date and time created 80/10/08 09:51:24 by kas

[unix-history] / usr / src / usr.bin / mail / strings.c

#

/*
* Mail -- a mail program
*
* String allocation routines.
* Strings handed out here are reclaimed at the top of the command
* loop each time, so they need not be freed.
*/

#include "rcv.h"

static char *SccsId = "@(#)strings.c    1.1 %G%";

/*
* Allocate size more bytes of space and return the address of the
* first byte to the caller.  An even number of bytes are always
* allocated so that the space will always be on a word boundary.
* The string spaces are of exponentially increasing size, to satisfy
* the occasional user with enormous string size requests.
*/

char *
salloc(size)
{
       register char *t;
       register int s;
       register struct strings *sp;
       int index;

       s = size;
       s++;
       s &= ~01;
       index = 0;
       for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++) {
               if (sp->s_topFree == NOSTR && (STRINGSIZE << index) >= s)
                       break;
               if (sp->s_nleft >= s)
                       break;
               index++;
       }
       if (sp >= &stringdope[NSPACE])
               panic("String too large");
       if (sp->s_topFree == NOSTR) {
               index = sp - &stringdope[0];
               sp->s_topFree = (char *) calloc(STRINGSIZE << index,
                   (unsigned) 1);
               if (sp->s_topFree == NOSTR) {
                       fprintf(stderr, "No room for space %d\n", index);
                       panic("Internal error");
               }
               sp->s_nextFree = sp->s_topFree;
               sp->s_nleft = STRINGSIZE << index;
       }
       sp->s_nleft -= s;
       t = sp->s_nextFree;
       sp->s_nextFree += s;
       return(t);
}

/*
* Reset the string area to be empty.
* Called to free all strings allocated
* since last reset.
*/

sreset()
{
       register struct strings *sp;
       register int index;

       if (noreset)
               return;
       minit();
       index = 0;
       for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++) {
               if (sp->s_topFree == NOSTR)
                       continue;
               sp->s_nextFree = sp->s_topFree;
               sp->s_nleft = STRINGSIZE << index;
               index++;
       }
}