tor-browser

cmsarray.c (4688B)

---

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
* CMS array functions.
*/

#include "cmslocal.h"

#include "secerr.h"

/*
* ARRAY FUNCTIONS
*
* In NSS, arrays are rather primitive arrays of pointers.
* Makes it easy to walk the array, but hard to count elements
* and manage the storage.
*
* This is a feeble attempt to encapsulate the functionality
* and get rid of hundreds of lines of similar code
*/

/*
* NSS_CMSArray_Alloc - allocate an array in an arena
*
* This allocates space for the array of pointers
*/
void **
NSS_CMSArray_Alloc(PLArenaPool *poolp, int n)
{
   return (void **)PORT_ArenaZAlloc(poolp, n * sizeof(void *));
}

/*
* NSS_CMSArray_Add - add an element to the end of an array
*
* The array of pointers is either created (if array was empty before) or grown.
*/
SECStatus
NSS_CMSArray_Add(PLArenaPool *poolp, void ***array, void *obj)
{
   void **p;
   int n;
   void **dest;

   PORT_Assert(array != NULL);
   if (array == NULL)
       return SECFailure;

   if (*array == NULL) {
       dest = (void **)PORT_ArenaAlloc(poolp, 2 * sizeof(void *));
       n = 0;
   } else {
       n = 0;
       p = *array;
       while (*p++)
           n++;
       dest = (void **)PORT_ArenaGrow(poolp,
                                      *array,
                                      (n + 1) * sizeof(void *),
                                      (n + 2) * sizeof(void *));
   }

   if (dest == NULL)
       return SECFailure;

   dest[n] = obj;
   dest[n + 1] = NULL;
   *array = dest;
   return SECSuccess;
}

/*
* NSS_CMSArray_IsEmpty - check if array is empty
*/
PRBool
NSS_CMSArray_IsEmpty(void **array)
{
   return (array == NULL || array[0] == NULL);
}

/*
* NSS_CMSArray_Count - count number of elements in array
*/
int
NSS_CMSArray_Count(void **array)
{
   int n = 0;

   if (array == NULL)
       return 0;

   while (*array++ != NULL)
       n++;

   return n;
}

/*
* NSS_CMSArray_Sort - sort an array in place
*
* If "secondary" or "tertiary are not NULL, it must be arrays with the same
*  number of elements as "primary". The same reordering will get applied to it.
*
* "compare" is a function that returns
*  < 0 when the first element is less than the second
*  = 0 when the first element is equal to the second
*  > 0 when the first element is greater than the second
* to acheive ascending ordering.
*/
void
NSS_CMSArray_Sort(void **primary, int (*compare)(void *, void *), void **secondary, void **tertiary)
{
   int n, i, limit, lastxchg;
   void *tmp;

   n = NSS_CMSArray_Count(primary);

   PORT_Assert(secondary == NULL || NSS_CMSArray_Count(secondary) == n);
   PORT_Assert(tertiary == NULL || NSS_CMSArray_Count(tertiary) == n);

   if (n <= 1) /* ordering is fine */
       return;

   /* yes, ladies and gentlemen, it's BUBBLE SORT TIME! */
   limit = n - 1;
   while (1) {
       lastxchg = 0;
       for (i = 0; i < limit; i++) {
           if ((*compare)(primary[i], primary[i + 1]) > 0) {
               /* exchange the neighbours */
               tmp = primary[i + 1];
               primary[i + 1] = primary[i];
               primary[i] = tmp;
               if (secondary) {            /* secondary array? */
                   tmp = secondary[i + 1]; /* exchange there as well */
                   secondary[i + 1] = secondary[i];
                   secondary[i] = tmp;
               }
               if (tertiary) {            /* tertiary array? */
                   tmp = tertiary[i + 1]; /* exchange there as well */
                   tertiary[i + 1] = tertiary[i];
                   tertiary[i] = tmp;
               }
               lastxchg = i + 1; /* index of the last element bubbled up */
           }
       }
       if (lastxchg == 0) /* no exchanges, so array is sorted */
           break;         /* we're done */
       limit = lastxchg;  /* array is sorted up to [limit] */
   }
}

#if 0

/* array iterator stuff... not used */

typedef void **NSSCMSArrayIterator;

/* iterator */
NSSCMSArrayIterator
NSS_CMSArray_First(void **array)
{
   if (array == NULL || array[0] == NULL)
   return NULL;
   return (NSSCMSArrayIterator)&(array[0]);
}

void *
NSS_CMSArray_Obj(NSSCMSArrayIterator iter)
{
   void **p = (void **)iter;

   return *iter;   /* which is NULL if we are at the end of the array */
}

NSSCMSArrayIterator
NSS_CMSArray_Next(NSSCMSArrayIterator iter)
{
   void **p = (void **)iter;

   return (NSSCMSArrayIterator)(p + 1);
}

#endif