Rename multi-char filter

filters/filter.go

@@ -184,7 +184,7 @@ func newRangeFilter(pattern string, backwards bool, seg chainSegment) (Filter, e
 				return nil, errInvalidFilterPattern
 			}
 
-			f, err := newMultiCharRangeFilter(pattern[i+1:i+1+endIdx], backwards)
+			f, err := newMultiCharSequenceFilter(pattern[i+1:i+1+endIdx], backwards)
 			if err != nil {
 				return nil, errInvalidFilterPattern
 			}
@@ -395,11 +395,13 @@ func newSingleRangeFilter(pattern string, backwards bool) (chainFilter, error) {
 	}
 
 	if len(pattern) > 1 && pattern[1] == rangeChar {
+		// If there is a '-' char at position 2, look for repeated instances
+		// of a-z
 		if len(pattern)%3 != 0 {
 			return nil, errInvalidFilterPattern
 		}
 
-		var patterns []string
+		patterns := make([]string, 0, len(pattern)%3)
 		for i := 0; i < len(pattern); i += 3 {
 			if pattern[i+1] != rangeChar || pattern[i] > pattern[i+2] {
 				return nil, errInvalidFilterPattern
@@ -508,27 +510,27 @@ func (f *singleCharSetFilter) matches(val string) (string, bool) {
 
 // multiCharRangeFilter is a filter that performs matches against multiple sets of chars
 // eg. {abc,defg}
-type multiCharRangeFilter struct {
+type multiCharSequenceFilter struct {
 	patterns  []string
 	backwards bool
 }
 
-func newMultiCharRangeFilter(patterns string, backwards bool) (chainFilter, error) {
+func newMultiCharSequenceFilter(patterns string, backwards bool) (chainFilter, error) {
 	if len(patterns) == 0 {
 		return nil, errInvalidFilterPattern
 	}
 
-	return &multiCharRangeFilter{
+	return &multiCharSequenceFilter{
 		patterns:  strings.Split(patterns, multiRangeSplit),
 		backwards: backwards,
 	}, nil
 }
 
-func (f *multiCharRangeFilter) String() string {
+func (f *multiCharSequenceFilter) String() string {
 	return "Range(\"" + strings.Join(f.patterns, multiRangeSplit) + "\")"
 }
 
-func (f *multiCharRangeFilter) matches(val string) (string, bool) {
+func (f *multiCharSequenceFilter) matches(val string) (string, bool) {
 	if len(val) == 0 {
 		return "", false
 	}

filters/filter_benchmark_test.go

@@ -141,7 +141,7 @@ func BenchmarkMultiRangeFilterTrieSix(b *testing.B) {
 }
 
 func benchMultiRangeFilter(b *testing.B, patterns string, backwards bool, vals []string) {
-	f, _ := newMultiCharRangeFilter(patterns, backwards)
+	f, _ := newMultiCharSequenceFilter(patterns, backwards)
 	for n := 0; n < b.N; n++ {
 		for _, val := range vals {
 			f.matches(val)
@@ -276,7 +276,7 @@ func newTestMultiCharRangeSelectFilter(pattern string, backwards bool) (chainFil
 	patterns := strings.Split(pattern, multiRangeSplit)
 	filters := make([]chainFilter, len(patterns))
 	for i, p := range patterns {
-		f, _ := newMultiCharRangeFilter(p, backwards)
+		f, _ := newMultiCharSequenceFilter(p, backwards)
 		filters[i] = f
 	}
 

filters/filter_test.go

@@ -222,11 +222,11 @@ func TestBadPatterns(t *testing.T) {
 	}
 }
 
-func TestMultiCharRangeFilter(t *testing.T) {
-	f, err := newMultiCharRangeFilter("", false)
+func TestMultiCharSequenceFilter(t *testing.T) {
+	f, err := newMultiCharSequenceFilter("", false)
 	require.Error(t, err)
 
-	f, err = newMultiCharRangeFilter("test2,test,tent,book", false)
+	f, err = newMultiCharSequenceFilter("test2,test,tent,book", false)
 	validateLookup(t, f, "", false, "")
 	validateLookup(t, f, "t", false, "")
 	validateLookup(t, f, "tes", false, "")
@@ -238,7 +238,7 @@ func TestMultiCharRangeFilter(t *testing.T) {
 	validateLookup(t, f, "test2", true, "")
 	validateLookup(t, f, "book123", true, "123")
 
-	f, err = newMultiCharRangeFilter("test2,test,tent,book", true)
+	f, err = newMultiCharSequenceFilter("test2,test,tent,book", true)
 	validateLookup(t, f, "", false, "")
 	validateLookup(t, f, "t", false, "")
 	validateLookup(t, f, "tes", false, "")