process.c

压缩解压,是unzip540的升级,这个外国网站摘来的源码,是evb编写.

          ((error_in_archive = find_ecrec(__G__ MIN(G.ziplen,66000L))) != 0 ||
          (error_in_archive = uz_end_central(__G)) > PK_WARN)))
    {
        CLOSE_INFILE();

#ifdef SFX
        ++lastchance;   /* avoid picky compiler warnings */
        return error_in_archive;
#else
        if (maybe_exe)
            Info(slide, 0x401, ((char *)slide, LoadFarString(MaybeExe),
            G.zipfn));
        if (lastchance)
            return error_in_archive;
        else {
            G.no_ecrec = TRUE;    /* assume we found wrong file:  e.g., */
            return PK_NOZIP;       /*  unzip instead of unzip.zip */
        }
#endif /* ?SFX */
    }

    if ((uO.zflag > 0) && !uO.zipinfo_mode) { /* unzip: zflag = comment ONLY */
        CLOSE_INFILE();
        return error_in_archive;
    }

/*---------------------------------------------------------------------------
    Test the end-of-central-directory info for incompatibilities (multi-disk
    archives) or inconsistencies (missing or extra bytes in zipfile).
  ---------------------------------------------------------------------------*/

#ifdef NO_MULTIPART
    error = !uO.zipinfo_mode && (G.ecrec.number_this_disk == 1) &&
            (G.ecrec.num_disk_start_cdir == 1);
#else
    error = !uO.zipinfo_mode && (G.ecrec.number_this_disk != 0);
#endif

#ifndef SFX
    if (uO.zipinfo_mode &&
        G.ecrec.number_this_disk != G.ecrec.num_disk_start_cdir)
    {
        if (G.ecrec.number_this_disk > G.ecrec.num_disk_start_cdir) {
            Info(slide, 0x401, ((char *)slide,
              LoadFarString(CentDirNotInZipMsg), G.zipfn,
              G.ecrec.number_this_disk, G.ecrec.num_disk_start_cdir));
            error_in_archive = PK_FIND;
            too_weird_to_continue = TRUE;
        } else {
            Info(slide, 0x401, ((char *)slide,
              LoadFarString(EndCentDirBogus), G.zipfn,
              G.ecrec.number_this_disk, G.ecrec.num_disk_start_cdir));
            error_in_archive = PK_WARN;
        }
#ifdef NO_MULTIPART   /* concatenation of multiple parts works in some cases */
    } else if (!uO.zipinfo_mode && !error && G.ecrec.number_this_disk != 0) {
        Info(slide, 0x401, ((char *)slide, LoadFarString(NoMultiDiskArcSupport),
          G.zipfn));
        error_in_archive = PK_FIND;
        too_weird_to_continue = TRUE;
#endif
    }

    if (!too_weird_to_continue) {  /* (relatively) normal zipfile:  go for it */
        if (error) {
            Info(slide, 0x401, ((char *)slide, LoadFarString(MaybePakBug),
              G.zipfn));
            error_in_archive = PK_WARN;
        }
#endif /* !SFX */
        if ((G.extra_bytes = G.real_ecrec_offset-G.expect_ecrec_offset) <
            (Z_OFF_T)0)
        {
            Info(slide, 0x401, ((char *)slide, LoadFarString(MissingBytes),
              G.zipfn, (long)(-G.extra_bytes)));
            error_in_archive = PK_ERR;
        } else if (G.extra_bytes > 0) {
            if ((G.ecrec.offset_start_central_directory == 0) &&
                (G.ecrec.size_central_directory != 0))   /* zip 1.5 -go bug */
            {
                Info(slide, 0x401, ((char *)slide,
                  LoadFarString(NullCentDirOffset), G.zipfn));
                G.ecrec.offset_start_central_directory = G.extra_bytes;
                G.extra_bytes = 0;
                error_in_archive = PK_ERR;
            }
#ifndef SFX
            else {
                Info(slide, 0x401, ((char *)slide,
                  LoadFarString(ExtraBytesAtStart), G.zipfn,
                  (long)G.extra_bytes, (G.extra_bytes == 1)? "":"s"));
                error_in_archive = PK_WARN;
            }
#endif /* !SFX */
        }

    /*-----------------------------------------------------------------------
        Check for empty zipfile and exit now if so.
      -----------------------------------------------------------------------*/

        if (G.expect_ecrec_offset==0L && G.ecrec.size_central_directory==0) {
            if (uO.zipinfo_mode)
                Info(slide, 0, ((char *)slide, "%sEmpty zipfile.\n",
                  uO.lflag>9? "\n  " : ""));
            else
                Info(slide, 0x401, ((char *)slide, LoadFarString(ZipfileEmpty),
                                    G.zipfn));
            CLOSE_INFILE();
            return (error_in_archive > PK_WARN)? error_in_archive : PK_WARN;
        }

