nt.c

压缩算法的源代码

    /* Only need check those characters which are legal in HPFS but not
     * in FAT:  to get here, must already have passed through mapname.
     * (GRR:  oops, small bug--if char was quoted, no longer have any
     * knowledge of that.)  Also must truncate path component to ensure
     * 8.3 compliance...
     */
    while ((workch = (uch)*ppc++) != 0) {
        switch (workch) {
            case '[':
            case ']':
                *pEnd++ = '_';      /* convert brackets to underscores */
                break;

            case '.':
                if (pEnd == *pEndFAT) {   /* nothing appended yet... */
                    if (*ppc == '\0')     /* don't bother appending a */
                        break;            /*  "./" component to the path */
                    else if (*ppc == '.' && ppc[1] == '\0') {   /* "../" */
                        *pEnd++ = '.';    /* add first dot, unchanged... */
                        ++ppc;            /* skip second dot, since it will */
                    } else {              /*  be "added" at end of if-block */
                        *pEnd++ = '_';    /* FAT doesn't allow null filename */
                        dotname = TRUE;   /*  bodies, so map .exrc -> _.exrc */
                    }                     /*  (extra '_' now, "dot" below) */
                } else if (dotname) {     /* found a second dot, but still */
                    dotname = FALSE;      /*  have extra leading underscore: */
                    *pEnd = '\0';         /*  remove it by shifting chars */
                    pEnd = *pEndFAT + 1;  /*  left one space (e.g., .p1.p2: */
                    while (pEnd[1]) {     /*  __p1 -> _p1_p2 -> _p1.p2 when */
                        *pEnd = pEnd[1];  /*  finished) [opt.:  since first */
                        ++pEnd;           /*  two chars are same, can start */
                    }                     /*  shifting at second position] */
                }
                last_dot = pEnd;    /* point at last dot so far... */
                *pEnd++ = '_';      /* convert dot to underscore for now */
                break;

            default:
                *pEnd++ = (char)workch;

        } /* end switch */
    } /* end while loop */

    *pEnd = '\0';                 /* terminate buildpathFAT */

    /* NOTE:  keep in mind that pEnd points to the end of the path
     * component, and *pEndFAT still points to the *beginning* of it...
     * Also note that the algorithm does not try to get too fancy:
     * if there are no dots already, the name either gets truncated
     * at 8 characters or the last underscore is converted to a dot
     * (only if more characters are saved that way).  In no case is
     * a dot inserted between existing characters.
     */
    if (last_dot == NULL) {       /* no dots:  check for underscores... */
        char *plu = strrchr(pBegin, '_');   /* pointer to last underscore */

        if (plu == NULL) {   /* no dots, no underscores:  truncate at 8 chars */
            *pEndFAT += 8;        /* (or could insert '.' and keep 11...?) */
            if (*pEndFAT > pEnd)
                *pEndFAT = pEnd;  /* oops...didn't have 8 chars to truncate */
            else
                **pEndFAT = '\0';
        } else if (MIN(plu - pBegin, 8) + MIN(pEnd - plu - 1, 3) > 8) {
            last_dot = plu;       /* be lazy:  drop through to next if-blk */
        } else if ((pEnd - *pEndFAT) > 8) {
            *pEndFAT += 8;        /* more fits into just basename than if */
            **pEndFAT = '\0';     /*  convert last underscore to dot */
        } else
            *pEndFAT = pEnd;      /* whole thing fits into 8 chars or less */
    }

    if (last_dot != NULL) {       /* one dot (or two, in the case of */
        *last_dot = '.';          /*  "..") is OK:  put it back in */

        if ((last_dot - pBegin) > 8) {
            char *p=last_dot, *q=pBegin+8;
            int i;

            for (i = 0;  (i < 4) && *p;  ++i)  /* too many chars in basename: */
                *q++ = *p++;                   /*  shift .ext left and trun- */
            *q = '\0';                         /*  cate/terminate it */
            *pEndFAT = q;
        } else if ((pEnd - last_dot) > 4) {    /* too many chars in extension */
            *pEndFAT = last_dot + 4;
            **pEndFAT = '\0';
        } else
            *pEndFAT = pEnd;   /* filename is fine; point at terminating zero */
    }
} /* end function map2fat() */




