example_original.c

/* example.c -- usage example of the zlib compression library
 */
/*
 Copyright (c) 1995-2006, 2011 Jean-loup Gailly

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgement in the product documentation would be
   appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

/* @(#) $Id$ */

#include "zlib.h"
#include <stdio.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); \
    } \
}

z_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_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[]));


#ifdef Z_SOLO

void *myalloc OF((void *, unsigned, unsigned));
void myfree OF((void *, void *));

void *myalloc(q, n, m)
    void *q;
    unsigned n, m;
{
    q = Z_NULL;
    return calloc(n, m);
}

void myfree(void *q, void *p)
{
    q = Z_NULL;
    free(p);
}

static alloc_func zalloc = myalloc;
static free_func zfree = myfree;

#else /* !Z_SOLO */

static alloc_func zalloc = (alloc_func)0;
static free_func zfree = (free_func)0;

void test_compress      OF((Byte *compr, uLong comprLen,
                            Byte *uncompr, uLong uncomprLen));
void test_gzio          OF((const char *fname,
                            Byte *uncompr, uLong uncomprLen));

/* ===========================================================================
 * 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((char*)uncompr, "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((char*)uncompr, "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
}

#endif /* Z_SOLO */

/* ===========================================================================
 * 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 = zalloc;
    c_stream.zfree = zfree;
    c_stream.opaque = (voidpf)0;

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

    c_stream.next_in  = (z_const unsigned char *)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((char*)uncompr, "garbage");

    d_stream.zalloc = zalloc;
    d_stream.zfree = zfree;
    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 = zalloc;
    c_stream.zfree = zfree;
    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((char*)uncompr, "garbage");

    d_stream.zalloc = zalloc;
    d_stream.zfree = zfree;
    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 = zalloc;
    c_stream.zfree = zfree;
    c_stream.opaque = (voidpf)0;

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

    c_stream.next_in  = (z_const unsigned char *)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((char*)uncompr, "garbage");

    d_stream.zalloc = zalloc;
    d_stream.zfree = zfree;
    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 = zalloc;
    c_stream.zfree = zfree;
    c_stream.opaque = (voidpf)0;

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

    err = deflateSetDictionary(&c_stream,
                (const Bytef*)dictionary, (int)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 = (z_const unsigned char *)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((char*)uncompr, "garbage");

    d_stream.zalloc = zalloc;
    d_stream.zfree = zfree;
    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,
                                       (int)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);
    }

#ifdef Z_SOLO
    argc = strlen(argv[0]);
#else
    test_compress(compr, comprLen, uncompr, uncomprLen);

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

    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;
}