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Diffstat (limited to 'gdb/common/vec.c')
-rw-r--r-- | gdb/common/vec.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/gdb/common/vec.c b/gdb/common/vec.c new file mode 100644 index 0000000..360dc96 --- /dev/null +++ b/gdb/common/vec.c @@ -0,0 +1,123 @@ +/* Vector API for GDB. + Copyright (C) 2004-2012 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/>. */ + +#ifdef GDBSERVER +#include "server.h" +#else +#include "defs.h" +#endif + +#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 |