zlib/minigzip.c

   1 /* minigzip.c -- simulate gzip using the zlib compression library
   2  * Copyright (C) 1995-2002 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,v 1.1.1.2 2002/03/11 21:53:26 tromey Exp $ */
  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 }