1 /* 2 * Copyright (c) Ian F. Darwin 1986-1995. 3 * Software written by Ian F. Darwin and others; 4 * maintained 1995-present by Christos Zoulas and others. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice immediately at the beginning of the file, without modification, 11 * this list of conditions, and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 /* 29 * Encoding -- determine the character encoding of a text file. 30 * 31 * Joerg Wunsch <joerg@freebsd.org> wrote the original support for 8-bit 32 * international characters. 33 */ 34 35 #include "file.h" 36 37 #ifndef lint 38 FILE_RCSID("@(#)$File: encoding.c,v 1.32 2021/04/27 19:37:14 christos Exp $") 39 #endif /* lint */ 40 41 #include "magic.h" 42 #include <string.h> 43 #include <stdlib.h> 44 45 46 private int looks_ascii(const unsigned char *, size_t, file_unichar_t *, 47 size_t *); 48 private int looks_utf8_with_BOM(const unsigned char *, size_t, file_unichar_t *, 49 size_t *); 50 private int looks_utf7(const unsigned char *, size_t, file_unichar_t *, 51 size_t *); 52 private int looks_ucs16(const unsigned char *, size_t, file_unichar_t *, 53 size_t *); 54 private int looks_ucs32(const unsigned char *, size_t, file_unichar_t *, 55 size_t *); 56 private int looks_latin1(const unsigned char *, size_t, file_unichar_t *, 57 size_t *); 58 private int looks_extended(const unsigned char *, size_t, file_unichar_t *, 59 size_t *); 60 private void from_ebcdic(const unsigned char *, size_t, unsigned char *); 61 62 #ifdef DEBUG_ENCODING 63 #define DPRINTF(a) printf a 64 #else 65 #define DPRINTF(a) 66 #endif 67 68 /* 69 * Try to determine whether text is in some character code we can 70 * identify. Each of these tests, if it succeeds, will leave 71 * the text converted into one-file_unichar_t-per-character Unicode in 72 * ubuf, and the number of characters converted in ulen. 73 */ 74 protected int 75 file_encoding(struct magic_set *ms, const struct buffer *b, 76 file_unichar_t **ubuf, size_t *ulen, const char **code, 77 const char **code_mime, const char **type) 78 { 79 const unsigned char *buf = CAST(const unsigned char *, b->fbuf); 80 size_t nbytes = b->flen; 81 size_t mlen; 82 int rv = 1, ucs_type; 83 unsigned char *nbuf = NULL; 84 file_unichar_t *udefbuf; 85 size_t udeflen; 86 87 if (ubuf == NULL) 88 ubuf = &udefbuf; 89 if (ulen == NULL) 90 ulen = &udeflen; 91 92 *type = "text"; 93 *ulen = 0; 94 *code = "unknown"; 95 *code_mime = "binary"; 96 97 if (nbytes > ms->encoding_max) 98 nbytes = ms->encoding_max; 99 100 mlen = (nbytes + 1) * sizeof((*ubuf)[0]); 101 *ubuf = CAST(file_unichar_t *, calloc(CAST(size_t, 1), mlen)); 102 if (*ubuf == NULL) { 103 file_oomem(ms, mlen); 104 goto done; 105 } 106 mlen = (nbytes + 1) * sizeof(nbuf[0]); 107 if ((nbuf = CAST(unsigned char *, 108 calloc(CAST(size_t, 1), mlen))) == NULL) { 109 file_oomem(ms, mlen); 110 goto done; 111 } 112 113 if (looks_ascii(buf, nbytes, *ubuf, ulen)) { 114 if (looks_utf7(buf, nbytes, *ubuf, ulen) > 0) { 115 DPRINTF(("utf-7 %" SIZE_T_FORMAT "u\n", *ulen)); 116 *code = "Unicode text, UTF-7"; 117 *code_mime = "utf-7"; 118 } else { 119 DPRINTF(("ascii %" SIZE_T_FORMAT "u\n", *ulen)); 120 *code = "ASCII"; 121 *code_mime = "us-ascii"; 122 } 123 } else if (looks_utf8_with_BOM(buf, nbytes, *ubuf, ulen) > 0) { 124 DPRINTF(("utf8/bom %" SIZE_T_FORMAT "u\n", *ulen)); 125 *code = "Unicode text, UTF-8 (with BOM)"; 126 *code_mime = "utf-8"; 127 } else if (file_looks_utf8(buf, nbytes, *ubuf, ulen) > 1) { 128 DPRINTF(("utf8 %" SIZE_T_FORMAT "u\n", *ulen)); 129 *code = "Unicode text, UTF-8"; 130 *code_mime = "utf-8"; 131 } else if ((ucs_type = looks_ucs32(buf, nbytes, *ubuf, ulen)) != 0) { 132 if (ucs_type == 1) { 133 *code = "Unicode text, UTF-32, little-endian"; 134 *code_mime = "utf-32le"; 135 } else { 136 *code = "Unicode text, UTF-32, big-endian"; 137 *code_mime = "utf-32be"; 138 } 139 DPRINTF(("ucs32 %" SIZE_T_FORMAT "u\n", *ulen)); 140 } else if ((ucs_type = looks_ucs16(buf, nbytes, *ubuf, ulen)) != 0) { 141 if (ucs_type == 1) { 142 *code = "Unicode text, UTF-16, little-endian"; 143 *code_mime = "utf-16le"; 144 } else { 145 *code = "Unicode text, UTF-16, big-endian"; 146 *code_mime = "utf-16be"; 147 } 148 DPRINTF(("ucs16 %" SIZE_T_FORMAT "u\n", *ulen)); 149 } else if (looks_latin1(buf, nbytes, *ubuf, ulen)) { 150 DPRINTF(("latin1 %" SIZE_T_FORMAT "u\n", *ulen)); 151 *code = "ISO-8859"; 152 *code_mime = "iso-8859-1"; 153 } else if (looks_extended(buf, nbytes, *ubuf, ulen)) { 154 DPRINTF(("extended %" SIZE_T_FORMAT "u\n", *ulen)); 155 *code = "Non-ISO extended-ASCII"; 156 *code_mime = "unknown-8bit"; 157 } else { 158 from_ebcdic(buf, nbytes, nbuf); 159 160 if (looks_ascii(nbuf, nbytes, *ubuf, ulen)) { 161 DPRINTF(("ebcdic %" SIZE_T_FORMAT "u\n", *ulen)); 162 *code = "EBCDIC"; 163 *code_mime = "ebcdic"; 164 } else if (looks_latin1(nbuf, nbytes, *ubuf, ulen)) { 165 DPRINTF(("ebcdic/international %" SIZE_T_FORMAT "u\n", 166 *ulen)); 167 *code = "International EBCDIC"; 168 *code_mime = "ebcdic"; 169 } else { /* Doesn't look like text at all */ 170 DPRINTF(("binary\n")); 171 rv = 0; 172 *type = "binary"; 173 } 174 } 175 176 done: 177 free(nbuf); 178 if (ubuf == &udefbuf) 179 free(udefbuf); 180 181 return rv; 182 } 183 184 /* 185 * This table reflects a particular philosophy about what constitutes 186 * "text," and there is room for disagreement about it. 187 * 188 * Version 3.31 of the file command considered a file to be ASCII if 189 * each of its characters was approved by either the isascii() or 190 * isalpha() function. On most systems, this would mean that any 191 * file consisting only of characters in the range 0x00 ... 0x7F 192 * would be called ASCII text, but many systems might reasonably 193 * consider some characters outside this range to be alphabetic, 194 * so the file command would call such characters ASCII. It might 195 * have been more accurate to call this "considered textual on the 196 * local system" than "ASCII." 197 * 198 * It considered a file to be "International language text" if each 199 * of its characters was either an ASCII printing character (according 200 * to the real ASCII standard, not the above test), a character in 201 * the range 0x80 ... 0xFF, or one of the following control characters: 202 * backspace, tab, line feed, vertical tab, form feed, carriage return, 203 * escape. No attempt was made to determine the language in which files 204 * of this type were written. 