src/zlib/minigzip.c

   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: minigzip.c 126 2003-11-09 01:53:27Z gabest $ */
  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 }