path: root/mbbsd/read.c

/* $Id$ */
#include "bbs.h"
#include "fnv_hash.h"

static int headers_size;
static fileheader_t *headers = NULL;
static int      last_line; // PTT: last_line 游標可指的最後一個

#include <sys/mman.h>

/* ----------------------------------------------------- */
/* Tag List 標籤                                         */
/* ----------------------------------------------------- */
static TagItem         *TagList;    /* ascending list */

/**
 * @param locus
 * @return void
 */
void
UnTagger(int locus)
{
    if (locus > TagNum)
    return;

    TagNum--;

    if (TagNum > locus)
    memmove(&TagList[locus], &TagList[locus + 1],
           (TagNum - locus) * sizeof(TagItem));
}

int
Tagger(time4_t chrono, int recno, int mode)
{
    int             head, tail, posi = 0, comp;

    if(TagList == NULL) {
    TagList = malloc(sizeof(TagItem)*MAXTAGS);
    }

    for (head = 0, tail = TagNum - 1, comp = 1; head <= tail;) {
    posi = (head + tail) >> 1;
    comp = TagList[posi].chrono - chrono;
    if (!comp) {
        break;
    } else if (comp < 0) {
        head = posi + 1;
    } else {
        tail = posi - 1;
    }
    }

    if (mode == TAG_NIN) {
    if (!comp && recno) /* 絕對嚴謹：連 recno 一起比對 */
        comp = recno - TagList[posi].recno;
    return comp;

    }
    if (!comp) {
    if (mode != TAG_TOGGLE)
        return NA;

    TagNum--;
    memmove(&TagList[posi], &TagList[posi + 1],
           (TagNum - posi) * sizeof(TagItem));
    } else if (TagNum < MAXTAGS) {
    TagItem        *tagp;

    memmove(&TagList[head+1], &TagList[head], sizeof(TagItem)*(TagNum-head));
    tagp = &TagList[head];
    tagp->chrono = chrono;
    tagp->recno = recno;
    TagNum++;
    } else {
    bell();
    return 0;       /* full */
    }
    return YEA;
}

#if 0
static void
EnumTagName(char *fname, int locus) /* unused */
{
    snprintf(fname, sizeof(fname), "M.%d.A", (int)TagList[locus].chrono);
}
#endif

void
EnumTagFhdr(fileheader_t * fhdr, char *direct, int locus)
{
    get_record(direct, fhdr, sizeof(fileheader_t), TagList[locus].recno);
}

/* -1 : 取消 */
/* 0 : single article */
/* ow: whole tag list */

int
AskTag(const char *msg)
{
    int             num;

    num = TagNum;
    switch (getans("◆ %s A)文章 T)標記 Q)uit?", msg)) {
    case 'q':
    num = -1;
    break;
    case 'a':
    num = 0;
    }
    return num;
}


#include <sys/mman.h>

#define BATCH_SIZE      65536

static char           *
f_map(const char *fpath, int *fsize)
{
    int             fd, size;
    struct stat     st;
    char *map;

    if ((fd = open(fpath, O_RDONLY)) < 0)
    return (char *)-1;

    if (fstat(fd, &st) || !S_ISREG(st.st_mode) || (size = st.st_size) <= 0) {
    close(fd);
    return (char *)-1;
    }
    map = (char *)mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
    close(fd);
    *fsize = size;
    return map;
}


static int
TagThread(const char *direct)
{
    int             fsize, count;
    char           *title, *fimage;
    fileheader_t   *head, *tail;

    fimage = f_map(direct, &fsize);
    if (fimage == (char *)-1)
    return DONOTHING;

    head = (fileheader_t *) fimage;
    tail = (fileheader_t *) (fimage + fsize);
    count = 0;
    do {
    count++;
    title = subject(head->title);
    if (!strncmp(currtitle, title, TTLEN)) {
        if (!Tagger(atoi(head->filename + 2), count, TAG_INSERT))
        break;
    }
    } while (++head < tail);

