path: root/lzf.c

/*
 * Copyright (c) 2006      Stefan Traby <stefan@hello-penguin.com>
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 *   3.  The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License version 2 (the "GPL"), in which case the
 * provisions of the GPL are applicable instead of the above. If you wish to
 * allow the use of your version of this file only under the terms of the
 * GPL and not to allow others to use your version of this file under the
 * BSD license, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the GPL. If
 * you do not delete the provisions above, a recipient may use your version
 * of this file under either the BSD or the GPL License.
 */

#include "config.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <limits.h>
#include "lzf.h"

#ifdef HAVE_GETOPT_H
# include <getopt.h>
#endif

#define BLOCKSIZE (1024 * 64 - 1)
#define MAX_BLOCKSIZE BLOCKSIZE

typedef unsigned char u8;

static off_t nr_read, nr_written;

static const char *imagename;
static enum { compress, uncompress, lzcat } mode = compress;
static int verbose = 0;
static int force = 0;
static long blocksize = BLOCKSIZE;

#ifdef HAVE_GETOPT_LONG

  struct option longopts[] = {
    {"compress", 0, 0, 'c'},
    {"decompress", 0, 0, 'd'},
    {"uncompress", 0, 0, 'd'},
    {"force", 0, 0, 'f'},
    {"help", 0, 0, 'h'},
    {"verbose", 0, 0, 'v'},
    {"blocksize", 1, 0, 'b'},
    {0, 0, 0, 0}
  };

  static const char *opt =
    "-c --compress    compress\n"
    "-d --decompress  decompress\n"
    "-f --force       force overwrite of output file\n"
    "-h --help        give this help\n" "-v --verbose     verbose mode\n" "-b # --blocksize # set blocksize\n" "\n";

#else

  static const char *opt =
    "-c   compress\n"
    "-d   decompress\n"
    "-f   force overwrite of output file\n"
    "-h   give this help\n"
    "-v   verbose mode\n"
    "-b # set blocksize\n"
    "\n";

#endif

static void
usage (int rc)
{
  fprintf (stderr, "\n"
           "lzf, a very lightweight compression/decompression utility written by Stefan Traby.\n"
           "uses liblzf written by Marc Lehmann <schmorp@schmorp.de> You can find more info at\n"
           "http://liblzf.plan9.de/\n"
           "\n"
           "usage: lzf [-dufhvb] [file ...]\n"
           "       unlzf [file ...]\n"
           "       lzcat [file ...]\n"
           "\n%s",
           opt);

  exit (rc);
}

static inline ssize_t
rread (int fd, void *buf, size_t len)
{
  ssize_t rc = 0, offset = 0;
  char *p = buf;

  while (len && (rc = read (fd, &p[offset], len)) > 0)
    {
      offset += rc;
      len -= rc;
    }

  nr_read += offset;

  if (rc < 0)
    return rc;

  return offset;
}

/* returns 0 if all written else -1 */
static inline ssize_t
wwrite (int fd, void *buf, size_t len)
{
  ssize_t rc;
  char *b = buf;
  size_t l = len;

  while (l)
    {
      rc = write (fd, b, l);
      if (rc < 0)
        {
          fprintf (stderr, "%s: write error: ", imagename);
          perror ("");
          return -1;
        }

      l -= rc;
      b += rc;
    }

  nr_written += len;
  return 0;
}

/*
 * Anatomy: an lzf file consists of any number of blocks in the following format:
 *
 * \x00   EOF (optional)
 * "ZV\0" 2-byte-usize <uncompressed data>
 * "ZV\1" 2-byte-csize 2-byte-usize <compressed data>
 * "ZV\2" 4-byte-crc32-0xdebb20e3 (NYI)
 */


