L006Linux和androidNDK之使用zlib 在解压缩数据
看一个一个http头
GET /fly-fish/p/4932314.html HTTP/1.1
Host: 42.121.252.58
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:48.0) Gecko/20100101 Firefox/48.0
Accept: text/plain, */*; q=0.01
Accept-Language: zh-CN,zh;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
这个头，是浏览器发给服务器，告诉web服务器我这儿支持gzip deflate，你如果支持gzip deflate 可发gzip deflate 压缩格式的数据过来，省传输时间，省带宽。
还是用代码说话吧：
//在内存中压缩数据，解压缩数据。
int gZipcompress( char *src, int srcLen,char *denst, int *denstLen)
{
int ret, flush;
unsigned have;
z_stream strm;
unsigned char out[CHUNK];
/* allocate deflate state */
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
ret = deflateInit(&strm, Z_DEFAULT_COMPRESSION);
if (ret != Z_OK)
return ret;
/* compress until end of file */
int times=0;
int pos=0;
do {
strm.avail_in = ((times+1)*CHUNK>srcLen)?(srcLen%CHUNK):CHUNK;
flush = ((times+1)*CHUNK>=srcLen) ? Z_FINISH : Z_NO_FLUSH;
T("%2d,%4d,%4d\n",times,strm.avail_in,flush);
strm.next_in = src+times*CHUNK;
/* run deflate() on input until output buffer not full, finish
compression if all of source has been read in */
do {
strm.avail_out = CHUNK;
strm.next_out = out;
ret = deflate(&strm, flush); /* no bad return value */
assert(ret != Z_STREAM_ERROR); /* state not clobbered */
have = CHUNK - strm.avail_out;
memcpy(denst+pos,out,have);
pos += have;
} while (strm.avail_out == 0);
assert(strm.avail_in == 0); /* all input will be used */
times++;
/* done when last data in file processed */
} while (flush != Z_FINISH);
assert(ret == Z_STREAM_END); /* stream will be complete */
/* clean up and return */
(void)deflateEnd(&strm);
*denstLen = pos;
return Z_OK;
}
int gZipuncompress( char *src, int srcLen,char *denst, int *denstLen)
{
int ret;
unsigned have;
z_stream strm;
//unsigned char in[CHUNK];
unsigned char out[CHUNK];
/* allocate inflate state */
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = 0;
strm.next_in = Z_NULL;
ret = inflateInit(&strm);
if (ret != Z_OK)
return ret;
int times=0;
int pos=0;
/* decompress until deflate stream ends or end of file */
do {
strm.avail_in = ((times+1)*CHUNK>srcLen)?(srcLen%CHUNK):CHUNK;
T("%2d,%4d\n",times,strm.avail_in);
if (strm.avail_in == 0)
break;
strm.next_in = src+times*CHUNK;;
/* run inflate() on input until output buffer not full */
do {
strm.avail_out = CHUNK;
strm.next_out = out;
ret = inflate(&strm, Z_NO_FLUSH);
assert(ret != Z_STREAM_ERROR); /* state not clobbered */
switch (ret) {
case Z_NEED_DICT:
ret = Z_DATA_ERROR; /* and fall through */
case Z_DATA_ERROR:
case Z_MEM_ERROR:
(void)inflateEnd(&strm);
return ret;
}
have = CHUNK - strm.avail_out;
memcpy(denst+pos,out,have);
pos += have;
} while (strm.avail_out == 0);
times++;
/* done when inflate() says it's done */
} while (ret != Z_STREAM_END);
/* clean up and return */
(void)inflateEnd(&strm);
*denstLen = pos;
return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}
