Click here to Skip to main content
Click here to Skip to main content
Add your own
alternative version

Remote Control PCs

, 20 Sep 2013
Two projects that work together to remote control PCs across a LAN.
/* example.c -- usage example of the zlib compression library
 * Copyright (C) 1995-2004 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/* @(#) $Id$ */

#include <stdio.h>
#include "zlib.h"
#ifdef STDC
#  include <string.h>
#  include <stdlib.h>
#endif

#if defined(VMS) || defined(RISCOS)
#  define TESTFILE "foo-gz"
#else
#  define TESTFILE "foo.gz"
#endif

#define CHECK_ERR(err, msg) { \
    if (err != Z_OK) { \
        fprintf(stderr, "%s error: %d\n", msg, err); \
        exit(1); \
    } \
}

const char hello[] = "hello, hello!";
/* "hello world" would be more standard, but the repeated "hello"
 * stresses the compression code better, sorry...
 */

const char dictionary[] = "hello";
uLong dictId; /* Adler32 value of the dictionary */

void test_compress      OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
void test_gzio          OF((const char *fname,
                            Byte *uncompr, uLong uncomprLen));
void test_deflate       OF((Byte *compr, uLong comprLen));
void test_inflate       OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
void test_large_deflate OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
void test_large_inflate OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
void test_flush         OF((Byte *compr, uLong *comprLen));
void test_sync          OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
void test_dict_deflate  OF((Byte *compr, uLong comprLen));
void test_dict_inflate  OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
int  main               OF((int argc, char *argv[]));

/* ===========================================================================
 * Test compress() and uncompress()
 */
void test_compress(compr, comprLen, uncompr, uncomprLen)
    Byte *compr, *uncompr;
    uLong comprLen, uncomprLen;
{
    int err;
    uLong len = (uLong)strlen(hello)+1;

    err = compress(compr, &comprLen, (const Bytef*)hello, len);
    CHECK_ERR(err, "compress");

    strcpy_s((char*)uncompr, uncomprLen, "garbage");

    err = uncompress(uncompr, &uncomprLen, compr, comprLen);
    CHECK_ERR(err, "uncompress");

    if (strcmp((char*)uncompr, hello)) {
        fprintf(stderr, "bad uncompress\n");
        exit(1);
    } else {
        printf("uncompress(): %s\n", (char *)uncompr);
    }
}

/* ===========================================================================
 * Test read/write of .gz files
 */
void test_gzio(fname, uncompr, uncomprLen)
    const char *fname; /* compressed file name */
    Byte *uncompr;
    uLong uncomprLen;
{
#ifdef NO_GZCOMPRESS
    fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n");
#else
    int err;
    int len = (int)strlen(hello)+1;
    gzFile file;
    z_off_t pos;

    file = gzopen(fname, "wb");
    if (file == NULL) {
        fprintf(stderr, "gzopen error\n");
        exit(1);
    }
    gzputc(file, 'h');
    if (gzputs(file, "ello") != 4) {
        fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err));
        exit(1);
    }
    if (gzprintf(file, ", %s!", "hello") != 8) {
        fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err));
        exit(1);
    }
    gzseek(file, 1L, SEEK_CUR); /* add one zero byte */
    gzclose(file);

    file = gzopen(fname, "rb");
    if (file == NULL) {
        fprintf(stderr, "gzopen error\n");
        exit(1);
    }
    strcpy_s((char*)uncompr, uncomprLen, "garbage");

    if (gzread(file, uncompr, (unsigned)uncomprLen) != len) {
        fprintf(stderr, "gzread err: %s\n", gzerror(file, &err));
        exit(1);
    }
    if (strcmp((char*)uncompr, hello)) {
        fprintf(stderr, "bad gzread: %s\n", (char*)uncompr);
        exit(1);
    } else {
        printf("gzread(): %s\n", (char*)uncompr);
    }

    pos = gzseek(file, -8L, SEEK_CUR);
    if (pos != 6 || gztell(file) != pos) {
        fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n",
                (long)pos, (long)gztell(file));
        exit(1);
    }

    if (gzgetc(file) != ' ') {
        fprintf(stderr, "gzgetc error\n");
        exit(1);
    }

    if (gzungetc(' ', file) != ' ') {
        fprintf(stderr, "gzungetc error\n");
        exit(1);
    }

    gzgets(file, (char*)uncompr, (int)uncomprLen);
    if (strlen((char*)uncompr) != 7) { /* " hello!" */
        fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
        exit(1);
    }
    if (strcmp((char*)uncompr, hello + 6)) {
        fprintf(stderr, "bad gzgets after gzseek\n");
        exit(1);
    } else {
        printf("gzgets() after gzseek: %s\n", (char*)uncompr);
    }