#define TYPE0_HDR_SIZE 5
#define TYPE1_HDR_SIZE 7
#define MAX_HDR_SIZE 7
#define MIN_HDR_SIZE 5

static int
compress_fd (int from, int to)
{
  ssize_t us, cs, len;
  u8 buf1[MAX_BLOCKSIZE + MAX_HDR_SIZE + 16];
  u8 buf2[MAX_BLOCKSIZE + MAX_HDR_SIZE + 16];
  u8 *header;

  nr_read = nr_written = 0;
  while ((us = rread (from, &buf1[MAX_HDR_SIZE], blocksize)) > 0)
    {
      cs = lzf_compress (&buf1[MAX_HDR_SIZE], us, &buf2[MAX_HDR_SIZE], us > 4 ? us - 4 : us);
      if (cs)
        {
          header = &buf2[MAX_HDR_SIZE - TYPE1_HDR_SIZE];
          header[0] = 'Z';
          header[1] = 'V';
          header[2] = 1;
          header[3] = cs >> 8;
          header[4] = cs & 0xff;
          header[5] = us >> 8;
          header[6] = us & 0xff;
          len = cs + TYPE1_HDR_SIZE;
        }
      else
        {                       // write uncompressed
          header = &buf1[MAX_HDR_SIZE - TYPE0_HDR_SIZE];
          header[0] = 'Z';
          header[1] = 'V';
          header[2] = 0;
          header[3] = us >> 8;
          header[4] = us & 0xff;
          len = us + TYPE0_HDR_SIZE;
        }

      if (wwrite (to, header, len) == -1)
        return -1;
    }

  return 0;
}

static int
uncompress_fd (int from, int to)
{
  u8 header[MAX_HDR_SIZE];
  u8 buf1[MAX_BLOCKSIZE + MAX_HDR_SIZE + 16];
  u8 buf2[MAX_BLOCKSIZE + MAX_HDR_SIZE + 16];
  u8 *p;
  int l, rd;
  ssize_t rc, cs, us, bytes, over = 0;

  nr_read = nr_written = 0;
  while (1)
    {
      rc = rread (from, header + over, MAX_HDR_SIZE - over);
      if (rc < 0)
        {
          fprintf (stderr, "%s: read error: ", imagename);
          perror ("");
          return -1;
        }

      rc += over;
      over = 0;
      if (!rc || header[0] == 0)
        return 0;

      if (rc < MIN_HDR_SIZE || header[0] != 'Z' || header[1] != 'V')
        {
          fprintf (stderr, "%s: invalid data stream - magic not found or short header\n", imagename);
          return -1;
        }

      switch (header[2])
        {
          case 0:
            cs = -1;
            us = (header[3] << 8) | header[4];
            p = &header[TYPE0_HDR_SIZE];
            break;
          case 1:
            if (rc < TYPE1_HDR_SIZE)
              {
                goto short_read;
              }
            cs = (header[3] << 8) | header[4];
            us = (header[5] << 8) | header[6];
            p = &header[TYPE1_HDR_SIZE];
            break;
          default:
            fprintf (stderr, "%s: unknown blocktype\n", imagename);
            return -1;
        }

      bytes = cs == -1 ? us : cs;
      l = &header[rc] - p;

      if (l > 0)
        memcpy (buf1, p, l);

      if (l > bytes)
        {
          over = l - bytes;
          memmove (header, &p[bytes], over);
        }

      p = &buf1[l];
      rd = bytes - l;
      if (rd > 0)
        if ((rc = rread (from, p, rd)) != rd)
          goto short_read;

      if (cs == -1)
        {
          if (wwrite (to, buf1, us))
            return -1;
        }
      else
        {
          if (lzf_decompress (buf1, cs, buf2, us) != us)
            {
              fprintf (stderr, "%s: decompress: invalid stream - data corrupted\n", imagename);
              return -1;
            }

          if (wwrite (to, buf2, us))
            return -1;
        }
    }

  return 0;

short_read:
  fprintf (stderr, "%s: short data\n", imagename);
  return -1;
}

static int
open_out (const char *name)
{
  int fd;
  int m = O_EXCL;

  if (force)
    m = 0;

  fd = open (name, O_CREAT | O_WRONLY | O_TRUNC | m, 600);
  return fd;
}

static int
compose_name (const char *fname, char *oname)
{
  char *p;

  if (mode == compress)
    {
      if (strlen (fname) > PATH_MAX - 4)
        {
          fprintf (stderr, "%s: %s.lzf: name too long", imagename, fname);
          return -1;
        }

      strcpy (oname, fname);
      strcat (oname, ".lzf");
    }
  else
    {
      if (strlen (fname) > PATH_MAX)
        {
          fprintf (stderr, "%s: %s: name too long\n", imagename, fname);
          return -1;
        }

      strcpy (oname, fname);
      p = &oname[strlen (oname)] - 4;
      if (p < oname || strcmp (p, ".lzf"))
        {
          fprintf (stderr, "%s: %s: unknown suffix\n", imagename, fname);
          return -1;
        }

