LXR qemu/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. */
  15struct 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
  20static 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. */
  40static 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. */
  46static 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. */
  54static 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
  64