205 * 206 * 207 * The table below considers a file to be ASCII if all of its characters 208 * are either ASCII printing characters (again, according to the X3.4 209 * standard, not isascii()) or any of the following controls: bell, 210 * backspace, tab, line feed, form feed, carriage return, esc, nextline. 211 * 212 * I include bell because some programs (particularly shell scripts) 213 * use it literally, even though it is rare in normal text. I exclude 214 * vertical tab because it never seems to be used in real text. I also 215 * include, with hesitation, the X3.64/ECMA-43 control nextline (0x85), 216 * because that's what the dd EBCDIC->ASCII table maps the EBCDIC newline 217 * character to. It might be more appropriate to include it in the 8859 218 * set instead of the ASCII set, but it's got to be included in *something* 219 * we recognize or EBCDIC files aren't going to be considered textual. 220 * Some old Unix source files use SO/SI (^N/^O) to shift between Greek 221 * and Latin characters, so these should possibly be allowed. But they 222 * make a real mess on VT100-style displays if they're not paired properly, 223 * so we are probably better off not calling them text. 224 * 225 * A file is considered to be ISO-8859 text if its characters are all 226 * either ASCII, according to the above definition, or printing characters 227 * from the ISO-8859 8-bit extension, characters 0xA0 ... 0xFF. 228 * 229 * Finally, a file is considered to be international text from some other 230 * character code if its characters are all either ISO-8859 (according to 231 * the above definition) or characters in the range 0x80 ... 0x9F, which 232 * ISO-8859 considers to be control characters but the IBM PC and Macintosh 233 * consider to be printing characters. 234 */ 235 236 #define F 0 /* character never appears in text */ 237 #define T 1 /* character appears in plain ASCII text */ 238 #define I 2 /* character appears in ISO-8859 text */ 239 #define X 3 /* character appears in non-ISO extended ASCII (Mac, IBM PC) */ 240 241 private char text_chars[256] = { 242 /* BEL BS HT LF VT FF CR */ 243 F, F, F, F, F, F, F, T, T, T, T, T, T, T, F, F, /* 0x0X */ 244 /* ESC */ 245 F, F, F, F, F, F, F, F, F, F, F, T, F, F, F, F, /* 0x1X */ 246 T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x2X */ 247 T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x3X */ 248 T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x4X */ 249 T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x5X */ 250 T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x6X */ 251 T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, F, /* 0x7X */ 252 /* NEL */ 253 X, X, X, X, X, T, X, X, X, X, X, X, X, X, X, X, /* 0x8X */ 254 X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, /* 0x9X */ 255 I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xaX */ 256 I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xbX */ 257 I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xcX */ 258 I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xdX */ 259 