zlib压缩和解压缩gzip格式字符串

#include
#include
#include
#include

#include

#define err(msg) perror(msg)

static int gzip_uncompress(char *bufin, int lenin, char *bufout, int lenout)
{
        z_stream d_stream;
        int result;

        memset(bufout, '\0', sizeof(bufout));
        d_stream.zalloc = NULL;
        d_stream.zfree  = NULL;
        d_stream.opaque = NULL;

        result = inflateInit2(&d_stream, MAX_WBITS + 16);
        d_stream.next_in   = bufin;
        d_stream.avail_in  = lenin;
        d_stream.next_out  = bufout;
        d_stream.avail_out = lenout;

        inflate(&d_stream, Z_SYNC_FLUSH);
        inflateEnd(&d_stream);
        return 0;
}

static int gzip_compress(char *bufin, int lenin, char *bufout, int lenout)
{
        z_stream d_stream;
        int result;

        memset(bufout, '\0', sizeof(lenout));
        d_stream.zalloc = NULL;
        d_stream.zfree  = NULL;
        d_stream.opaque = NULL;

        result = deflateInit2(&d_stream, Z_DEFAULT_COMPRESSION,
                                Z_DEFLATED, MAX_WBITS + 16,
                                9, Z_DEFAULT_STRATEGY);
        if (result != Z_OK) {
                err("deflateInit2");
                goto out;
        }
        d_stream.next_in   = bufin;
        d_stream.avail_in  = lenin;
        d_stream.next_out  = bufout;
        d_stream.avail_out = lenout;

        deflate(&d_stream, Z_SYNC_FLUSH);
        deflateEnd(&d_stream);

        return d_stream.total_out;
out:
        return -1;
}

int main(void)
{
        int result;
        char bufin[] = "hello world";
        char bufout[1024];
        char bufout2[BUFSIZ];
        int lenout;

        lenout = gzip_compress(bufin, strlen(bufin), bufout, sizeof(bufout));
        gzip_uncompress(bufout, lenout, bufout2, sizeof(bufout2));
        printf("bufout2: %s\n", bufout2);

        return 0;
out:
        return -1;
}