1 /*
2 * QEMU 64-bit address ranges
3 *
4 * Copyright (c) 2015-2016 Red Hat, Inc.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #ifndef QEMU_RANGE_H
21 #define QEMU_RANGE_H
22
23 #include "qemu/bitops.h"
24
25 /*
26 * Operations on 64 bit address ranges.
27 * Notes:
28 * - Ranges must not wrap around 0, but can include UINT64_MAX.
29 */
30
31 struct Range {
32 /*
33 * Do not access members directly, use the functions!
34 * A non-empty range has @lob <= @upb.
35 * An empty range has @lob == @upb + 1.
36 */
37 uint64_t lob; /* inclusive lower bound */
38 uint64_t upb; /* inclusive upper bound */
39 };
40
range_invariant(const Range * range)41 static inline void range_invariant(const Range *range)
42 {
43 assert(range->lob <= range->upb || range->lob == range->upb + 1);
44 }
45
46 /* Compound literal encoding the empty range */
47 #define range_empty ((Range){ .lob = 1, .upb = 0 })
48
49 /* Is @range empty? */
range_is_empty(const Range * range)50 static inline bool range_is_empty(const Range *range)
51 {
52 range_invariant(range);
53 return range->lob > range->upb;
54 }
55
56 /* Does @range contain @val? */
range_contains(const Range * range,uint64_t val)57 static inline bool range_contains(const Range *range, uint64_t val)
58 {
59 return val >= range->lob && val <= range->upb;
60 }
61
62 /* Initialize @range to the empty range */
range_make_empty(Range * range)63 static inline void range_make_empty(Range *range)
64 {
65 *range = range_empty;
66 assert(range_is_empty(range));
67 }
68
69 /*
70 * Initialize @range to span the interval [@lob,@upb].
71 * Both bounds are inclusive.
72 * The interval must not be empty, i.e. @lob must be less than or
73 * equal @upb.
74 */
range_set_bounds(Range * range,uint64_t lob,uint64_t upb)75 static inline void range_set_bounds(Range *range, uint64_t lob, uint64_t upb)
76 {
77 range->lob = lob;
78 range->upb = upb;
79 assert(!range_is_empty(range));
80 }
81
82 /*
83 * Initialize @range to span the interval [@lob,@upb_plus1).
84 * The lower bound is inclusive, the upper bound is exclusive.
85 * Zero @upb_plus1 is special: if @lob is also zero, set @range to the
86 * empty range. Else, set @range to [@lob,UINT64_MAX].
87 */
range_set_bounds1(Range * range,uint64_t lob,uint64_t upb_plus1)88 static inline void range_set_bounds1(Range *range,
89 uint64_t lob, uint64_t upb_plus1)
90 {
91 if (!lob && !upb_plus1) {
92 *range = range_empty;
93 } else {
94 range->lob = lob;
95 range->upb = upb_plus1 - 1;
96 }
97 range_invariant(range);
98 }
99
100 /* Return @range's lower bound. @range must not be empty. */
range_lob(Range * range)101 static inline uint64_t range_lob(Range *range)
102 {
103 assert(!range_is_empty(range));
104 return range->lob;
105 }
106
107 /* Return @range's upper bound. @range must not be empty. */
range_upb(Range * range)108 static inline uint64_t range_upb(Range *range)
109 {
110 assert(!range_is_empty(range));
111 return range->upb;
112 }
113
114 /*
115 * Initialize @range to span the interval [@lob,@lob + @size - 1].
116 * @size may be 0. If the range would overflow, returns -ERANGE, otherwise
117 * 0.
118 */
119 G_GNUC_WARN_UNUSED_RESULT
range_init(Range * range,uint64_t lob,uint64_t size)120 static inline int range_init(Range *range, uint64_t lob, uint64_t size)
121 {
122 if (lob + size < lob) {
123 return -ERANGE;
124 }
125 range->lob = lob;
126 range->upb = lob + size - 1;
127 range_invariant(range);
128 return 0;
129 }
130
131 /*
132 * Initialize @range to span the interval [@lob,@lob + @size - 1].
