fileio.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.

    if (G.outfile == (FILE *)NULL) {
        Info(slide, 1, ((char *)slide, LoadFarString(CannotCreateFile),
          FnFilter1(G.filename)));
        return 1;
    }
#else /* !MTS */
#ifdef DEBUG
    Info(slide, 1, ((char *)slide,
      "open_outfile:  doing fopen(%s) for reading\n", FnFilter1(G.filename)));
    if ((G.outfile = fopen(G.filename, FOPR)) == (FILE *)NULL)
        Info(slide, 1, ((char *)slide,
          "open_outfile:  fopen(%s) for reading failed:  does not exist\n",
          FnFilter1(G.filename)));
    else {
        Info(slide, 1, ((char *)slide,
          "open_outfile:  fopen(%s) for reading succeeded:  file exists\n",
          FnFilter1(G.filename)));
        fclose(G.outfile);
    }
#endif /* DEBUG */
#ifdef NOVELL_BUG_FAILSAFE
    if (G.dne && ((G.outfile = fopen(G.filename, FOPR)) != (FILE *)NULL)) {
        Info(slide, 0x401, ((char *)slide, LoadFarString(NovellBug),
          FnFilter1(G.filename)));
        fclose(G.outfile);
        return 1;   /* with "./" fix in checkdir(), should never reach here */
    }
#endif /* NOVELL_BUG_FAILSAFE */
    Trace((stderr, "open_outfile:  doing fopen(%s) for writing\n",
      FnFilter1(G.filename)));
    if ((G.outfile = fopen(G.filename, FOPW)) == (FILE *)NULL) {
        Info(slide, 0x401, ((char *)slide, LoadFarString(CannotCreateFile),
          FnFilter1(G.filename)));
        return 1;
    }
    Trace((stderr, "open_outfile:  fopen(%s) for writing succeeded\n",
      FnFilter1(G.filename)));
#endif /* !MTS */
#endif /* !TOPS20 */

#ifdef USE_FWRITE
#ifdef DOS_NLM_OS2_W32
    /* 16-bit MSC: buffer size must be strictly LESS than 32K (WSIZE):  bogus */
    setbuf(G.outfile, (char *)NULL);   /* make output unbuffered */
#else /* !DOS_NLM_OS2_W32 */
#ifndef RISCOS
#ifdef _IOFBF  /* make output fully buffered (works just about like write()) */
    setvbuf(G.outfile, (char *)slide, _IOFBF, WSIZE);
#else
    setbuf(G.outfile, (char *)slide);
#endif
#endif /* !RISCOS */
#endif /* ?DOS_NLM_OS2_W32 */
#endif /* USE_FWRITE */
#ifdef OS2_W32
    /* preallocate the final file size to prevent file fragmentation */
    SetFileSize(G.outfile, G.lrec.ucsize);
#endif
    return 0;

} /* end function open_outfile() */

#endif /* !TANDEM */
#endif /* !VMS && !AOS_VS && !CMS_MVS && !MACOS */





/*
 * These functions allow NEXTBYTE to function without needing two bounds
 * checks.  Call defer_leftover_input() if you ever have filled G.inbuf
 * by some means other than readbyte(), and you then want to start using
 * NEXTBYTE.  When going back to processing bytes without NEXTBYTE, call
 * undefer_input().  For example, extract_or_test_member brackets its
 * central section that does the decompression with these two functions.
 * If you need to check the number of bytes remaining in the current
 * file while using NEXTBYTE, check (G.csize + G.incnt), not G.csize.
 */

/****************************/
/* function undefer_input() */
/****************************/

void undefer_input(__G)
    __GDEF
{
    if (G.incnt > 0)
        G.csize += G.incnt;
    if (G.incnt_leftover > 0) {
        /* We know that "(G.csize < MAXINT)" so we can cast G.csize to int:
         * This condition was checked when G.incnt_leftover was set > 0 in
         * defer_leftover_input(), and it is NOT allowed to touch G.csize
         * before calling undefer_input() when (G.incnt_leftover > 0)
         * (single exception: see read_byte()'s  "G.csize <= 0" handling) !!
         */
        G.incnt = G.incnt_leftover + (int)G.csize;
        G.inptr = G.inptr_leftover - (int)G.csize;
        G.incnt_leftover = 0;
    } else if (G.incnt < 0)
        G.incnt = 0;
} /* end function undefer_input() */





