src/runtime/util.h

   1 /*
   2  * miscellaneous utilities
   3  */
   4
   5 /*
   6  * This software is part of the SBCL system. See the README file for
   7  * more information.
   8  *
   9  * This software is derived from the CMU CL system, which was
  10  * written at Carnegie Mellon University and released into the
  11  * public domain. The software is in the public domain and is
  12  * provided with absolutely no warranty. See the COPYING and CREDITS
  13  * files for more information.
  14  */
  15
  16 /*
  17  * a utility to accumulate a zero-terminated array of void* values
  18  *
  19  * (Ah, lovely C, makes it such a delight to accumulate a collection
  20  * whose length isn't known in advance.. but it's probably more fun
  21  * than trying to teach the SBCL debugger to walk g++ stack frames, not to
  22  * mention dealing with g++'s lovely in-which-file-do-templates-expand
  23  * issues; or than trying to use Lisp for all accumulation and having to
  24  * hassle about FFIing all the details of opendir/readdir/closedir
  25  * and so forth.)
  26  *
  27  * We more or less simulate C++-style ctors and dtors.
  28  */
  29 typedef struct
  30 voidacc { /* the accumulator itself, to be treated as an opaque data type */
  31 /*private:*/
  32     void **result;
  33     int n_avail;
  34     int n_used;
  35 } voidacc;
  36 int voidacc_ctor(voidacc*); /* the ctor, returning 0 for success */
  37 int voidacc_acc(voidacc*, void*); /* Accumulate an element into result,
  38                                    * returning 0 for success. */
  39 void** voidacc_give_away_result(voidacc*); /* giving away ownership */
  40 void voidacc_dtor(voidacc*); /* the dtor */