    munmap(fimage, fsize);
    return FULLUPDATE;
}


int
TagPruner(int bid)
{
    boardheader_t  *bp=NULL;
    assert(bid >= 0);   /* bid == 0 means in mailbox */
    if (bid){
    bp = getbcache(bid);
    if (strcmp(bp->brdname, "Security") == 0)
        return DONOTHING;
    }
    if (TagNum && ((currstat != READING) || (currmode & MODE_BOARD))) {
    if (getans("刪除所有標記[N]?") != 'y')
        return READ_REDRAW;
#ifdef SAFE_ARTICLE_DELETE
        if(bp && !(currmode & MODE_DIGEST) && bp->nuser>30 )
            safe_delete_range(currdirect, 0, 0);
        else
#endif
        delete_range(currdirect, 0, 0);
    TagNum = 0;
    if (bid)
        setbtotal(bid);
        else if(currstat == RMAIL)
            setupmailusage();

    return NEWDIRECT;
    }
    return DONOTHING;
}


/* ----------------------------------------------------- */
/* cursor & reading record position control              */
/* ----------------------------------------------------- */
keeploc_t      *
getkeep(const char *s, int def_topline, int def_cursline)
{
    /* 為省記憶體, 且避免 malloc/free 不成對, getkeep 最好不要 malloc,
     * 只記 s 的 hash 值,
     * fvn1a-32bit collision 機率約小於十萬分之一 */
    /* 原本使用 link list, 可是一方面會造成 malloc/free 不成對, 
     * 一方面 size 小, malloc space overhead 就高, 因此改成 link block,
     * 以 KEEPSLOT 為一個 block 的 link list.
     * 只有第一個 block 可能沒滿. */
    /* TODO LRU recycle? 麻煩在於別處可能把 keeploc_t pointer 記著... */
#define KEEPSLOT 10
    struct keepsome {
    unsigned char used;
    keeploc_t arr[KEEPSLOT];
    struct keepsome *next;
    };
    static struct keepsome preserv_keepblock;
    static struct keepsome *keeplist = &preserv_keepblock;
    struct keeploc_t *p;
    unsigned int key=fnv1a_32_str(s, FNV1_32_INIT);
    int i;

    if (def_cursline >= 0) {
    struct keepsome *kl=keeplist;
    while(kl) {
        for(i=0; i<kl->used; i++)
        if(key == kl->arr[i].hashkey) {
            p = &kl->arr[i];
            if (p->crs_ln < 1)
            p->crs_ln = 1;
            return p;
        }
        kl=kl->next;
    }
    } else
    def_cursline = -def_cursline;

    if(keeplist->used==KEEPSLOT) {
    struct keepsome *kl;
    kl = (struct keepsome*)malloc(sizeof(struct keepsome));
    memset(kl, 0, sizeof(struct keepsome));
    kl->next = keeplist;
    keeplist = kl;
    }
    p = &keeplist->arr[keeplist->used];
    keeplist->used++;
    p->hashkey = key;
    p->top_ln = def_topline;
    p->crs_ln = def_cursline;
    return p;
}

void
fixkeep(const char *s, int first)
{
    keeploc_t      *k;

    k = getkeep(s, 1, 1);
    if (k->crs_ln >= first) {
    k->crs_ln = (first == 1 ? 1 : first - 1);
    k->top_ln = (first < 11 ? 1 : first - 10);
    }
}

/* calc cursor pos and show cursor correctly */
static int
cursor_pos(keeploc_t * locmem, int val, int from_top, int isshow)
{
    int  top=locmem->top_ln;
    if (!last_line){
    cursor_show(3 , 0);
    return DONOTHING;
    }
    if (val > last_line)
    val = last_line;
    if (val <= 0)
    val = 1;
    if (val >= top && val < top + headers_size) {
        if(isshow){
        cursor_clear(3 + locmem->crs_ln - top, 0);
        cursor_show(3 + val - top, 0);
    }
    locmem->crs_ln = val;
    return DONOTHING;
    }
    locmem->top_ln = val - from_top;
    if (locmem->top_ln <= 0)
    locmem->top_ln = 1;
    locmem->crs_ln = val;
    return isshow ? PARTUPDATE : HEADERS_RELOAD;
}

