From: Robert Griesemer Date: Tue, 27 Sep 2011 23:21:28 +0000 (-0700) Subject: index/suffixarray: revert change from int -> int32 X-Git-Tag: weekly.2011-10-06~79 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=71557713b0a7cf53c9c8a80986c89ae4036af74c;p=gostls13.git index/suffixarray: revert change from int -> int32 CL 5040041 (https://golang.org/cl/5040041) changed the use of []int to []int32 internally so that encoding/binary could be used. This is no longer needed (gobs can encode ints), and using []int is more in sync w/ the semantics of the data structure (the index elements are indices which are ints). Changing it back. R=r CC=golang-dev https://golang.org/cl/5141049 --- diff --git a/src/pkg/index/suffixarray/qsufsort.go b/src/pkg/index/suffixarray/qsufsort.go index f4ec3a1037..c69be43c2a 100644 --- a/src/pkg/index/suffixarray/qsufsort.go +++ b/src/pkg/index/suffixarray/qsufsort.go @@ -26,7 +26,7 @@ package suffixarray import "sort" -func qsufsort(data []byte) []int32 { +func qsufsort(data []byte) []int { // initial sorting by first byte of suffix sa := sortedByFirstByte(data) if len(sa) < 2 { @@ -39,20 +39,20 @@ func qsufsort(data []byte) []int32 { // the index starts 1-ordered sufSortable := &suffixSortable{sa: sa, inv: inv, h: 1} - for int(sa[0]) > -len(sa) { // until all suffixes are one big sorted group + for sa[0] > -len(sa) { // until all suffixes are one big sorted group // The suffixes are h-ordered, make them 2*h-ordered pi := 0 // pi is first position of first group sl := 0 // sl is negated length of sorted groups for pi < len(sa) { - if s := int(sa[pi]); s < 0 { // if pi starts sorted group + if s := sa[pi]; s < 0 { // if pi starts sorted group pi -= s // skip over sorted group sl += s // add negated length to sl } else { // if pi starts unsorted group if sl != 0 { - sa[pi+sl] = int32(sl) // combine sorted groups before pi + sa[pi+sl] = sl // combine sorted groups before pi sl = 0 } - pk := int(inv[s]) + 1 // pk-1 is last position of unsorted group + pk := inv[s] + 1 // pk-1 is last position of unsorted group sufSortable.sa = sa[pi:pk] sort.Sort(sufSortable) sufSortable.updateGroups(pi) @@ -60,19 +60,19 @@ func qsufsort(data []byte) []int32 { } } if sl != 0 { // if the array ends with a sorted group - sa[pi+sl] = int32(sl) // combine sorted groups at end of sa + sa[pi+sl] = sl // combine sorted groups at end of sa } sufSortable.h *= 2 // double sorted depth } for i := range sa { // reconstruct suffix array from inverse - sa[inv[i]] = int32(i) + sa[inv[i]] = i } return sa } -func sortedByFirstByte(data []byte) []int32 { +func sortedByFirstByte(data []byte) []int { // total byte counts var count [256]int for _, b := range data { @@ -84,17 +84,17 @@ func sortedByFirstByte(data []byte) []int32 { count[b], sum = sum, count[b]+sum } // iterate through bytes, placing index into the correct spot in sa - sa := make([]int32, len(data)) + sa := make([]int, len(data)) for i, b := range data { - sa[count[b]] = int32(i) + sa[count[b]] = i count[b]++ } return sa } -func initGroups(sa []int32, data []byte) []int32 { +func initGroups(sa []int, data []byte) []int { // label contiguous same-letter groups with the same group number - inv := make([]int32, len(data)) + inv := make([]int, len(data)) prevGroup := len(sa) - 1 groupByte := data[sa[prevGroup]] for i := len(sa) - 1; i >= 0; i-- { @@ -105,7 +105,7 @@ func initGroups(sa []int32, data []byte) []int32 { groupByte = b prevGroup = i } - inv[sa[i]] = int32(prevGroup) + inv[sa[i]] = prevGroup if prevGroup == 0 { sa[0] = -1 } @@ -120,9 +120,9 @@ func initGroups(sa []int32, data []byte) []int32 { if data[sa[i]] == lastByte && s == -1 { s = i } - if int(sa[i]) == len(sa)-1 { + if sa[i] == len(sa)-1 { sa[i], sa[s] = sa[s], sa[i] - inv[sa[s]] = int32(s) + inv[sa[s]] = s sa[s] = -1 // mark it as an isolated sorted group break } @@ -132,9 +132,9 @@ func initGroups(sa []int32, data []byte) []int32 { } type suffixSortable struct { - sa []int32 - inv []int32 - h int32 + sa []int + inv []int + h int buf []int // common scratch space } @@ -158,7 +158,7 @@ func (x *suffixSortable) updateGroups(offset int) { prev := 0 for _, b := range bounds { for i := prev; i < b; i++ { - x.inv[x.sa[i]] = int32(offset + b - 1) + x.inv[x.sa[i]] = offset + b - 1 } if b-prev == 1 { x.sa[prev] = -1 diff --git a/src/pkg/index/suffixarray/suffixarray.go b/src/pkg/index/suffixarray/suffixarray.go index 4747ba9907..05b06c6bdc 100644 --- a/src/pkg/index/suffixarray/suffixarray.go +++ b/src/pkg/index/suffixarray/suffixarray.go @@ -28,7 +28,7 @@ import ( // Index implements a suffix array for fast substring search. type Index struct { data []byte - sa []int32 // suffix array for data; len(sa) == len(data) + sa []int // suffix array for data; len(sa) == len(data) } // New creates a new Index for data. @@ -52,7 +52,7 @@ func (x *Index) Read(r io.Reader) os.Error { // new data is significantly smaller or larger then // existing buffers - allocate new ones x.data = make([]byte, n) - x.sa = make([]int32, n) + x.sa = make([]int, n) } else { // re-use existing buffers x.data = x.data[0:n] @@ -120,7 +120,7 @@ func (x *Index) at(i int) []byte { // lookupAll returns a slice into the matching region of the index. // The runtime is O(log(N)*len(s)). -func (x *Index) lookupAll(s []byte) []int32 { +func (x *Index) lookupAll(s []byte) []int { // find matching suffix index range [i:j] // find the first index where s would be the prefix i := sort.Search(len(x.sa), func(i int) bool { return bytes.Compare(x.at(i), s) >= 0 }) @@ -144,9 +144,7 @@ func (x *Index) Lookup(s []byte, n int) (result []int) { // 0 <= n <= len(matches) if n > 0 { result = make([]int, n) - for i, x := range matches[0:n] { - result[i] = int(x) - } + copy(result, matches) } } return