From 904699bf1ee886dd911858936bdfe31cef8497c4 Mon Sep 17 00:00:00 2001 From: "Matthew R. Wilson" Date: Sat, 25 Oct 2025 16:06:14 -0700 Subject: [PATCH] Fix broken EBCDIC conversions. Fully switch to CP1047<->UTF-8. --- README.md | 11 ++++ ebcdic.go | 149 ++++++++++++++++++++++++++++++++++------------------ response.go | 14 ++--- screen.go | 2 +- 4 files changed, 117 insertions(+), 59 deletions(-) diff --git a/README.md b/README.md index ae07f50..84842f0 100644 --- a/README.md +++ b/README.md @@ -24,6 +24,17 @@ Here's [a video introducing the library][introVideo] as well. [introVideo]: https://www.youtube.com/watch?v=h9XTjup5W5U +A note on code pages +-------------------- + +After careful consideration, I have decided that the code page we will support for EBCDIC is IBM CP1047. + +In suite3270 (e.g. c3270/x3270), the default code page is what it calls "brackets". This is CP37 with the [, ], Ý, and ¨ characters swapped around. This ends up placing all four of those characters in the correct place for 1047 (and thus they will work correctly with go3270 by default). However, the ^ and ¬ characters are swapped relative to CP1047. (Or, more succinctly, you could say the suite3270 "brackets" codepage is CP1047 with the ^ and ¬ characters swapped back to where they are in CP37). If you plan on using the ^ and ¬ characters, run c/x3270 in proper 1047 mode, `c3270 -codepage 1047` or make it your default by setting the `c3270.codePage` resource to `1047` in your `.c3270pro` file, for example. + +In Vista TN3270, "United States" is the default code page. This is CP1047 and will map 100% correctly. + +In IBM PCOMM, CP37 is the default. For correct mapping of [, ], Ý, ¨, ^, and ¬, you must switch the session parameters from "037 United States" to "1047 United States". + 3270 information ---------------- diff --git a/ebcdic.go b/ebcdic.go index b83ebf9..f882c5f 100644 --- a/ebcdic.go +++ b/ebcdic.go @@ -4,61 +4,106 @@ package go3270 -// Each index in this array is the ASCII value, and the value at the index is -// the corresponding EBCDIC (codepage 37) value. -var ebcdic = []byte{ - 0, 1, 2, 3, 55, 45, 46, 47, 22, 5, 37, 11, 12, 13, 14, 15, 16, 17, 18, 19, - 60, 61, 50, 38, 24, 25, 63, 39, 28, 29, 30, 31, 64, 90, 127, 123, 91, 108, - 80, 125, 77, 93, 92, 78, 107, 96, 75, 97, 240, 241, 242, 243, 244, 245, - 246, 247, 248, 249, 122, 94, 76, 126, 110, 111, 124, 193, 194, 195, 196, - 197, 198, 199, 200, 201, 209, 210, 211, 212, 213, 214, 215, 216, 217, 226, - 227, 228, 229, 230, 231, 232, 233, 74, 224, 90, 95, 109, 121, 129, 130, - 131, 132, 133, 134, 135, 136, 137, 145, 146, 147, 148, 149, 150, 151, 152, - 153, 162, 163, 164, 165, 166, 167, 168, 169, 192, 106, 208, 161, 7, 32, - 33, 34, 35, 36, 21, 6, 23, 40, 41, 42, 43, 44, 9, 10, 27, 48, 49, 26, 51, - 52, 53, 54, 8, 56, 57, 58, 59, 4, 20, 62, 225, 65, 66, 67, 68, 69, 70, 71, - 72, 73, 81, 82, 83, 84, 85, 86, 87, 88, 89, 98, 99, 100, 101, 102, 103, - 104, 105, 112, 113, 114, 115, 116, 117, 118, 119, 120, 128, 138, 139, 140, - 141, 142, 143, 144, 154, 155, 156, 157, 158, 159, 160, 170, 171, 172, 173, - 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, - 189, 190, 191, 202, 203, 204, 205, 