I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xeX */ 260 I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I /* 0xfX */ 261 }; 262 263 #define LOOKS(NAME, COND) \ 264 private int \ 265 looks_ ## NAME(const unsigned char *buf, size_t nbytes, file_unichar_t *ubuf, \ 266 size_t *ulen) \ 267 { \ 268 size_t i; \ 269 \ 270 *ulen = 0; \ 271 \ 272 for (i = 0; i < nbytes; i++) { \ 273 int t = text_chars[buf[i]]; \ 274 \ 275 if (COND) \ 276 return 0; \ 277 \ 278 ubuf[(*ulen)++] = buf[i]; \ 279 } \ 280 return 1; \ 281 } 282 283 LOOKS(ascii, t != T) 284 LOOKS(latin1, t != T && t != I) 285 LOOKS(extended, t != T && t != I && t != X) 286 287 /* 288 * Decide whether some text looks like UTF-8. Returns: 289 * 290 * -1: invalid UTF-8 291 * 0: uses odd control characters, so doesn't look like text 292 * 1: 7-bit text 293 * 2: definitely UTF-8 text (valid high-bit set bytes) 294 * 295 * If ubuf is non-NULL on entry, text is decoded into ubuf, *ulen; 296 * ubuf must be big enough! 297 */ 298 299 // from: https://golang.org/src/unicode/utf8/utf8.go 300 301 #define XX 0xF1 // invalid: size 1 302 #define AS 0xF0 // ASCII: size 1 303 #define S1 0x02 // accept 0, size 2 304 #define S2 0x13 // accept 1, size 3 305 #define S3 0x03 // accept 0, size 3 306 #define S4 0x23 // accept 2, size 3 307 #define S5 0x34 // accept 3, size 4 308 #define S6 0x04 // accept 0, size 4 309 #define S7 0x44 // accept 4, size 4 310 311 #define LOCB 0x80 312 #define HICB 0xBF 313 314 // first is information about the first byte in a UTF-8 sequence. 315 static const uint8_t first[] = { 316 // 1 2 3 4 5 6 7 8 9 A B C D E F 317 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x00-0x0F 318 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x10-0x1F 319 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x20-0x2F 320 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x30-0x3F 321 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x40-0x4F 322 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x50-0x5F 323 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x60-0x6F 324 AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x70-0x7F 325 // 1 2 3 4 5 6 7 8 9 A B C D E F 326 XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0x80-0x8F 327 XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0x90-0x9F 328 XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xA0-0xAF 329 XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xB0-0xBF 330 XX, XX, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, // 0xC0-0xCF 331 S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, // 0xD0-0xDF 332 S2, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S4, S3, S3, // 0xE0-0xEF 333 S5, S6, S6, S6, S7, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xF0-0xFF 334 }; 335 336 // acceptRange gives the range of valid values for the second byte in a UTF-8 337 // sequence. 