    gzclose(file);
#endif
}

/* ===========================================================================
 * Test deflate() with small buffers
 */
void test_deflate(compr, comprLen)
    Byte *compr;
    uLong comprLen;
{
    z_stream c_stream; /* compression stream */
    int err;
    uLong len = (uLong)strlen(hello)+1;

    c_stream.zalloc = (alloc_func)0;
    c_stream.zfree = (free_func)0;
    c_stream.opaque = (voidpf)0;

    err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
    CHECK_ERR(err, "deflateInit");

    c_stream.next_in  = (Bytef*)hello;
    c_stream.next_out = compr;

    while (c_stream.total_in != len && c_stream.total_out < comprLen) {
        c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */
        err = deflate(&c_stream, Z_NO_FLUSH);
        CHECK_ERR(err, "deflate");
    }
    /* Finish the stream, still forcing small buffers: */
    for (;;) {
        c_stream.avail_out = 1;
        err = deflate(&c_stream, Z_FINISH);
        if (err == Z_STREAM_END) break;
        CHECK_ERR(err, "deflate");
    }

    err = deflateEnd(&c_stream);
    CHECK_ERR(err, "deflateEnd");
}

/* ===========================================================================
 * Test inflate() with small buffers
 */
void test_inflate(compr, comprLen, uncompr, uncomprLen)
    Byte *compr, *uncompr;
    uLong comprLen, uncomprLen;
{
    int err;
    z_stream d_stream; /* decompression stream */

    strcpy_s((char*)uncompr, uncomprLen, "garbage");

    d_stream.zalloc = (alloc_func)0;
    d_stream.zfree = (free_func)0;
    d_stream.opaque = (voidpf)0;

    d_stream.next_in  = compr;
    d_stream.avail_in = 0;
    d_stream.next_out = uncompr;

    err = inflateInit(&d_stream);
    CHECK_ERR(err, "inflateInit");

    while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {
        d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */
        err = inflate(&d_stream, Z_NO_FLUSH);
        if (err == Z_STREAM_END) break;
        CHECK_ERR(err, "inflate");
    }

    err = inflateEnd(&d_stream);
    CHECK_ERR(err, "inflateEnd");

    if (strcmp((char*)uncompr, hello)) {
        fprintf(stderr, "bad inflate\n");
        exit(1);
    } else {
        printf("inflate(): %s\n", (char *)uncompr);
    }
}

/* ===========================================================================
 * Test deflate() with large buffers and dynamic change of compression level
 */
void test_large_deflate(compr, comprLen, uncompr, uncomprLen)
    Byte *compr, *uncompr;
    uLong comprLen, uncomprLen;
{
    z_stream c_stream; /* compression stream */
    int err;

    c_stream.zalloc = (alloc_func)0;
    c_stream.zfree = (free_func)0;
    c_stream.opaque = (voidpf)0;

    err = deflateInit(&c_stream, Z_BEST_SPEED);
    CHECK_ERR(err, "deflateInit");

    c_stream.next_out = compr;
    c_stream.avail_out = (uInt)comprLen;

    /* At this point, uncompr is still mostly zeroes, so it should compress
     * very well:
     */
    c_stream.next_in = uncompr;
    c_stream.avail_in = (uInt)uncomprLen;
    err = deflate(&c_stream, Z_NO_FLUSH);
    CHECK_ERR(err, "deflate");
    if (c_stream.avail_in != 0) {
        fprintf(stderr, "deflate not greedy\n");
        exit(1);
    }

    /* Feed in already compressed data and switch to no compression: */
    deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);
    c_stream.next_in = compr;
    c_stream.avail_in = (uInt)comprLen/2;
    err = deflate(&c_stream, Z_NO_FLUSH);
    CHECK_ERR(err, "deflate");

    /* Switch back to compressing mode: */
    deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED);
    c_stream.next_in = uncompr;
    c_stream.avail_in = (uInt)uncomprLen;
    err = deflate(&c_stream, Z_NO_FLUSH);
    CHECK_ERR(err, "deflate");

    err = deflate(&c_stream, Z_FINISH);
    if (err != Z_STREAM_END) {
        fprintf(stderr, "deflate should report Z_STREAM_END\n");
        exit(1);
    }
    err = deflateEnd(&c_stream);
    CHECK_ERR(err, "deflateEnd");
}

