1 /* minigzip.c -- simulate gzip using the zlib compression library

     2  * Copyright (C) 1995-2005 Jean-loup Gailly.

     3  * For conditions of distribution and use, see copyright notice in zlib.h

     4  */

     5 

     6 /*

     7  * minigzip is a minimal implementation of the gzip utility. This is

     8  * only an example of using zlib and isn't meant to replace the

     9  * full-featured gzip. No attempt is made to deal with file systems

    10  * limiting names to 14 or 8+3 characters, etc... Error checking is

    11  * very limited. So use minigzip only for testing; use gzip for the

    12  * real thing. On MSDOS, use only on file names without extension

    13  * or in pipe mode.

    14  */

    15 

    16 /* @(#) $Id$ */

    17 

    18 #include <stdio.h>

    19 #include "zlib.h"

    20 

    21 #ifdef STDC

    22 #  include <string.h>

    23 #  include <stdlib.h>

    24 #endif

    25 

    26 #ifdef USE_MMAP

    27 #  include <sys/types.h>

    28 #  include <sys/mman.h>

    29 #  include <sys/stat.h>

    30 #endif

    31 

    32 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)

    33 #  include <fcntl.h>

    34 #  include <io.h>

    35 #  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)

    36 #else

    37 #  define SET_BINARY_MODE(file)

    38 #endif

    39 

    40 #ifdef VMS

    41 #  define unlink delete

    42 #  define GZ_SUFFIX "-gz"

    43 #endif

    44 #ifdef RISCOS

    45 #  define unlink remove

    46 #  define GZ_SUFFIX "-gz"

    47 #  define fileno(file) file->__file

    48 #endif

    49 #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os

    50 #  include <unix.h> /* for fileno */

    51 #endif

    52 

    53 #ifndef WIN32 /* unlink already in stdio.h for WIN32 */

    54   extern int unlink OF((const char *));

    55 #endif

    56 

    57 #ifndef GZ_SUFFIX

    58 #  define GZ_SUFFIX ".gz"

    59 #endif

    60 #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)

    61 

    62 #define BUFLEN      16384

    63 #define MAX_NAME_LEN 1024

    64 

    65 #ifdef MAXSEG_64K

    66 #  define local static

    67    /* Needed for systems with limitation on stack size. */

    68 #else

    69 #  define local

    70 #endif

    71 

    72 char *prog;

    73 

    74 void error            OF((const char *msg));

    75 void gz_compress      OF((FILE   *in, gzFile out));

    76 #ifdef USE_MMAP

    77 int  gz_compress_mmap OF((FILE   *in, gzFile out));

    78 #endif

    79 void gz_uncompress    OF((gzFile in, FILE   *out));

    80 void file_compress    OF((char  *file, char *mode));

    81 void file_uncompress  OF((char  *file));

    82 int  main             OF((int argc, char *argv[]));

    83 

    84 /* ===========================================================================

    85  * Display error message and exit

    86  */

    87 void error(msg)

    88     const char *msg;

    89 {

    90     fprintf(stderr, "%s: %s\n", prog, msg);

    91     exit(1);

    92 }

    93 

    94 /* ===========================================================================

    95  * Compress input to output then close both files.

    96  */

    97 

    98 void gz_compress(in, out)

    99     FILE   *in;

   100     gzFile out;

   101 {

   102     local char buf[BUFLEN];

   103     int len;

   104     int err;

   105 

   106 #ifdef USE_MMAP

   107     /* Try first compressing with mmap. If mmap fails (minigzip used in a

   108      * pipe), use the normal fread loop.

   109      */

   110     if (gz_compress_mmap(in, out) == Z_OK) return;

   111 #endif

   112     for (;;) {

   113         len = (int)fread(buf, 1, sizeof(buf), in);

   114         if (ferror(in)) {

   115             perror("fread");

   116             exit(1);

   117         }

   118         if (len == 0) break;

   119 

   120         if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));

   121     }

   122     fclose(in);

   123     if (gzclose(out) != Z_OK) error("failed gzclose");

   124 }

   125 

   126 #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */

   127 

   128 /* Try compressing the input file at once using mmap. Return Z_OK if

   129  * if success, Z_ERRNO otherwise.

   130  */

   131 int gz_compress_mmap(in, out)

   132     FILE   *in;

   133     gzFile out;

   134 {

   135     int len;

   136     int err;

   137     int ifd = fileno(in);

   138     caddr_t buf;    /* mmap'ed buffer for the entire input file */

   139     off_t buf_len;  /* length of the input file */

   140     struct stat sb;

   141 

   142     /* Determine the size of the file, needed for mmap: */

   143     if (fstat(ifd, &sb) < 0) return Z_ERRNO;

   144     buf_len = sb.st_size;

   145     if (buf_len <= 0) return Z_ERRNO;

   146 

   147     /* Now do the actual mmap: */

   148     buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);

   149     if (buf == (caddr_t)(-1)) return Z_ERRNO;

   150 

   151     /* Compress the whole file at once: */

   152     len = gzwrite(out, (char *)buf, (unsigned)buf_len);

   153 

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

   155 

   156     munmap(buf, buf_len);

   157     fclose(in);

   158     if (gzclose(out) != Z_OK) error("failed gzclose");

   159     return Z_OK;

   160 }

   161 #endif /* USE_MMAP */

   162 

   163 /* ===========================================================================

   164  * Uncompress input to output then close both files.