/**
 * 根據 stypen 選擇上/下一篇文章
 *
 * @param locmem  用來存在某看板游標位置的 structure。
 * @param stypen  游標移動的方法
 *           CURSOR_FIRST, CURSOR_NEXT, CURSOR_PREV:
 *             與游標目前位置的文章同標題 的 第一篇/下一篇/前一篇 文章。
 *           RELATE_FIRST, RELATE_NEXT, RELATE_PREV:
 *             與目前正閱讀的文章同標題 的 第一篇/下一篇/前一篇 文章。
 *           NEWPOST_NEXT, NEWPOST_PREV:
 *             下一個/前一個 thread 的第一篇。
 *           AUTHOR_NEXT, AUTHOR_PREV:
 *             XXX 這功能目前好像沒用到?
 *
 * @return 新的游標位置
 */
static int
thread(const keeploc_t * locmem, int stypen)
{
    fileheader_t fh;
    int     pos = locmem->crs_ln, jump = THREAD_SEARCH_RANGE, new_ln;
    int     fd = -1, amatch = -1;
    int     step = (stypen & RS_FORWARD) ? 1 : -1;
    char    *key;
    
    STATINC(STAT_THREAD);
    if (stypen & RS_AUTHOR)
    key = headers[pos - locmem->top_ln].owner;
    else if (stypen & RS_CURRENT)
        key = subject(currtitle);
    else
    key = subject(headers[pos - locmem->top_ln].title );

    for( new_ln = pos + step ;
     new_ln > 0 && new_ln <= last_line && --jump > 0;
     new_ln += step ) {
    get_record_keep(currdirect, &fh, sizeof(fileheader_t), new_ln, &fd);
        if( stypen & RS_TITLE ){
            if( stypen & RS_FIRST ){
        if( !strncmp(fh.title, key, PROPER_TITLE_LEN) )
            break;
        else if( !strncmp(&fh.title[4], key, PROPER_TITLE_LEN) ) {
            amatch = new_ln;
            jump = THREAD_SEARCH_RANGE; 
            /* 當搜尋同主題第一篇, 連續找不到多少篇才停 */
        }
        }
            else if( !strncmp(subject(fh.title), key, PROPER_TITLE_LEN) )
        break;
    }
        else if( stypen & RS_NEWPOST ){
            if( strncmp(fh.title, "Re:", 3) )
        break;
    }
        else{  // RS_AUTHOR
            if( !strcmp(subject(fh.owner), key) )
        break;
    }
    }
    if( fd != -1 )
    close(fd);
    if( jump <= 0 || new_ln <= 0 || new_ln > last_line )
    new_ln = (amatch == -1 ? pos : amatch); //didn't find
    return new_ln;
}

#ifdef INTERNET_EMAIL
static void
mail_forward(const fileheader_t * fhdr, const char *direct, int mode)
{
    int             i;
    char            buf[STRLEN];
    char           *p;

    strncpy(buf, direct, sizeof(buf)-1);
    buf[sizeof(buf)-1] = 0;
    if ((p = strrchr(buf, '/')))
    *p = '\0';
    switch (i = doforward(buf, fhdr, mode)) {
    case 0:
    vmsg(msg_fwd_ok);
    break;
    case -1:
    vmsg(msg_fwd_err1);
    break;
    case -2:
#ifndef DEBUG_FWDADDRERR
    vmsg(msg_fwd_err2);
#endif
    break;
    default:
    break;
    }
}
#endif

inline static int
dbcs_strcasestr(const char* pool, const char *ptr)
{
    int len = strlen(ptr);

    while(*pool)
    {
    if(strncasecmp(pool, ptr, len) == 0)
        return 1;
    /* else */
    if(*pool < 0)
    {
        pool ++;
        if(*pool == 0)
        return 0;
    }
    pool ++;
    }
    return 0;
}

static int
select_read(const keeploc_t * locmem, int sr_mode)
{
#define READSIZE 64  // 8192 / sizeof(fileheader_t)
   time4_t filetime;
   fileheader_t    fhs[READSIZE];
   char newdirect[MAXPATHLEN];
   char keyword[TTLEN + 1] = "";
   char genbuf[MAXPATHLEN], *p = strstr(currdirect, "SR.");
   static int _mode = 0;
   int    len, fd, fr, i, count=0, reference = 0, n_recommend = 0,
          n_money=0, diff;
   fileheader_t *fh = &headers[locmem->crs_ln - locmem->top_ln]; 