206, 207, 218, 219, 220, 221, 222, 223, - 234, 235, 236, 237, 238, 239, 250, 251, 252, 253, 254, 255} +import ( + "unicode/utf8" +) -// Each index in this array is the EBCDIC (codepage 37) value, and the value -// at the index is the corresponding ASCII value. -var ascii = []byte{ - 0, 1, 2, 3, 156, 9, 134, 127, 151, 141, 142, 11, 12, 13, 14, 15, - 16, 17, 18, 19, 157, 133, 8, 135, 24, 25, 146, 143, 28, 29, 30, 31, - 128, 129, 130, 131, 132, 10, 23, 27, 136, 137, 138, 139, 140, 5, 6, 7, - 144, 145, 22, 147, 148, 149, 150, 4, 152, 153, 154, 155, 20, 21, 158, 26, - 32, 160, 161, 162, 163, 164, 165, 166, 167, 168, 91, 46, 60, 40, 43, 33, - 38, 169, 170, 171, 172, 173, 174, 175, 176, 177, 33, 36, 42, 41, 59, 94, - 45, 47, 178, 179, 180, 181, 182, 183, 184, 185, 124, 44, 37, 95, 62, 63, - 186, 187, 188, 189, 190, 191, 192, 193, 194, 96, 58, 35, 64, 39, 61, 34, - 195, 97, 98, 99, 100, 101, 102, 103, 104, 105, 196, 197, 198, 199, 200, - 201, 202, 106, 107, 108, 109, 110, 111, 112, 113, 114, 203, 204, 205, 206, - 207, 208, 209, 126, 115, 116, 117, 118, 119, 120, 121, 122, 210, 211, 212, - 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, - 228, 229, 230, 231, 123, 65, 66, 67, 68, 69, 70, 71, 72, 73, 232, 233, - 234, 235, 236, 237, 125, 74, 75, 76, 77, 78, 79, 80, 81, 82, 238, 239, - 240, 241, 242, 243, 92, 159, 83, 84, 85, 86, 87, 88, 89, 90, 244, 245, - 246, 247, 248, 249, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 250, 251, 252, - 253, 254, 255} +// After careful consideration, I have decided that the code page we will +// support for EBCDIC is IBM CP 1047. +// +// In suite3270 (e.g. c3270/x3270), the default code page is what it calls +// "brackets". This is CP37 with the [, ], Ý, and ¨ characters swapped around. +// This ends up placing all four of those characters in the correct place for +// 1047 (and thus they will all work correctly with go3270 by default). +// HOWEVER, the ^ and ¬ characters are swapped relative to CP1047. (Or, more +// succinctly, you could say the suite3270 "brackets" codepage is CP1047 with +// the ^ and ¬ characters swapped back to where they are in CP37). If you plan +// on using the ^ and ¬ characters, run c/x3270 in proper 1047 mode, +// `c3270-codepage 1047` or make it your default by setting the +// `c3270.codePage` resource to `1047` in your `.c3270pro` file, for example. +// +// In Vista TN3270, "United States" is the default code page. This is CP1047 +// and will map 100% correctly. +// +// In IBM PCOMM, CP37 is the default. For correct mapping of [, ], Ý, ¨, ^, +// and ¬, you must switch the session parameters from "037 United States" to +// "1047 United States". -// a2e converts the input byte array, a, from ASCII to EBCDIC. -func a2e(a []byte) []byte { - result := make([]byte, len(a)) - for i := 0; i < len(a); i++ { - result[i] = ebcdic[a[i]] - } - return result +// IBM CP 1047 <-> Unicode mappings from: +// https://raw.githubusercontent.com/unicode-org/icu-data/refs/heads/main/charset/data/ucm/glibc-IBM1047-2.1.2.ucm + +var cp1047ToUnicode []rune = []rune{ + /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */ + /* 0x */ 0x00, 0x01, 0x02, 0x03, 0x9C, 0x09, 0x86, 0x7F, 0x97, 0x8D, 