/* minigzip.c -- simulate gzip using the zlib compression library
* Copyright (C) 1995-2006, 2010 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/

/*
* minigzip is a minimal implementation of the gzip utility. This is
* only an example of using zlib and isn't meant to replace the
* full-featured gzip. No attempt is made to deal with file systems
* limiting names to 14 or 8+3 characters, etc... Error checking is
* very limited. So use minigzip only for testing; use gzip for the
* real thing. On MSDOS, use only on file names without extension
* or in pipe mode.
*/

/* @(#) Id: minigzip.c,v 1.1.1.2 2002/03/11 21:53:26 tromey Exp  */

#include "zlib.h"
#include <stdio.h>

#ifdef STDC
#  include <string.h>
#  include <stdlib.h>
#endif

#ifdef USE_MMAP
#  include <sys/types.h>
#  include <sys/mman.h>
#  include <sys/stat.h>
#endif

#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
#  include <fcntl.h>
#  include <io.h>
#  ifdef UNDER_CE
#    include <stdlib.h>
#  endif
#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
#else
#  define SET_BINARY_MODE(file)
#endif

#ifdef VMS
#  define unlink delete
#  define GZ_SUFFIX "-gz"
#endif
#ifdef RISCOS
#  define unlink remove
#  define GZ_SUFFIX "-gz"
#  define fileno(file) file->__file
#endif
#if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
#  include <unix.h> /* for fileno */
#endif

#if !defined(Z_HAVE_UNISTD_H) && !defined(_LARGEFILE64_SOURCE)
#ifndef WIN32 /* unlink already in stdio.h for WIN32 */
 extern int unlink OF((const char *));
#endif
#endif

#if defined(UNDER_CE)
#  include <windows.h>
#  define perror(s) pwinerror(s)

/* Map the Windows error number in ERROR to a locale-dependent error
  message string and return a pointer to it.  Typically, the values
  for ERROR come from GetLastError.

  The string pointed to shall not be modified by the application,
  but may be overwritten by a subsequent call to strwinerror

  The strwinerror function does not change the current setting
  of GetLastError.  */

static char *strwinerror (error)
    DWORD error;
{
   static char buf[1024];

   wchar_t *msgbuf;
   DWORD lasterr = GetLastError();
   DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
       | FORMAT_MESSAGE_ALLOCATE_BUFFER,
       NULL,
       error,
       0, /* Default language */
       (LPVOID)&msgbuf,
       0,
       NULL);
   if (chars != 0) {
       /* If there is an \r\n appended, zap it.  */
       if (chars >= 2
           && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
           chars -= 2;
           msgbuf[chars] = 0;
       }

       if (chars > sizeof (buf) - 1) {
           chars = sizeof (buf) - 1;
           msgbuf[chars] = 0;
       }

       wcstombs(buf, msgbuf, chars + 1);
       LocalFree(msgbuf);
   }
   else {
       sprintf(buf, "unknown win32 error (%ld)", error);
   }

   SetLastError(lasterr);
   return buf;
}

static void pwinerror (s)
   const char *s;
{
   if (s && *s)
       fprintf(stderr, "%s: %s\n", s, strwinerror(GetLastError ()));
   else
       fprintf(stderr, "%s\n", strwinerror(GetLastError ()));
}

#endif /* UNDER_CE */

#ifndef GZ_SUFFIX
#  define GZ_SUFFIX ".gz"
#endif
#define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)

#define BUFLEN      16384
#define MAX_NAME_LEN 1024

#ifdef MAXSEG_64K
#  define local static
  /* Needed for systems with limitation on stack size. */
#else
#  define local
#endif

char *prog;

void error            OF((const char *msg));
void gz_compress      OF((FILE   *in, gzFile out));
#ifdef USE_MMAP
int  gz_compress_mmap OF((FILE   *in, gzFile out));
#endif
void gz_uncompress    OF((gzFile in, FILE   *out));
void file_compress    OF((char  *file, char *mode));
void file_uncompress  OF((char  *file));
int  main             OF((int argc, char *argv[]));

/* ===========================================================================
* Display error message and exit
*/
void error(msg)
   const char *msg;
{
   fprintf(stderr, "%s: %s\n", prog, msg);
   exit(1);
}

/* ===========================================================================
* Compress input to output then close both files.
*/

void gz_compress(in, out)
   FILE   *in;
   gzFile out;
{
   local char buf[BUFLEN];
   int len;
   int err;

#ifdef USE_MMAP
   /* Try first compressing with mmap. If mmap fails (minigzip used in a
    * pipe), use the normal fread loop.
    */
   if (gz_compress_mmap(in, out) == Z_OK) return;
#endif
   for (;;) {
       len = (int)fread(buf, 1, sizeof(buf), in);
       if (ferror(in)) {
           perror("fread");
           exit(1);
       }
       if (len == 0) break;

       if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
   }
   fclose(in);
   if (gzclose(out) != Z_OK) error("failed gzclose");
}

#ifdef USE_MMAP /* MMAP version, Miguel Albrecht <[email protected]> */

/* Try compressing the input file at once using mmap. Return Z_OK if
* if success, Z_ERRNO otherwise.
*/
int gz_compress_mmap(in, out)
   FILE   *in;
   gzFile out;
{
   int len;
   int err;
   int ifd = fileno(in);
   caddr_t buf;    /* mmap'ed buffer for the entire input file */
   off_t buf_len;  /* length of the input file */
   struct stat sb;

   /* Determine the size of the file, needed for mmap: */
   if (fstat(ifd, &sb) < 0) return Z_ERRNO;
   buf_len = sb.st_size;
   if (buf_len <= 0) return Z_ERRNO;