/* ===========================================================================
 * Test inflate() with large buffers
 */
void test_large_inflate(compr, comprLen, uncompr, uncomprLen)
    Byte *compr, *uncompr;
    uLong comprLen, uncomprLen;
{
    int err;
    z_stream d_stream; /* decompression stream */

    strcpy_s((char*)uncompr, uncomprLen, "garbage");

    d_stream.zalloc = (alloc_func)0;
    d_stream.zfree = (free_func)0;
    d_stream.opaque = (voidpf)0;

    d_stream.next_in  = compr;
    d_stream.avail_in = (uInt)comprLen;

    err = inflateInit(&d_stream);
    CHECK_ERR(err, "inflateInit");

    for (;;) {
        d_stream.next_out = uncompr;            /* discard the output */
        d_stream.avail_out = (uInt)uncomprLen;
        err = inflate(&d_stream, Z_NO_FLUSH);
        if (err == Z_STREAM_END) break;
        CHECK_ERR(err, "large inflate");
    }

    err = inflateEnd(&d_stream);
    CHECK_ERR(err, "inflateEnd");

    if (d_stream.total_out != 2*uncomprLen + comprLen/2) {
        fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out);
        exit(1);
    } else {
        printf("large_inflate(): OK\n");
    }
}

/* ===========================================================================
 * Test deflate() with full flush
 */
void test_flush(compr, comprLen)
    Byte *compr;
    uLong *comprLen;
{
    z_stream c_stream; /* compression stream */
    int err;
    uInt len = (uInt)strlen(hello)+1;

    c_stream.zalloc = (alloc_func)0;
    c_stream.zfree = (free_func)0;
    c_stream.opaque = (voidpf)0;

    err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
    CHECK_ERR(err, "deflateInit");

    c_stream.next_in  = (Bytef*)hello;
    c_stream.next_out = compr;
    c_stream.avail_in = 3;
    c_stream.avail_out = (uInt)*comprLen;
    err = deflate(&c_stream, Z_FULL_FLUSH);
    CHECK_ERR(err, "deflate");

    compr[3]++; /* force an error in first compressed block */
    c_stream.avail_in = len - 3;

    err = deflate(&c_stream, Z_FINISH);
    if (err != Z_STREAM_END) {
        CHECK_ERR(err, "deflate");
    }
    err = deflateEnd(&c_stream);
    CHECK_ERR(err, "deflateEnd");

    *comprLen = c_stream.total_out;
}

/* ===========================================================================
 * Test inflateSync()
 */
void test_sync(compr, comprLen, uncompr, uncomprLen)
    Byte *compr, *uncompr;
    uLong comprLen, uncomprLen;
{
    int err;
    z_stream d_stream; /* decompression stream */

    strcpy_s((char*)uncompr, uncomprLen, "garbage");

    d_stream.zalloc = (alloc_func)0;
    d_stream.zfree = (free_func)0;
    d_stream.opaque = (voidpf)0;

    d_stream.next_in  = compr;
    d_stream.avail_in = 2; /* just read the zlib header */

    err = inflateInit(&d_stream);
    CHECK_ERR(err, "inflateInit");

    d_stream.next_out = uncompr;
    d_stream.avail_out = (uInt)uncomprLen;

    inflate(&d_stream, Z_NO_FLUSH);
    CHECK_ERR(err, "inflate");

    d_stream.avail_in = (uInt)comprLen-2;   /* read all compressed data */
    err = inflateSync(&d_stream);           /* but skip the damaged part */
    CHECK_ERR(err, "inflateSync");

    err = inflate(&d_stream, Z_FINISH);
    if (err != Z_DATA_ERROR) {
        fprintf(stderr, "inflate should report DATA_ERROR\n");
        /* Because of incorrect adler32 */
        exit(1);
    }
    err = inflateEnd(&d_stream);
    CHECK_ERR(err, "inflateEnd");

    printf("after inflateSync(): hel%s\n", (char *)uncompr);
}

/* ===========================================================================
 * Test deflate() with preset dictionary
 */
void test_dict_deflate(compr, comprLen)
    Byte *compr;
    uLong comprLen;
{
    z_stream c_stream; /* compression stream */
    int err;

    c_stream.zalloc = (alloc_func)0;
    c_stream.zfree = (free_func)0;
    c_stream.opaque = (voidpf)0;

    err = deflateInit(&c_stream, Z_BEST_COMPRESSION);
    CHECK_ERR(err, "deflateInit");

    err = deflateSetDictionary(&c_stream,
                               (const Bytef*)dictionary, sizeof(dictionary));
    CHECK_ERR(err, "deflateSetDictionary");

    dictId = c_stream.adler;
    c_stream.next_out = compr;
    c_stream.avail_out = (uInt)comprLen;

    c_stream.next_in = (Bytef*)hello;
    c_stream.avail_in = (uInt)strlen(hello)+1;

    err = deflate(&c_stream, Z_FINISH);
    if (err != Z_STREAM_END) {
        fprintf(stderr, "deflate should report Z_STREAM_END\n");
        exit(1);
    }
    err = deflateEnd(&c_stream);
    CHECK_ERR(err, "deflateEnd");
}

