msdos.c

压缩算法的源代码

        } else if (isalpha(filename[0]) && filename[1] == ':') {
            renamed_fullpath = TRUE;
            pp = pathcomp;
            *pp++ = *cp++;      /* copy the "d:" (+ '/', possibly) */
            *pp++ = *cp++;
            if (*cp == '/')
                *pp++ = *cp++;  /* otherwise add "./"? */
            *pp = '\0';
        }
    }

    /* pathcomp is ignored unless renamed_fullpath is TRUE: */
    if ((error = checkdir(pathcomp, INIT)) != 0)    /* initialize path buffer */
        return error;           /* ...unless no mem or vol label on hard disk */

    *pathcomp = '\0';           /* initialize translation buffer */
    pp = pathcomp;              /* point to translation buffer */
    if (!renamed) {             /* cp already set if renamed */
        if (jflag)              /* junking directories */
            cp = (char *)strrchr(filename, '/');
        if (cp == (char *)NULL) /* no '/' or not junking dirs */
            cp = filename;      /* point to internal zipfile-member pathname */
        else
            ++cp;               /* point to start of last component of path */
    }

/*---------------------------------------------------------------------------
    Begin main loop through characters in filename.
  ---------------------------------------------------------------------------*/

    while ((workch = (uch)*cp++) != 0) {

        if (quote) {              /* if character quoted, */
            *pp++ = (char)workch; /*  include it literally */
            quote = FALSE;
        } else
            switch (workch) {
            case '/':             /* can assume -j flag not given */
                *pp = '\0';
/* GRR:  can add 8.3 truncation here */
                if (last_dot) {   /* one dot in directory name is legal */
                    *last_dot = '.';
                    last_dot = (char *)NULL;
                }
                if ((error = checkdir(pathcomp, APPEND_DIR)) > 1)
                    return error;
                pp = pathcomp;    /* reset conversion buffer for next piece */
                lastsemi = (char *)NULL; /* leave directory semi-colons alone */
                break;

            case ':':             /* drive names not stored in zipfile, */
            case '[':             /*  so no colons allowed; no brackets, */
            case ']':             /*  either */
                *pp++ = '_';
                break;

            case '.':
                if (pp == pathcomp) {     /* nothing appended yet... */
                    if (*cp == '/') {     /* don't bother appending a "./" */
                        ++cp;             /*  component to the path:  skip */
                        break;            /*  to next char after the '/' */
                    } else if (*cp == '.' && cp[1] == '/') {   /* "../" */
                        *pp++ = '.';      /* add first dot, unchanged... */
                        ++cp;             /* skip second dot, since it will */
                    } else {              /*  be "added" at end of if-block */
                        *pp++ = '_';      /* 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: */
                    *pp = '\0';           /*  remove it by shifting chars */
                    pp = pathcomp + 1;    /*  left one space (e.g., .p1.p2: */
                    while (pp[1]) {       /*  __p1 -> _p1_p2 -> _p1.p2 when */
                        *pp = pp[1];      /*  finished) [opt.:  since first */
                        ++pp;             /*  two chars are same, can start */
                    }                     /*  shifting at second position] */
                }
                last_dot = pp;    /* point at last dot so far... */
                *pp++ = '_';      /* convert dot to underscore for now */
                break;

            case ';':             /* start of VMS version? */
                lastsemi = pp;    /* omit for now; remove VMS vers. later */
                break;

            case '\026':          /* control-V quote for special chars */
                quote = TRUE;     /* set flag for next character */
                break;

            case ' ':             /* change spaces to underscore only */
                if (sflag)        /*  if specifically requested */
                    *pp++ = '_';
                else
                    *pp++ = (char)workch;
                break;

            default:
                /* allow European characters in filenames: */
                if (isprint(workch) || (128 <= workch && workch <= 254))
                    *pp++ = (char)workch;
            } /* end switch */

    } /* end while loop */

    *pp = '\0';                   /* done with pathcomp:  terminate it */

    /* if not saving them, remove VMS version numbers (appended "###") */
    if (!V_flag && lastsemi) {
        pp = lastsemi;            /* semi-colon was omitted:  expect all #'s */
        while (isdigit((uch)(*pp)))
            ++pp;
        if (*pp == '\0')          /* only digits between ';' and end:  nuke */
            *lastsemi = '\0';
    }

/* GRR:  can add 8.3 truncation here */
    if (last_dot != (char *)NULL) /* one dot is OK:  put it back in */
        *last_dot = '.';          /* (already done for directories) */

/*---------------------------------------------------------------------------
    Report if directory was created (and no file to create:  filename ended
    in '/'), check name to be sure it exists, and combine path and name be-
    fore exiting.
  ---------------------------------------------------------------------------*/

    if (filename[strlen(filename) - 1] == '/') {
        checkdir(filename, GETPATH);
        if (created_dir && QCOND2) {
            FPRINTF(stdout, "   creating: %s\n", filename);
            return IZ_CREATED_DIR;   /* set dir time (note trailing '/') */
        }
        return 2;   /* dir existed already; don't look for data to extract */
    }

    if (*pathcomp == '\0') {
        FPRINTF(stderr, LoadFarString(ConversionFailed), filename);
        return 3;
    }

    checkdir(pathcomp, APPEND_NAME);   /* returns 1 if truncated:  care? */
    checkdir(filename, GETPATH);

    if (pInfo->vollabel) {   /* set the volume label now */
        if (QCOND2)
            FPRINTF(stdout, "labelling %c: %-22s\n", (nLabelDrive + 'a' - 1),
              filename);
        if (volumelabel(filename)) {
            FPRINTF(stderr, LoadFarString(ErrSetVolLabel));
            return 3;
        }
        return 2;   /* success:  skip the "extraction" quietly */
    }

    return error;