/***********************************/
/* function defer_leftover_input() */
/***********************************/

void defer_leftover_input(__G)
    __GDEF
{
    if ((long)G.incnt > G.csize) {
        /* (G.csize < MAXINT), we can safely cast it to int !! */
        if (G.csize < 0L)
            G.csize = 0L;
        G.inptr_leftover = G.inptr + (int)G.csize;
        G.incnt_leftover = G.incnt - (int)G.csize;
        G.incnt = (int)G.csize;
    } else
        G.incnt_leftover = 0;
    G.csize -= G.incnt;
} /* end function defer_leftover_input() */





/**********************/
/* Function readbuf() */
/**********************/

unsigned readbuf(__G__ buf, size)   /* return number of bytes read into buf */
    __GDEF
    char *buf;
    register unsigned size;
{
    register unsigned count;
    unsigned n;

    n = size;
    while (size) {
        if (G.incnt <= 0) {
            if ((G.incnt = read(G.zipfd, (char *)G.inbuf, INBUFSIZ)) == 0)
                return (n-size);
            else if (G.incnt < 0) {
                /* another hack, but no real harm copying same thing twice */
                (*G.message)((zvoid *)&G,
                  (uch *)LoadFarString(ReadError),  /* CANNOT use slide */
                  (ulg)strlen(LoadFarString(ReadError)), 0x401);
                return 0;  /* discarding some data; better than lock-up */
            }
            /* buffer ALWAYS starts on a block boundary:  */
            G.cur_zipfile_bufstart += INBUFSIZ;
            G.inptr = G.inbuf;
        }
        count = MIN(size, (unsigned)G.incnt);
        memcpy(buf, G.inptr, count);
        buf += count;
        G.inptr += count;
        G.incnt -= count;
        size -= count;
    }
    return n;

} /* end function readbuf() */





/***********************/
/* Function readbyte() */
/***********************/

int readbyte(__G)   /* refill inbuf and return a byte if available, else EOF */
    __GDEF
{
    if (G.mem_mode)
        return EOF;
    if (G.csize <= 0) {
        G.csize--;             /* for tests done after exploding */
        G.incnt = 0;
        return EOF;
    }
    if (G.incnt <= 0) {
        if ((G.incnt = read(G.zipfd, (char *)G.inbuf, INBUFSIZ)) == 0) {
            G.incnt = 0;       /* do not allow negative value to affect stuff */
            return EOF;
        } else if (G.incnt < 0) {  /* "fail" (abort, retry, ...) returns this */
            /* another hack, but no real harm copying same thing twice */
            (*G.message)((zvoid *)&G,
              (uch *)LoadFarString(ReadError),
              (ulg)strlen(LoadFarString(ReadError)), 0x401);
            echon();
#ifdef WINDLL
            longjmp(dll_error_return, 1);
#else
            DESTROYGLOBALS();
            EXIT(PK_BADERR);    /* totally bailing; better than lock-up */
#endif
        }
        G.cur_zipfile_bufstart += INBUFSIZ; /* always starts on block bndry */
        G.inptr = G.inbuf;
        defer_leftover_input(__G);           /* decrements G.csize */
    }

#if CRYPT
    if (G.pInfo->encrypted) {
        uch *p;
        int n;

        /* This was previously set to decrypt one byte beyond G.csize, when
         * incnt reached that far.  GRR said, "but it's required:  why?"  This
         * was a bug in fillinbuf() -- was it also a bug here?
         */
        for (n = G.incnt, p = G.inptr;  n--;  p++)
            zdecode(*p);
    }
#endif /* CRYPT */

    --G.incnt;
    return *G.inptr++;

} /* end function readbyte() */





#ifdef USE_ZLIB

/************************/
/* Function fillinbuf() */
/************************/

int fillinbuf(__G) /* like readbyte() except returns number of bytes in inbuf */
    __GDEF
{
    if (G.mem_mode ||
                  (G.incnt = read(G.zipfd, (char *)G.inbuf, INBUFSIZ)) <= 0)
        return 0;
    G.cur_zipfile_bufstart += INBUFSIZ;  /* always starts on a block boundary */
    G.inptr = G.inbuf;
    defer_leftover_input(__G);           /* decrements G.csize */

#if CRYPT
    if (G.pInfo->encrypted) {
        uch *p;
        int n;

        for (n = G.incnt, p = G.inptr;  n--;  p++)
            zdecode(*p);
    }
#endif /* CRYPT */

    return G.incnt;

