Optimize script detection

unidetect_test.go

@@ -1,9 +1,12 @@
 package unidetect
 
 import (
+	"fmt"
 	"reflect"
+	"sort"
 	"strings"
 	"testing"
+	"unicode"
 )
 
 var w = strings.Fields
@@ -43,3 +46,157 @@ func TestDetect(t *testing.T) {
 	}
 
 }
+
+func TestUnicodeScripts(t *testing.T) {
+	scriptNames := make([]string, 0, len(unicode.Scripts))
+	for name := range unicode.Scripts {
+		scriptNames = append(scriptNames, name)
+	}
+	sort.Strings(scriptNames)
+
+	sortedNames := scriptNames[:]
+	sort.Sort(ByRanges(sortedNames))
+
+	printScripts(t, sortedNames)
+}
+
+func printScripts(t *testing.T, scriptNames []string) {
+	for _, name := range scriptNames {
+		script := unicode.Scripts[name]
+		nranges := len(script.R16) + len(script.R32)
+		n := rangeTableCount(script)
+		lo := rangeTableLo(script)
+		hi := rangeTableHi(script)
+
+		var o []string
+		for _, name2 := range scriptNames {
+			if name2 == name {
+				continue
+			}
+			script2 := unicode.Scripts[name2]
+			if intersects(script, script2) {
+				o = append(o, name2)
+			}
+		}
+		fmt.Printf("%d\t%d\t%d\t%d\t%s\t%s\n",
+			lo, hi, nranges, n, name, strings.Join(o, ","))
+
+	}
+}
+
+func rangeTableLo(t *unicode.RangeTable) int {
+	if len(t.R16) != 0 {
+		return int(t.R16[0].Lo)
+	} else if len(t.R32) != 0 {
+		return int(t.R32[0].Lo)
+	}
+	return 0
+}
+
+func rangeTableHi(t *unicode.RangeTable) int {
+	if len(t.R32) != 0 {
+		return int(t.R32[len(t.R32)-1].Hi)
+	} else if len(t.R16) != 0 {
+		return int(t.R16[len(t.R16)-1].Hi)
+	}
+	return 0
+}
+
+func rangeTableCount(t *unicode.RangeTable) int {
+	var n int
+	for _, r := range t.R16 {
+		n += int(r.Hi-r.Lo)/int(r.Stride) + 1
+	}
+	for _, r := range t.R32 {
+		n += int(r.Hi-r.Lo)/int(r.Stride) + 1
+	}
+	return n
+}
+
+func overlaps(a, b *unicode.RangeTable) bool {
+	return rangeTableHi(a) >= rangeTableLo(b) && rangeTableHi(b) >= rangeTableLo(a)
+}
+
+var _ = unicode.Tamil
+
+func intersects(a, b *unicode.RangeTable) bool {
+	if !overlaps(a, b) {
+		return false
+	}
+	for _, ar := range a.R16 {
+		if ar.Stride != 1 && ar.Stride != (ar.Hi-ar.Lo) {
+			fmt.Printf("%d:%d ", (ar.Hi - ar.Lo), ar.Stride)
+		}
+		for _, br := range b.R16 {
+			if ar.Hi >= br.Lo && br.Hi >= ar.Lo {
+				return true
+			}
+		}
+		for _, br := range b.R32 {
+			if uint32(ar.Hi) >= br.Lo && br.Hi >= uint32(ar.Lo) {
+				return true
+			}
+		}
+	}
+	for _, ar := range a.R32 {
+		if ar.Stride != 1 && ar.Stride != (ar.Hi-ar.Lo) {
+			fmt.Printf("%d:%d ", (ar.Hi - ar.Lo), ar.Stride)
+		}
+		for _, br := range b.R16 {
+			if ar.Hi >= uint32(br.Lo) && uint32(br.Hi) >= ar.Lo {
+				return true
+			}
+		}
+		for _, br := range b.R32 {
+			if ar.Hi >= br.Lo && br.Hi >= ar.Lo {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// ByRanges implments sort.Interface.
+type ByRanges []string
+
+func (s ByRanges) Len() int {
+	return len(s)
+}
+
+func (s ByRanges) Less(i, j int) bool {
+	a := unicode.Scripts[s[i]]
+	b := unicode.Scripts[s[j]]
+
+	alo := rangeTableLo(a)
+	blo := rangeTableLo(b)
+	if alo < blo {
+		return true
+	}
+	if alo > blo {
+		return false
+	}
+
+	ac := rangeTableCount(a)
+	bc := rangeTableCount(b)
+	if ac < bc {
+		return true
+	}
+	if ac > bc {
+		return false
+	}
+
+	an := len(a.R16) + len(a.R32)
+	bn := len(b.R16) + len(b.R32)
+	if an < bn {
+		return true
+	}
+	if an > bn {
+		return false
+	}
+
+	return rangeTableHi(a) < rangeTableHi(b)
+}
+
+func (s ByRanges) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}