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

     2  * Copyright (C) 1995-1998 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 #else

    25    extern void exit  OF((int));

    26 #endif

    27 

    28 #ifdef USE_MMAP

    29 #  include <sys/types.h>

    30 #  include <sys/mman.h>

    31 #  include <sys/stat.h>

    32 #endif

    33 

    34 #if defined(MSDOS) || defined(OS2) || defined(WIN32)

    35 #  include <fcntl.h>

    36 #  include <io.h>

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

    38 #else

    39 #  define SET_BINARY_MODE(file)

    40 #endif

    41 

    42 #ifdef VMS

    43 #  define unlink delete

    44 #  define GZ_SUFFIX "-gz"

    45 #endif

    46 #ifdef RISCOS

    47 #  define unlink remove

    48 #  define GZ_SUFFIX "-gz"

    49 #  define fileno(file) file->__file

    50 #endif

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

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

    53 #endif

    54 

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

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

    57 #endif

    58 

    59 #ifndef GZ_SUFFIX

    60 #  define GZ_SUFFIX ".gz"

    61 #endif

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

    63 

    64 #define BUFLEN      16384

    65 #define MAX_NAME_LEN 1024

    66 

    67 #ifdef MAXSEG_64K

    68 #  define local static

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

    70 #else

    71 #  define local

    72 #endif

    73 

    74 char *prog;

    75 

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

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

    78 #ifdef USE_MMAP

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

    80 #endif

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

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

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

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

    85 

    86 /* ===========================================================================

    87  * Display error message and exit

    88  */

    89 void error(msg)

    90     const char *msg;

    91 {

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

    93     exit(1);

    94 }

    95 

    96 /* ===========================================================================

    97  * Compress input to output then close both files.

    98  */

    99 

   100 void gz_compress(in, out)

   101     FILE   *in;

   102     gzFile out;

   103 {

   104     local char buf[BUFLEN];

   105     int len;

   106     int err;

   107 

   108 #ifdef USE_MMAP

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

   110      * pipe), use the normal fread loop.

   111      */

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

   113 #endif

   114     for (;;) {

   115         len = fread(buf, 1, sizeof(buf), in);

   116         if (ferror(in)) {

   117             perror("fread");

   118             exit(1);

   119         }

   120         if (len == 0) break;

   121 

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

   123     }

   124     fclose(in);

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

   126 }

   127 

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

   129 

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

   131  * if success, Z_ERRNO otherwise.

   132  */

   133 int gz_compress_mmap(in, out)

   134     FILE   *in;

   135     gzFile out;

   136 {

   137     int len;

   138     int err;

   139     int ifd = fileno(in);

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

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

   142     struct stat sb;

   143 

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

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

   146     buf_len = sb.st_size;

   147     if (buf_len <= 0) return Z_ERRNO;

   148 

   149     /* Now do the actual mmap: */

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

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

   152 

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

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

   155 

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

   157 

   158     munmap(buf, buf_len);

   159     fclose(in);

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

   161     return Z_OK;

   162 }

   163 #endif /* USE_MMAP */

   164 

   165 /* ===========================================================================

   166  * Uncompress input to output then close both files.

   167  */

   168 void gz_uncompress(in, out)

   169     gzFile in;

   170     FILE   *out;

   171 {

   172     local char buf[BUFLEN];

   173     int len;

   174     int err;

   175 

   176     for (;;) {

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

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

   179         if (len == 0) break;

   180 

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

   182 	    error("failed fwrite");

   183 	}

   184     }

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

   186 

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

   188 }

   189 

   190 

   191 /* ===========================================================================

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

   193  * original.

   194  */

   195 void file_compress(file, mode)

   196     char  *file;

   197     char  *mode;

   198 {

   199     local char outfile[MAX_NAME_LEN];

   200     FILE  *in;

   201     gzFile out;

   202 

   203     strcpy(outfile, file);

   204     strcat(outfile, GZ_SUFFIX);

   205 

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

   207     if (in == NULL) {

   208         perror(file);

   209         exit(1);

   210     }

   211     out = gzopen(outfile, mode);

   212     if (out == NULL) {

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

   214         exit(1);

   215     }

   216     gz_compress(in, out);

   217 

   218     unlink(file);

   219 }

   220 

   221 

   222 /* ===========================================================================

   223  * Uncompress the given file and remove the original.

   224  */

   225 void file_uncompress(file)

   226     char  *file;

   227 {

   228     local char buf[MAX_NAME_LEN];

   229     char *infile, *outfile;

   230     FILE  *out;

   231     gzFile in;

   232     int len = strlen(file);

   233 

   234     strcpy(buf, file);

   235 

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

   237         infile = file;

   238         outfile = buf;

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

   240     } else {

   241         outfile = file;

   242         infile = buf;

   243         strcat(infile, GZ_SUFFIX);

   244     }

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

   246     if (in == NULL) {

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

   248         exit(1);

   249     }

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

   251     if (out == NULL) {

   252         perror(file);

   253         exit(1);

   254     }

   255 

   256     gz_uncompress(in, out);

   257 

   258     unlink(infile);

   259 }

   260 

   261 

   262 /* ===========================================================================

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

   264  *   -d : decompress

   265  *   -f : compress with Z_FILTERED

   266  *   -h : compress with Z_HUFFMAN_ONLY

   267  *   -1 to -9 : compression level

   268  */

   269 

   270 int main(argc, argv)

   271     int argc;

   272     char *argv[];

   273 {

   274     int uncompr = 0;

   275     gzFile file;

   276     char outmode[20];

   277 

   278     strcpy(outmode, "wb6 ");

   279 

   280     prog = argv[0];

   281     argc--, argv++;

   282 

   283     while (argc > 0) {

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

   285 	uncompr = 1;

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

   287 	outmode[3] = 'f';

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

   289 	outmode[3] = 'h';

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

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

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

   293       else

   294 	break;

   295       argc--, argv++;

   296     }

   297     if (argc == 0) {

   298         SET_BINARY_MODE(stdin);

   299         SET_BINARY_MODE(stdout);

   300         if (uncompr) {

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

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

   303             gz_uncompress(file, stdout);

   304         } else {

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

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

   307             gz_compress(stdin, file);

   308         }

   309     } else {

   310         do {

   311             if (uncompr) {

   312                 file_uncompress(*argv);

   313             } else {

   314                 file_compress(*argv, outmode);

   315             }

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

   317     }

   318     exit(0);

   319     return 0; /* to avoid warning */

   320 }