LXR qemu/include/qemu/range.h

   1#ifndef QEMU_RANGE_H
   2#define QEMU_RANGE_H
   3
   4#include "qemu/queue.h"
   5
   6/*
   7 * Operations on 64 bit address ranges.
   8 * Notes:
   9 *   - ranges must not wrap around 0, but can include the last byte ~0x0LL.
  10 *   - this can not represent a full 0 to ~0x0LL range.
  11 */
  12
  13/* A structure representing a range of addresses. */
  14struct Range {
  15    uint64_t begin; /* First byte of the range, or 0 if empty. */
  16    uint64_t end;   /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */
  17};
  18
  19static inline void range_extend(Range *range, Range *extend_by)
  20{
  21    if (!extend_by->begin && !extend_by->end) {
  22        return;
  23    }
  24    if (!range->begin && !range->end) {
  25        *range = *extend_by;
  26        return;
  27    }
  28    if (range->begin > extend_by->begin) {
  29        range->begin = extend_by->begin;
  30    }
  31    /* Compare last byte in case region ends at ~0x0LL */
  32    if (range->end - 1 < extend_by->end - 1) {
  33        range->end = extend_by->end;
  34    }
  35}
  36
  37/* Get last byte of a range from offset + length.
  38 * Undefined for ranges that wrap around 0. */
  39static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
  40{
  41    return offset + len - 1;
  42}
  43
  44/* Check whether a given range covers a given byte. */
  45static inline int range_covers_byte(uint64_t offset, uint64_t len,
  46                                    uint64_t byte)
  47{
  48    return offset <= byte && byte <= range_get_last(offset, len);
  49}
  50
  51/* Check whether 2 given ranges overlap.
  52 * Undefined if ranges that wrap around 0. */
  53static inline int ranges_overlap(uint64_t first1, uint64_t len1,
  54                                 uint64_t first2, uint64_t len2)
  55{
  56    uint64_t last1 = range_get_last(first1, len1);
  57    uint64_t last2 = range_get_last(first2, len2);
  58
  59    return !(last2 < first1 || last1 < first2);
  60}
  61
  62/* 0,1 can merge with 1,2 but don't overlap */
  63static inline bool ranges_can_merge(Range *range1, Range *range2)
  64{
  65    return !(range1->end < range2->begin || range2->end < range1->begin);
  66}
  67
  68static inline int range_merge(Range *range1, Range *range2)
  69{
  70    if (ranges_can_merge(range1, range2)) {
  71        if (range1->end < range2->end) {
  72            range1->end = range2->end;
  73        }
  74        if (range1->begin > range2->begin) {
  75            range1->begin = range2->begin;
  76        }
  77        return 0;
  78    }
  79
  80    return -1;
  81}
  82
  83static inline GList *g_list_insert_sorted_merged(GList *list,
  84                                                 gpointer data,
  85                                                 GCompareFunc func)
  86{
  87    GList *l, *next = NULL;
  88    Range *r, *nextr;
  89
  90    if (!list) {
  91        list = g_list_insert_sorted(list, data, func);
  92        return list;
  93    }
  94
  95    nextr = data;
  96    l = list;
  97    while (l && l != next && nextr) {
  98        r = l->data;
  99        if (ranges_can_merge(r, nextr)) {
 100            range_merge(r, nextr);
 101            l = g_list_remove_link(l, next);
 102            next = g_list_next(l);
 103            if (next) {
 104                nextr = next->data;
 105            } else {
 106                nextr = NULL;
 107            }
 108        } else {
 109            l = g_list_next(l);
 110        }
 111    }
 112
 113    if (!l) {
 114        list = g_list_insert_sorted(list, data, func);
 115    }
 116
 117    return list;
 118}
 119
 120static inline gint range_compare(gconstpointer a, gconstpointer b)
 121{
 122    Range *ra = (Range *)a, *rb = (Range *)b;
 123    if (ra->begin == rb->begin && ra->end == rb->end) {
 124        return 0;
 125    } else if (range_get_last(ra->begin, ra->end) <
 126               range_get_last(rb->begin, rb->end)) {
 127        return -1;
 128    } else {
 129        return 1;
 130    }
 131}
 132
 133#endif
 134