/***********************/       /* Borrowed from os2.c for UnZip 5.1.        */
/* Function checkdir() */       /* Difference: no EA stuff                   */
/***********************/       /*             HPFS stuff works on NTFS too  */

int checkdir(pathcomp, flag)
    char *pathcomp;
    int flag;
/*
 * returns:  1 - (on APPEND_NAME) truncated filename
 *           2 - path doesn't exist, not allowed to create
 *           3 - path doesn't exist, tried to create and failed; or
 *               path exists and is not a directory, but is supposed to be
 *           4 - path is too long
 *          10 - can't allocate memory for filename buffers
 */
{
    static int rootlen = 0;      /* length of rootpath */
    static char *rootpath;       /* user's "extract-to" directory */
    static char *buildpathHPFS;  /* full path (so far) to extracted file, */
    static char *buildpathFAT;   /*  both HPFS/EA (main) and FAT versions */
    static char *endHPFS;        /* corresponding pointers to end of */
    static char *endFAT;         /*  buildpath ('\0') */

#   define FN_MASK   7
#   define FUNCTION  (flag & FN_MASK)



/*---------------------------------------------------------------------------
    APPEND_DIR:  append the path component to the path being built and check
    for its existence.  If doesn't exist and we are creating directories, do
    so for this one; else signal success or error as appropriate.
  ---------------------------------------------------------------------------*/

    if (FUNCTION == APPEND_DIR) {
        char *p = pathcomp;
        int too_long=FALSE;

        Trace((stderr, "appending dir segment [%s]\n", pathcomp));
        while ((*endHPFS = *p++) != '\0')     /* copy to HPFS filename */
            ++endHPFS;
        if (IsFileNameValid(buildpathHPFS)) {
            p = pathcomp;
            while ((*endFAT = *p++) != '\0')  /* copy to FAT filename, too */
                ++endFAT;
        } else {
/* GRR:  check error return? */
            map2fat(pathcomp, &endFAT);  /* map, put in FAT fn, update endFAT */
        }

        /* GRR:  could do better check, see if overrunning buffer as we go:
         * check endHPFS-buildpathHPFS after each append, set warning variable
         * if within 20 of FILNAMSIZ; then if var set, do careful check when
         * appending.  Clear variable when begin new path. */

        /* next check:  need to append '/', at least one-char name, '\0' */
        if ((endHPFS-buildpathHPFS) > FILNAMSIZ-3)
            too_long = TRUE;                 /* check if extracting dir? */
        if (stat(buildpathFAT, &statbuf))    /* path doesn't exist */
        {
            if (!create_dirs) {   /* told not to create (freshening) */
                free(buildpathHPFS);
                free(buildpathFAT);
                return 2;         /* path doesn't exist:  nothing to do */
            }
            if (too_long) {   /* GRR:  should allow FAT extraction w/o EAs */
                FPRINTF(stderr, "checkdir error:  path too long: %s\n",
                  buildpathHPFS);
                fflush(stderr);
                free(buildpathHPFS);
                free(buildpathFAT);
                return 4;         /* no room for filenames:  fatal */
            }
            if (MKDIR(buildpathFAT, 0777) == -1) {   /* create the directory */
                FPRINTF(stderr, "checkdir error:  can't create %s\n\
                 unable to process %s.\n", buildpathFAT, filename);
                fflush(stderr);
                free(buildpathHPFS);
                free(buildpathFAT);
                return 3;      /* path didn't exist, tried to create, failed */
            }
            created_dir = TRUE;
        } else if (!S_ISDIR(statbuf.st_mode)) {
            FPRINTF(stderr, "checkdir error:  %s exists but is not directory\n\
                 unable to process %s.\n", buildpathFAT, filename);
            fflush(stderr);
            free(buildpathHPFS);
            free(buildpathFAT);
            return 3;          /* path existed but wasn't dir */
        }
        if (too_long) {
            FPRINTF(stderr, "checkdir error:  path too long: %s\n",
              buildpathHPFS);
            fflush(stderr);
            free(buildpathHPFS);
            free(buildpathFAT);
            return 4;         /* no room for filenames:  fatal */
        }
        *endHPFS++ = '/';
        *endFAT++ = '/';
        *endHPFS = *endFAT = '\0';
        Trace((stderr, "buildpathHPFS now = [%s]\n", buildpathHPFS));
        Trace((stderr, "buildpathFAT now =  [%s]\n", buildpathFAT));
        return 0;