    /*-----------------------------------------------------------------------
        Compensate for missing or extra bytes, and seek to where the start
        of central directory should be.  If header not found, uncompensate
        and try again (necessary for at least some Atari archives created
        with STZip, as well as archives created by J.H. Holm's ZIPSPLIT 1.1).
      -----------------------------------------------------------------------*/

        error = seek_zipf(__G__ G.ecrec.offset_start_central_directory);
        if (error == PK_BADERR) {
            CLOSE_INFILE();
            return PK_BADERR;
        }
#ifdef OLD_SEEK_TEST
        if (error != PK_OK || readbuf(__G__ G.sig, 4) == 0) {
            CLOSE_INFILE();
            return PK_ERR;  /* file may be locked, or possibly disk error(?) */
        }
        if (strncmp(G.sig, central_hdr_sig, 4))
#else
        if ((error != PK_OK) || (readbuf(__G__ G.sig, 4) == 0) ||
            strncmp(G.sig, central_hdr_sig, 4))
#endif
        {
#ifndef SFX
            long tmp = G.extra_bytes;
#endif

            G.extra_bytes = 0;
            error = seek_zipf(__G__ G.ecrec.offset_start_central_directory);
            if ((error != PK_OK) || (readbuf(__G__ G.sig, 4) == 0) ||
                strncmp(G.sig, central_hdr_sig, 4))
            {
                if (error != PK_BADERR)
                  Info(slide, 0x401, ((char *)slide,
                    LoadFarString(CentDirStartNotFound), G.zipfn,
                    LoadFarStringSmall(ReportMsg)));
                CLOSE_INFILE();
                return (error != PK_OK ? error : PK_BADERR);
            }
#ifndef SFX
            Info(slide, 0x401, ((char *)slide, LoadFarString(CentDirTooLong),
              G.zipfn, -tmp));
#endif
            error_in_archive = PK_ERR;
        }

    /*-----------------------------------------------------------------------
        Seek to the start of the central directory one last time, since we
        have just read the first entry's signature bytes; then list, extract
        or test member files as instructed, and close the zipfile.
      -----------------------------------------------------------------------*/

        error = seek_zipf(__G__ G.ecrec.offset_start_central_directory);
        if (error != PK_OK) {
            CLOSE_INFILE();
            return error;
        }

        Trace((stderr, "about to extract/list files (error = %d)\n",
          error_in_archive));

#ifdef DLL
        /* G.fValidate is used only to look at an archive to see if
           it appears to be a valid archive.  There is no interest
           in what the archive contains, nor in validating that the
           entries in the archive are in good condition.  This is
           currently used only in the Windows DLLs for purposes of
           checking archives within an archive to determine whether
           or not to display the inner archives.
         */
        if (!G.fValidate)
#endif
        {
#ifndef NO_ZIPINFO
            if (uO.zipinfo_mode)
                error = zipinfo(__G);                 /* ZIPINFO 'EM */
            else
#endif
#ifndef SFX
#ifdef TIMESTAMP
            if (uO.T_flag)
                error = get_time_stamp(__G__ &uxstamp, &nmember);
            else
#endif
            if (uO.vflag && !uO.tflag && !uO.cflag)
                error = list_files(__G);              /* LIST 'EM */
            else
#endif /* !SFX */
                error = extract_or_test_files(__G);   /* EXTRACT OR TEST 'EM */

            Trace((stderr, "done with extract/list files (error = %d)\n",
                   error));
        }

        if (error > error_in_archive)   /* don't overwrite stronger error */
            error_in_archive = error;   /*  with (for example) a warning */
#ifndef SFX
    } /* end if (!too_weird_to_continue) */
#endif

    CLOSE_INFILE();

#ifdef TIMESTAMP
    if (uO.T_flag && !uO.zipinfo_mode && (nmember > 0L)) {
# ifdef WIN32
        if (stamp_file(__G__ G.zipfn, uxstamp)) {       /* TIME-STAMP 'EM */
# else
        if (stamp_file(G.zipfn, uxstamp)) {             /* TIME-STAMP 'EM */
# endif
            if (uO.qflag < 3)
                Info(slide, 0x201, ((char *)slide,
                  "warning:  cannot set time for %s\n", G.zipfn));
            if (error_in_archive < PK_WARN)
                error_in_archive = PK_WARN;
        }
    }
#endif
    return error_in_archive;

