include/qemu/range.h

   1 #ifndef QEMU_RANGE_H
   2 #define QEMU_RANGE_H
   3
   4 #include <inttypes.h>
   5 #include <qemu/typedefs.h>
   6
   7 /*
   8  * Operations on 64 bit address ranges.
   9  * Notes:
  10  *   - ranges must not wrap around 0, but can include the last byte ~0x0LL.
  11  *   - this can not represent a full 0 to ~0x0LL range.
  12  */
  13
  14 /* A structure representing a range of addresses. */
  15 struct Range {
  16     uint64_t begin; /* First byte of the range, or 0 if empty. */
  17     uint64_t end;   /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */
  18 };
  19
  20 static inline void range_extend(Range *range, Range *extend_by)
  21 {
  22     if (!extend_by->begin && !extend_by->end) {
  23         return;
  24     }
  25     if (!range->begin && !range->end) {
  26         *range = *extend_by;
  27         return;
  28     }
  29     if (range->begin > extend_by->begin) {
  30         range->begin = extend_by->begin;
  31     }
  32     /* Compare last byte in case region ends at ~0x0LL */
  33     if (range->end - 1 < extend_by->end - 1) {
  34         range->end = extend_by->end;
  35     }
  36 }
  37
  38 /* Get last byte of a range from offset + length.
  39  * Undefined for ranges that wrap around 0. */
  40 static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
  41 {
  42     return offset + len - 1;
  43 }
  44
  45 /* Check whether a given range covers a given byte. */
  46 static inline int range_covers_byte(uint64_t offset, uint64_t len,
  47                                     uint64_t byte)
  48 {
  49     return offset <= byte && byte <= range_get_last(offset, len);
  50 }
  51
  52 /* Check whether 2 given ranges overlap.
  53  * Undefined if ranges that wrap around 0. */
  54 static inline int ranges_overlap(uint64_t first1, uint64_t len1,
  55                                  uint64_t first2, uint64_t len2)
  56 {
  57     uint64_t last1 = range_get_last(first1, len1);
  58     uint64_t last2 = range_get_last(first2, len2);
  59
  60     return !(last2 < first1 || last1 < first2);
  61 }
  62
  63 #endif