   STATINC(STAT_SELECTREAD);
   if(sr_mode & RS_AUTHOR)
           {
         if(!getdata(b_lines, 0,
                 currmode & MODE_SELECT ? "增加條件 作者: ":"搜尋作者: ",
                  keyword, IDLEN+1, LCECHO))
                return READ_REDRAW; 
           }
   else if(sr_mode  & RS_KEYWORD)
          {
             if(!getdata(b_lines, 0, 
                 currmode & MODE_SELECT ? "增加條件 標題: ":"搜尋標題: ",
                 keyword, TTLEN, DOECHO))
                return READ_REDRAW;
#ifdef KEYWORD_LOG
             log_file("keyword_search_log", LOG_CREAT | LOG_VF,
              "%s:%s\n", currboard, keyword);
#endif
          }
   else if(sr_mode  & RS_KEYWORD_EXCLUDE)
          {
             if(!(currmode & MODE_SELECT) ||
                !getdata(b_lines, 0, "增加條件 排除標題: ", 
                 keyword, TTLEN, DOECHO))
                return READ_REDRAW;
          }
   else if (sr_mode  & RS_RECOMMEND)
          {
             if(currstat == RMAIL || (
            !getdata(b_lines, 0, 
                 (currmode & MODE_SELECT) ? 
         "增加條件 推文數: ":"搜尋推文數高於多少的文章: ",
                 keyword, 7, LCECHO) || (n_recommend = atoi(keyword)) <= 0 ))
                return READ_REDRAW;
      }
   else if (sr_mode  & RS_MONEY)
          {
             if(currstat == RMAIL || (
            !getdata(b_lines, 0, 
                 (currmode & MODE_SELECT) ?
         "增加條件 文章價格: ":"搜尋價格高於多少的文章: ",
                 keyword, 7, LCECHO) || (n_money = atoi(keyword)) <= 0 ))
                return READ_REDRAW;
             strcat(keyword, "M");
      }
   else
    {
     if(p && _mode & sr_mode & (RS_TITLE | RS_NEWPOST | RS_MARK))
            return DONOTHING;
                // Ptt: only once for these modes.
     if(sr_mode & RS_TITLE)
       strcpy(keyword, subject(fh->title));           
    }

   if(p == NULL)
      _mode = sr_mode;
   else
      _mode |= sr_mode;
   
   snprintf(genbuf, sizeof(genbuf), "%s%X.%X.%X",
            p ? p : "SR.",
            sr_mode, (int)strlen(keyword), StringHash(keyword));
   if( strlen(genbuf) > MAXPATHLEN - 50 )
       return  READ_REDRAW; // avoid overflow

   if (currstat == RMAIL)
       sethomefile(newdirect, cuser.userid, genbuf);
   else
       setbfile(newdirect, currboard, genbuf);

   filetime = dasht(newdirect);
   count = dashs(newdirect) / sizeof(fileheader_t);

   diff = now - filetime;
   if( diff > 180)
      {
       if( diff > 3600)
           {
             len = O_CREAT | O_RDWR;
             count=0;
           }
       else
       len = O_APPEND | O_RDWR;
 
       if( (fd = open(newdirect, len, 0600)) == -1 )
           return READ_REDRAW;

       if( (fr = open(currdirect, O_RDONLY, 0)) != -1 ) {
           if( diff <= 3600)
            {
             sprintf(fhs[0].filename, "X.%d", (int)filetime); 
             len = - getindex(currdirect, &fhs[0], 0);
             if(len>0)
             {
                     lseek(fr, len*sizeof(fileheader_t), SEEK_SET);
                 reference = len;
         }
            }

