Add more code pages

internal/codepage/generate/generate.go

@@ -0,0 +1,210 @@
+// This file is part of https://github.com/racingmars/go3270/
+// Copyright 2020, 2025 by Matthew R. Wilson, licensed under the MIT license.
+// See LICENSE in the project root for license information.
+
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// Tool to generate codepage implementation files for go3270 using the
+// Unicode icu-data UCM format files.
+
+func main() {
+	cpName := flag.String("n", "", "Code page name (e.g. 037)")
+	cpPath := flag.String("i", "", "Input file path")
+	flag.Parse()
+
+	if *cpName == "" || *cpPath == "" {
+		fmt.Fprintln(os.Stderr, "-n and -i arguments are required.")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	u2e, err := read(*cpPath)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+
+	// Build the reverse map
+	e2u := make(map[int]int)
+	for k, v := range u2e {
+		e2u[v] = k
+	}
+
+	fmt.Println("// This file is part of https://github.com/racingmars/go3270/")
+	fmt.Println("// Copyright 2020, 2025 by Matthew R. Wilson, licensed under the MIT license.")
+	fmt.Println("// See LICENSE in the project root for license information.")
+	fmt.Println()
+
+	fmt.Println("package codepage")
+	fmt.Println()
+	fmt.Printf("// Codepage%s implements the IBM CP %s code page.\n",
+		*cpName, *cpName)
+	fmt.Println("//")
+	fmt.Printf("// IBM CP %s <-> Unicode mappings from https://github.com/unicode-org/icu-data\n", *cpName)
+	fmt.Printf("// file: %s\n", filepath.Base(*cpPath))
+	fmt.Printf("var Codepage%s *codepage = &codepage{\n", *cpName)
+	fmt.Printf("\tid: \"%s\",\n", *cpName)
+
+	// Print 0x00-0xFF EBCDIC-to-Unicode
+	line := 0
+	pos := -1
+	fmt.Printf("\te2u: []rune{\n")
+	fmt.Printf("\t\t/*         x0    x1    x2    x3    x4    x5    x6    x7    x8    x9    xA    xB    xC    xD    xE    xF */\n")
+	fmt.Printf("\t\t/* 0x */ ")
+	for i := 0; i <= 0xFF; i++ {
+		pos++
+		if pos >= 16 {
+			line++
+			pos = 0
+			fmt.Printf("\n")
+			fmt.Printf("\t\t/* %Xx */ ", line)
+		}
+		v, ok := e2u[i]
+		if !ok {
+			fmt.Printf(" '�', ")
+			continue
+		}
+		fmt.Printf("0x%02X, ", v)
+	}
+	fmt.Printf("\n\t},\n")
+
+	// Print 0x00-0xFF Unicode-to-EBCDIC
+	line = 0
+	pos = -1
+	fmt.Printf("\tu2e: []byte{\n")
+	fmt.Printf("\t\t/*         x0    x1    x2    x3    x4    x5    x6    x7    x8    x9    xA    xB    xC    xD    xE    xF */\n")
+	fmt.Printf("\t\t/* 0x */ ")
+	for i := 0; i <= 0xFF; i++ {
+		pos++
+		if pos >= 16 {
+			line++
+			pos = 0
+			fmt.Printf("\n")
+			fmt.Printf("\t\t/* %Xx */ ", line)
+		}
+		v, ok := u2e[i]
+		if !ok {
+			fmt.Printf("0x3F, ")
+			continue
+		}
+		fmt.Printf("0x%02X, ", v)
+	}
+	fmt.Printf("\n\t},\n")
+
+	// Print Unicode-to-EBCDIC for codepoints >0xFF
+	pos = -1
+	fmt.Printf("\thighu2e: map[rune]byte{\n")
+	fmt.Printf("\t\t")
+	for k, v := range u2e {
+		if k <= 0xFF {
+			continue
+		}
+		pos++
+		if pos >= 4 {
+			pos = 0
+			fmt.Printf("\n\t\t")
+		}
+		fmt.Printf("0x%04X: 0x%02X, ", k, v)
+	}
+	fmt.Printf("\n\t},\n")
+
+	fmt.Println("\tesub:    0x3f,")
+	fmt.Println("\tge:      0x08,")
+	fmt.Println("\tge2u:    cp310ToUnicode,")
+	fmt.Println("\tu2ge:    unicodeToCP310,")
+	fmt.Println("}")
+}
+
+// read reads a UCM file and returns a map of Unicode CPs to EBCDIC
+func read(input string) (map[int]int, error) {
+	f, err := os.Open(input)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	u2e := make(map[int]int)
+
+	s := bufio.NewScanner(f)
+
+	var incharmap bool
+	for s.Scan() {
+		line := s.Text()
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		if !incharmap && line != "CHARMAP" {
+			continue
+		}
+
+		if line == "CHARMAP" {
+			incharmap = true
+			continue
+		}
+
+		// Skip non-roundtrip characters
+		if strings.HasSuffix(line, "|1") {
+			continue
+		}
+
+		if line == "END CHARMAP" {
+			break
+		}
+
+		codepoint, ebcdic, err := parseUcmLine(line)
+		if err != nil {
+			panic(err)
+		}
+
+		if _, ok := u2e[codepoint]; ok {
+			fmt.Fprintf(os.Stderr, "WARNING: duplicate codepoint U%04x\n",
+				codepoint)
+		}
+		u2e[codepoint] = ebcdic
+	}
+
+	if err := s.Err(); err != nil {
+		panic(err)
+	}
+
+	return u2e, nil
+}
+
+func parseUcmLine(s string) (int, int, error) {
+	// Regex to match <UXXXX> and \xYY patterns
+	reU := regexp.MustCompile(`U([0-9A-Fa-f]+)`)
+	reX := regexp.MustCompile(`\\x([0-9A-Fa-f]+)`)
+
+	// Find matches
+	matchU := reU.FindStringSubmatch(s)
+	matchX := reX.FindStringSubmatch(s)
+
+	if matchU == nil || matchX == nil {
+		return 0, 0, fmt.Errorf("could not find both hex patterns in input")
+	}
+
+	// Convert hex strings to integers
+	valU, err := strconv.ParseInt(matchU[1], 16, 64)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	valX, err := strconv.ParseInt(matchX[1], 16, 64)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	return int(valU), int(valX), nil
+}