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
  17 #include <stdio.h>
  18 #include "zlib.h"
  19
  20 #ifdef STDC
  21 #  include <string.h>
  22 #  include <stdlib.h>
  23 #endif
  24
  25 #ifdef USE_MMAP
  26 #  include <sys/types.h>
  27 #  include <sys/mman.h>
  28 #  include <sys/stat.h>
  29 #endif
  30
  31 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
  32 #  include <fcntl.h>
  33 #  include <io.h>
  34 #  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
  35 #else
  36 #  define SET_BINARY_MODE(file)
  37 #endif
  38
  39 #ifdef VMS
  40 #  define unlink delete
  41 #  define GZ_SUFFIX "-gz"
  42 #endif
  43 #ifdef RISCOS
  44 #  define unlink remove
  45 #  define GZ_SUFFIX "-gz"
  46 #  define fileno(file) file->__file
  47 #endif
  48 #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
  49 #  include <unix.h> /* for fileno */
  50 #endif
  51
  52 #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
  53   extern int unlink OF((const char *));
  54 #endif
  55
  56 #ifndef GZ_SUFFIX
  57 #  define GZ_SUFFIX ".gz"
  58 #endif
  59 #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
  60
  61 #define BUFLEN      16384
  62 #define MAX_NAME_LEN 1024
  63
  64 #ifdef MAXSEG_64K
  65 #  define local static
  66    /* Needed for systems with limitation on stack size. */
  67 #else
  68 #  define local
  69 #endif
  70
  71 char *prog;
  72
  73 void error            OF((const char *msg));
  74 void gz_compress      OF((FILE   *in, gzFile out));
  75 #ifdef USE_MMAP
  76 int  gz_compress_mmap OF((FILE   *in, gzFile out));
  77 #endif
  78 void gz_uncompress    OF((gzFile in, FILE   *out));
  79 void file_compress    OF((char  *file, char *mode));
  80 void file_uncompress  OF((char  *file));
  81 int  main             OF((int argc, char *argv[]));
  82
  83 /* ===========================================================================
  84  * Display error message and exit
  85  */
  86 void error(msg)
  87     const char *msg;
  88 {
  89     fprintf(stderr, "%s: %s\n", prog, msg);
  90     exit(1);
  91 }
  92
  93 /* ===========================================================================
  94  * Compress input to output then close both files.
  95  */
  96
  97 void gz_compress(in, out)
  98     FILE   *in;
  99     gzFile out;
 100 {
 101     local char buf[BUFLEN];
 102     int len;
 103     int err;
 104
 105 #ifdef USE_MMAP
 106     /* Try first compressing with mmap. If mmap fails (minigzip used in a
 107      * pipe), use the normal fread loop.
 108      */
 109     if (gz_compress_mmap(in, out) == Z_OK) return;
 110 #endif
 111     for (;;) {
 112         len = (int)fread(buf, 1, sizeof(buf), in);
 113         if (ferror(in)) {
 114             perror("fread");
 115             exit(1);
 116         }
 117         if (len == 0) break;
 118
 119         if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
 120     }
 121     fclose(in);
 122     if (gzclose(out) != Z_OK) error("failed gzclose");
 123 }
 124
 125 #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
 126
 127 /* Try compressing the input file at once using mmap. Return Z_OK if
 128  * if success, Z_ERRNO otherwise.
 129  */
 130 int gz_compress_mmap(in, out)
 131     FILE   *in;
 132     gzFile out;
 133 {
 134     int len;
 135     int err;
 136     int ifd = fileno(in);
 137     caddr_t buf;    /* mmap'ed buffer for the entire input file */
 138     off_t buf_len;  /* length of the input file */
 139     struct stat sb;
 140
 141     /* Determine the size of the file, needed for mmap: */
 142     if (fstat(ifd, &sb) < 0) return Z_ERRNO;
 143     buf_len = sb.st_size;
 144     if (buf_len <= 0) return Z_ERRNO;
 145
 146     /* Now do the actual mmap: */
 147     buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
 148     if (buf == (caddr_t)(-1)) return Z_ERRNO;
 149
 150     /* Compress the whole file at once: */
 151     len = gzwrite(out, (char *)buf, (unsigned)buf_len);
 152
 153     if (len != (int)buf_len) error(gzerror(out, &err));
 154
 155     munmap(buf, buf_len);
 156     fclose(in);
 157     if (gzclose(out) != Z_OK) error("failed gzclose");
 158     return Z_OK;
 159 }
 160 #endif /* USE_MMAP */
 161
 162 /* ===========================================================================
 163  * Uncompress input to output then close both files.