338 struct accept_range { 339 uint8_t lo; // lowest value for second byte. 340 uint8_t hi; // highest value for second byte. 341 } accept_ranges[16] = { 342 // acceptRanges has size 16 to avoid bounds checks in the code that uses it. 343 { LOCB, HICB }, 344 { 0xA0, HICB }, 345 { LOCB, 0x9F }, 346 { 0x90, HICB }, 347 { LOCB, 0x8F }, 348 }; 349 350 protected int 351 file_looks_utf8(const unsigned char *buf, size_t nbytes, file_unichar_t *ubuf, 352 size_t *ulen) 353 { 354 size_t i; 355 int n; 356 file_unichar_t c; 357 int gotone = 0, ctrl = 0; 358 359 if (ubuf) 360 *ulen = 0; 361 362 for (i = 0; i < nbytes; i++) { 363 if ((buf[i] & 0x80) == 0) { /* 0xxxxxxx is plain ASCII */ 364 /* 365 * Even if the whole file is valid UTF-8 sequences, 366 * still reject it if it uses weird control characters. 367 */ 368 369 if (text_chars[buf[i]] != T) 370 ctrl = 1; 371 372 if (ubuf) 373 ubuf[(*ulen)++] = buf[i]; 374 } else if ((buf[i] & 0x40) == 0) { /* 10xxxxxx never 1st byte */ 375 return -1; 376 } else { /* 11xxxxxx begins UTF-8 */ 377 int following; 378 uint8_t x = first[buf[i]]; 379 const struct accept_range *ar = 380 &accept_ranges[(unsigned int)x >> 4]; 381 if (x == XX) 382 return -1; 383 384 if ((buf[i] & 0x20) == 0) { /* 110xxxxx */ 385 c = buf[i] & 0x1f; 386 following = 1; 387 } else if ((buf[i] & 0x10) == 0) { /* 1110xxxx */ 388 c = buf[i] & 0x0f; 389 following = 2; 390 } else if ((buf[i] & 0x08) == 0) { /* 11110xxx */ 391 c = buf[i] & 0x07; 392 following = 3; 393 } else if ((buf[i] & 0x04) == 0) { /* 111110xx */ 394 c = buf[i] & 0x03; 395 following = 4; 396 } else if ((buf[i] & 0x02) == 0) { /* 1111110x */ 397 c = buf[i] & 0x01; 398 following = 5; 399 } else 400 return -1; 401 402 for (n = 0; n < following; n++) { 403 i++; 404 if (i >= nbytes) 405 goto done; 406 407 if (n == 0 && 408 (buf[i] < ar->lo || buf[i] > ar->hi)) 409 return -1; 410 411 if ((buf[i] & 0x80) == 0 || (buf[i] & 0x40)) 412 return -1; 413 414 c = (c << 6) + (buf[i] & 0x3f); 415 } 416 417 if (ubuf) 418 ubuf[(*ulen)++] = c; 419 gotone = 1; 420 } 421 } 422 done: 423 return ctrl ? 0 : (gotone ? 2 : 1); 424 } 425 426 /* 427 * Decide whether some text looks like UTF-8 with BOM. If there is no 428 * BOM, return -1; otherwise return the result of looks_utf8 on the 429 * rest of the text. 430 */ 431 private int 432 looks_utf8_with_BOM(const unsigned char *buf, size_t nbytes, 433 file_unichar_t *ubuf, size_t *ulen) 434 { 435 if (nbytes > 3 && buf[0] == 0xef && buf[1] == 0xbb && buf[2] == 0xbf) 436 return file_looks_utf8(buf + 3, nbytes - 3, ubuf, ulen); 437 else 438 return -1; 439 } 440 441 private int 442 looks_utf7(const unsigned char *buf, size_t nbytes, file_unichar_t *ubuf, 443 size_t *ulen) 444 { 445 if (nbytes > 4 && buf[0] == '+' && buf[1] == '/' && buf[2] == 'v') 446 switch (buf[3]) { 447 case '8': 448 case '9': 449 case '+': 450 case '/': 451 if (ubuf) 452 *ulen = 0; 453 return 1; 454 default: 455 return -1; 456 } 457 else 458 return -1; 459 } 460 461 private int 462 looks_ucs16(const unsigned char *bf, size_t nbytes, file_unichar_t *ubf, 463 size_t *ulen) 464 { 465 int bigend; 466 size_t i; 467 468 if (nbytes < 2) 469 return 0; 470 471 if (bf[0] == 0xff && bf[1] == 0xfe) 472 bigend = 0; 473 else if (bf[0] == 0xfe && bf[1] == 0xff) 474 bigend = 1; 475 else 476 return 0; 477 478 *ulen = 0; 479 480 for (i = 2; i + 1 < nbytes; i += 2) { 481 /* XXX fix to properly handle chars > 65536 */ 482 483 if (bigend) 484 ubf[(*ulen)++] = bf[i + 1] 485 | (CAST(file_unichar_t, bf[i]) << 8); 486 else 487 ubf[(*ulen)++] = bf[i] 488 | (CAST(file_unichar_t, bf[i + 1]) << 8); 489 490 if (ubf[*ulen - 1] == 0xfffe) 491 return 0; 492 if (ubf[*ulen - 1] < 128 && 493 text_chars[CAST(size_t, ubf[*ulen - 1])] != T) 494 return 0; 495 } 496 497 return 1 + bigend; 498 } 499 500 private int 501 looks_ucs32(const unsigned char *bf, size_t nbytes, file_unichar_t *ubf, 502 size_t *ulen) 503 { 504 int bigend; 505 size_t i; 506 507 if (nbytes < 4) 508 return 0; 509 510 if (bf[0] == 0xff && bf[1] == 0xfe && bf[2] == 0 && bf[3] == 0) 511 bigend = 0; 512 else if (bf[0] == 0 && bf[1] == 0 && bf[2] == 0xfe && bf[3] == 0xff) 513 bigend = 1; 514 else 515 return 0; 516 517 *ulen = 0; 518 519 for (i = 4; i + 3 < nbytes; i += 4) { 520 /* XXX fix to properly handle chars > 65536 */ 521 522 if (bigend) 523 ubf[(*ulen)++] = CAST(file_unichar_t, bf[i + 3]) 524 | (CAST(file_unichar_t, bf[i + 2]) << 8) 525 | (CAST(file_unichar_t, bf[i + 1]) << 16) 526 | (CAST(file_unichar_t, bf[i]) << 24); 527 else 528 ubf[(*ulen)++] = CAST(file_unichar_t, bf[i + 0]) 529 | (CAST(file_unichar_t, bf[i + 1]) << 8) 530 | (CAST(file_unichar_t, bf[i + 2]) << 16) 531 | (CAST(file_unichar_t, bf[i + 3]) << 24); 532 533 if (ubf[*ulen - 1] == 0xfffe) 534 return 0; 535 if (ubf[*ulen - 1] < 128 && 536 text_chars[CAST(size_t, ubf[*ulen - 1])] != T) 537 return 0; 538 } 539 540 return 1 + bigend; 541 } 542 #undef F 543 #undef T 544 #undef I 545 #undef X 546 547 /* 548 * This table maps each EBCDIC character to an (8-bit extended) ASCII 549 * character, as specified in the rationale for the dd(1) command in 550 * draft 11.2 (September, 1991) of the POSIX P1003.2 standard. 551 * 552 * Unfortunately it does not seem to correspond exactly to any of the 553 * five variants of EBCDIC documented in IBM's _Enterprise Systems 554 * Architecture/390: Principles of Operation_, SA22-7201-06, Seventh 555 * Edition, July, 1999, pp. I-1 - I-4. 556 * 557 * Fortunately, though, all versions of EBCDIC, including this one, agree 558 * on most of the printing characters that also appear in (7-bit) ASCII. 559 * Of these, only '|', '!', '~', '^', '[', and ']' are in question at all. 560 * 561 * Fortunately too, there is general agreement that codes 0x00 through 562 * 0x3F represent control characters, 0x41 a nonbreaking space, and the 563 * remainder printing characters. 564 * 565 * This is sufficient to allow us to identify EBCDIC text and to distinguish 566 * between old-style and internationalized examples of text. 567 */ 568 569 private unsigned char ebcdic_to_ascii[] = { 570 0, 1, 2, 3, 156, 9, 134, 127, 151, 141, 142, 11, 12, 13, 14, 15, 571 16, 17, 18, 19, 157, 133, 8, 135, 24, 25, 146, 143, 28, 29, 30, 31, 572 128, 129, 130, 131, 132, 10, 23, 27, 136, 137, 138, 139, 140, 5, 6, 7, 573 144, 145, 22, 147, 148, 149, 150, 4, 152, 153, 154, 155, 20, 21, 158, 26, 574 ' ', 160, 161, 162, 163, 164, 165, 166, 167, 168, 213, '.', '<', '(', '+', '|', 575 '&', 169, 170, 171, 172, 173, 174, 175, 176, 177, '!', '$', '*', ')', ';', '~', 576 '-', '/', 178, 179, 180, 181, 182, 183, 184, 185, 203, ',', '%', '_', '>', '?', 577 186, 187, 188, 189, 190, 