   /* Now do the actual mmap: */
   buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
   if (buf == (caddr_t)(-1)) return Z_ERRNO;

   /* Compress the whole file at once: */
   len = gzwrite(out, (char *)buf, (unsigned)buf_len);

   if (len != (int)buf_len) error(gzerror(out, &err));

   munmap(buf, buf_len);
   fclose(in);
   if (gzclose(out) != Z_OK) error("failed gzclose");
   return Z_OK;
}
#endif /* USE_MMAP */

/* ===========================================================================
* Uncompress input to output then close both files.
*/
void gz_uncompress(in, out)
   gzFile in;
   FILE   *out;
{
   local char buf[BUFLEN];
   int len;
   int err;

   for (;;) {
       len = gzread(in, buf, sizeof(buf));
       if (len < 0) error (gzerror(in, &err));
       if (len == 0) break;

       if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
           error("failed fwrite");
       }
   }
   if (fclose(out)) error("failed fclose");

   if (gzclose(in) != Z_OK) error("failed gzclose");
}


/* ===========================================================================
* Compress the given file: create a corresponding .gz file and remove the
* original.
*/
void file_compress(file, mode)
   char  *file;
   char  *mode;
{
   local char outfile[MAX_NAME_LEN];
   FILE  *in;
   gzFile out;

   if (strlen(file) + strlen(GZ_SUFFIX) >= sizeof(outfile)) {
       fprintf(stderr, "%s: filename too long\n", prog);
       exit(1);
   }

   strcpy(outfile, file);
   strcat(outfile, GZ_SUFFIX);

   in = fopen(file, "rb");
   if (in == NULL) {
       perror(file);
       exit(1);
   }
   out = gzopen(outfile, mode);
   if (out == NULL) {
       fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
       exit(1);
   }
   gz_compress(in, out);

   unlink(file);
}


/* ===========================================================================
* Uncompress the given file and remove the original.
*/
void file_uncompress(file)
   char  *file;
{
   local char buf[MAX_NAME_LEN];
   char *infile, *outfile;
   FILE  *out;
   gzFile in;
   size_t len = strlen(file);

   if (len + strlen(GZ_SUFFIX) >= sizeof(buf)) {
       fprintf(stderr, "%s: filename too long\n", prog);
       exit(1);
   }

   strcpy(buf, file);

   if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
       infile = file;
       outfile = buf;
       outfile[len-3] = '\0';
   } else {
       outfile = file;
       infile = buf;
       strcat(infile, GZ_SUFFIX);
   }
   in = gzopen(infile, "rb");
   if (in == NULL) {
       fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
       exit(1);
   }
   out = fopen(outfile, "wb");
   if (out == NULL) {
       perror(file);
       exit(1);
   }

   gz_uncompress(in, out);

   unlink(infile);
}


/* ===========================================================================
* Usage:  minigzip [-c] [-d] [-f] [-h] [-r] [-1 to -9] [files...]
*   -c : write to standard output
*   -d : decompress
*   -f : compress with Z_FILTERED
*   -h : compress with Z_HUFFMAN_ONLY
*   -r : compress with Z_RLE
*   -1 to -9 : compression level
*/

int main(argc, argv)
   int argc;
   char *argv[];
{
   int copyout = 0;
   int uncompr = 0;
   gzFile file;
   char *bname, outmode[20];

   strcpy(outmode, "wb6 ");

   prog = argv[0];
   bname = strrchr(argv[0], '/');
   if (bname)
     bname++;
   else
     bname = argv[0];
   argc--, argv++;

   if (!strcmp(bname, "gunzip"))
     uncompr = 1;
   else if (!strcmp(bname, "zcat"))
     copyout = uncompr = 1;

   while (argc > 0) {
     if (strcmp(*argv, "-c") == 0)
       copyout = 1;
     else if (strcmp(*argv, "-d") == 0)
       uncompr = 1;
     else if (strcmp(*argv, "-f") == 0)
       outmode[3] = 'f';
     else if (strcmp(*argv, "-h") == 0)
       outmode[3] = 'h';
     else if (strcmp(*argv, "-r") == 0)
       outmode[3] = 'R';
     else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
              (*argv)[2] == 0)
       outmode[2] = (*argv)[1];
     else
       break;
     argc--, argv++;
   }
   if (outmode[3] == ' ')
       outmode[3] = 0;
   if (argc == 0) {
       SET_BINARY_MODE(stdin);
       SET_BINARY_MODE(stdout);
       if (uncompr) {
           file = gzdopen(fileno(stdin), "rb");
           if (file == NULL) error("can't gzdopen stdin");
           gz_uncompress(file, stdout);
       } else {
           file = gzdopen(fileno(stdout), outmode);
           if (file == NULL) error("can't gzdopen stdout");
           gz_compress(stdin, file);
       }
   } else {
       if (copyout) {
           SET_BINARY_MODE(stdout);
       }
       do {
           if (uncompr) {
               if (copyout) {
                   file = gzopen(*argv, "rb");
                   if (file == NULL)
                       fprintf(stderr, "%s: can't gzopen %s\n", prog, *argv);
                   else
                       gz_uncompress(file, stdout);
               } else {
                   file_uncompress(*argv);
               }
           } else {
               if (copyout) {
                   FILE * in = fopen(*argv, "rb");

                   if (in == NULL) {
                       perror(*argv);
                   } else {
                       file = gzdopen(fileno(stdout), outmode);
                       if (file == NULL) error("can't gzdopen stdout");

                       gz_compress(in, file);
                   }

               } else {
                   file_compress(*argv, outmode);
               }
           }
       } while (argv++, --argc);
   }
   return 0;
}

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