} /* end function fillinbuf() */

#endif /* USE_ZLIB */





/************************/
/* Function seek_zipf() */
/************************/

int seek_zipf(__G__ abs_offset)
    __GDEF
    Z_OFF_T abs_offset;
{
/*
 *  Seek to the block boundary of the block which includes abs_offset,
 *  then read block into input buffer and set pointers appropriately.
 *  If block is already in the buffer, just set the pointers.  This function
 *  is used by do_seekable (process.c), extract_or_test_entrylist (extract.c)
 *  and do_string (fileio.c).  Also, a slightly modified version is embedded
 *  within extract_or_test_entrylist (extract.c).  readbyte() and readbuf()
 *  (fileio.c) are compatible.  NOTE THAT abs_offset is intended to be the
 *  "proper offset" (i.e., if there were no extra bytes prepended);
 *  cur_zipfile_bufstart contains the corrected offset.
 *
 *  Since seek_zipf() is never used during decompression, it is safe to
 *  use the slide[] buffer for the error message.
 *
 * returns PK error codes:
 *  PK_BADERR if effective offset in zipfile is negative
 *  PK_EOF if seeking past end of zipfile
 *  PK_OK when seek was successful
 */
    Z_OFF_T request = abs_offset + G.extra_bytes;
    Z_OFF_T inbuf_offset = request % INBUFSIZ;
    Z_OFF_T bufstart = request - inbuf_offset;

    if (request < 0) {
        Info(slide, 1, ((char *)slide, LoadFarStringSmall(SeekMsg),
             G.zipfn, LoadFarString(ReportMsg)));
        return(PK_BADERR);
    } else if (bufstart != G.cur_zipfile_bufstart) {
        Trace((stderr,
          "fpos_zip: abs_offset = %ld, G.extra_bytes = %ld\n",
          abs_offset, G.extra_bytes));
#ifdef USE_STRM_INPUT
        fseek(G.zipfd, bufstart, SEEK_SET);
        G.cur_zipfile_bufstart = ftell(G.zipfd);
#else /* !USE_STRM_INPUT */
        G.cur_zipfile_bufstart = lseek(G.zipfd, bufstart, SEEK_SET);
#endif /* ?USE_STRM_INPUT */
        Trace((stderr,
          "       request = %ld, (abs+extra) = %ld, inbuf_offset = %ld\n",
          request, (abs_offset+G.extra_bytes), inbuf_offset));
        Trace((stderr, "       bufstart = %ld, cur_zipfile_bufstart = %ld\n",
          bufstart, G.cur_zipfile_bufstart));
        if ((G.incnt = read(G.zipfd, (char *)G.inbuf, INBUFSIZ)) <= 0)
            return(PK_EOF);
        G.incnt -= (int)inbuf_offset;
        G.inptr = G.inbuf + (int)inbuf_offset;
    } else {
        G.incnt += (G.inptr-G.inbuf) - (int)inbuf_offset;
        G.inptr = G.inbuf + (int)inbuf_offset;
    }
    return(PK_OK);
} /* end function seek_zipf() */





#ifndef VMS  /* for VMS use code in vms.c */

/********************/
/* Function flush() */   /* returns PK error codes: */
/********************/   /* if cflag => always 0; PK_DISK if write error */

int flush(__G__ rawbuf, size, unshrink)
    __GDEF
    uch *rawbuf;
    ulg size;
    int unshrink;
#if (defined(USE_DEFLATE64) && defined(__16BIT__))
{
    int ret;

    /* On 16-bit systems (MSDOS, OS/2 1.x), the standard C library functions
     * cannot handle writes of 64k blocks at once.  For these systems, the
     * blocks to flush are split into pieces of 32k or less.
     */
    while (size > 0x8000L) {
        ret = partflush(__G__ rawbuf, 0x8000L, unshrink);
        if (ret != PK_OK)
            return ret;
        size -= 0x8000L;
        rawbuf += (extent)0x8000;
    }
    return partflush(__G__ rawbuf, size, unshrink);
} /* end function flush() */


/************************/
/* Function partflush() */  /* returns PK error codes: */
/************************/  /* if cflag => always 0; PK_DISK if write error */

static int partflush(__G__ rawbuf, size, unshrink)
    __GDEF
    uch *rawbuf;        /* cannot be ZCONST, gets passed to (*G.message)() */
    ulg size;
    int unshrink;
#endif /* USE_DEFLATE64 && __16BIT__ */
{
    register uch *p;
    register uch *q;
    uch *transbuf;
#if (defined(SMALL_MEM) || defined(MED_MEM) || defined(VMS_TEXT_CONV))
    ulg transbufsiz;
#endif
    /* static int didCRlast = FALSE;    moved to globals.h */


/*---------------------------------------------------------------------------
    Compute the CRC first; if testing or if disk is full, that's it.