} /* end function mapname() */





/***********************/
/* Function checkdir() */
/***********************/

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 *buildpath;   /* full path (so far) to extracted file */
    static char *end;         /* pointer to end of buildpath ('\0') */
#ifdef MSC
    int attrs;                /* work around MSC stat() bug */
#endif

#   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) {
        int too_long = FALSE;

        Trace((stderr, "appending dir segment [%s]\n", pathcomp));
        while ((*end = *pathcomp++) != '\0')
            ++end;

        /* GRR:  could do better check, see if overrunning buffer as we go:
         * check end-buildpath 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. */

        if ((end-buildpath) > FILNAMSIZ-3)  /* need '/', one-char name, '\0' */
            too_long = TRUE;                /* check if extracting directory? */
#ifdef MSC /* MSC 6.00 bug:  stat(non-existent-dir) == 0 [exists!] */
        if (_dos_getfileattr(buildpath, &attrs) || stat(buildpath, &statbuf))  
#else
        if (stat(buildpath, &statbuf))      /* path doesn't exist */
#endif
        {
            if (!create_dirs) {   /* told not to create (freshening) */
                free(buildpath);
                return 2;         /* path doesn't exist:  nothing to do */
            }
            if (too_long) {
                FPRINTF(stderr, LoadFarString(PathTooLong), buildpath);
                fflush(stderr);
                free(buildpath);
                return 4;         /* no room for filenames:  fatal */
            }
            if (MKDIR(buildpath, 0777) == -1) {   /* create the directory */
                FPRINTF(stderr, LoadFarString(CantCreateDir), buildpath,
                        filename);
                fflush(stderr);
                free(buildpath);
                return 3;      /* path didn't exist, tried to create, failed */
            }
            created_dir = TRUE;
        } else if (!S_ISDIR(statbuf.st_mode)) {
            FPRINTF(stderr, LoadFarString(DirIsntDirectory), buildpath,
                    filename);
            fflush(stderr);
            free(buildpath);
            return 3;          /* path existed but wasn't dir */
        }
        if (too_long) {
            FPRINTF(stderr, LoadFarString(PathTooLong), buildpath);
            fflush(stderr);
            free(buildpath);
            return 4;         /* no room for filenames:  fatal */
        }
        *end++ = '/';
        *end = '\0';
        Trace((stderr, "buildpath now = [%s]\n", buildpath));
        return 0;

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

/*---------------------------------------------------------------------------
    GETPATH:  copy full path to the string pointed at by pathcomp, and free
    buildpath.
  ---------------------------------------------------------------------------*/

    if (FUNCTION == GETPATH) {
        strcpy(pathcomp, buildpath);
        Trace((stderr, "getting and freeing path [%s]\n", pathcomp));
        free(buildpath);
        buildpath = end = (char *)NULL;
        return 0;
    }

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

    if (FUNCTION == APPEND_NAME) {
        Trace((stderr, "appending filename [%s]\n", pathcomp));
        while ((*end = *pathcomp++) != '\0') {
            ++end;
            if ((end-buildpath) >= FILNAMSIZ) {
                *--end = '\0';
                FPRINTF(stderr, LoadFarString(PathTooLongTrunc),
                        filename, buildpath);
                fflush(stderr);
                return 1;   /* filename truncated */
            }
        }
        Trace((stderr, "buildpath now = [%s]\n", buildpath));
        return 0;  /* could check for existence here, prompt for new 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) {
        Trace((stderr, "initializing buildpath to "));
        if ((buildpath = (char *)malloc(strlen(filename)+rootlen+1)) ==
            (char *)NULL)
            return 10;
        if (pInfo->vollabel) {
/* GRR:  for network drives, do strchr() and return IZ_VOL_LABEL if not [1] */
            if (renamed_fullpath && pathcomp[1] == ':')
                *buildpath = ToLower(*pathcomp);
            else if (!renamed_fullpath && rootpath && rootpath[1] == ':')
                *buildpath = ToLower(*rootpath);
            else {
                GETDRIVE(nLabelDrive);   /* assumed that a == 1, b == 2, etc. */
                *buildpath = (char)(nLabelDrive - 1 + 'a');
            }
            nLabelDrive = *buildpath - 'a' + 1;       /* save for mapname() */
            if (volflag == 0 || *buildpath < 'a' ||   /* no labels/bogus disk */
                (volflag == 1 && !isfloppy(nLabelDrive))) {  /* -$:  no fixed */
                free(buildpath);
                return IZ_VOL_LABEL;     /* skipping with message */
            }
            *buildpath = '\0';
            end = buildpath;
        } else if (renamed_fullpath) {   /* pathcomp = valid data */
            end = buildpath;
            while ((*end = *pathcomp++) != '\0')
                ++end;
        } else if (rootlen > 0) {
            strcpy(buildpath, rootpath);
            end = buildpath + rootlen;
        } else {
            *buildpath = '\0';
            end = buildpath;
        }
        Trace((stderr, "[%s]\n", buildpath));
        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