misc.c

WINDOWS下的ZIP解压软件,我是个学生,请让我加入这个网站学习

/*---------------------------------------------------------------------------

  misc.c

  This file contains a number of useful but not particularly closely related
  functions; their main claim to fame is that they don't change much, so this
  file should rarely need to be recompiled.  The CRC-32 stuff is from crc32.c;
  do_string() is from nunzip.c; makeword() and makelong() are from unzip.c;
  memset() and memcpy() are from zmemset.c and zmemcpy.c, respectively; and
  dos_to_unix_time() is from set_file_time_and_close() in file_io.c.  ebcdic[],
  check_for_newer(), dateformat(), and return_VMS() are new.  Things lumped
  together here to cut down on the size of unzip.c and the number of associ-
  ated files floating around.

  ---------------------------------------------------------------------------

  Copyrights:  see accompanying file "COPYING" in UnZip source distribution.

  ---------------------------------------------------------------------------*/


#include "unzip.h"
#ifdef MSWIN
#  include "wizunzip.h"
#endif



#ifndef ZIPINFO   /* no need to calculate CRCs */

/**************************/
/*  Function UpdateCRC()  */
/**************************/

 /*--------------------------------------------------------------------

   First, the polynomial itself and its table of feedback terms.  The
   polynomial is
   X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0

   Note that we take it "backwards" and put the highest-order term in
   the lowest-order bit.  The X^32 term is "implied"; the LSB is the
   X^31 term, etc.  The X^0 term (usually shown as "+1") results in
   the MSB being 1.

   Note that the usual hardware shift register implementation, which
   is what we're using (we're merely optimizing it by doing eight-bit
   chunks at a time) shifts bits into the lowest-order term.  In our
   implementation, that means shifting towards the right.  Why do we
   do it this way?  Because the calculated CRC must be transmitted in
   order from highest-order term to lowest-order term.  UARTs transmit
   characters in order from LSB to MSB.  By storing the CRC this way,
   we hand it to the UART in the order low-byte to high-byte; the UART
   sends each low-bit to hight-bit; and the result is transmission bit
   by bit from highest- to lowest-order term without requiring any bit
   shuffling on our part.  Reception works similarly.

   The feedback terms table consists of 256, 32-bit entries.  Notes:

       The table can be generated at runtime if desired; code to do so
       is shown later.  It might not be obvious, but the feedback
       terms simply represent the results of eight shift/xor opera-
       tions for all combinations of data and CRC register values.

       The values must be right-shifted by eight bits by the "updcrc"
       logic; the shift must be unsigned (bring in zeroes).  On some
       hardware you could probably optimize the shift in assembler by
       using byte-swap instructions.
       polynomial $edb88320

   --------------------------------------------------------------------*/

ULONG crc_32_tab[] =
{
    0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
    0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
    0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
    0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
    0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
    0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
    0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
    0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
    0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
    0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
    0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
    0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
    0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
    0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
    0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
    0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
    0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
    0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
    0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
    0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
    0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
    0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
    0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
    0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
    0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
    0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
    0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
    0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
    0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
    0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
    0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
    0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
    0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
    0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
    0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
    0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
    0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
    0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
    0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
    0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
    0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
    0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
    0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
    0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
    0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
    0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
    0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
    0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
    0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
    0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
    0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
    0x2d02ef8dL
}; /* end crc_32_tab[] */


void UpdateCRC(s, len)
    register byte *s;
    register int len;
{
    register ULONG crcval = crc32val;

    /* update running CRC calculation with contents of a buffer */
    while (len--)
        crcval = crc_32_tab[((byte) crcval ^ (*s++)) & 0xff] ^ (crcval >> 8);
    crc32val = crcval;
}

#endif /* !ZIPINFO */





/**************************/
/*  Function do_string()  */
/**************************/

int do_string(len, option)      /* return PK-type error code */
    unsigned int len;           /* without prototype, UWORD converted to this */
    int option;
{
    int block_length, error = 0;
    UWORD comment_bytes_left, extra_len;


