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/*
* QEMU 64-bit address ranges
*
* Copyright (c) 2015-2016 Red Hat, Inc.
*
* This library 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 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef QEMU_RANGE_H
#define QEMU_RANGE_H
#include "qemu/queue.h"
/*
* Operations on 64 bit address ranges.
* Notes:
* - ranges must not wrap around 0, but can include the last byte ~0x0LL.
* - this can not represent a full 0 to ~0x0LL range.
*/
/* A structure representing a range of addresses. */
struct Range {
uint64_t begin; /* First byte of the range, or 0 if empty. */
uint64_t end; /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */
};
static inline void range_invariant(Range *range)
{
assert((!range->begin && !range->end) /* empty */
|| range->begin <= range->end - 1); /* non-empty */
}
/* Compound literal encoding the empty range */
#define range_empty ((Range){ .begin = 0, .end = 0 })
/* Is @range empty? */
static inline bool range_is_empty(Range *range)
{
range_invariant(range);
return !range->begin && !range->end;
}
/* Does @range contain @val? */
static inline bool range_contains(Range *range, uint64_t val)
{
return !range_is_empty(range)
&& val >= range->begin && val <= range->end - 1;
}
/* Initialize @range to the empty range */
static inline void range_make_empty(Range *range)
{
*range = range_empty;
assert(range_is_empty(range));
}
/*
* Initialize @range to span the interval [@lob,@upb].
* Both bounds are inclusive.
* The interval must not be empty, i.e. @lob must be less than or
* equal @upb.
* The interval must not be [0,UINT64_MAX], because Range can't
* represent that.
*/
static inline void range_set_bounds(Range *range, uint64_t lob, uint64_t upb)
{
assert(lob <= upb);
range->begin = lob;
range->end = upb + 1; /* may wrap to zero, that's okay */
assert(!range_is_empty(range));
}
/*
* Initialize @range to span the interval [@lob,@upb_plus1).
* The lower bound is inclusive, the upper bound is exclusive.
* Zero @upb_plus1 is special: if @lob is also zero, set @range to the
* empty range. Else, set @range to [@lob,UINT64_MAX].
*/
static inline void range_set_bounds1(Range *range,
uint64_t lob, uint64_t upb_plus1)
{
range->begin = lob;
range->end = upb_plus1;
range_invariant(range);
}
/* Return @range's lower bound. @range must not be empty. */
static inline uint64_t range_lob(Range *range)
{
assert(!range_is_empty(range));
return range->begin;
}
/* Return @range's upper bound. @range must not be empty. */
static inline uint64_t range_upb(Range *range)
{
assert(!range_is_empty(range));
return range->end - 1;
}
/*
* Extend @range to the smallest interval that includes @extend_by, too.
* This must not extend @range to cover the interval [0,UINT64_MAX],
* because Range can't represent that.
*/
static inline void range_extend(Range *range, Range *extend_by)
{
if (range_is_empty(extend_by)) {
return;
}
if (range_is_empty(range)) {
*range = *extend_by;
return;
}
if (range->begin > extend_by->begin) {
range->begin = extend_by->begin;
}
/* Compare last byte in case region ends at ~0x0LL */
if (range->end - 1 < extend_by->end - 1) {
range->end = extend_by->end;
}
/* Must not extend to { .begin = 0, .end = 0 }: */
assert(!range_is_empty(range));
}
/* Get last byte of a range from offset + length.
* Undefined for ranges that wrap around 0. */
static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
{
return offset + len - 1;
}
/* Check whether a given range covers a given byte. */
static inline int range_covers_byte(uint64_t offset, uint64_t len,
uint64_t byte)
{
return offset <= byte && byte <= range_get_last(offset, len);
}
/* Check whether 2 given ranges overlap.
* Undefined if ranges that wrap around 0. */
static inline int ranges_overlap(uint64_t first1, uint64_t len1,
uint64_t first2, uint64_t len2)
{
uint64_t last1 = range_get_last(first1, len1);
uint64_t last2 = range_get_last(first2, len2);
return !(last2 < first1 || last1 < first2);
}
GList *range_list_insert(GList *list, Range *data);
#endif
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