191, 192, 193, 194, '`', ':', '#', '@', '\'','=', '"', 578 195, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 196, 197, 198, 199, 200, 201, 579 202, 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', '^', 204, 205, 206, 207, 208, 580 209, 229, 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 210, 211, 212, '[', 214, 215, 581 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, ']', 230, 231, 582 '{', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 232, 233, 234, 235, 236, 237, 583 '}', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 238, 239, 240, 241, 242, 243, 584 '\\',159, 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 244, 245, 246, 247, 248, 249, 585 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 250, 251, 252, 253, 254, 255 586 }; 587 588 #ifdef notdef 589 /* 590 * The following EBCDIC-to-ASCII table may relate more closely to reality, 591 * or at least to modern reality. It comes from 592 * 593 * http://ftp.s390.ibm.com/products/oe/bpxqp9.html 594 * 595 * and maps the characters of EBCDIC code page 1047 (the code used for 596 * Unix-derived software on IBM's 390 systems) to the corresponding 597 * characters from ISO 8859-1. 598 * 599 * If this table is used instead of the above one, some of the special 600 * cases for the NEL character can be taken out of the code. 601 */ 602 603 private unsigned char ebcdic_1047_to_8859[] = { 604 0x00,0x01,0x02,0x03,0x9C,0x09,0x86,0x7F,0x97,0x8D,0x8E,0x0B,0x0C,0x0D,0x0E,0x0F, 605 0x10,0x11,0x12,0x13,0x9D,0x0A,0x08,0x87,0x18,0x19,0x92,0x8F,0x1C,0x1D,0x1E,0x1F, 606 0x80,0x81,0x82,0x83,0x84,0x85,0x17,0x1B,0x88,0x89,0x8A,0x8B,0x8C,0x05,0x06,0x07, 607 0x90,0x91,0x16,0x93,0x94,0x95,0x96,0x04,0x98,0x99,0x9A,0x9B,0x14,0x15,0x9E,0x1A, 608 0x20,0xA0,0xE2,0xE4,0xE0,0xE1,0xE3,0xE5,0xE7,0xF1,0xA2,0x2E,0x3C,0x28,0x2B,0x7C, 609 0x26,0xE9,0xEA,0xEB,0xE8,0xED,0xEE,0xEF,0xEC,0xDF,0x21,0x24,0x2A,0x29,0x3B,0x5E, 610 0x2D,0x2F,0xC2,0xC4,0xC0,0xC1,0xC3,0xC5,0xC7,0xD1,0xA6,0x2C,0x25,0x5F,0x3E,0x3F, 611 0xF8,0xC9,0xCA,0xCB,0xC8,0xCD,0xCE,0xCF,0xCC,0x60,0x3A,0x23,0x40,0x27,0x3D,0x22, 612 0xD8,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0xAB,0xBB,0xF0,0xFD,0xFE,0xB1, 613 0xB0,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,0x70,0x71,0x72,0xAA,0xBA,0xE6,0xB8,0xC6,0xA4, 614 0xB5,0x7E,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0xA1,0xBF,0xD0,0x5B,0xDE,0xAE, 615 0xAC,0xA3,0xA5,0xB7,0xA9,0xA7,0xB6,0xBC,0xBD,0xBE,0xDD,0xA8,0xAF,0x5D,0xB4,0xD7, 616 0x7B,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0xAD,0xF4,0xF6,0xF2,0xF3,0xF5, 617 0x7D,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,0x50,0x51,0x52,0xB9,0xFB,0xFC,0xF9,0xFA,0xFF, 618 0x5C,0xF7,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0xB2,0xD4,0xD6,0xD2,0xD3,0xD5, 619 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0xB3,0xDB,0xDC,0xD9,0xDA,0x9F 620 }; 621 #endif 622 623 /* 624 * Copy buf[0 ... nbytes-1] into out[], translating EBCDIC to ASCII. 625 */ 626 private void 627 from_ebcdic(const unsigned char *buf, size_t nbytes, unsigned char *out) 628 { 629 size_t i; 630 631 for (i = 0; i < nbytes; i++) { 632 out[i] = ebcdic_to_ascii[buf[i]]; 633 } 634 } 635