encoding.c 22 KB

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  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. #include "file.h"
  35. #ifndef lint
  36. FILE_RCSID("@(#)$File: encoding.c,v 1.27 2021/02/05 21:33:49 christos Exp $")
  37. #endif /* lint */
  38. #include "magic.h"
  39. #include <string.h>
  40. #include <stdlib.h>
  41. private int looks_ascii(const unsigned char *, size_t, file_unichar_t *,
  42. size_t *);
  43. private int looks_utf8_with_BOM(const unsigned char *, size_t, file_unichar_t *,
  44. size_t *);
  45. private int looks_utf7(const unsigned char *, size_t, file_unichar_t *,
  46. size_t *);
  47. private int looks_ucs16(const unsigned char *, size_t, file_unichar_t *,
  48. size_t *);
  49. private int looks_ucs32(const unsigned char *, size_t, file_unichar_t *,
  50. size_t *);
  51. private int looks_latin1(const unsigned char *, size_t, file_unichar_t *,
  52. size_t *);
  53. private int looks_extended(const unsigned char *, size_t, file_unichar_t *,
  54. size_t *);
  55. private void from_ebcdic(const unsigned char *, size_t, unsigned char *);
  56. #ifdef DEBUG_ENCODING
  57. #define DPRINTF(a) printf a
  58. #else
  59. #define DPRINTF(a)
  60. #endif
  61. /*
  62. * Try to determine whether text is in some character code we can
  63. * identify. Each of these tests, if it succeeds, will leave
  64. * the text converted into one-file_unichar_t-per-character Unicode in
  65. * ubuf, and the number of characters converted in ulen.
  66. */
  67. protected int
  68. file_encoding(struct magic_set *ms, const struct buffer *b,
  69. file_unichar_t **ubuf, size_t *ulen, const char **code,
  70. const char **code_mime, const char **type)
  71. {
  72. const unsigned char *buf = CAST(const unsigned char *, b->fbuf);
  73. size_t nbytes = b->flen;
  74. size_t mlen;
  75. int rv = 1, ucs_type;
  76. unsigned char *nbuf = NULL;
  77. file_unichar_t *udefbuf;
  78. size_t udeflen;
  79. if (ubuf == NULL)
  80. ubuf = &udefbuf;
  81. if (ulen == NULL)
  82. ulen = &udeflen;
  83. *type = "text";
  84. *ulen = 0;
  85. *code = "unknown";
  86. *code_mime = "binary";
  87. if (nbytes > ms->encoding_max)
  88. nbytes = ms->encoding_max;
  89. mlen = (nbytes + 1) * sizeof((*ubuf)[0]);
  90. *ubuf = CAST(file_unichar_t *, ecalloc(CAST(size_t, 1), mlen));
  91. if (*ubuf == NULL) {
  92. file_oomem(ms, mlen);
  93. goto done;
  94. }
  95. mlen = (nbytes + 1) * sizeof(nbuf[0]);
  96. if ((nbuf = CAST(unsigned char *,
  97. ecalloc(CAST(size_t, 1), mlen))) == NULL) {
  98. file_oomem(ms, mlen);
  99. goto done;
  100. }
  101. if (looks_ascii(buf, nbytes, *ubuf, ulen)) {
  102. if (looks_utf7(buf, nbytes, *ubuf, ulen) > 0) {
  103. DPRINTF(("utf-7 %" SIZE_T_FORMAT "u\n", *ulen));
  104. *code = "Unicode text, UTF-7";
  105. *code_mime = "utf-7";
  106. } else {
  107. DPRINTF(("ascii %" SIZE_T_FORMAT "u\n", *ulen));
  108. *code = "ASCII";
  109. *code_mime = "us-ascii";
  110. }
  111. } else if (looks_utf8_with_BOM(buf, nbytes, *ubuf, ulen) > 0) {
  112. DPRINTF(("utf8/bom %" SIZE_T_FORMAT "u\n", *ulen));
  113. *code = "Unicode text, UTF-8 (with BOM)";
  114. *code_mime = "utf-8";
