index/suffixarray: use sort.Search
R=gri
CC=golang-dev
https://golang.org/cl/3200041
diff --git a/src/pkg/index/suffixarray/suffixarray.go b/src/pkg/index/suffixarray/suffixarray.go
index 0a17472..4839dbb 100644
--- a/src/pkg/index/suffixarray/suffixarray.go
+++ b/src/pkg/index/suffixarray/suffixarray.go
@@ -54,21 +54,8 @@
}
-// Binary search according to "A Method of Programming", E.W. Dijkstra.
func (x *Index) search(s []byte) int {
- i, j := 0, len(x.sa)
- // i < j for non-empty x
- for i+1 < j {
- // 0 <= i < j <= len(x.sa) && (x.at(i) <= s < x.at(j) || (s is not in x))
- h := i + (j-i)/2 // i < h < j
- if bytes.Compare(x.at(h), s) <= 0 {
- i = h
- } else { // s < x.at(h)
- j = h
- }
- }
- // i+1 == j for non-empty x
- return i
+ return sort.Search(len(x.sa), func(i int) bool { return bytes.Compare(x.at(i), s) >= 0 })
}
@@ -84,12 +71,7 @@
if len(s) > 0 && n != 0 {
// find matching suffix index i
i := x.search(s)
- // x.at(i) <= s < x.at(i+1)
-
- // ignore the first suffix if it is < s
- if i < len(x.sa) && bytes.Compare(x.at(i), s) < 0 {
- i++
- }
+ // x.at(i-1) < s <= x.at(i)
// collect the following suffixes with matching prefixes
for (n < 0 || len(res) < n) && i < len(x.sa) && bytes.HasPrefix(x.at(i), s) {
