text: /* example.c -- usage example of the zlib compression library
   * Copyright (C) 1995-1998 Jean-loup Gailly.
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* @(#) $Id: example.c,v 1.1.1.1 2006/05/30 06:15:04 hhzhou Exp $ */
  
  #include <stdio.h>
  #include "zlib.h"
  
  #ifdef STDC
  #  include <string.h>
  #  include <stdlib.h>
  #else
     extern void exit  OF((int));
  #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 *out, const char *in, 
  		            Byte *uncompr, int 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 = 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(out, in, uncompr, uncomprLen)
      const char *out; /* compressed output file */
      const char *in;  /* compressed input file */
      Byte *uncompr;
      int  uncomprLen;
  {
      int err;
      int len = strlen(hello)+1;
      gzFile file;
      z_off_t pos;
  
      file = gzopen(out, "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(in, "rb");
      if (file == NULL) {
          fprintf(stderr, "gzopen error\n");
      }
      strcpy((char*)uncompr, "garbage");
  
      uncomprLen = gzread(file, uncompr, (unsigned)uncomprLen);
      if (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);
      }
  
      gzgets(file, (char*)uncompr, uncomprLen);
      uncomprLen = strlen((char*)uncompr);
      if (uncomprLen != 6) { /* "hello!" */
          fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err));
  	exit(1);
      }
      if (strcmp((char*)uncompr, hello+7)) {
          fprintf(stderr, "bad gzgets after gzseek\n");
  	exit(1);
      } else {
          printf("gzgets() after gzseek: %s\n", (char *)uncompr);
      }
  
      gzclose(file);
  }
  
  /* ===========================================================================
   * Test deflate() with small buffers
   */
  void test_deflate(compr, comprLen)
      Byte *compr;
      uLong comprLen;
  {
      z_stream c_stream; /* compression stream */
      int err;
      int len = 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 != (uLong)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;
      int len = 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");
      }
  
      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),
                (argc > 2 ? argv[2] : TESTFILE),
  	      uncompr, (int)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);
  
      exit(0);
      return 0; /* to avoid warning */
  }
  