  115. } else if (file_looks_utf8(buf, nbytes, *ubuf, ulen) > 1) {
  116. DPRINTF(("utf8 %" SIZE_T_FORMAT "u\n", *ulen));
  117. *code = "Unicode text, UTF-8";
  118. *code_mime = "utf-8";
  119. } else if ((ucs_type = looks_ucs32(buf, nbytes, *ubuf, ulen)) != 0) {
  120. if (ucs_type == 1) {
  121. *code = "Unicode text, UTF-32, little-endian";
  122. *code_mime = "utf-32le";
  123. } else {
  124. *code = "Unicode text, UTF-32, big-endian";
  125. *code_mime = "utf-32be";
  126. }
  127. DPRINTF(("ucs32 %" SIZE_T_FORMAT "u\n", *ulen));
  128. } else if ((ucs_type = looks_ucs16(buf, nbytes, *ubuf, ulen)) != 0) {
  129. if (ucs_type == 1) {
  130. *code = "Unicode text, UTF-16, little-endian";
  131. *code_mime = "utf-16le";
  132. } else {
  133. *code = "Unicode text, UTF-16, big-endian";
  134. *code_mime = "utf-16be";
  135. }
  136. DPRINTF(("ucs16 %" SIZE_T_FORMAT "u\n", *ulen));
  137. } else if (looks_latin1(buf, nbytes, *ubuf, ulen)) {
  138. DPRINTF(("latin1 %" SIZE_T_FORMAT "u\n", *ulen));
  139. *code = "ISO-8859";
  140. *code_mime = "iso-8859-1";
  141. } else if (looks_extended(buf, nbytes, *ubuf, ulen)) {
  142. DPRINTF(("extended %" SIZE_T_FORMAT "u\n", *ulen));
  143. *code = "Non-ISO extended-ASCII";
  144. *code_mime = "unknown-8bit";
  145. } else {
  146. from_ebcdic(buf, nbytes, nbuf);
  147. if (looks_ascii(nbuf, nbytes, *ubuf, ulen)) {
  148. DPRINTF(("ebcdic %" SIZE_T_FORMAT "u\n", *ulen));
  149. *code = "EBCDIC";
  150. *code_mime = "ebcdic";
  151. } else if (looks_latin1(nbuf, nbytes, *ubuf, ulen)) {
  152. DPRINTF(("ebcdic/international %" SIZE_T_FORMAT "u\n",
  153. *ulen));
  154. *code = "International EBCDIC";
  155. *code_mime = "ebcdic";
  156. } else { /* Doesn't look like text at all */
  157. DPRINTF(("binary\n"));
  158. rv = 0;
  159. *type = "binary";
  160. }
  161. }
  162. done:
  163. efree(nbuf);
  164. if (ubuf == &udefbuf)
  165. efree(udefbuf);
  166. return rv;
  167. }
  168. /*
  169. * This table reflects a particular philosophy about what constitutes
  170. * "text," and there is room for disagreement about it.
  171. *
  172. * Version 3.31 of the file command considered a file to be ASCII if
  173. * each of its characters was approved by either the isascii() or
  174. * isalpha() function. On most systems, this would mean that any
  175. * file consisting only of characters in the range 0x00 ... 0x7F
  176. * would be called ASCII text, but many systems might reasonably
  177. * consider some characters outside this range to be alphabetic,
  178. * so the file command would call such characters ASCII. It might
  179. * have been more accurate to call this "considered textual on the
  180. * local system" than "ASCII."
  181. *
  182. * It considered a file to be "International language text" if each
  183. * of its characters was either an ASCII printing character (according
  184. * to the real ASCII standard, not the above test), a character in
  185. * the range 0x80 ... 0xFF, or one of the following control characters:
  186. * backspace, tab, line feed, vertical tab, form feed, carriage return,
  187. * escape. No attempt was made to determine the language in which files
  188. * of this type were written.
