1 files changed, 203 insertions, 0 deletions
diff --git a/src/strconv/makeisprint.go b/src/strconv/makeisprint.go
new file mode 100644
index 0000000..ff361e7
--- /dev/null
+++ b/src/strconv/makeisprint.go
@@ -0,0 +1,203 @@
+// Copyright 2012 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
+
+//
+// usage:
+//
+// go run makeisprint.go -output isprint.go
+//
+
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/format"
+	"log"
+	"os"
+	"unicode"
+)
+
+var filename = flag.String("output", "isprint.go", "output file name")
+
+var (
+	range16  []uint16
+	except16 []uint16
+	range32  []uint32
+	except32 []uint32
+)
+
+// bsearch16 returns the smallest i such that a[i] >= x.
+// If there is no such i, bsearch16 returns len(a).
+func bsearch16(a []uint16, x uint16) int {
+	i, j := 0, len(a)
+	for i < j {
+		h := i + (j-i)>>1
+		if a[h] < x {
+			i = h + 1
+		} else {
+			j = h
+		}
+	}
+	return i
+}
+
+// bsearch32 returns the smallest i such that a[i] >= x.
+// If there is no such i, bsearch32 returns len(a).
+func bsearch32(a []uint32, x uint32) int {
+	i, j := 0, len(a)
+	for i < j {
+		h := i + (j-i)>>1
+		if a[h] < x {
+			i = h + 1
+		} else {
+			j = h
+		}
+	}
+	return i
+}
+
+func isPrint(r rune) bool {
+	// Same algorithm, either on uint16 or uint32 value.
+	// First, find first i such that rang[i] >= x.
+	// This is the index of either the start or end of a pair that might span x.
+	// The start is even (rang[i&^1]) and the end is odd (rang[i|1]).
+	// If we find x in a range, make sure x is not in exception list.
+
+	if 0 <= r && r < 1<<16 {
+		rr, rang, except := uint16(r), range16, except16
+		i := bsearch16(rang, rr)
+		if i >= len(rang) || rr < rang[i&^1] || rang[i|1] < rr {
+			return false
+		}
+		j := bsearch16(except, rr)
+		return j >= len(except) || except[j] != rr
+	}
+
+	rr, rang, except := uint32(r), range32, except32
+	i := bsearch32(rang, rr)
+	if i >= len(rang) || rr < rang[i&^1] || rang[i|1] < rr {
+		return false
+	}
+	j := bsearch32(except, rr)
+	return j >= len(except) || except[j] != rr
+}
+
+func scan(min, max rune) (rang, except []uint32) {
+	lo := rune(-1)
+	for i := min; ; i++ {
+		if (i > max || !unicode.IsPrint(i)) && lo >= 0 {
+			// End range, but avoid flip flop.
+			if i+1 <= max && unicode.IsPrint(i+1) {
+				except = append(except, uint32(i))
+				continue
+			}
+			rang = append(rang, uint32(lo), uint32(i-1))
+			lo = -1
+		}
+		if i > max {
+			break
+		}
+		if lo < 0 && unicode.IsPrint(i) {
+			lo = i
+		}
+	}
+	return
+}
+
+func to16(x []uint32) []uint16 {
+	var y []uint16
+	for _, v := range x {
+		if uint32(uint16(v)) != v {
+			panic("bad 32->16 conversion")
+		}
+		y = append(y, uint16(v))
+	}
+	return y
+}
+
+func main() {
+	flag.Parse()
+
+	rang, except := scan(0, 0xFFFF)
+	range16 = to16(rang)
+	except16 = to16(except)
+	range32, except32 = scan(0x10000, unicode.MaxRune)
+
+	for i := rune(0); i <= unicode.MaxRune; i++ {
+		if isPrint(i) != unicode.IsPrint(i) {
+			log.Fatalf("%U: isPrint=%v, want %v\n", i, isPrint(i), unicode.IsPrint(i))
+		}
+	}
+
+	var buf bytes.Buffer
+
+	fmt.Fprintf(&buf, `// Copyright 2013 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.`+"\n\n")
+	fmt.Fprintf(&buf, "// Code generated by go run makeisprint.go -output isprint.go; DO NOT EDIT.\n\n")
+	fmt.Fprintf(&buf, "package strconv\n\n")
+
+	fmt.Fprintf(&buf, "// (%d+%d+%d)*2 + (%d)*4 = %d bytes\n\n",
+		len(range16), len(except16), len(except32),
+		len(range32),
+		(len(range16)+len(except16)+len(except32))*2+
+			(len(range32))*4)
+
+	fmt.Fprintf(&buf, "var isPrint16 = []uint16{\n")
+	for i := 0; i < len(range16); i += 2 {
+		fmt.Fprintf(&buf, "\t%#04x, %#04x,\n", range16[i], range16[i+1])
+	}
+	fmt.Fprintf(&buf, "}\n\n")
+
+	fmt.Fprintf(&buf, "var isNotPrint16 = []uint16{\n")
+	for _, r := range except16 {
+		fmt.Fprintf(&buf, "\t%#04x,\n", r)
+	}
+	fmt.Fprintf(&buf, "}\n\n")
+
+	fmt.Fprintf(&buf, "var isPrint32 = []uint32{\n")
+	for i := 0; i < len(range32); i += 2 {
+		fmt.Fprintf(&buf, "\t%#06x, %#06x,\n", range32[i], range32[i+1])
+	}
+	fmt.Fprintf(&buf, "}\n\n")
+
+	fmt.Fprintf(&buf, "var isNotPrint32 = []uint16{ // add 0x10000 to each entry\n")
+	for _, r := range except32 {
+		if r >= 0x20000 {
+			log.Fatalf("%U too big for isNotPrint32\n", r)
+		}
+		fmt.Fprintf(&buf, "\t%#04x,\n", r-0x10000)
+	}
+	fmt.Fprintf(&buf, "}\n\n")
+
+	// The list of graphic but not "printable" runes is short. Just make one easy table.
+	fmt.Fprintf(&buf, "// isGraphic lists the graphic runes not matched by IsPrint.\n")
+	fmt.Fprintf(&buf, "var isGraphic = []uint16{\n")
+	for r := rune(0); r <= unicode.MaxRune; r++ {
+		if unicode.IsPrint(r) != unicode.IsGraphic(r) {
+			// Sanity check.
+			if !unicode.IsGraphic(r) {
+				log.Fatalf("%U is printable but not graphic\n", r)
+			}
+			if r > 0xFFFF { // We expect only 16-bit values.
+				log.Fatalf("%U too big for isGraphic\n", r)
+			}
+			fmt.Fprintf(&buf, "\t%#04x,\n", r)
+		}
+	}
+	fmt.Fprintf(&buf, "}\n")
+
+	data, err := format.Source(buf.Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = os.WriteFile(*filename, data, 0644)
+	if err != nil {
+		log.Fatal(err)
+	}
+}