#ifdef DEBUG
       vmsgf("search: %s", currdirect);
#endif
       while( (len = read(fr, fhs, sizeof(fhs))) > 0 ){
           len /= sizeof(fileheader_t);
           for( i = 0 ; i < len ; ++i ){
           reference++;
           if( (sr_mode & RS_MARK)  &&
               !(fhs[i].filemode & FILE_MARKED) )
               continue;
           else if((sr_mode & RS_NEWPOST)  &&
              !strncmp(fhs[i].title,  "Re:", 3))
               continue;
           else if((sr_mode & RS_AUTHOR)  &&
              !dbcs_strcasestr(fhs[i].owner, keyword))
               continue;
           else if((sr_mode & RS_KEYWORD)  &&
              !dbcs_strcasestr(fhs[i].title, keyword))
               continue;
                   else if(sr_mode  & RS_KEYWORD_EXCLUDE &&
                       dbcs_strcasestr(fhs[i].title, keyword))
               continue;
           else if((sr_mode & RS_TITLE)  &&          
              strcasecmp(subject(fhs[i].title), keyword))
               continue;
           else if ((sr_mode & RS_RECOMMEND)  &&
               fhs[i].recommend < n_recommend )
               continue;
           /* please put money test in last */
           else if ((sr_mode & RS_MONEY) &&
               query_file_money(fhs+i) < n_money)
               continue;

                   if(p == NULL)
           {
               fhs[i].multi.refer.flag = 1;
               fhs[i].multi.refer.ref = reference;
           }
           ++count;
           write(fd, &fhs[i], sizeof(fileheader_t));
           }
       } // end while
           close(fr);
       }
       ftruncate(fd, count*sizeof(fileheader_t));
       close(fd);
   }

   if(count) {
       strlcpy(currdirect, newdirect, sizeof(currdirect));
       currmode |= MODE_SELECT;
       currsrmode |= sr_mode;
       return NEWDIRECT;
   }
   return READ_REDRAW;
}

static int
i_read_key(const onekey_t * rcmdlist, keeploc_t * locmem, 
           int bid, int bottom_line)
{
    int     mode = DONOTHING, num, new_top=10;
    int     ch, new_ln = locmem->crs_ln, lastmode=0;
    char    direct[60];
    static  char default_ch = 0;
    
    do {
    if( (mode = cursor_pos(locmem, new_ln, new_top, default_ch ? 0 : 1))
        != DONOTHING )
        return mode;
    
    if( !default_ch )
        ch = igetch();
    else{
        if(new_ln != locmem->crs_ln) {// move fault
        default_ch=0;
        return FULLUPDATE;
        }
        ch = default_ch;
    }

    new_top = 10; // default 10 
    switch (ch) {
        case '0':    case '1':    case '2':    case '3':    case '4':
    case '5':    case '6':    case '7':    case '8':    case '9':
        if( (num = search_num(ch, last_line)) != -1 )
        new_ln = num + 1; 
        break;
        case 'q':
        case 'e':
        case KEY_LEFT:
        if(currmode & MODE_SELECT){
        char genbuf[PATHLEN];
        fileheader_t *fhdr = &headers[locmem->crs_ln - locmem->top_ln];
        board_select();
        setbdir(genbuf, currboard);
        locmem = getkeep(genbuf, 0, 1);
        locmem->crs_ln = fhdr->multi.refer.ref;
        num = locmem->crs_ln - p_lines + 1;
        locmem->top_ln = num < 1 ? 1 : num;
        mode =  NEWDIRECT;
        }
        else
        mode =  
            (currmode & MODE_DIGEST) ? board_digest() : DOQUIT;
        break;
        case Ctrl('L'):
        redoscr();
        break;

        case Ctrl('H'):
        mode = select_read(locmem, RS_NEWPOST);
        break;
        
    case 'Z':
        mode = select_read(locmem, RS_RECOMMEND);
        break;
        
        case 'a':
        mode = select_read(locmem, RS_AUTHOR);
        break;

        case 'A':
        mode = select_read(locmem, RS_MONEY);
        break;

        case 'G':
        mode = select_read(locmem, RS_MARK);
        break;

        case '/':
        case '?':
        mode = select_read(locmem, RS_KEYWORD);
        break;

        case 'S':
        mode = select_read(locmem, RS_TITLE);
        break;

        case '!':
        mode = select_read(locmem, RS_KEYWORD_EXCLUDE);
        break;

