1 files changed, 93 insertions, 0 deletions
diff --git a/src/index/suffixarray/gen.go b/src/index/suffixarray/gen.go
new file mode 100644
index 0000000..3bc9b1e
--- /dev/null
+++ b/src/index/suffixarray/gen.go
@@ -0,0 +1,93 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+// +build ignore
+
+// Gen generates sais2.go by duplicating functions in sais.go
+// using different input types.
+// See the comment at the top of sais.go for details.
+package main
+
+import (
+	"bytes"
+	"log"
+	"os"
+	"strings"
+)
+
+func main() {
+	log.SetPrefix("gen: ")
+	log.SetFlags(0)
+
+	data, err := os.ReadFile("sais.go")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	x := bytes.Index(data, []byte("\n\n"))
+	if x < 0 {
+		log.Fatal("cannot find blank line after copyright comment")
+	}
+
+	var buf bytes.Buffer
+	buf.Write(data[:x])
+	buf.WriteString("\n\n// Code generated by go generate; DO NOT EDIT.\n\npackage suffixarray\n")
+
+	for {
+		x := bytes.Index(data, []byte("\nfunc "))
+		if x < 0 {
+			break
+		}
+		data = data[x:]
+		p := bytes.IndexByte(data, '(')
+		if p < 0 {
+			p = len(data)
+		}
+		name := string(data[len("\nfunc "):p])
+
+		x = bytes.Index(data, []byte("\n}\n"))
+		if x < 0 {
+			log.Fatalf("cannot find end of func %s", name)
+		}
+		fn := string(data[:x+len("\n}\n")])
+		data = data[x+len("\n}"):]
+
+		if strings.HasSuffix(name, "_32") {
+			buf.WriteString(fix32.Replace(fn))
+		}
+		if strings.HasSuffix(name, "_8_32") {
+			// x_8_32 -> x_8_64 done above
+			fn = fix8_32.Replace(stripByteOnly(fn))
+			buf.WriteString(fn)
+			buf.WriteString(fix32.Replace(fn))
+		}
+	}
+
+	if err := os.WriteFile("sais2.go", buf.Bytes(), 0666); err != nil {
+		log.Fatal(err)
+	}
+}
+
+var fix32 = strings.NewReplacer(
+	"32", "64",
+	"int32", "int64",
+)
+
+var fix8_32 = strings.NewReplacer(
+	"_8_32", "_32",
+	"byte", "int32",
+)
+
+func stripByteOnly(s string) string {
+	lines := strings.SplitAfter(s, "\n")
+	w := 0
+	for _, line := range lines {
+		if !strings.Contains(line, "256") && !strings.Contains(line, "byte-only") {
+			lines[w] = line
+			w++
+		}
+	}
+	return strings.Join(lines[:w], "")
+}