 164  */
 165 void gz_uncompress(in, out)
 166     gzFile in;
 167     FILE   *out;
 168 {
 169     local char buf[BUFLEN];
 170     int len;
 171     int err;
 172
 173     for (;;) {
 174         len = gzread(in, buf, sizeof(buf));
 175         if (len < 0) error (gzerror(in, &err));
 176         if (len == 0) break;
 177
 178         if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
 179             error("failed fwrite");
 180         }
 181     }
 182     if (fclose(out)) error("failed fclose");
 183
 184     if (gzclose(in) != Z_OK) error("failed gzclose");
 185 }
 186
 187
 188 /* ===========================================================================
 189  * Compress the given file: create a corresponding .gz file and remove the
 190  * original.
 191  */
 192 void file_compress(file, mode)
 193     char  *file;
 194     char  *mode;
 195 {
 196     local char outfile[MAX_NAME_LEN];
 197     FILE  *in;
 198     gzFile out;
 199
 200     strcpy(outfile, file);
 201     strcat(outfile, GZ_SUFFIX);
 202
 203     in = fopen(file, "rb");
 204     if (in == NULL) {
 205         perror(file);
 206         exit(1);
 207     }
 208     out = gzopen(outfile, mode);
 209     if (out == NULL) {
 210         fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
 211         exit(1);
 212     }
 213     gz_compress(in, out);
 214
 215     unlink(file);
 216 }
 217
 218
 219 /* ===========================================================================
 220  * Uncompress the given file and remove the original.
 221  */
 222 void file_uncompress(file)
 223     char  *file;
 224 {
 225     local char buf[MAX_NAME_LEN];
 226     char *infile, *outfile;
 227     FILE  *out;
 228     gzFile in;
 229     uInt len = (uInt)strlen(file);
 230
 231     strcpy(buf, file);
 232
 233     if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
 234         infile = file;
 235         outfile = buf;
 236         outfile[len-3] = '\0';
 237     } else {
 238         outfile = file;
 239         infile = buf;
 240         strcat(infile, GZ_SUFFIX);
 241     }
 242     in = gzopen(infile, "rb");
 243     if (in == NULL) {
 244         fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
 245         exit(1);
 246     }
 247     out = fopen(outfile, "wb");
 248     if (out == NULL) {
 249         perror(file);
 250         exit(1);
 251     }
 252
 253     gz_uncompress(in, out);
 254
 255     unlink(infile);
 256 }
 257
 258
 259 /* ===========================================================================
 260  * Usage:  minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]
 261  *   -d : decompress
 262  *   -f : compress with Z_FILTERED
 263  *   -h : compress with Z_HUFFMAN_ONLY
 264  *   -r : compress with Z_RLE
 265  *   -1 to -9 : compression level
 266  */
 267
 268 int main(argc, argv)
 269     int argc;
 270     char *argv[];
 271 {
 272     int uncompr = 0;
 273     gzFile file;
 274     char outmode[20];
 275
 276     strcpy(outmode, "wb6 ");
 277
 278     prog = argv[0];
 279     argc--, argv++;
 280
 281     while (argc > 0) {
 282       if (strcmp(*argv, "-d") == 0)
 283         uncompr = 1;
 284       else if (strcmp(*argv, "-f") == 0)
 285         outmode[3] = 'f';
 286       else if (strcmp(*argv, "-h") == 0)
 287         outmode[3] = 'h';
 288       else if (strcmp(*argv, "-r") == 0)
 289         outmode[3] = 'R';
 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 (outmode[3] == ' ')
 298         outmode[3] = 0;
 299     if (argc == 0) {
 300         SET_BINARY_MODE(stdin);
 301         SET_BINARY_MODE(stdout);
 302         if (uncompr) {
 303             file = gzdopen(fileno(stdin), "rb");
 304             if (file == NULL) error("can't gzdopen stdin");
 305             gz_uncompress(file, stdout);
 306         } else {
 307             file = gzdopen(fileno(stdout), outmode);
 308             if (file == NULL) error("can't gzdopen stdout");
 309             gz_compress(stdin, file);
 310         }
 311     } else {
 312         do {
 313             if (uncompr) {
 314                 file_uncompress(*argv);
 315             } else {
 316                 file_compress(*argv, outmode);
 317             }
 318         } while (argv++, --argc);
 319     }
 320     return 0;
 321 }