        case '=':
        new_ln = thread(locmem, RELATE_FIRST);
        break;

        case '\\':
        new_ln = thread(locmem, CURSOR_FIRST);
        break;

        case ']':
        new_ln = thread(locmem, RELATE_NEXT);
        break;

        case '+':
        new_ln = thread(locmem, CURSOR_NEXT);
        break;

        case '[':
        new_ln = thread(locmem, RELATE_PREV);
        break;

        case '-':
        new_ln = thread(locmem, CURSOR_PREV);
        break;

        case '<':
        case ',':
        new_ln = thread(locmem, NEWPOST_PREV);
        break;

        case '.':
        case '>':
        new_ln = thread(locmem, NEWPOST_NEXT);
        break;

        case 'p':
        case 'k':
    case KEY_UP:
        new_ln = locmem->crs_ln - 1; 
        new_top = p_lines - 2;
        break;

    case 'n':
    case 'j':
    case KEY_DOWN:
        new_ln = locmem->crs_ln + 1; 
        new_top = 1;
        break;

    case ' ':
    case KEY_PGDN:
    case 'N':
    case Ctrl('F'):
        new_ln = locmem->top_ln + p_lines; 
        new_top = 0;
        break;

    case KEY_PGUP:
    case Ctrl('B'):
    case 'P':
        new_ln = locmem->top_ln - p_lines; 
        new_top = 0;
        break;

        /* add home(top entry) support? */
    case KEY_HOME:
        new_ln = 0;
        new_top = 0;
        break;

    case KEY_END:
    case '$':
        new_ln = last_line;
        new_top = p_lines-1;
        break;

    case 'F':
    case 'U':
        if (HasUserPerm(PERM_FORWARD)) {
        mail_forward(&headers[locmem->crs_ln - locmem->top_ln],
                 currdirect, ch /* == 'U' */ );
        /* by CharlieL */
        // mode = READ_REDRAW;
        return FULLUPDATE;
        }
        break;

    case Ctrl('Q'):
        mode = my_query(headers[locmem->crs_ln - locmem->top_ln].owner);
        break;

    case Ctrl('S'):
        if (HasUserPerm(PERM_ACCOUNTS)) {
        int             id;
        userec_t        muser;

        strlcpy(currauthor,
            headers[locmem->crs_ln - locmem->top_ln].owner,
            sizeof(currauthor));
        stand_title("使用者設定");
        move(1, 0);
        if ((id = getuser(headers[locmem->crs_ln - locmem->top_ln].owner, &muser))) {
            user_display(&muser, 1);
            uinfo_query(&muser, 1, id);
        }
        mode = FULLUPDATE;
        }
        break;

        /* rocker.011018: 採用新的tag模式 */
    case 't':
        /* 將原本在 Read() 裡面的 "TagNum = 0" 移至此處 */
        if ((currstat & RMAIL && TagBoard != 0) ||
        (!(currstat & RMAIL) && TagBoard != bid)) {
        if (currstat & RMAIL)
            TagBoard = 0;
        else
            TagBoard = bid;
        TagNum = 0;
        }
        /* rocker.011112: 解決再select mode標記文章的問題 */
        if (Tagger(atoi(headers[locmem->crs_ln - locmem->top_ln].filename + 2),
               (currmode & MODE_SELECT) ?
               (headers[locmem->crs_ln - locmem->top_ln].multi.refer.ref) :
               locmem->crs_ln, TAG_TOGGLE))
        locmem->crs_ln = locmem->crs_ln + 1; 
        mode = FULLUPDATE;
        break;

    case Ctrl('C'):
    if (TagNum) {
        TagNum = 0;
        mode = FULLUPDATE;
    }
        break;

    case Ctrl('T'):
    /* XXX duplicated code, copy from case 't' */
    if ((currstat & RMAIL && TagBoard != 0) ||
        (!(currstat & RMAIL) && TagBoard != bid)) {
        if (currstat & RMAIL)
        TagBoard = 0;
        else
        TagBoard = bid;
        TagNum = 0;
    }
    mode = TagThread(currdirect);
        break;