} /* end function do_seekable() */





/*************************/
/* Function find_ecrec() */
/*************************/

static int find_ecrec(__G__ searchlen)          /* return PK-class error */
    __GDEF
    long searchlen;
{
    int i, numblks, found=FALSE;
    Z_OFF_T tail_len;
    ec_byte_rec byterec;


/*---------------------------------------------------------------------------
    Treat case of short zipfile separately.
  ---------------------------------------------------------------------------*/

    if (G.ziplen <= INBUFSIZ) {
        lseek(G.zipfd, 0L, SEEK_SET);
        if ((G.incnt = read(G.zipfd,(char *)G.inbuf,(unsigned int)G.ziplen))
            == (int)G.ziplen)

            /* 'P' must be at least (ECREC_SIZE+4) bytes from end of zipfile */
            for (G.inptr = G.inbuf+(int)G.ziplen-(ECREC_SIZE+4);
                 G.inptr >= G.inbuf;
                 --G.inptr) {
                if ( (*G.inptr == (uch)0x50) &&         /* ASCII 'P' */
                     !strncmp((char *)G.inptr, end_central_sig, 4)) {
                    G.incnt -= (int)(G.inptr - G.inbuf);
                    found = TRUE;
                    break;
                }
            }

/*---------------------------------------------------------------------------
    Zipfile is longer than INBUFSIZ:  may need to loop.  Start with short
    block at end of zipfile (if not TOO short).
  ---------------------------------------------------------------------------*/

    } else {
        if ((tail_len = G.ziplen % INBUFSIZ) > ECREC_SIZE) {
#ifdef USE_STRM_INPUT
            fseek((FILE *)G.zipfd, G.ziplen-tail_len, SEEK_SET);
            G.cur_zipfile_bufstart = ftell((FILE *)G.zipfd);
#else /* !USE_STRM_INPUT */
            G.cur_zipfile_bufstart = lseek(G.zipfd, G.ziplen-tail_len,
              SEEK_SET);
#endif /* ?USE_STRM_INPUT */
            if ((G.incnt = read(G.zipfd, (char *)G.inbuf,
                (unsigned int)tail_len)) != (int)tail_len)
                goto fail;      /* it's expedient... */

            /* 'P' must be at least (ECREC_SIZE+4) bytes from end of zipfile */
            for (G.inptr = G.inbuf+(int)tail_len-(ECREC_SIZE+4);
                 G.inptr >= G.inbuf;
                 --G.inptr) {
                if ( (*G.inptr == (uch)0x50) &&         /* ASCII 'P' */
                     !strncmp((char *)G.inptr, end_central_sig, 4)) {
                    G.incnt -= (int)(G.inptr - G.inbuf);
                    found = TRUE;
                    break;
                }
            }
            /* sig may span block boundary: */
            memcpy((char *)G.hold, (char *)G.inbuf, 3);
        } else
            G.cur_zipfile_bufstart = G.ziplen - tail_len;

    /*-----------------------------------------------------------------------
        Loop through blocks of zipfile data, starting at the end and going
        toward the beginning.  In general, need not check whole zipfile for
        signature, but may want to do so if testing.
      -----------------------------------------------------------------------*/

        numblks = (int)((searchlen - tail_len + (INBUFSIZ-1)) / INBUFSIZ);
        /*               ==amount=   ==done==   ==rounding==    =blksiz=  */

        for (i = 1;  !found && (i <= numblks);  ++i) {
            G.cur_zipfile_bufstart -= INBUFSIZ;
            lseek(G.zipfd, G.cur_zipfile_bufstart, SEEK_SET);
            if ((G.incnt = read(G.zipfd,(char *)G.inbuf,INBUFSIZ))
                != INBUFSIZ)
                break;          /* fall through and fail */

            for (G.inptr = G.inbuf+INBUFSIZ-1;  G.inptr >= G.inbuf;
                 --G.inptr)
                if ((native(*G.inptr) == 'P')  &&
                     !strncmp((char *)G.inptr, end_central_sig, 4)) {
                    G.incnt -= (int)(G.inptr - G.inbuf);
                    found = TRUE;
                    break;
                }
            /* sig may span block boundary: */
            memcpy((char *)G.hold, (char *)G.inbuf, 3);
        }
    } /* end if (ziplen > INBUFSIZ) */

/*---------------------------------------------------------------------------
    Searched through whole region where signature should be without finding
    it.  Print informational message and die a horrible death.