    } /* end if (FUNCTION == APPEND_DIR) */

/*---------------------------------------------------------------------------
    GETPATH:  copy full FAT path to the string pointed at by pathcomp (want
    filename to reflect name used on disk, not EAs; if full path is HPFS,
    buildpathFAT and buildpathHPFS will be identical).  Also free both paths.
  ---------------------------------------------------------------------------*/

    if (FUNCTION == GETPATH) {
        Trace((stderr, "getting and freeing FAT path [%s]\n", buildpathFAT));
        Trace((stderr, "freeing HPFS path [%s]\n", buildpathHPFS));
        strcpy(pathcomp, buildpathFAT);
        free(buildpathFAT);
        free(buildpathHPFS);
        buildpathHPFS = buildpathFAT = endHPFS = endFAT = NULL;
        return 0;
    }

/*---------------------------------------------------------------------------
    APPEND_NAME:  assume the path component is the filename; append it and
    return without checking for existence.
  ---------------------------------------------------------------------------*/

    if (FUNCTION == APPEND_NAME) {
        char *p = pathcomp;
        int error = 0;

        Trace((stderr, "appending filename [%s]\n", pathcomp));
        while ((*endHPFS = *p++) != '\0') {    /* copy to HPFS filename */
            ++endHPFS;
            if ((endHPFS-buildpathHPFS) >= FILNAMSIZ) {
                *--endHPFS = '\0';
                FPRINTF(stderr, "checkdir warning:  path too long; truncating\n\
                   %s\n                -> %s\n", filename, buildpathHPFS);
                fflush(stderr);
                error = 1;   /* filename truncated */
            }
        }

        if ( pInfo->vollabel || IsFileNameValid(buildpathHPFS)) {
            p = pathcomp;
            while ((*endFAT = *p++) != '\0')   /* copy to FAT filename, too */
                ++endFAT;
        } else {
            map2fat(pathcomp, &endFAT);  /* map, put in FAT fn, update endFAT */
        }
        Trace((stderr, "buildpathHPFS: %s\nbuildpathFAT:  %s\n",
          buildpathHPFS, buildpathFAT));

        return error;  /* could check for existence, prompt for new name... */

    } /* end if (FUNCTION == APPEND_NAME) */

/*---------------------------------------------------------------------------
    INIT:  allocate and initialize buffer space for the file currently being
    extracted.  If file was renamed with an absolute path, don't prepend the
    extract-to path.
  ---------------------------------------------------------------------------*/