  189. *
  190. *
  191. * The table below considers a file to be ASCII if all of its characters
  192. * are either ASCII printing characters (again, according to the X3.4
  193. * standard, not isascii()) or any of the following controls: bell,
  194. * backspace, tab, line feed, form feed, carriage return, esc, nextline.
  195. *
  196. * I include bell because some programs (particularly shell scripts)
  197. * use it literally, even though it is rare in normal text. I exclude
  198. * vertical tab because it never seems to be used in real text. I also
  199. * include, with hesitation, the X3.64/ECMA-43 control nextline (0x85),
  200. * because that's what the dd EBCDIC->ASCII table maps the EBCDIC newline
  201. * character to. It might be more appropriate to include it in the 8859
  202. * set instead of the ASCII set, but it's got to be included in *something*
  203. * we recognize or EBCDIC files aren't going to be considered textual.
  204. * Some old Unix source files use SO/SI (^N/^O) to shift between Greek
  205. * and Latin characters, so these should possibly be allowed. But they
  206. * make a real mess on VT100-style displays if they're not paired properly,
  207. * so we are probably better off not calling them text.
  208. *
  209. * A file is considered to be ISO-8859 text if its characters are all
  210. * either ASCII, according to the above definition, or printing characters
  211. * from the ISO-8859 8-bit extension, characters 0xA0 ... 0xFF.
  212. *
  213. * Finally, a file is considered to be international text from some other
  214. * character code if its characters are all either ISO-8859 (according to
  215. * the above definition) or characters in the range 0x80 ... 0x9F, which
  216. * ISO-8859 considers to be control characters but the IBM PC and Macintosh
  217. * consider to be printing characters.
  218. */
  219. #define F 0 /* character never appears in text */
  220. #define T 1 /* character appears in plain ASCII text */
  221. #define I 2 /* character appears in ISO-8859 text */
  222. #define X 3 /* character appears in non-ISO extended ASCII (Mac, IBM PC) */
  223. private char text_chars[256] = {
  224. /* BEL BS HT LF VT FF CR */
  225. F, F, F, F, F, F, F, T, T, T, T, T, T, T, F, F, /* 0x0X */
  226. /* ESC */
  227. F, F, F, F, F, F, F, F, F, F, F, T, F, F, F, F, /* 0x1X */
  228. T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x2X */
  229. T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x3X */
  230. T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x4X */
  231. T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x5X */
  232. T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x6X */
  233. T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, F, /* 0x7X */
  234. /* NEL */
  235. X, X, X, X, X, T, X, X, X, X, X, X, X, X, X, X, /* 0x8X */
  236. X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, /* 0x9X */
  237. I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xaX */
  238. I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xbX */
  239. I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xcX */
  240. I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xdX */
  241. I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xeX */
  242. I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I /* 0xfX */
  243. };
  244. #define LOOKS(NAME, COND) \
  245. private int \
  246. looks_ ## NAME(const unsigned char *buf, size_t nbytes, file_unichar_t *ubuf, \
  247. size_t *ulen) \
  248. { \
  249. size_t i, u; \
  250. unsigned char dist[256]; \
  251. memset(dist, 0, sizeof(dist)); \
  252. \
  253. *ulen = 0; \
  254. \
  255. for (i = 0; i < nbytes; i++) { \
  256. int t = text_chars[buf[i]]; \
  257. \
  258. if (COND) \
  259. return 0; \
  260. \
  261. ubuf[(*ulen)++] = buf[i]; \
  262. dist[buf[i]]++; \
  263. } \
  264. u = 0; \
  265. for (i = 0; i < __arraycount(dist); i++) { \
  266. if (dist[i]) \
  267. u += dist[i]; \
  268. } \
  269. if (u < 3) \
  270. return 0; \
  271. \
  272. return 1; \
  273. }
  274. LOOKS(ascii, t != T)
  275. LOOKS(latin1, t != T && t != I)
  276. LOOKS(extended, t != T && t != I && t != X)
  277. /*
  278. * Decide whether some text looks like UTF-8. Returns:
  279. *
  280. * -1: invalid UTF-8
  281. * 0: uses odd control characters, so doesn't look like text
  282. * 1: 7-bit text
  283. * 2: definitely UTF-8 text (valid high-bit set bytes)
  284. *
  285. * If ubuf is non-NULL on entry, text is decoded into ubuf, *ulen;
  286. * ubuf must be big enough!
