使用ZLib库压缩解压缩Demo

迷南。 2022-08-08 11:51 219阅读 0赞

头文件：

\#include "zlib.h"

编译：

需要加上 -lz

解压缩：

1.  \#define CHUNK 100000  
    
2.    
    
3.  int decodeZip(char \*source,int len,char \*\*dest)  
    
4.  \{   
    
5.  int ret;  
    
6.  unsigned have;  
    
7.  z\_stream strm;  
    
8.  unsigned char out\[CHUNK\];  
    
9.  int totalsize = 0;  
    
10.   
    
11. /\* allocate inflate state \*/  
    
12. strm.zalloc = Z\_NULL;  
    
13. strm.zfree = Z\_NULL;  
    
14. strm.opaque = Z\_NULL;  
    
15. strm.avail\_in = 0;  
    
16. strm.next\_in = Z\_NULL;  
    
17.   
    
18. ret = inflateInit2(&strm, 31);  
    
19.   
    
20. if (ret != Z\_OK)  
    
21. return ret;  
    
22.   
    
23. strm.avail\_in = len;  
    
24. strm.next\_in = (unsigned char\*)source;  
    
25.   
    
26. /\* run inflate() on input until output buffer not full \*/  
    
27. do \{   
    
28. strm.avail\_out = CHUNK;  
    
29. strm.next\_out = out;  
    
30. ret = inflate(&strm, Z\_NO\_FLUSH);  
    
31. switch (ret)  
    
32. \{   
    
33. case Z\_NEED\_DICT:  
    
34. ret = Z\_DATA\_ERROR; /\* and fall through \*/  
    
35. case Z\_DATA\_ERROR:  
    
36. case Z\_MEM\_ERROR:  
    
37. inflateEnd(&strm);  
    
38. return ret;  
    
39. \}  
    
40.   
    
41. have = CHUNK \- strm.avail\_out;  
    
42. totalsize \+= have;  
    
43. \*dest = (char\*)realloc(\*dest,totalsize);  
    
44. memcpy(\*dest \+ totalsize \- have,out,have);  
    
45. \} while (strm.avail\_out == 0);  
    
46.   
    
47. /\* clean up and return \*/  
    
48. inflateEnd(&strm);  
    
49. return ret == Z\_STREAM\_END ? Z\_OK : Z\_DATA\_ERROR;  
    
50. \}

压缩：

1.  \#define MaxLen 10000000
2.    
    
3.  /\*\*  
    
4.  \* 对内容进行压缩和编码工作  
    
5.  \*/  
    
6.  void encodeZip(const string &buffer, string& zipBuf, int& zipLen)  
    
7.  \{   
    
8.  unsigned char \_zipSrc\[MaxLen\];
9.  unsigned char \_zipDst\[MaxLen\];
10. unsigned char \_scBuffer\[MaxLen\];
11.   
    
12. //先对原始内容进行压缩工作  
    
13. unsigned int tmpLen = buffer.length();  
    
14. memcpy(\_zipSrc, buffer.c\_str(), tmpLen);
15. z\_stream c\_stream;  
    
16. c\_stream.zalloc = (alloc\_func)0;  
    
17. c\_stream.zfree = (free\_func)0;  
    
18. c\_stream.opaque = (voidpf)0;  
    
19. c\_stream.next\_in = (Bytef\*)\_zipSrc;  
    
20. c\_stream.avail\_in = tmpLen;  
    
21. c\_stream.next\_out = (Bytef\*)\_zipDst;  
    
22. c\_stream.avail\_out = (unsigned int)MaxLen;  
    
23. int ret = deflateInit2(&c\_stream, Z\_DEFAULT\_COMPRESSION,Z\_DEFLATED, 31,8, Z\_DEFAULT\_STRATEGY);  
    
24. if(ret != Z\_OK)  
    
25. \{   
    
26. cout <<"|"<<"deflateInit2 error "<<endl;  
    
27. return;  
    
28. \}  
    
29. ret = deflate(&c\_stream, Z\_FINISH);  
    
30. if (ret != Z\_STREAM\_END)  
    
31. \{   
    
32. deflateEnd(&c\_stream);  
    
33. cout <<"|"<<"ret != Z\_STREAM\_END err="<< ret <<endl;  
    
34. return;  
    
35. \}  
    
36. 
37.  zipLen = c\_stream.total\_out;  
    
38. ret = deflateEnd(&c\_stream);  
    
39. if (ret != Z\_OK)  
    
40. \{   
    
41. cout <<"|"<<"deflateEnd error "<<endl;  
    
42. return;  
    
43. \}  
    
44. //压缩完毕进行返回包组织  
    
45. memcpy(\_scBuffer, \_zipDst, zipLen);
46. zipBuf = string(\_scBuffer, zipLen);  
    
47. return;
48. \}