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#include "qemu/queue.h"
   7
   8/*
   9 * Operations on 64 bit address ranges.
  10 * Notes:
  11 *   - ranges must not wrap around 0, but can include the last byte ~0x0LL.
  12 *   - this can not represent a full 0 to ~0x0LL range.
  13 */
  14
  15/* A structure representing a range of addresses. */
  16struct Range {
  17    uint64_t begin; /* First byte of the range, or 0 if empty. */
  18    uint64_t end;   /* 1 + the last byte. 0 if range empty or ends at ~0x0LL. */
  19};
  20
  21static inline void range_extend(Range *range, Range *extend_by)
  22{
  23    if (!extend_by->begin && !extend_by->end) {
  24        return;
  25    }
  26    if (!range->begin && !range->end) {
  27        *range = *extend_by;
  28        return;
  29    }
  30    if (range->begin > extend_by->begin) {
  31        range->begin = extend_by->begin;
  32    }
  33    /* Compare last byte in case region ends at ~0x0LL */
  34    if (range->end - 1 < extend_by->end - 1) {
  35        range->end = extend_by->end;
  36    }
  37}
  38
  39/* Get last byte of a range from offset + length.
  40 * Undefined for ranges that wrap around 0. */
  41static inline uint64_t range_get_last(uint64_t offset, uint64_t len)
  42{
  43    return offset + len - 1;
  44}
  45
  46/* Check whether a given range covers a given byte. */
  47static inline int range_covers_byte(uint64_t offset, uint64_t len,
  48                                    uint64_t byte)
  49{
  50    return offset <= byte && byte <= range_get_last(offset, len);
  51}
  52
  53/* Check whether 2 given ranges overlap.
  54 * Undefined if ranges that wrap around 0. */
  55static inline int ranges_overlap(uint64_t first1, uint64_t len1,
  56                                 uint64_t first2, uint64_t len2)
  57{
  58    uint64_t last1 = range_get_last(first1, len1);
  59    uint64_t last2 = range_get_last(first2, len2);
  60
  61    return !(last2 < first1 || last1 < first2);
  62}
  63
  64/* 0,1 can merge with 1,2 but don't overlap */
  65static inline bool ranges_can_merge(Range *range1, Range *range2)
  66{
  67    return !(range1->end < range2->begin || range2->end < range1->begin);
  68}
  69
  70static inline int range_merge(Range *range1, Range *range2)
  71{
  72    if (ranges_can_merge(range1, range2)) {
  73        if (range1->end < range2->end) {
  74            range1->end = range2->end;
  75        }
  76        if (range1->begin > range2->begin) {
  77            range1->begin = range2->begin;
  78        }
  79        return 0;
  80    }
  81
  82    return -1;
  83}
  84
  85static inline GList *g_list_insert_sorted_merged(GList *list,
  86                                                 gpointer data,
  87                                                 GCompareFunc func)
  88{
  89    GList *l, *next = NULL;
  90    Range *r, *nextr;
  91
  92    if (!list) {
  93        list = g_list_insert_sorted(list, data, func);
  94        return list;
  95    }
  96
  97    nextr = data;
  98    l = list;
  99    while (l && l != next && nextr) {
 100        r = l->data;
 101        if (ranges_can_merge(r, nextr)) {
 102            range_merge(r, nextr);
 103            l = g_list_remove_link(l, next);
 104            next = g_list_next(l);
 105            if (next) {
 106                nextr = next->data;
 107            } else {
 108                nextr = NULL;
 109            }
 110        } else {
 111            l = g_list_next(l);
 112        }
 113    }
 114
 115    if (!l) {
 116        list = g_list_insert_sorted(list, data, func);
 117    }
 118
 119    return list;
 120}
 121
 122static inline gint range_compare(gconstpointer a, gconstpointer b)
 123{
 124    Range *ra = (Range *)a, *rb = (Range *)b;
 125    if (ra->begin == rb->begin && ra->end == rb->end) {
 126        return 0;
 127    } else if (range_get_last(ra->begin, ra->end) <
 128               range_get_last(rb->begin, rb->end)) {
 129        return -1;
 130    } else {
 131        return 1;
 132    }
 133}
 134
 135#endif
 136