:buf length:dataLen];
}
}

break;
}
}

if (!isUncompressOK) {
break;
}
}

if (inflateEnd(&stream) != Z_OK) {
return nil;
}

if (isUncompressOK) {
return decompressed;
} else {
return nil;
}
}

//GZip压缩
+ (NSData *)gzipCompress:(NSData *)sourceData {

NSUInteger sourceDataLength = [sourceData length];

if (sourceDataLength == 0) {
return sourceData;
}

z_stream stream;
memset(&stream, 0, sizeof(z_stream));

stream.next_in = (Bytef *)[sourceData bytes];
stream.avail_in = (uInt)sourceDataLength;
stream.total_out = 0;
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;

//只有设置为MAX_WBITS + 16才能在在压缩文本中带header和trailer
if (deflateInit2(&stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, MAX_WBITS + 16,
8, Z_DEFAULT_STRATEGY) != Z_OK) {
return nil;
}

const int KBufLen = 1024;
Byte buf[KBufLen];
memset(buf, 0, KBufLen * sizeof(Byte));

BOOL isCompressOK = NO;

NSMutableData *compressedData =
[NSMutableData dataWithLength:sourceDataLength];
[compressedData setData:nil]; //必须得加

int res = 0;

while (stream.avail_out == 0) {

memset(buf, 0, KBufLen * sizeof(Byte));
stream.avail_out = KBufLen;
stream.next_out = buf;

res = deflate(&stream, Z_FINISH);
;

switch (res) {
case Z_NEED_DICT:
case Z_DATA_ERROR:
case Z_MEM_ERROR:
case Z_STREAM_ERROR:
case Z_BUF_ERROR: {
isCompressOK = NO;
break;
}

default: {
if (res == Z_OK || res == Z_STREAM_END) {
const int dataLen = KBufLen - stream.avail_out;
isCompressOK = YES;

if (dataLen > 0) {
[compressedData appendBytes:buf length:dataLen];
}
}

break;
}
}

if (!isCompressOK) {
break;
}
}

res = deflateEnd(&stream);
if (res != Z_OK) {
return nil;
}

if (isCompressOK) {
return compressedData;
} else {
return nil;
}
}

//GZip解压
+ (NSData *)gzipUncompress:(NSData *)sourceData {

NSUInteger sourceDataLength = [sourceData length];

if (sourceDataLength == 0) {
return sourceData;
}

z_stream stream;
memset(&stream, 0, sizeof(z_stream));

stream.next_in = (Bytef *)[sourceData bytes];
stream.avail_in = (uInt)sourceDataLength;
stream.total_out = 0;
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;

int res = inflateInit2(&stream, MAX_WBITS + 16);
// inflateInit2(&strm, (15+32))
//只有设置为MAX_WBITS + 16才能在解压带header和trailer的文本

if (res != Z_OK) {
return nil;
}

const int KBufLen = 1024;
Byte buf[KBufLen];
memset(buf, 0, KBufLen * sizeof(Byte));

BOOL isUncompressOK = NO;

NSMutableData *decompressed = [NSMutableData dataWithLength:sourceDataLength];
[decompressed setData:nil]; //必须得加

while (stream.avail_out == 0) {

memset(buf, 0, KBufLen * sizeof(Byte));
stream.avail_out = KBufLen;
stream.next_out = buf;

res = inflate(&stream, Z_SYNC_FLUSH);

switch (res) {
case Z_NEED_DICT:
case Z_DATA_ERROR:
case Z_MEM_ERROR:
case Z_STREAM_ERROR:
case Z_BUF_ERROR: {
isUncompressOK = NO;
break;
}

default: {
if (res == Z_OK || res == Z_STREAM_END) {
const int dataLen = KBufLen - stream.avail_out;
isUncompressOK = YES;

if (dataLen > 0) {
[decompressed appendBytes:buf length:dataLen];
}
}

break;
}
}

if (!isUncompressOK) {
break;
}
}

if (inflateEnd(&stream) != Z_OK) {
return nil;
}

if (isUncompressOK) {
return decompressed;
} else {
return nil;
}
}