/*---------------------------------------------------------------------------
    This function processes arbitrary-length (well, usually) strings.  Three
    options are allowed:  SKIP, wherein the string is skipped pretty logical,
    eh?); DISPLAY, wherein the string is printed to standard output after un-
    dergoing any necessary or unnecessary character conversions; and FILENAME,
    wherein the string is put into the filename[] array after undergoing ap-
    propriate conversions (including case-conversion, if that is indicated:
    see the global variable pInfo->lcflag).  The latter option should be OK,
    since filename is now dimensioned at 1025, but we check anyway.

    The string, by the way, is assumed to start at the current file-pointer
    position; its length is given by len.  So start off by checking length
    of string:  if zero, we're already set.
  ---------------------------------------------------------------------------*/

    if (!len)
        return (0);             /* 0:  no error */

    switch (option) {

    /*
     * First case:  print string on standard output.  First set loop vari-
     * ables, then loop through the comment in chunks of OUTBUFSIZ bytes,
     * converting formats and printing as we go.  The second half of the
     * loop conditional was added because the file might be truncated, in
     * which case comment_bytes_left will remain at some non-zero value for
     * all time.  outbuf is used as a scratch buffer because it is avail-
     * able (we should be either before or in between any file processing).
     * [The typecast in front of the MIN() macro was added because of the
     * new promotion rules under ANSI C; readbuf() wants an int, but MIN()
     * returns a signed long, if I understand things correctly.  The proto-
     * type should handle it, but just in case...]
     */

    case DISPLAY:
        comment_bytes_left = len;
        block_length = OUTBUFSIZ;    /* for the while statement, first time */
        while (comment_bytes_left > 0 && block_length > 0) {
            if ((block_length = readbuf((char *)outbuf,
                   (int) MIN(OUTBUFSIZ, comment_bytes_left))) <= 0)
                return 51;                      /* 51:  unexpected EOF */
            comment_bytes_left -= block_length;
            NUKE_CRs(outbuf, block_length);     /* (modifies block_length) */

            /*  this is why we allocated an extra byte for outbuf: */
            outbuf[block_length] = '\0';        /* terminate w/zero:  ASCIIZ */

            A_TO_N(outbuf);     /* translate string to native */
#ifdef MSWIN
            /* ran out of local mem -- had to cheat */
            WriteStringToMsgWin(outbuf, bRealTimeMsgUpdate);
#else /* !MSWIN */
            printf("%s", outbuf);
#endif /* ?MSWIN */
        }
        printf("\n");   /* assume no newline at end */
        break;

    /*
     * Second case:  read string into filename[] array.  The filename should
     * never ever be longer than FILNAMSIZ-1 (1024), but for now we'll check,
     * just to be sure.
     */

    case FILENAME:
        extra_len = 0;
        if (len >= FILNAMSIZ) {
            fprintf(stderr, "warning:  filename too long--truncating.\n");
            error = 1;          /* 1:  warning error */
            extra_len = len - FILNAMSIZ + 1;
            len = FILNAMSIZ - 1;
        }
        if (readbuf(filename, len) <= 0)
            return 51;          /* 51:  unexpected EOF */
        filename[len] = '\0';   /* terminate w/zero:  ASCIIZ */

        A_TO_N(filename);       /* translate string to native */

#ifndef ZIPINFO
        if (pInfo->lcflag)
            TOLOWER(filename, filename);  /* replace with lowercase filename */
#endif

        if (!extra_len)         /* we're done here */
            break;

        /*
         * We truncated the filename, so print what's left and then fall
         * through to the SKIP routine.
         */
        fprintf(stderr, "[ %s ]\n", filename);
        len = extra_len;
        /*  FALL THROUGH...  */