  287. */
  288. // from: https://golang.org/src/unicode/utf8/utf8.go
  289. #define XX 0xF1 // invalid: size 1
  290. #define AS 0xF0 // ASCII: size 1
  291. #define S1 0x02 // accept 0, size 2
  292. #define S2 0x13 // accept 1, size 3
  293. #define S3 0x03 // accept 0, size 3
  294. #define S4 0x23 // accept 2, size 3
  295. #define S5 0x34 // accept 3, size 4
  296. #define S6 0x04 // accept 0, size 4
  297. #define S7 0x44 // accept 4, size 4
  298. #define LOCB 0x80
  299. #define HICB 0xBF
  300. // first is information about the first byte in a UTF-8 sequence.
  301. static const uint8_t first[] = {
  302. // 1 2 3 4 5 6 7 8 9 A B C D E F
  303. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x00-0x0F
  304. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x10-0x1F
  305. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x20-0x2F
  306. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x30-0x3F
  307. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x40-0x4F
  308. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x50-0x5F
  309. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x60-0x6F
  310. AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, AS, // 0x70-0x7F
  311. // 1 2 3 4 5 6 7 8 9 A B C D E F
  312. XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0x80-0x8F
  313. XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0x90-0x9F
  314. XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xA0-0xAF
  315. XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xB0-0xBF
  316. XX, XX, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, // 0xC0-0xCF
  317. S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, S1, // 0xD0-0xDF
  318. S2, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S3, S4, S3, S3, // 0xE0-0xEF
  319. S5, S6, S6, S6, S7, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0xF0-0xFF
  320. };
  321. // acceptRange gives the range of valid values for the second byte in a UTF-8
  322. // sequence.
  323. struct accept_range {
  324. uint8_t lo; // lowest value for second byte.
  325. uint8_t hi; // highest value for second byte.
  326. } accept_ranges[16] = {
  327. // acceptRanges has size 16 to avoid bounds checks in the code that uses it.
  328. { LOCB, HICB },
  329. { 0xA0, HICB },
  330. { LOCB, 0x9F },
  331. { 0x90, HICB },
  332. { LOCB, 0x8F },
  333. };
  334. protected int
  335. file_looks_utf8(const unsigned char *buf, size_t nbytes, file_unichar_t *ubuf,
  336. size_t *ulen)
  337. {
  338. size_t i;
  339. int n;
  340. file_unichar_t c;
  341. int gotone = 0, ctrl = 0;
  342. if (ubuf)
  343. *ulen = 0;
  344. for (i = 0; i < nbytes; i++) {
  345. if ((buf[i] & 0x80) == 0) { /* 0xxxxxxx is plain ASCII */
  346. /*
  347. * Even if the whole file is valid UTF-8 sequences,
  348. * still reject it if it uses weird control characters.