133 * @size may be 0. Range must not overflow.
134 */
range_init_nofail(Range * range,uint64_t lob,uint64_t size)135 static inline void range_init_nofail(Range *range, uint64_t lob, uint64_t size)
136 {
137 range->lob = lob;
138 range->upb = lob + size - 1;
139 range_invariant(range);
140 }
141
142 /*
143 * Get the size of @range.
144 */
range_size(const Range * range)145 static inline uint64_t range_size(const Range *range)
146 {
147 return range->upb - range->lob + 1;
148 }
149
150 /*
151 * Check if @range1 overlaps with @range2. If one of the ranges is empty,
152 * the result is always "false".
153 */
range_overlaps_range(const Range * range1,const Range * range2)154 static inline bool range_overlaps_range(const Range *range1,
155 const Range *range2)
156 {
157 if (range_is_empty(range1) || range_is_empty(range2)) {
158 return false;
159 }
160 return !(range2->upb < range1->lob || range1->upb < range2->lob);
161 }
162
163 /*
164 * Check if @range1 contains @range2. If one of the ranges is empty,
165 * the result is always "false".
166 */
range_contains_range(const Range * range1,const Range * range2)167 static inline bool range_contains_range(const Range *range1,
168 const Range *range2)
169 {
170 if (range_is_empty(range1) || range_is_empty(range2)) {
171 return false;
172 }
173 return range1->lob <= range2->lob && range1->upb >= range2->upb;
174 }
175
176 /*
177 * Extend @range to the smallest interval that includes @extend_by, too.
178 */
range_extend(Range * range,Range * extend_by)179 static inline void range_extend(Range *range, Range *extend_by)
180 {
181 if (range_is_empty(extend_by)) {
182 return;
183 }
184 if (range_is_empty(range)) {
185 *range = *extend_by;
186 return;
187 }
188 if (range->lob > extend_by->lob) {
189 range->lob = extend_by->lob;
190 }
191 if (range->upb < extend_by->upb) {
192 range->upb = extend_by->upb;
193 }
194 range_invariant(range);
195 }
196
197 /* Get last byte of a range from offset + length.
198 * Undefined for ranges that wrap around 0. */
range_get_last(uint64_t offset,uint64_t len)199 static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
200 {
201 return offset + len - 1;
202 }
203
204 /* Check whether a given range covers a given byte. */
range_covers_byte(uint64_t offset,uint64_t len,uint64_t byte)205 static inline int range_covers_byte(uint64_t offset, uint64_t len,
206 uint64_t byte)
207 {
208 return offset <= byte && byte <= range_get_last(offset, len);
209 }
210
211 /* Check whether 2 given ranges overlap.
212 * Undefined if ranges that wrap around 0. */
ranges_overlap(uint64_t first1,uint64_t len1,uint64_t first2,uint64_t len2)213 static inline bool ranges_overlap(uint64_t first1, uint64_t len1,
214 uint64_t first2, uint64_t len2)
215 {
216 uint64_t last1 = range_get_last(first1, len1);
217 uint64_t last2 = range_get_last(first2, len2);
218
219 return !(last2 < first1 || last1 < first2);
220 }
221
222 /* Get highest non-zero bit position of a range */
range_get_last_bit(Range * range)223 static inline int range_get_last_bit(Range *range)
224 {
225 if (range_is_empty(range)) {
226 return -1;
227 }
228 return 63 - clz64(range->upb);
229 }
230
231 /*
232 * Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap.
233 * Both @a and @b must not be empty.
234 */
235 int range_compare(Range *a, Range *b);
236
237 GList *range_list_insert(GList *list, Range *data);
238
239 /*
240 * Inverse an array of sorted ranges over the [low, high] span, ie.
241 * original ranges becomes holes in the newly allocated inv_ranges
242 */
243 void range_inverse_array(GList *in_ranges,
244 GList **out_ranges,
245 uint64_t low, uint64_t high);
246
247 #endif
248