diff --git a/demos/zlib/example.c b/demos/zlib/example.c
new file mode 100644
index 0000000..6c8a0ee
--- /dev/null
+++ b/demos/zlib/example.c
@@ -0,0 +1,565 @@
+/* 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((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
+}
+
+/* ===========================================================================
+ * 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((char*)uncompr, "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((char*)uncompr, "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((char*)uncompr, "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((char*)uncompr, "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;
+}