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Annotation of OpenXM_contrib/gmp/tal-notreent.c, Revision 1.1

1.1     ! ohara       1: /* Stack allocation routines.  This is intended for machines without support
        !             2:    for the `alloca' function.
        !             3:
        !             4: Copyright 1996, 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
        !             5:
        !             6: This file is part of the GNU MP Library.
        !             7:
        !             8: The GNU MP Library is free software; you can redistribute it and/or modify
        !             9: it under the terms of the GNU Lesser General Public License as published by
        !            10: the Free Software Foundation; either version 2.1 of the License, or (at your
        !            11: option) any later version.
        !            12:
        !            13: The GNU MP Library is distributed in the hope that it will be useful, but
        !            14: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            15: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
        !            16: License for more details.
        !            17:
        !            18: You should have received a copy of the GNU Lesser General Public License
        !            19: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            20: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            21: MA 02111-1307, USA. */
        !            22:
        !            23: #include "gmp.h"
        !            24: #include "gmp-impl.h"
        !            25:
        !            26:
        !            27: struct tmp_stack
        !            28: {
        !            29:   void *end;
        !            30:   void *alloc_point;
        !            31:   struct tmp_stack *prev;
        !            32: };
        !            33: typedef struct tmp_stack tmp_stack;
        !            34:
        !            35:
        !            36: static unsigned long max_total_allocation = 0;
        !            37: static unsigned long current_total_allocation = 0;
        !            38:
        !            39: static tmp_stack xxx = {&xxx, &xxx, 0};
        !            40: static tmp_stack *current = &xxx;
        !            41:
        !            42: /* The rounded size of the header of each allocation block.  */
        !            43: #define HSIZ   ROUND_UP_MULTIPLE (sizeof (tmp_stack), __TMP_ALIGN)
        !            44:
        !            45:
        !            46: /* Allocate a block of exactly <size> bytes.  This should only be called
        !            47:    through the TMP_ALLOC macro, which takes care of rounding/alignment.  */
        !            48: void *
        !            49: __gmp_tmp_alloc (unsigned long size)
        !            50: {
        !            51:   void *that;
        !            52:
        !            53:   ASSERT ((size % __TMP_ALIGN) == 0);
        !            54:   ASSERT (((unsigned) current->alloc_point % __TMP_ALIGN) == 0);
        !            55:
        !            56:   if (size > (char *) current->end - (char *) current->alloc_point)
        !            57:     {
        !            58:       void *chunk;
        !            59:       tmp_stack *header;
        !            60:       unsigned long chunk_size;
        !            61:       unsigned long now;
        !            62:
        !            63:       /* Allocate a chunk that makes the total current allocation somewhat
        !            64:         larger than the maximum allocation ever.  If size is very large, we
        !            65:         allocate that much.  */
        !            66:
        !            67:       now = current_total_allocation + size;
        !            68:       if (now > max_total_allocation)
        !            69:        {
        !            70:          /* We need more temporary memory than ever before.  Increase
        !            71:             for future needs.  */
        !            72:          now = (now * 3 / 2 + __TMP_ALIGN - 1) & -__TMP_ALIGN;
        !            73:          chunk_size = now - current_total_allocation + HSIZ;
        !            74:          current_total_allocation = now;
        !            75:          max_total_allocation = current_total_allocation;
        !            76:        }
        !            77:       else
        !            78:        {
        !            79:          chunk_size = max_total_allocation - current_total_allocation + HSIZ;
        !            80:          current_total_allocation = max_total_allocation;
        !            81:        }
        !            82:
        !            83:       chunk = (*__gmp_allocate_func) (chunk_size);
        !            84:       header = (tmp_stack *) chunk;
        !            85:       header->end = (char *) chunk + chunk_size;
        !            86:       header->alloc_point = (char *) chunk + HSIZ;
        !            87:       header->prev = current;
        !            88:       current = header;
        !            89:     }
        !            90:
        !            91:   that = current->alloc_point;
        !            92:   current->alloc_point = (char *) that + size;
        !            93:   ASSERT (((unsigned) that % __TMP_ALIGN) == 0);
        !            94:   return that;
        !            95: }
        !            96:
        !            97: /* Typically called at function entry.  <mark> is assigned so that
        !            98:    __gmp_tmp_free can later be used to reclaim all subsequently allocated
        !            99:    storage.  */
        !           100: void
        !           101: __gmp_tmp_mark (tmp_marker *mark)
        !           102: {
        !           103:   mark->which_chunk = current;
        !           104:   mark->alloc_point = current->alloc_point;
        !           105: }
        !           106:
        !           107: /* Free everything allocated since <mark> was assigned by __gmp_tmp_mark */
        !           108: void
        !           109: __gmp_tmp_free (tmp_marker *mark)
        !           110: {
        !           111:   while (mark->which_chunk != current)
        !           112:     {
        !           113:       tmp_stack *tmp;
        !           114:
        !           115:       tmp = current;
        !           116:       current = tmp->prev;
        !           117:       current_total_allocation -= (((char *) (tmp->end) - (char *) tmp) - HSIZ);
        !           118:       (*__gmp_free_func) (tmp, (char *) tmp->end - (char *) tmp);
        !           119:     }
        !           120:   current->alloc_point = mark->alloc_point;
        !           121: }