diplodocus.org Git - nmh/blob - sbr/folder_realloc.c

   1
   2 /*
   3  * folder_realloc.c -- realloc a folder/msgs structure
   4  *
   5  * $Id$
   6  */
   7
   8 #include <h/mh.h>
   9
  10 /*
  11  * Reallocate some of the space in the folder
  12  * structure (currently just message status array).
  13  *
  14  * Return pointer to new folder structure.
  15  * If error, return NULL.
  16  */
  17
  18 struct msgs *
  19 folder_realloc (struct msgs *mp, int lo, int hi)
  20 {
  21     int msgnum;
  22
  23     /* sanity checks */
  24     if (lo < 1)
  25         adios (NULL, "BUG: called folder_realloc with lo (%d) < 1", lo);
  26     if (hi < 1)
  27         adios (NULL, "BUG: called folder_realloc with hi (%d) < 1", hi);
  28     if (mp->nummsg > 0 && lo > mp->lowmsg)
  29         adios (NULL, "BUG: called folder_realloc with lo (%d) > mp->lowmsg (%d)",
  30                lo, mp->lowmsg);
  31     if (mp->nummsg > 0 && hi < mp->hghmsg)
  32         adios (NULL, "BUG: called folder_realloc with hi (%d) < mp->hghmsg (%d)",
  33                hi, mp->hghmsg);
  34
  35     /* Check if we really need to reallocate anything */
  36     if (lo == mp->lowoff && hi == mp->hghoff)
  37         return mp;
  38
  39     if (lo == mp->lowoff) {
  40         /*
  41          * We are just extending (or shrinking) the end of message
  42          * status array.  So we don't have to move anything and can
  43          * just realloc the message status array.
  44          */
  45         if (!(mp->msgstats = realloc (mp->msgstats, MSGSTATSIZE(mp, lo, hi)))) {
  46             advise (NULL, "unable to reallocate message storage");
  47             return NULL;
  48         }
  49     } else {
  50         /*
  51          * We are changing the offset of the message status
  52          * array.  So we will need to shift everything.
  53          */
  54         seqset_t *tmpstats;
  55
  56         /* first allocate the new message status space */
  57         if (!(tmpstats = malloc (MSGSTATSIZE(mp, lo, hi)))) {
  58             advise (NULL, "unable to reallocate message storage");
  59             return NULL;
  60         }
  61
  62         /* then copy messages status array with shift */
  63         if (mp->nummsg > 0) {
  64             for (msgnum = mp->lowmsg; msgnum <= mp->hghmsg; msgnum++)
  65                 tmpstats[msgnum - lo] = mp->msgstats[msgnum - mp->lowoff];
  66         }
  67         free(mp->msgstats);
  68         mp->msgstats = tmpstats;
  69     }
  70
  71     mp->lowoff = lo;
  72     mp->hghoff = hi;
  73
  74     /*
  75      * Clear all the flags for entries outside
  76      * the current message range for this folder.
  77      */
  78     if (mp->nummsg > 0) {
  79         for (msgnum = mp->lowoff; msgnum < mp->lowmsg; msgnum++)
  80             clear_msg_flags (mp, msgnum);
  81         for (msgnum = mp->hghmsg + 1; msgnum <= mp->hghoff; msgnum++)
  82             clear_msg_flags (mp, msgnum);
  83     } else {
  84         /* no messages, so clear entire range */
  85         for (msgnum = mp->lowoff; msgnum <= mp->hghoff; msgnum++)
  86             clear_msg_flags (mp, msgnum);
  87     }
  88
  89     return mp;
  90 }