  349. */
  350. if (text_chars[buf[i]] != T)
  351. ctrl = 1;
  352. if (ubuf)
  353. ubuf[(*ulen)++] = buf[i];
  354. } else if ((buf[i] & 0x40) == 0) { /* 10xxxxxx never 1st byte */
  355. return -1;
  356. } else { /* 11xxxxxx begins UTF-8 */
  357. int following;
  358. uint8_t x = first[buf[i]];
  359. const struct accept_range *ar = &accept_ranges[x >> 4];
  360. if (x == XX)
  361. return -1;
  362. if ((buf[i] & 0x20) == 0) { /* 110xxxxx */
  363. c = buf[i] & 0x1f;
  364. following = 1;
  365. } else if ((buf[i] & 0x10) == 0) { /* 1110xxxx */
  366. c = buf[i] & 0x0f;
  367. following = 2;
  368. } else if ((buf[i] & 0x08) == 0) { /* 11110xxx */
  369. c = buf[i] & 0x07;
  370. following = 3;
  371. } else if ((buf[i] & 0x04) == 0) { /* 111110xx */
  372. c = buf[i] & 0x03;
  373. following = 4;
  374. } else if ((buf[i] & 0x02) == 0) { /* 1111110x */
  375. c = buf[i] & 0x01;
  376. following = 5;
  377. } else
  378. return -1;
  379. for (n = 0; n < following; n++) {
  380. i++;
  381. if (i >= nbytes)
  382. goto done;
  383. if (n == 0 &&
  384. (buf[i] < ar->lo || buf[i] > ar->hi))
  385. return -1;
  386. if ((buf[i] & 0x80) == 0 || (buf[i] & 0x40))
  387. return -1;
  388. c = (c << 6) + (buf[i] & 0x3f);
  389. }
  390. if (ubuf)
  391. ubuf[(*ulen)++] = c;
  392. gotone = 1;
  393. }
  394. }
  395. done:
  396. return ctrl ? 0 : (gotone ? 2 : 1);
  397. }
  398. /*
  399. * Decide whether some text looks like UTF-8 with BOM. If there is no
  400. * BOM, return -1; otherwise return the result of looks_utf8 on the
  401. * rest of the text.
  402. */
  403. private int
  404. looks_utf8_with_BOM(const unsigned char *buf, size_t nbytes,
  405. file_unichar_t *ubuf, size_t *ulen)
  406. {
  407. if (nbytes > 3 && buf[0] == 0xef && buf[1] == 0xbb && buf[2] == 0xbf)
  408. return file_looks_utf8(buf + 3, nbytes - 3, ubuf, ulen);
  409. else
  410. return -1;
  411. }
  412. private int
  413. looks_utf7(const unsigned char *buf, size_t nbytes, file_unichar_t *ubuf,
  414. size_t *ulen)
  415. {
  416. if (nbytes > 4 && buf[0] == '+' && buf[1] == '/' && buf[2] == 'v')
  417. switch (buf[3]) {
  418. case '8':
  419. case '9':
  420. case '+':
  421. case '/':
  422. if (ubuf)
  423. *ulen = 0;
  424. return 1;
  425. default:
  426. return -1;
  427. }
  428. else
  429. return -1;
  430. }
  431. private int
  432. looks_ucs16(const unsigned char *bf, size_t nbytes, file_unichar_t *ubf,
  433. size_t *ulen)
  434. {
  435. int bigend;
  436. size_t i;
  437. if (nbytes < 2)
  438. return 0;
  439. if (bf[0] == 0xff && bf[1] == 0xfe)
  440. bigend = 0;
  441. else if (bf[0] == 0xfe && bf[1] == 0xff)
  442. bigend = 1;
  443. else
  444. return 0;
  445. *ulen = 0;
  446. for (i = 2; i + 1 < nbytes; i += 2) {
  447. /* XXX fix to properly handle chars > 65536 */
  448. if (bigend)
  449. ubf[(*ulen)++] = bf[i + 1]
  450. | (CAST(file_unichar_t, bf[i]) << 8);
  451. else
  452. ubf[(*ulen)++] = bf[i]
  453. | (CAST(file_unichar_t, bf[i + 1]) << 8);
  454. if (ubf[*ulen - 1] == 0xfffe)
  455. return 0;
  456. if (ubf[*ulen - 1] < 128 &&
  457. text_chars[CAST(size_t, ubf[*ulen - 1])] != T)
  458. return 0;
  459. }
  460. return 1 + bigend;
  461. }
  462. private int
  463. looks_ucs32(const unsigned char *bf, size_t nbytes, file_unichar_t *ubf,
  464. size_t *ulen)
  465. {
  466. int bigend;
  467. size_t i;
  468. if (nbytes < 4)
  469. return 0;
  470. if (bf[0] == 0xff && bf[1] == 0xfe && bf[2] == 0 && bf[3] == 0)
  471. bigend = 0;
  472. else if (bf[0] == 0 && bf[1] == 0 && bf[2] == 0xfe && bf[3] == 0xff)
  473. bigend = 1;
  474. else
  475. return 0;
  476. *ulen = 0;
  477. for (i = 4; i + 3 < nbytes; i += 4) {
  478. /* XXX fix to properly handle chars > 65536 */
