/* Vector API for GDB. Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. Contributed by Nathan Sidwell <nathan@codesourcery.com> This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "defs.h" #include "vec.h" struct vec_prefix { unsigned num; unsigned alloc; void *vec[1]; }; /* Calculate the new ALLOC value, making sure that abs(RESERVE) slots are free. If RESERVE < 0 grow exactly, otherwise grow exponentially. */ static inline unsigned calculate_allocation (const struct vec_prefix *pfx, int reserve) { unsigned alloc = 0; unsigned num = 0; if (pfx) { alloc = pfx->alloc; num = pfx->num; } else if (!reserve) /* If there's no prefix, and we've not requested anything, then we will create a NULL vector. */ return 0; /* We must have run out of room. */ gdb_assert (alloc - num < (unsigned)(reserve < 0 ? -reserve : reserve)); if (reserve < 0) /* Exact size. */ alloc = num + -reserve; else { /* Exponential growth. */ if (!alloc) alloc = 4; else if (alloc < 16) /* Double when small. */ alloc = alloc * 2; else /* Grow slower when large. */ alloc = (alloc * 3 / 2); /* If this is still too small, set it to the right size. */ if (alloc < num + reserve) alloc = num + reserve; } return alloc; } /* Ensure there are at least abs(RESERVE) free slots in VEC. If RESERVE < 0 grow exactly, else grow exponentially. As a special case, if VEC is NULL, and RESERVE is 0, no vector will be created. */ void * vec_p_reserve (void *vec, int reserve) { return vec_o_reserve (vec, reserve, offsetof (struct vec_prefix, vec), sizeof (void *)); } /* As vec_p_reserve, but for object vectors. The vector's trailing array is at VEC_OFFSET offset and consists of ELT_SIZE sized elements. */ void * vec_o_reserve (void *vec, int reserve, size_t vec_offset, size_t elt_size) { struct vec_prefix *pfx = vec; unsigned alloc = calculate_allocation (pfx, reserve); if (!alloc) return NULL; vec = xrealloc (vec, vec_offset + alloc * elt_size); ((struct vec_prefix *)vec)->alloc = alloc; if (!pfx) ((struct vec_prefix *)vec)->num = 0; return vec; } #if 0 /* Example uses. */ DEF_VEC_I (int); typedef struct X { int i; } obj_t; typedef obj_t *ptr_t; DEF_VEC_P (ptr_t); DEF_VEC_O (obj_t); #endif