Merge pull request #73 from xairy/ranged_arrays

Allow range sized arrays

2 files changed, 23 insertions, 6 deletions

diff --git a/prog/mutation.go b/prog/mutation.go
index a00f64e43..a428d27cd 100644
--- a/prog/mutation.go
+++ b/prog/mutation.go
@@ -102,9 +102,19 @@ func (p *Prog) Mutate(rs rand.Source, ncalls int, ct *ChoiceTable) {
 						filename := r.filename(s)
 						arg.Data = []byte(filename)
 					case sys.ArrayType:
-						count := r.rand(6)
-						if count == uintptr(len(arg.Inner)) {
-							count++
+						count := uintptr(0)
+						switch a.Kind {
+						case sys.ArrayRandLen:
+							for count == uintptr(len(arg.Inner)) {
+								count = r.rand(6)
+							}
+						case sys.ArrayRangeLen:
+							if a.RangeBegin == a.RangeEnd {
+								panic("trying to mutate fixed length array")
+							}
+							for count == uintptr(len(arg.Inner)) {
+								count = r.randRange(int(a.RangeBegin), int(a.RangeEnd))
+							}
 						}
 						if count > uintptr(len(arg.Inner)) {
 							var calls []*Call
@@ -344,7 +354,7 @@ func mutationArgs(c *Call) (args, bases []*Arg, parents []*[]*Arg) {
 			// These special structs are mutated as a whole.
 		case sys.ArrayType:
 			// Don't mutate fixed-size arrays.
-			if typ.Len != 0 {
+			if typ.Kind == sys.ArrayRangeLen && typ.RangeBegin == typ.RangeEnd {
 				return
 			}
 		case sys.LenType:
diff --git a/prog/rand.go b/prog/rand.go
index 97033b434..26063b626 100644
--- a/prog/rand.go
+++ b/prog/rand.go
@@ -26,6 +26,10 @@ func (r *randGen) rand(n int) uintptr {
 	return uintptr(r.Intn(n))
 }
 
+func (r *randGen) randRange(begin int, end int) uintptr {
+	return uintptr(begin + r.Intn(end-begin+1))
+}
+
 func (r *randGen) bin() bool {
 	return r.Intn(2) == 0
 }
@@ -770,9 +774,12 @@ func (r *randGen) generateArg(s *state, typ sys.Type, dir ArgDir, sizes map[stri
 		filename := r.filename(s)
 		return dataArg([]byte(filename)), nil, nil
 	case sys.ArrayType:
-		count := a.Len
-		if count == 0 {
+		count := uintptr(0)
+		switch a.Kind {
+		case sys.ArrayRandLen:
 			count = r.rand(6)
+		case sys.ArrayRangeLen:
+			count = r.randRange(int(a.RangeBegin), int(a.RangeEnd))
 		}
 		sz := constArg(count)
 		var inner []*Arg