0x8E, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, + /* 1x */ 0x10, 0x11, 0x12, 0x13, 0x9D, 0x85, 0x08, 0x87, 0x18, 0x19, 0x92, 0x8F, 0x1C, 0x1D, 0x1E, 0x1F, + /* 2x */ 0x80, 0x81, 0x82, 0x83, 0x84, 0x0A, 0x17, 0x1B, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x05, 0x06, 0x07, + /* 3x */ 0x90, 0x91, 0x16, 0x93, 0x94, 0x95, 0x96, 0x04, 0x98, 0x99, 0x9A, 0x9B, 0x14, 0x15, 0x9E, 0x1A, + /* 4x */ 0x20, 0xA0, 0xE2, 0xE4, 0xE0, 0xE1, 0xE3, 0xE5, 0xE7, 0xF1, 0xA2, 0x2E, 0x3C, 0x28, 0x2B, 0x7C, + /* 5x */ 0x26, 0xE9, 0xEA, 0xEB, 0xE8, 0xED, 0xEE, 0xEF, 0xEC, 0xDF, 0x21, 0x24, 0x2A, 0x29, 0x3B, 0x5E, + /* 6x */ 0x2D, 0x2F, 0xC2, 0xC4, 0xC0, 0xC1, 0xC3, 0xC5, 0xC7, 0xD1, 0xA6, 0x2C, 0x25, 0x5F, 0x3E, 0x3F, + /* 7x */ 0xF8, 0xC9, 0xCA, 0xCB, 0xC8, 0xCD, 0xCE, 0xCF, 0xCC, 0x60, 0x3A, 0x23, 0x40, 0x27, 0x3D, 0x22, + /* 8x */ 0xD8, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0xAB, 0xBB, 0xF0, 0xFD, 0xFE, 0xB1, + /* 9x */ 0xB0, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0xAA, 0xBA, 0xE6, 0xB8, 0xC6, 0xA4, + /* Ax */ 0xB5, 0x7E, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0xA1, 0xBF, 0xD0, 0x5B, 0xDE, 0xAE, + /* Bx */ 0xAC, 0xA3, 0xA5, 0xB7, 0xA9, 0xA7, 0xB6, 0xBC, 0xBD, 0xBE, 0xDD, 0xA8, 0xAF, 0x5D, 0xB4, 0xD7, + /* Cx */ 0x7B, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0xAD, 0xF4, 0xF6, 0xF2, 0xF3, 0xF5, + /* Dx */ 0x7D, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0xB9, 0xFB, 0xFC, 0xF9, 0xFA, 0xFF, + /* Ex */ 0x5C, 0xF7, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0xB2, 0xD4, 0xD6, 0xD2, 0xD3, 0xD5, + /* Fx */ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0xB3, 0xDB, 0xDC, 0xD9, 0xDA, 0x9F, } -// e2a converts the input byte array, e, from EBCDIC to ASCII -func e2a(e []byte) []byte { - result := make([]byte, len(e)) - for i := 0; i < len(e); i++ { - result[i] = ascii[e[i]] +var unicodeToCP1047 []byte = []byte{ + /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */ + /* 0x */ 0x00, 0x01, 0x02, 0x03, 0x37, 0x2D, 0x2E, 0x2F, 0x16, 0x05, 0x25, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, + /* 1x */ 0x10, 0x11, 0x12, 0x13, 0x3C, 0x3D, 0x32, 0x26, 0x18, 0x19, 0x3F, 0x27, 0x1C, 0x1D, 0x1E, 0x1F, + /* 2x */ 0x40, 0x5A, 0x7F, 0x7B, 0x5B, 0x6C, 0x50, 0x7D, 0x4D, 0x5D, 0x5C, 0x4E, 0x6B, 0x60, 0x4B, 0x61, + /* 3x */ 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0x7A, 0x5E, 0x4C, 0x7E, 0x6E, 0x6F, + /* 4x */ 0x7C, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, + /* 5x */ 0xD7, 0xD8, 0xD9, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xAD, 0xE0, 0xBD, 0x5F, 0x6D, + /* 6x */ 0x79, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, + /* 7x */ 0x97, 0x98, 0x99, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xC0, 0x4F, 0xD0, 0xA1, 0x07, + /* 8x */ 0x20, 0x21, 0x22, 0x23, 0x24, 0x15, 0x06, 0x17, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x09, 0x0A, 0x1B, + /* 9x */ 0x30, 0x31, 0x1A, 0x33, 0x34, 0x35, 0x36, 0x08, 0x38, 0x39, 0x3A, 0x3B, 0x04, 0x14, 0x3E, 0xFF, + /* Ax */ 0x41, 0xAA, 0x4A, 0xB1, 0x9F, 0xB2, 0x6A, 0xB5, 0xBB, 0xB4, 0x9A, 0x8A, 0xB0, 0xCA, 0xAF, 0xBC, + /* Bx */ 0x90, 0x8F, 0xEA, 0xFA, 0xBE, 0xA0, 0xB6, 0xB3, 0x9D, 0xDA, 