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  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   8  * COPYRIGHT file in the root directory of the nmh distribution for
   9  * complete copyright information.
  10  */
  11
  12 #include <h/mh.h>
  13
  14 /*
  15  * Reallocate some of the space in the folder
  16  * structure (currently just message status array).
  17  *
  18  * Return pointer to new folder structure.
  19  * If error, return NULL.
  20  */
  21
  22 struct msgs *
  23 folder_realloc (struct msgs *mp, int lo, int hi)
  24 {
  25     int msgnum;
  26
  27     /* sanity checks */
  28     if (lo < 1)
  29         adios (NULL, "BUG: called folder_realloc with lo (%d) < 1", lo);
  30     if (hi < 1)
  31         adios (NULL, "BUG: called folder_realloc with hi (%d) < 1", hi);
  32     if (mp->nummsg > 0 && lo > mp->lowmsg)
  33         adios (NULL, "BUG: called folder_realloc with lo (%d) > mp->lowmsg (%d)",
  34                lo, mp->lowmsg);
  35     if (mp->nummsg > 0 && hi < mp->hghmsg)
  36         adios (NULL, "BUG: called folder_realloc with hi (%d) < mp->hghmsg (%d)",
  37                hi, mp->hghmsg);
  38
  39     /* Check if we really need to reallocate anything */
  40     if (lo == mp->lowoff && hi == mp->hghoff)
  41         return mp;
  42
  43     if (lo == mp->lowoff) {
  44         /*
  45          * We are just extending (or shrinking) the end of message
  46          * status array.  So we don't have to move anything and can
  47          * just realloc the message status array.
  48          */
  49         if (!(mp->msgstats = realloc (mp->msgstats, MSGSTATSIZE(mp, lo, hi)))) {
  50             advise (NULL, "unable to reallocate message storage");
  51             return NULL;
  52         }
  53     } else {
  54         /*
  55          * We are changing the offset of the message status
  56          * array.  So we will need to shift everything.
  57          */
  58         seqset_t *tmpstats;
  59
  60         /* first allocate the new message status space */
  61         if (!(tmpstats = malloc (MSGSTATSIZE(mp, lo, hi)))) {
  62             advise (NULL, "unable to reallocate message storage");
  63             return NULL;
  64         }
  65
  66         /* then copy messages status array with shift */
  67         if (mp->nummsg > 0) {
  68             for (msgnum = mp->lowmsg; msgnum <= mp->hghmsg; msgnum++)
  69                 tmpstats[msgnum - lo] = mp->msgstats[msgnum - mp->lowoff];
  70         }
  71         free(mp->msgstats);
  72         mp->msgstats = tmpstats;
  73     }
  74
  75     mp->lowoff = lo;
  76     mp->hghoff = hi;
  77
  78     /*
  79      * Clear all the flags for entries outside
  80      * the current message range for this folder.
  81      */
  82     if (mp->nummsg > 0) {
  83         for (msgnum = mp->lowoff; msgnum < mp->lowmsg; msgnum++)
  84             clear_msg_flags (mp, msgnum);
  85         for (msgnum = mp->hghmsg + 1; msgnum <= mp->hghoff; msgnum++)
  86             clear_msg_flags (mp, msgnum);
  87     } else {
  88         /* no messages, so clear entire range */
  89         for (msgnum = mp->lowoff; msgnum <= mp->hghoff; msgnum++)
  90             clear_msg_flags (mp, msgnum);
  91     }
  92
  93     return mp;
  94 }