    case Ctrl('D'):
    mode = TagPruner(bid);
        break;

    case '\n':
    case '\r':
    case 'l':
    case KEY_RIGHT:
    ch = 'r';
    default:
    if( ch == 'h' && currmode & (MODE_DIGEST) )
        break;
    if (ch > 0 && ch <= onekey_size) {
        int (*func)() = rcmdlist[ch - 1];
        if (func != NULL){
        num  = locmem->crs_ln - bottom_line;
                   
        if( num > 0 ){
                    sprintf(direct,"%s.bottom", currdirect);
            mode= (*func)(num, &headers[locmem->crs_ln-locmem->top_ln],
                  direct);
        }
        else
                    mode = (*func)(locmem->crs_ln, 
                   &headers[locmem->crs_ln - locmem->top_ln],
                   currdirect);
        if(mode == READ_SKIP)
                    mode = lastmode;

        // 以下這幾種 mode 要再處理游標
                if(mode == READ_PREV || mode == READ_NEXT || 
                   mode == RELATE_PREV || mode == RELATE_FIRST || 
                   mode == AUTHOR_NEXT || mode ==  AUTHOR_PREV ||
                   mode == RELATE_NEXT){
            lastmode = mode;

            switch(mode){
                    case READ_PREV:
                        new_ln =  locmem->crs_ln - 1;
                        break;
                    case READ_NEXT:
                        new_ln =  locmem->crs_ln + 1;
                        break;
                case RELATE_PREV:
                        new_ln = thread(locmem, RELATE_PREV);
            break;
                    case RELATE_NEXT:
                        new_ln = thread(locmem, RELATE_NEXT);
            /* XXX: 讀到最後一篇要跳出來 */
            if( new_ln == locmem->crs_ln ){
                default_ch = 0;
                return FULLUPDATE;
            }
                break;
                    case RELATE_FIRST:
                        new_ln = thread(locmem, RELATE_FIRST);
                break;
                    case AUTHOR_PREV:
                        new_ln = thread(locmem, AUTHOR_PREV);
                break;
                    case AUTHOR_NEXT:
                        new_ln = thread(locmem, AUTHOR_NEXT);
                break;
            }
            mode = DONOTHING; default_ch = 'r';
                }
        else {
            default_ch = 0;
            lastmode = 0;
        }
        } //end if (func != NULL)
    } // ch > 0 && ch <= onekey_size 
        break;
    } // end switch
    } while (mode == DONOTHING);
    return mode;
}

static int
get_records_and_bottom(char *direct,  fileheader_t* headers,
                     int recbase, int headers_size, int last_line, int bottom_line)
{
    int     n = bottom_line - recbase + 1, rv;
    char    directbottom[60];

    if( !last_line )
    return 0;
    if( n >= headers_size || (currmode & (MODE_SELECT | MODE_DIGEST)) )
    return get_records(direct, headers, sizeof(fileheader_t), recbase, 
               headers_size);

    sprintf(directbottom, "%s.bottom", direct);
    if( n <= 0 )
    return get_records(directbottom, headers, sizeof(fileheader_t), 1-n, 
               last_line-recbase + 1);
      
    rv = get_records(direct, headers, sizeof(fileheader_t), recbase, n);

    if( bottom_line < last_line )
    rv += get_records(directbottom, headers+n, sizeof(fileheader_t), 1, 
              headers_size - n );
    return rv;
}

void
i_read(int cmdmode, const char *direct, void (*dotitle) (),
       void (*doentry) (), const onekey_t * rcmdlist, int bidcache)
{
    keeploc_t      *locmem = NULL;
    int             recbase = 0, mode;
    int             num = 0, entries = 0, n_bottom=0;
    int             i;
    char            currdirect0[PATHLEN];
    int             last_line0 = last_line;
    int             bottom_line = 0;
    fileheader_t   *headers0 = headers;
    int             headers_size0 = headers_size;

    strlcpy(currdirect0, currdirect, sizeof(currdirect0));
#define FHSZ    sizeof(fileheader_t)
    /* Ptt: 這邊 headers 可以針對看板的最後 60 篇做 cache */
    headers_size = p_lines;
    headers = (fileheader_t *) calloc(headers_size, FHSZ);
    strlcpy(currdirect, direct, sizeof(currdirect));
    mode = NEWDIRECT;