0x9B, 0x8B, 0xB7, 0xB8, 0xB9, 0xAB, + /* Cx */ 0x64, 0x65, 0x62, 0x66, 0x63, 0x67, 0x9E, 0x68, 0x74, 0x71, 0x72, 0x73, 0x78, 0x75, 0x76, 0x77, + /* Dx */ 0xAC, 0x69, 0xED, 0xEE, 0xEB, 0xEF, 0xEC, 0xBF, 0x80, 0xFD, 0xFE, 0xFB, 0xFC, 0xBA, 0xAE, 0x59, + /* Ex */ 0x44, 0x45, 0x42, 0x46, 0x43, 0x47, 0x9C, 0x48, 0x54, 0x51, 0x52, 0x53, 0x58, 0x55, 0x56, 0x57, + /* Fx */ 0x8C, 0x49, 0xCD, 0xCE, 0xCB, 0xCF, 0xCC, 0xE1, 0x70, 0xDD, 0xDE, 0xDB, 0xDC, 0x8D, 0x8E, 0xDF, +} + +// decode will convert a CP1047 byte array into a UTF-8 Go string. +func decode(b []byte) string { + // There is complete 1:1 mapping of all 8-bit values + runes := make([]rune, len(b)) + for i := range b { + runes[i] = cp1047ToUnicode[b[i]] } - return result + return string(runes) // conversion to UTF-8 is automatic +} + +// encode will convert a UTF-8 Go string into a CP1047 byte array. +func encode(s string) []byte { + // Output CP1047 bytes will be no more than input UTF-8 bytes + out := make([]byte, len(s)) + n := 0 + + for len(s) > 0 { + r, size := utf8.DecodeRuneInString(s) + if r == utf8.RuneError { + debugf("invalid UTF-8 encoding detected, aborting conversion") + break + } + + if int(r) < len(unicodeToCP1047) { + out[n] = unicodeToCP1047[r] + } else { + // replacement/substitute character + out[n] = 0x3f + } + n++ + s = s[size:] + } + + return out[:n] } diff --git a/response.go b/response.go index a46f247..111ea57 100644 --- a/response.go +++ b/response.go @@ -160,8 +160,9 @@ func readFields(c net.Conn, fm fieldmap, cols int) (map[string]string, error) { if eor { // Finish the current field if infield { - debugf("Field %d: %s\n", fieldpos, e2a(fieldval.Bytes())) - handleField(fieldpos, fieldval.Bytes(), fm, values) + value := decode(fieldval.Bytes()) + debugf("Field %d: %s\n", fieldpos, value) + handleField(fieldpos, value, fm, values) } return values, nil @@ -171,8 +172,9 @@ func readFields(c net.Conn, fm fieldmap, cols int) (map[string]string, error) { if b == 0x11 { // Finish the previous field, if necessary if infield { - debugf("Field %d: %s\n", fieldpos, e2a(fieldval.Bytes())) - handleField(fieldpos, fieldval.Bytes(), fm, values) + value := decode(fieldval.Bytes()) + debugf("Field %d: %s\n", fieldpos, value) + handleField(fieldpos, value, fm, values) } // Start a new field infield = true @@ -194,7 +196,7 @@ func readFields(c net.Conn, fm fieldmap, cols int) (map[string]string, error) { } } -func handleField(addr int, value []byte, fm fieldmap, values map[string]string) bool { +func handleField(addr int, value string, fm fieldmap, values map[string]string) bool { name, ok := fm[addr] // Field is not present in the fieldmap @@ -203,7 +205,7 @@ func handleField(addr int, value []byte, fm fieldmap, values map[string]string) } // Otherwise, populate the value - values[name] = string(e2a(value)) + values[name] = value return true } diff --git a/screen.go b/screen.go index 11d2f99..d7640e6 100644 --- a/screen.go +++ b/screen.go @@ -286,7 +286,7 @@ func showScreenInternal(screen Screen, values map[string]string, } } if content != "" { - b.Write(a2e([]byte(content))) + b.Write(encode(content)) } // If a writable field, add it to the field map. We add 1 to bufaddr