/* ===========================================================================
 * Test inflate() with a preset dictionary
 */
void test_dict_inflate(compr, comprLen, uncompr, uncomprLen)
    Byte *compr, *uncompr;
    uLong comprLen, uncomprLen;
{
    int err;
    z_stream d_stream; /* decompression stream */

    strcpy_s((char*)uncompr, uncomprLen, "garbage");

    d_stream.zalloc = (alloc_func)0;
    d_stream.zfree = (free_func)0;
    d_stream.opaque = (voidpf)0;

    d_stream.next_in  = compr;
    d_stream.avail_in = (uInt)comprLen;

    err = inflateInit(&d_stream);
    CHECK_ERR(err, "inflateInit");

    d_stream.next_out = uncompr;
    d_stream.avail_out = (uInt)uncomprLen;

    for (;;) {
        err = inflate(&d_stream, Z_NO_FLUSH);
        if (err == Z_STREAM_END) break;
        if (err == Z_NEED_DICT) {
            if (d_stream.adler != dictId) {
                fprintf(stderr, "unexpected dictionary");
                exit(1);
            }
            err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary,
                                       sizeof(dictionary));
        }
        CHECK_ERR(err, "inflate with dict");
    }

    err = inflateEnd(&d_stream);
    CHECK_ERR(err, "inflateEnd");

    if (strcmp((char*)uncompr, hello)) {
        fprintf(stderr, "bad inflate with dict\n");
        exit(1);
    } else {
        printf("inflate with dictionary: %s\n", (char *)uncompr);
    }
}

/* ===========================================================================
 * Usage:  example [output.gz  [input.gz]]
 */

int main(argc, argv)
    int argc;
    char *argv[];
{
    Byte *compr, *uncompr;
    uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */
    uLong uncomprLen = comprLen;
    static const char* myVersion = ZLIB_VERSION;

    if (zlibVersion()[0] != myVersion[0]) {
        fprintf(stderr, "incompatible zlib version\n");
        exit(1);

    } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) {
        fprintf(stderr, "warning: different zlib version\n");
    }

    printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n",
            ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags());

    compr    = (Byte*)calloc((uInt)comprLen, 1);
    uncompr  = (Byte*)calloc((uInt)uncomprLen, 1);
    /* compr and uncompr are cleared to avoid reading uninitialized
     * data and to ensure that uncompr compresses well.
     */
    if (compr == Z_NULL || uncompr == Z_NULL) {
        printf("out of memory\n");
        exit(1);
    }
    test_compress(compr, comprLen, uncompr, uncomprLen);

    test_gzio((argc > 1 ? argv[1] : TESTFILE),
              uncompr, uncomprLen);

    test_deflate(compr, comprLen);
    test_inflate(compr, comprLen, uncompr, uncomprLen);

    test_large_deflate(compr, comprLen, uncompr, uncomprLen);
    test_large_inflate(compr, comprLen, uncompr, uncomprLen);

    test_flush(compr, &comprLen);
    test_sync(compr, comprLen, uncompr, uncomprLen);
    comprLen = uncomprLen;

    test_dict_deflate(compr, comprLen);
    test_dict_inflate(compr, comprLen, uncompr, uncomprLen);

    free(compr);
    free(uncompr);

    return 0;
}

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article, along with any associated source code and files, is licensed under The GNU General Public License (GPLv3)

Share

About the Author

Andy Bantly
Founder
United States United States
Working as a software developer since 1989. Started out with Basic, FORTRAN and JCL, moved into Visual Basic 1.0, C, then C++, and now I work mainly in C++ using MFC, Win32, and ATL/COM. I use Microsoft Products only because that is what gives me gainful employment. Through work, I have a lot of experience with HTML, JavaScript, XSL transformations, the XMLHTTP object, PHP 4.x, and simple COM object integrations.
 
I've worked for the University of Oklahoma in the school of meteorology (Go SOONERS!), consulting, and now as a Senior Software Engineer. These things keep my lights on and electricity going. My dream job is to own a bowling alley and rub elbows with pro-bowlers! I'm also an avid pedicab driver and have my own cab. I like the hustle of picking up people in downtown and biking them to their destination.
Follow on   Google+   LinkedIn

| Advertise | Privacy | Mobile
Web03 | 2.8.140821.1 | Last Updated 20 Sep 2013
Article Copyright 2000 by Andy Bantly
Everything else Copyright © CodeProject, 1999-2014
Terms of Service
Layout: fixed | fluid