    /*
     * Third case:  skip string, adjusting readbuf's internal variables
     * as necessary (and possibly skipping to and reading a new block of
     * data).
     */

    case SKIP:
        LSEEK(cur_zipfile_bufstart + (inptr-inbuf) + len)
        break;

    /*
     * Fourth case:  assume we're at the start of an "extra field"; malloc
     * storage for it and read data into the allocated space.
     */

    case EXTRA_FIELD:
        if (extra_field != (byte *)NULL)
            free(extra_field);
        if ((extra_field = (byte *)malloc(len)) == (byte *)NULL) {
            fprintf(stderr,
              "warning:  extra field too long (%d).  Ignoring...\n", len);
            LSEEK(cur_zipfile_bufstart + (inptr-inbuf) + len)
        } else
            if (readbuf((char *)extra_field, len) <= 0)
                return 51;      /* 51:  unexpected EOF */
        break;

    } /* end switch (option) */
    return error;

} /* end function do_string() */





#ifndef ZIPINFO
#ifndef VMS

/*********************************/
/*  Function dos_to_unix_time()  */
/*********************************/

time_t dos_to_unix_time(ddate, dtime)
    unsigned ddate, dtime;
{
    static short yday[]={0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
    int yr, mo, dy, hh, mm, ss, leap;
    long m_time, days=0;
#if (!defined(MACOS) && !defined(MSC) && !defined(__GO32__))
#if (defined(BSD) || defined(MTS))
#ifndef __386BSD__
    static struct timeb tbp;
#endif /* __386BSD__ */
#else /* !(BSD || MTS) */
    extern long timezone;    /* declared in <time.h> for MSC (& Borland?) */
#endif /* ?(BSD || MTS) */
#endif /* !MACOS && !MSC && !__GO32__ */

#   define YRBASE  1970

    /* dissect date */
    yr = ((ddate >> 9) & 0x7f) + (1980 - YRBASE);
    mo = ((ddate >> 5) & 0x0f) - 1;
    dy = (ddate & 0x1f) - 1;

    /* dissect time */
    hh = (dtime >> 11) & 0x1f;
    mm = (dtime >> 5) & 0x3f;
    ss = (dtime & 0x1f) * 2;

    /* leap = # of leap years from BASE up to but not including current year */
    leap = ((yr + YRBASE - 1) / 4);   /* leap year base factor */

    /* How many days from BASE to this year? (& add expired days this year) */
    days = (yr * 365) + (leap - 492) + yday[mo];

    /* if year is a leap year and month is after February, add another day */
    if ((mo > 1) && ((yr+YRBASE)%4 == 0) && ((yr+YRBASE) != 2100))
        ++days;                 /* OK through 2199 */

    /* convert date & time to seconds relative to 00:00:00, 01/01/YRBASE */
    m_time = ((long)(days + dy) * 86400L) + ((long)hh * 3600) + (mm * 60) + ss;
      /* - 1;   MS-DOS times always rounded up to nearest even second */

#if (!defined(MACOS) && !defined(__GO32__))
#if (defined(BSD) || defined(MTS))
#ifndef __386BSD__
    ftime(&tbp);
    m_time += tbp.timezone * 60L;
#endif
#else /* !(BSD || MTS) */
#ifdef WIN32
    /* later... */
#else /* !WIN32 */
    tzset();                    /* set `timezone' */
#endif /* ?WIN32 */
    m_time += timezone;         /* account for timezone differences */
#endif /* ?(BSD || MTS) */
#endif /* !MACOS && !__GO32__ */

#ifdef __386BSD__
    m_time += localtime((time_t *) &m_time)->tm_gmtoff;
#else
    if (localtime((time_t *)&m_time)->tm_isdst)
        m_time -= 60L * 60L;    /* adjust for daylight savings time */
#endif /* __386BSD__ */

    return m_time;

} /* end function dos_to_unix_time() */

#endif /* !VMS */





/********************************/