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[/] [openrisc/] [trunk/] [gnu-src/] [gdb-7.1/] [gdb/] [vec.c] - Blame information for rev 227

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1 227 jeremybenn
/* Vector API for GDB.
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   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
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   Free Software Foundation, Inc.
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   Contributed by Nathan Sidwell <nathan@codesourcery.com>
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   This file is part of GDB.
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   This program is free software; you can redistribute it and/or modify
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   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3 of the License, or
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   (at your option) any later version.
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   This program is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
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   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
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#include "defs.h"
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#include "vec.h"
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struct vec_prefix
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{
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  unsigned num;
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  unsigned alloc;
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  void *vec[1];
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};
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/* Calculate the new ALLOC value, making sure that abs(RESERVE) slots
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   are free.  If RESERVE < 0 grow exactly, otherwise grow
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   exponentially.  */
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static inline unsigned
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calculate_allocation (const struct vec_prefix *pfx, int reserve)
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{
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  unsigned alloc = 0;
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  unsigned num = 0;
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  if (pfx)
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    {
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      alloc = pfx->alloc;
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      num = pfx->num;
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    }
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  else if (!reserve)
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    /* If there's no prefix, and we've not requested anything, then we
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       will create a NULL vector.  */
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    return 0;
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  /* We must have run out of room.  */
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  gdb_assert (alloc - num < (unsigned)(reserve < 0 ? -reserve : reserve));
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  if (reserve < 0)
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    /* Exact size.  */
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    alloc = num + -reserve;
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  else
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    {
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      /* Exponential growth. */
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      if (!alloc)
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        alloc = 4;
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      else if (alloc < 16)
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        /* Double when small.  */
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        alloc = alloc * 2;
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      else
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        /* Grow slower when large.  */
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        alloc = (alloc * 3 / 2);
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      /* If this is still too small, set it to the right size. */
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      if (alloc < num + reserve)
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        alloc = num + reserve;
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    }
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  return alloc;
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}
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/* Ensure there are at least abs(RESERVE) free slots in VEC.  If
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   RESERVE < 0 grow exactly, else grow exponentially.  As a special
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   case, if VEC is NULL, and RESERVE is 0, no vector will be created. */
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void *
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vec_p_reserve (void *vec, int reserve)
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{
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  return vec_o_reserve (vec, reserve,
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                        offsetof (struct vec_prefix, vec), sizeof (void *));
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}
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/* As vec_p_reserve, but for object vectors.  The vector's trailing
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   array is at VEC_OFFSET offset and consists of ELT_SIZE sized
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   elements.  */
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void *
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vec_o_reserve (void *vec, int reserve, size_t vec_offset, size_t elt_size)
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{
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  struct vec_prefix *pfx = vec;
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  unsigned alloc = calculate_allocation (pfx, reserve);
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  if (!alloc)
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    return NULL;
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  vec = xrealloc (vec, vec_offset + alloc * elt_size);
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  ((struct vec_prefix *)vec)->alloc = alloc;
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  if (!pfx)
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    ((struct vec_prefix *)vec)->num = 0;
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  return vec;
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}
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#if 0
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/* Example uses.  */
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DEF_VEC_I (int);
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typedef struct X
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{
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  int i;
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} obj_t;
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typedef obj_t *ptr_t;
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DEF_VEC_P (ptr_t);
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DEF_VEC_O (obj_t);
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#endif

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