    do {
    /* 依據 mode 顯示 fileheader */
    setutmpmode(cmdmode);
    switch (mode) {
    case NEWDIRECT: /* 第一次載入此目錄 */
    case DIRCHANGED:
        if (bidcache > 0 && !(currmode & (MODE_SELECT | MODE_DIGEST))){
        if( (last_line = getbtotal(currbid)) == 0 ){
            setbtotal(currbid);
                    setbottomtotal(currbid);
            last_line = getbtotal(currbid);
        }
                bottom_line = last_line;
                last_line += (n_bottom = getbottomtotal(currbid)); 
        }
        else
        bottom_line = last_line = get_num_records(currdirect, FHSZ);

        if (mode == NEWDIRECT) {
        num = last_line - p_lines + 1;
        locmem = getkeep(currdirect, num < 1 ? 1 : num, last_line);
        }
        recbase = -1;

    case FULLUPDATE:
        (*dotitle) ();

    case PARTUPDATE:
        if (last_line < locmem->top_ln + headers_size) {
        if (bidcache > 0 && !(currmode & (MODE_SELECT | MODE_DIGEST))){
            bottom_line = getbtotal(currbid);
            num = bottom_line+getbottomtotal(currbid);
            if(num == 0)
            {
            recbase = -1;
            }
        }
        else
        {
            num = get_num_records(currdirect, FHSZ);
            if(num == 0)
            {
            recbase = -1;
            }
        }

        if (last_line != num) {
            last_line = num;
            recbase = -1;
        }
        }
        if (recbase != locmem->top_ln) { //headers reload
        recbase = locmem->top_ln;
        if (recbase > last_line) {
            recbase = last_line - p_lines + 1;
            if (recbase < 1)
            recbase = 1;
            locmem->top_ln = recbase;
        }
        if(headers_size != p_lines) {
            headers_size = p_lines;
            headers = (fileheader_t *) realloc(headers, headers_size*FHSZ);
            assert(headers);
        }
                entries=get_records_and_bottom(currdirect,
                           headers, recbase, headers_size, last_line, bottom_line);
        }
        if (locmem->crs_ln > last_line)
        locmem->crs_ln = last_line;
        move(3, 0);
        clrtobot();
    case PART_REDRAW:
        move(3, 0);
            if( last_line == 0 )
                  outs("    沒有文章...");
            else
        for( i = 0; i < entries ; i++ )
            (*doentry) (locmem->top_ln + i, &headers[i]);
    case READ_REDRAW:
        if(curredit & EDIT_ITEM)
        outmsglr(ANSI_COLOR(44) " 私人收藏 " ANSI_COLOR(30;47), 10,
                " 繼續? ", 7);
        else if (curredit & EDIT_MAIL)
        outmsglr(MSG_MAILER, MSG_MAILER_LEN, "", 0);
        else
        outmsglr(MSG_POSTER, MSG_POSTER_LEN, "", 0);
        break;
    case TITLE_REDRAW:
        (*dotitle) ();
            break;
        
        case HEADERS_RELOAD:
        if (recbase != locmem->top_ln) {
        recbase = locmem->top_ln;
        if (recbase > last_line) {
            recbase = last_line - p_lines + 1;
            if (recbase < 1)
            recbase = 1;
            locmem->top_ln = recbase;
        }
        if(headers_size != p_lines) {
            headers_size = p_lines;
            headers = (fileheader_t *) realloc(headers, headers_size*FHSZ);
            assert(headers);
        }
                entries = 
            get_records_and_bottom(currdirect, headers, recbase,
                       headers_size, last_line, bottom_line);
        }
            break;
    } //end switch
    mode = i_read_key(rcmdlist, locmem, currbid, bottom_line);
    } while (mode != DOQUIT);
#undef  FHSZ

    free(headers);
    last_line = last_line0;
    headers = headers0;
    headers_size = headers_size0;
    strlcpy(currdirect, currdirect0, sizeof(currdirect));
    return;
}