    if (FUNCTION == INIT) {

/* HG: variable not used here */
/*      char *p;              */

        Trace((stderr, "initializing buildpathHPFS and buildpathFAT to "));
        if ((buildpathHPFS = (char *)malloc(fnlen+rootlen+1)) == NULL)
            return 10;
        if ((buildpathFAT = (char *)malloc(fnlen+rootlen+1)) == NULL) {
            free(buildpathHPFS);
            return 10;
        }
        if (pInfo->vollabel) {  /* use root or renamed path, but don't store */
/* GRR:  for network drives, do strchr() and return IZ_VOL_LABEL if not [1] */
            if (renamed_fullpath && pathcomp[1] == ':')
                *buildpathHPFS = ToLower(*pathcomp);
            else if (!renamed_fullpath && rootpath && rootpath[1] == ':')
                *buildpathHPFS = ToLower(*rootpath);
            else {
                char tmpN[MAX_PATH], *tmpP;
                if (GetFullPathName(".", MAX_PATH, tmpN, &tmpP) > MAX_PATH)
                { /* by definition of MAX_PATH we should never get here */
                    FPRINTF(stderr,
                            "checkdir warning: current dir path too long\n");
                    return 1;   /* can't get drive letter */
                }
                nLabelDrive = *tmpN - 'a' + 1;
                *buildpathHPFS = (char)(nLabelDrive - 1 + 'a');
            }
            nLabelDrive = *buildpathHPFS - 'a' + 1;     /* save for mapname() */
            if (volflag == 0 || *buildpathHPFS < 'a' ||   /* no labels/bogus? */
                (volflag == 1 && !isfloppy(nLabelDrive))) {  /* -$:  no fixed */
                free(buildpathHPFS);
                free(buildpathFAT);
                return IZ_VOL_LABEL;   /* skipping with message */
            }
            *buildpathHPFS = '\0';
        } else if (renamed_fullpath)   /* pathcomp = valid data */
            strcpy(buildpathHPFS, pathcomp);
        else if (rootlen > 0)
            strcpy(buildpathHPFS, rootpath);
        else
            *buildpathHPFS = '\0';
        endHPFS = buildpathHPFS;
        endFAT = buildpathFAT;
        while ((*endFAT = *endHPFS) != '\0') {
            ++endFAT;
            ++endHPFS;
        }
        Trace((stderr, "[%s]\n", buildpathHPFS));
        return 0;
    }

/*---------------------------------------------------------------------------
    ROOT:  if appropriate, store the path in rootpath and create it if neces-
    sary; else assume it's a zipfile member and return.  This path segment
    gets used in extracting all members from every zipfile specified on the
    command line.  Note that under OS/2 and MS-DOS, if a candidate extract-to
    directory specification includes a drive letter (leading "x:"), it is
    treated just as if it had a trailing '/'--that is, one directory level
    will be created if the path doesn't exist, unless this is otherwise pro-
    hibited (e.g., freshening).
  ---------------------------------------------------------------------------*/

#if (!defined(SFX) || defined(SFX_EXDIR))
    if (FUNCTION == ROOT) {
        Trace((stderr, "initializing root path to [%s]\n", pathcomp));
        if (pathcomp == NULL) {
            rootlen = 0;
            return 0;
        }
        if ((rootlen = strlen(pathcomp)) > 0) {
            int had_trailing_pathsep=FALSE, has_drive=FALSE, xtra=2;

            if (isalpha(pathcomp[0]) && pathcomp[1] == ':')
                has_drive = TRUE;   /* drive designator */
            if (pathcomp[rootlen-1] == '/') {
                pathcomp[--rootlen] = '\0';
                had_trailing_pathsep = TRUE;
            }
            if (has_drive && (rootlen == 2)) {
                if (!had_trailing_pathsep)   /* i.e., original wasn't "x:/" */
                    xtra = 3;      /* room for '.' + '/' + 0 at end of "x:" */
            } else if (rootlen > 0) {     /* need not check "x:." and "x:/" */
                if (SSTAT(pathcomp, &statbuf) || !S_ISDIR(statbuf.st_mode)) {
                    /* path does not exist */
                    if (!create_dirs                 /* || iswild(pathcomp) */
#ifdef OLD_EXDIR
                                     || (!has_drive && !had_trailing_pathsep)
#endif
                                                                             ) {
                        rootlen = 0;
                        return 2;   /* treat as stored file */
                    }
                    /* create directory (could add loop here to scan pathcomp
                     * and create more than one level, but really necessary?) */
                    if (MKDIR(pathcomp, 0777) == -1) {
                        FPRINTF(stderr,
                          "checkdir:  can't create extraction directory: %s\n",
                          pathcomp);
                        fflush(stderr);
                        rootlen = 0;   /* path didn't exist, tried to create, */
                        return 3;  /* failed:  file exists, or need 2+ levels */
                    }
                }
            }
            if ((rootpath = (char *)malloc(rootlen+xtra)) == NULL) {
                rootlen = 0;
                return 10;
            }
            strcpy(rootpath, pathcomp);
            if (xtra == 3)                  /* had just "x:", make "x:." */
                rootpath[rootlen++] = '.';
            rootpath[rootlen++] = '/';