  479. if (bigend)
  480. ubf[(*ulen)++] = CAST(file_unichar_t, bf[i + 3])
  481. | (CAST(file_unichar_t, bf[i + 2]) << 8)
  482. | (CAST(file_unichar_t, bf[i + 1]) << 16)
  483. | (CAST(file_unichar_t, bf[i]) << 24);
  484. else
  485. ubf[(*ulen)++] = CAST(file_unichar_t, bf[i + 0])
  486. | (CAST(file_unichar_t, bf[i + 1]) << 8)
  487. | (CAST(file_unichar_t, bf[i + 2]) << 16)
  488. | (CAST(file_unichar_t, bf[i + 3]) << 24);
  489. if (ubf[*ulen - 1] == 0xfffe)
  490. return 0;
  491. if (ubf[*ulen - 1] < 128 &&
  492. text_chars[CAST(size_t, ubf[*ulen - 1])] != T)
  493. return 0;
  494. }
  495. return 1 + bigend;
  496. }
  497. #undef F
  498. #undef T
  499. #undef I
  500. #undef X
  501. /*
  502. * This table maps each EBCDIC character to an (8-bit extended) ASCII
  503. * character, as specified in the rationale for the dd(1) command in
  504. * draft 11.2 (September, 1991) of the POSIX P1003.2 standard.
  505. *
  506. * Unfortunately it does not seem to correspond exactly to any of the
  507. * five variants of EBCDIC documented in IBM's _Enterprise Systems
  508. * Architecture/390: Principles of Operation_, SA22-7201-06, Seventh
  509. * Edition, July, 1999, pp. I-1 - I-4.
  510. *
  511. * Fortunately, though, all versions of EBCDIC, including this one, agree
  512. * on most of the printing characters that also appear in (7-bit) ASCII.
  513. * Of these, only '|', '!', '~', '^', '[', and ']' are in question at all.
  514. *
  515. * Fortunately too, there is general agreement that codes 0x00 through
  516. * 0x3F represent control characters, 0x41 a nonbreaking space, and the
  517. * remainder printing characters.
  518. *
  519. * This is sufficient to allow us to identify EBCDIC text and to distinguish
  520. * between old-style and internationalized examples of text.
  521. */
  522. private unsigned char ebcdic_to_ascii[] = {
  523. 0, 1, 2, 3, 156, 9, 134, 127, 151, 141, 142, 11, 12, 13, 14, 15,
  524. 16, 17, 18, 19, 157, 133, 8, 135, 24, 25, 146, 143, 28, 29, 30, 31,
  525. 128, 129, 130, 131, 132, 10, 23, 27, 136, 137, 138, 139, 140, 5, 6, 7,
  526. 144, 145, 22, 147, 148, 149, 150, 4, 152, 153, 154, 155, 20, 21, 158, 26,
  527. ' ', 160, 161, 162, 163, 164, 165, 166, 167, 168, 213, '.', '<', '(', '+', '|',
  528. '&', 169, 170, 171, 172, 173, 174, 175, 176, 177, '!', '$', '*', ')', ';', '~',
  529. '-', '/', 178, 179, 180, 181, 182, 183, 184, 185, 203, ',', '%', '_', '>', '?',
  530. 186, 187, 188, 189, 190, 191, 192, 193, 194, '`', ':', '#', '@', '\'','=', '"',
  531. 195, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 196, 197, 198, 199, 200, 201,
  532. 202, 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', '^', 204, 205, 206, 207, 208,
  533. 209, 229, 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 210, 211, 212, '[', 214, 215,
  534. 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, ']', 230, 231,
  535. '{', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 232, 233, 234, 235, 236, 237,
  536. '}', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 238, 239, 240, 241, 242, 243,
  537. '\\',159, 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 244, 245, 246, 247, 248, 249,
  538. '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 250, 251, 252, 253, 254, 255
  539. };
  540. #ifdef notdef
  541. /*
  542. * The following EBCDIC-to-ASCII table may relate more closely to reality,
  543. * or at least to modern reality. It comes from
  544. *
  545. * http://ftp.s390.ibm.com/products/oe/bpxqp9.html
  546. *
  547. * and maps the characters of EBCDIC code page 1047 (the code used for
  548. * Unix-derived software on IBM's 390 systems) to the corresponding
  549. * characters from ISO 8859-1.
