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 <[email protected]> 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
file_encoding(struct magic_set * ms,const struct buffer * b,file_unichar_t ** ubuf,size_t * ulen,const char ** code,const char ** code_mime,const char ** type)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
file_looks_utf8(const unsigned char * buf,size_t nbytes,file_unichar_t * ubuf,size_t * ulen)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
looks_utf8_with_BOM(const unsigned char * buf,size_t nbytes,file_unichar_t * ubuf,size_t * ulen)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
looks_utf7(const unsigned char * buf,size_t nbytes,file_unichar_t * ubuf,size_t * ulen)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
looks_ucs16(const unsigned char * bf,size_t nbytes,file_unichar_t * ubf,size_t * ulen)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
looks_ucs32(const unsigned char * bf,size_t nbytes,file_unichar_t * ubf,size_t * ulen)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
from_ebcdic(const unsigned char * buf,size_t nbytes,unsigned char * out)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