diff options
Diffstat (limited to 'Test/dafny2/Intervals.dfy')
| -rw-r--r-- | Test/dafny2/Intervals.dfy | 102 |
1 files changed, 52 insertions, 50 deletions
diff --git a/Test/dafny2/Intervals.dfy b/Test/dafny2/Intervals.dfy index df14c1e9..ef40910e 100644 --- a/Test/dafny2/Intervals.dfy +++ b/Test/dafny2/Intervals.dfy @@ -4,63 +4,65 @@ // The RoundDown and RoundUp methods in this file are the ones in the Boogie
// implementation Source/AbsInt/IntervalDomain.cs.
-var thresholds: array<int>;
+class Rounding {
+ var thresholds: array<int>;
-function Valid(): bool
- reads this, thresholds;
-{
- thresholds != null &&
- forall m,n :: 0 <= m < n < thresholds.Length ==> thresholds[m] <= thresholds[n]
-}
-
-method RoundDown(k: int) returns (r: int)
- requires Valid();
- ensures -1 <= r < thresholds.Length;
- ensures forall m :: r < m < thresholds.Length ==> k < thresholds[m];
- ensures 0 <= r ==> thresholds[r] <= k;
-{
- if (thresholds.Length == 0 || k < thresholds[0]) {
- return -1;
+ function Valid(): bool
+ reads this, thresholds;
+ {
+ thresholds != null &&
+ forall m,n :: 0 <= m < n < thresholds.Length ==> thresholds[m] <= thresholds[n]
}
- var i, j := 0, thresholds.Length - 1;
- while (i < j)
- invariant 0 <= i <= j < thresholds.Length;
- invariant thresholds[i] <= k;
- invariant forall m :: j < m < thresholds.Length ==> k < thresholds[m];
+
+ method RoundDown(k: int) returns (r: int)
+ requires Valid();
+ ensures -1 <= r < thresholds.Length;
+ ensures forall m :: r < m < thresholds.Length ==> k < thresholds[m];
+ ensures 0 <= r ==> thresholds[r] <= k;
{
- var mid := i + (j - i + 1) / 2;
- assert i < mid <= j;
- if (thresholds[mid] <= k) {
- i := mid;
- } else {
- j := mid - 1;
+ if (thresholds.Length == 0 || k < thresholds[0]) {
+ return -1;
}
+ var i, j := 0, thresholds.Length - 1;
+ while (i < j)
+ invariant 0 <= i <= j < thresholds.Length;
+ invariant thresholds[i] <= k;
+ invariant forall m :: j < m < thresholds.Length ==> k < thresholds[m];
+ {
+ var mid := i + (j - i + 1) / 2;
+ assert i < mid <= j;
+ if (thresholds[mid] <= k) {
+ i := mid;
+ } else {
+ j := mid - 1;
+ }
+ }
+ return i;
}
- return i;
-}
-method RoundUp(k: int) returns (r: int)
- requires Valid();
- ensures 0 <= r <= thresholds.Length;
- ensures forall m :: 0 <= m < r ==> thresholds[m] < k;
- ensures r < thresholds.Length ==> k <= thresholds[r];
-{
- if (thresholds.Length == 0 || thresholds[thresholds.Length-1] < k) {
- return thresholds.Length;
- }
- var i, j := 0, thresholds.Length - 1;
- while (i < j)
- invariant 0 <= i <= j < thresholds.Length;
- invariant k <= thresholds[j];
- invariant forall m :: 0 <= m < i ==> thresholds[m] < k;
+ method RoundUp(k: int) returns (r: int)
+ requires Valid();
+ ensures 0 <= r <= thresholds.Length;
+ ensures forall m :: 0 <= m < r ==> thresholds[m] < k;
+ ensures r < thresholds.Length ==> k <= thresholds[r];
{
- var mid := i + (j - i) / 2;
- assert i <= mid < j;
- if (thresholds[mid] < k) {
- i := mid + 1;
- } else {
- j := mid;
+ if (thresholds.Length == 0 || thresholds[thresholds.Length-1] < k) {
+ return thresholds.Length;
+ }
+ var i, j := 0, thresholds.Length - 1;
+ while (i < j)
+ invariant 0 <= i <= j < thresholds.Length;
+ invariant k <= thresholds[j];
+ invariant forall m :: 0 <= m < i ==> thresholds[m] < k;
+ {
+ var mid := i + (j - i) / 2;
+ assert i <= mid < j;
+ if (thresholds[mid] < k) {
+ i := mid + 1;
+ } else {
+ j := mid;
+ }
}
+ return i;
}
- return i;
}
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