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350da6ee | 1 | /* Vector API for GDB. |
28e7fd62 | 2 | Copyright (C) 2004-2013 Free Software Foundation, Inc. |
350da6ee DJ |
3 | Contributed by Nathan Sidwell <nathan@codesourcery.com> |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 9 | the Free Software Foundation; either version 3 of the License, or |
350da6ee DJ |
10 | (at your option) any later version. |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
350da6ee | 19 | |
aad9eab9 YQ |
20 | #ifdef GDBSERVER |
21 | #include "server.h" | |
22 | #else | |
350da6ee | 23 | #include "defs.h" |
aad9eab9 YQ |
24 | #endif |
25 | ||
8aceae7e | 26 | #include "vec.h" |
350da6ee DJ |
27 | |
28 | struct vec_prefix | |
29 | { | |
30 | unsigned num; | |
31 | unsigned alloc; | |
32 | void *vec[1]; | |
33 | }; | |
34 | ||
35 | /* Calculate the new ALLOC value, making sure that abs(RESERVE) slots | |
36 | are free. If RESERVE < 0 grow exactly, otherwise grow | |
37 | exponentially. */ | |
38 | ||
39 | static inline unsigned | |
40 | calculate_allocation (const struct vec_prefix *pfx, int reserve) | |
41 | { | |
42 | unsigned alloc = 0; | |
43 | unsigned num = 0; | |
44 | ||
45 | if (pfx) | |
46 | { | |
47 | alloc = pfx->alloc; | |
48 | num = pfx->num; | |
49 | } | |
50 | else if (!reserve) | |
51 | /* If there's no prefix, and we've not requested anything, then we | |
52 | will create a NULL vector. */ | |
53 | return 0; | |
54 | ||
55 | /* We must have run out of room. */ | |
56 | gdb_assert (alloc - num < (unsigned)(reserve < 0 ? -reserve : reserve)); | |
57 | ||
58 | if (reserve < 0) | |
59 | /* Exact size. */ | |
60 | alloc = num + -reserve; | |
61 | else | |
62 | { | |
581e13c1 | 63 | /* Exponential growth. */ |
350da6ee DJ |
64 | if (!alloc) |
65 | alloc = 4; | |
66 | else if (alloc < 16) | |
67 | /* Double when small. */ | |
68 | alloc = alloc * 2; | |
69 | else | |
70 | /* Grow slower when large. */ | |
71 | alloc = (alloc * 3 / 2); | |
72 | ||
581e13c1 | 73 | /* If this is still too small, set it to the right size. */ |
350da6ee DJ |
74 | if (alloc < num + reserve) |
75 | alloc = num + reserve; | |
76 | } | |
77 | return alloc; | |
78 | } | |
79 | ||
80 | /* Ensure there are at least abs(RESERVE) free slots in VEC. If | |
81 | RESERVE < 0 grow exactly, else grow exponentially. As a special | |
581e13c1 | 82 | case, if VEC is NULL, and RESERVE is 0, no vector will be created. */ |
350da6ee DJ |
83 | |
84 | void * | |
85 | vec_p_reserve (void *vec, int reserve) | |
86 | { | |
87 | return vec_o_reserve (vec, reserve, | |
88 | offsetof (struct vec_prefix, vec), sizeof (void *)); | |
89 | } | |
90 | ||
91 | /* As vec_p_reserve, but for object vectors. The vector's trailing | |
92 | array is at VEC_OFFSET offset and consists of ELT_SIZE sized | |
93 | elements. */ | |
94 | ||
95 | void * | |
96 | vec_o_reserve (void *vec, int reserve, size_t vec_offset, size_t elt_size) | |
97 | { | |
98 | struct vec_prefix *pfx = vec; | |
99 | unsigned alloc = calculate_allocation (pfx, reserve); | |
100 | ||
101 | if (!alloc) | |
102 | return NULL; | |
103 | ||
104 | vec = xrealloc (vec, vec_offset + alloc * elt_size); | |
105 | ((struct vec_prefix *)vec)->alloc = alloc; | |
106 | if (!pfx) | |
107 | ((struct vec_prefix *)vec)->num = 0; | |
108 | ||
109 | return vec; | |
110 | } | |
111 | ||
112 | #if 0 | |
113 | /* Example uses. */ | |
114 | DEF_VEC_I (int); | |
115 | typedef struct X | |
116 | { | |
117 | int i; | |
118 | } obj_t; | |
119 | typedef obj_t *ptr_t; | |
120 | ||
121 | DEF_VEC_P (ptr_t); | |
122 | DEF_VEC_O (obj_t); | |
123 | #endif |