  550. *
  551. * If this table is used instead of the above one, some of the special
  552. * cases for the NEL character can be taken out of the code.
  553. */
  554. private unsigned char ebcdic_1047_to_8859[] = {
  555. 0x00,0x01,0x02,0x03,0x9C,0x09,0x86,0x7F,0x97,0x8D,0x8E,0x0B,0x0C,0x0D,0x0E,0x0F,
  556. 0x10,0x11,0x12,0x13,0x9D,0x0A,0x08,0x87,0x18,0x19,0x92,0x8F,0x1C,0x1D,0x1E,0x1F,
  557. 0x80,0x81,0x82,0x83,0x84,0x85,0x17,0x1B,0x88,0x89,0x8A,0x8B,0x8C,0x05,0x06,0x07,
  558. 0x90,0x91,0x16,0x93,0x94,0x95,0x96,0x04,0x98,0x99,0x9A,0x9B,0x14,0x15,0x9E,0x1A,
  559. 0x20,0xA0,0xE2,0xE4,0xE0,0xE1,0xE3,0xE5,0xE7,0xF1,0xA2,0x2E,0x3C,0x28,0x2B,0x7C,
  560. 0x26,0xE9,0xEA,0xEB,0xE8,0xED,0xEE,0xEF,0xEC,0xDF,0x21,0x24,0x2A,0x29,0x3B,0x5E,
  561. 0x2D,0x2F,0xC2,0xC4,0xC0,0xC1,0xC3,0xC5,0xC7,0xD1,0xA6,0x2C,0x25,0x5F,0x3E,0x3F,
  562. 0xF8,0xC9,0xCA,0xCB,0xC8,0xCD,0xCE,0xCF,0xCC,0x60,0x3A,0x23,0x40,0x27,0x3D,0x22,
  563. 0xD8,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0xAB,0xBB,0xF0,0xFD,0xFE,0xB1,
  564. 0xB0,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,0x70,0x71,0x72,0xAA,0xBA,0xE6,0xB8,0xC6,0xA4,
  565. 0xB5,0x7E,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0xA1,0xBF,0xD0,0x5B,0xDE,0xAE,
  566. 0xAC,0xA3,0xA5,0xB7,0xA9,0xA7,0xB6,0xBC,0xBD,0xBE,0xDD,0xA8,0xAF,0x5D,0xB4,0xD7,
  567. 0x7B,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0xAD,0xF4,0xF6,0xF2,0xF3,0xF5,
  568. 0x7D,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,0x50,0x51,0x52,0xB9,0xFB,0xFC,0xF9,0xFA,0xFF,
  569. 0x5C,0xF7,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0xB2,0xD4,0xD6,0xD2,0xD3,0xD5,
  570. 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0xB3,0xDB,0xDC,0xD9,0xDA,0x9F
  571. };
  572. #endif
  573. /*
  574. * Copy buf[0 ... nbytes-1] into out[], translating EBCDIC to ASCII.
  575. */
  576. private void
  577. from_ebcdic(const unsigned char *buf, size_t nbytes, unsigned char *out)
  578. {
  579. size_t i;
  580. for (i = 0; i < nbytes; i++) {
  581. out[i] = ebcdic_to_ascii[buf[i]];
  582. }
  583. }