      *p = 0;
    }

  return 0;
}

static int
run_file (const char *fname)
{
  int fd, fd2;
  int rc;
  struct stat mystat;
  char oname[PATH_MAX + 1];

  if (mode != lzcat)
    if (compose_name (fname, oname))
      return -1;

  rc = lstat (fname, &mystat);
  fd = open (fname, O_RDONLY);
  if (rc || fd == -1)
    {
      fprintf (stderr, "%s: %s: ", imagename, fname);
      perror ("");
      return -1;
    }

  if (!S_ISREG (mystat.st_mode))
    {
      fprintf (stderr, "%s: %s: not a regular file.\n", imagename, fname);
      close (fd);
      return -1;
    }

  if (mode == lzcat)
    {
      rc = uncompress_fd (fd, 1);
      close (fd);
      return rc;
    }

  fd2 = open_out (oname);
  if (fd2 == -1)
    {
      fprintf (stderr, "%s: %s: ", imagename, oname);
      perror ("");
      close (fd);
      return -1;
    }

  if (mode == compress)
    {
      rc = compress_fd (fd, fd2);
      if (!rc && verbose)
        fprintf (stderr, "%s:  %5.1f%% -- replaced with %s\n",
                 fname, nr_read == 0 ? 0 : 100.0 - nr_written / ((double) nr_read / 100.0), oname);
    }
  else
    {
      rc = uncompress_fd (fd, fd2);
      if (!rc && verbose)
        fprintf (stderr, "%s:  %5.1f%% -- replaced with %s\n",
                 fname, nr_written == 0 ? 0 : 100.0 - nr_read / ((double) nr_written / 100.0), oname);
    }

  fchmod (fd2, mystat.st_mode);
  close (fd);
  close (fd2);

  if (!rc)
    unlink (fname);

  return rc;
}

int
main (int argc, char *argv[])
{
  char *p = argv[0];
  int optc;
  int rc = 0;

  errno = 0;
  p = getenv ("LZF_BLOCKSIZE");
  if (p)
    {
      blocksize = strtoul (p, 0, 0);
      if (errno || !blocksize || blocksize > MAX_BLOCKSIZE)
        blocksize = BLOCKSIZE;
    }

  p = strrchr (argv[0], '/');
  imagename = p ? ++p : argv[0];

  if (!strncmp (imagename, "un", 2) || !strncmp (imagename, "de", 2))
    mode = uncompress;

  if (strstr (imagename, "cat"))
    mode = lzcat;

#ifdef HAVE_GETOPT_LONG
  while ((optc = getopt_long (argc, argv, "cdfhvb:", longopts, 0)) != -1)
#else
  while ((optc = getopt (argc, argv, "cdfhvb:")) != -1)
#endif
    {
      switch (optc)
        {
          case 'c':
            mode = compress;
            break;
          case 'd':
            mode = uncompress;
            break;
          case 'f':
            force = 1;
            break;
          case 'h':
            usage (0);
            break;
          case 'v':
            verbose = 1;
            break;
          case 'b':
            errno = 0;
            blocksize = strtoul (optarg, 0, 0);
            if (errno || !blocksize || blocksize > MAX_BLOCKSIZE)
              blocksize = BLOCKSIZE;
            break;
          default:
            usage (1);
            break;
        }
    }

  if (optind == argc)
    {                           // stdin stdout
      if (!force)
        {
          if ((mode == uncompress || mode == lzcat) && isatty (0))
            {
              fprintf (stderr, "%s: compressed data not read from a terminal. Use -f to force decompression.\n", imagename);
              exit (1);
            }
          if (mode == compress && isatty (1))
            {
              fprintf (stderr, "%s: compressed data not written to a terminal. Use -f to force compression.\n", imagename);
              exit (1);
            }
        }

      if (mode == compress)
        rc = compress_fd (0, 1);
      else
        rc = uncompress_fd (0, 1);

      exit (rc ? 1 : 0);
    }

  while (optind < argc)
    rc |= run_file (argv[optind++]);

  exit (rc ? 1 : 0);
}