   165  */

   166 void gz_uncompress(in, out)

   167     gzFile in;

   168     FILE   *out;

   169 {

   170     local char buf[BUFLEN];

   171     int len;

   172     int err;

   173 

   174     for (;;) {

   175         len = gzread(in, buf, sizeof(buf));

   176         if (len < 0) error (gzerror(in, &err));

   177         if (len == 0) break;

   178 

   179         if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {

   180             error("failed fwrite");

   181         }

   182     }

   183     if (fclose(out)) error("failed fclose");

   184 

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

   186 }

   187 

   188 

   189 /* ===========================================================================

   190  * Compress the given file: create a corresponding .gz file and remove the

   191  * original.

   192  */

   193 void file_compress(file, mode)

   194     char  *file;

   195     char  *mode;

   196 {

   197     local char outfile[MAX_NAME_LEN];

   198     FILE  *in;

   199     gzFile out;

   200 

   201     strcpy(outfile, file);

   202     strcat(outfile, GZ_SUFFIX);

   203 

   204     in = fopen(file, "rb");

   205     if (in == NULL) {

   206         perror(file);

   207         exit(1);

   208     }

   209     out = gzopen(outfile, mode);

   210     if (out == NULL) {

   211         fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);

   212         exit(1);

   213     }

   214     gz_compress(in, out);

   215 

   216     unlink(file);

   217 }

   218 

   219 

   220 /* ===========================================================================

   221  * Uncompress the given file and remove the original.

   222  */

   223 void file_uncompress(file)

   224     char  *file;

   225 {

   226     local char buf[MAX_NAME_LEN];

   227     char *infile, *outfile;

   228     FILE  *out;

   229     gzFile in;

   230     uInt len = (uInt)strlen(file);

   231 

   232     strcpy(buf, file);

   233 

   234     if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {

   235         infile = file;

   236         outfile = buf;

   237         outfile[len-3] = '\0';

   238     } else {

   239         outfile = file;

   240         infile = buf;

   241         strcat(infile, GZ_SUFFIX);

   242     }

   243     in = gzopen(infile, "rb");

   244     if (in == NULL) {

   245         fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);

   246         exit(1);

   247     }

   248     out = fopen(outfile, "wb");

   249     if (out == NULL) {

   250         perror(file);

   251         exit(1);

   252     }

   253 

   254     gz_uncompress(in, out);

   255 

   256     unlink(infile);

   257 }

   258 

   259 

   260 /* ===========================================================================

   261  * Usage:  minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]

   262  *   -d : decompress

   263  *   -f : compress with Z_FILTERED

   264  *   -h : compress with Z_HUFFMAN_ONLY

   265  *   -r : compress with Z_RLE

   266  *   -1 to -9 : compression level

   267  */

   268 

   269 int main(argc, argv)

   270     int argc;

   271     char *argv[];

   272 {

   273     int uncompr = 0;

   274     gzFile file;

   275     char outmode[20];

   276 

   277     strcpy(outmode, "wb6 ");

   278 

   279     prog = argv[0];

   280     argc--, argv++;

   281 

   282     while (argc > 0) {

   283       if (strcmp(*argv, "-d") == 0)

   284         uncompr = 1;

   285       else if (strcmp(*argv, "-f") == 0)

   286         outmode[3] = 'f';

   287       else if (strcmp(*argv, "-h") == 0)

   288         outmode[3] = 'h';

   289       else if (strcmp(*argv, "-r") == 0)

   290         outmode[3] = 'R';

   291       else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&

   292                (*argv)[2] == 0)

   293         outmode[2] = (*argv)[1];

   294       else

   295         break;

   296       argc--, argv++;

   297     }

   298     if (outmode[3] == ' ')

   299         outmode[3] = 0;

   300     if (argc == 0) {

   301         SET_BINARY_MODE(stdin);

   302         SET_BINARY_MODE(stdout);

   303         if (uncompr) {

   304             file = gzdopen(fileno(stdin), "rb");

   305             if (file == NULL) error("can't gzdopen stdin");

   306             gz_uncompress(file, stdout);

   307         } else {

   308             file = gzdopen(fileno(stdout), outmode);

   309             if (file == NULL) error("can't gzdopen stdout");

   310             gz_compress(stdin, file);

   311         }

   312     } else {

   313         do {

   314             if (uncompr) {

   315                 file_uncompress(*argv);

   316             } else {

   317                 file_compress(*argv, outmode);

   318             }

   319         } while (argv++, --argc);

   320     }

   321     return 0;

   322 }