diff options
author | delphij <delphij@FreeBSD.org> | 2014-06-26 06:03:39 +0000 |
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committer | delphij <delphij@FreeBSD.org> | 2014-06-26 06:03:39 +0000 |
commit | cd5514ba3b318b16aa00b1048bf9160a9f28fb35 (patch) | |
tree | 5b4f7850752944df750e0c678951b78d9484b67e /contrib/file/src/encoding.c | |
parent | 8b39363d0d5f3d274de63dac41aaba59cdf00cdb (diff) | |
parent | 02573f2d7154bbe159ba99728d5db9be8a29bd9b (diff) | |
download | FreeBSD-src-cd5514ba3b318b16aa00b1048bf9160a9f28fb35.zip FreeBSD-src-cd5514ba3b318b16aa00b1048bf9160a9f28fb35.tar.gz |
MFV r267843: update file/libmagic to 5.19.
MFC after: 2 weeks
Diffstat (limited to 'contrib/file/src/encoding.c')
-rw-r--r-- | contrib/file/src/encoding.c | 504 |
1 files changed, 504 insertions, 0 deletions
diff --git a/contrib/file/src/encoding.c b/contrib/file/src/encoding.c new file mode 100644 index 0000000..b75e0cc --- /dev/null +++ b/contrib/file/src/encoding.c @@ -0,0 +1,504 @@ +/* + * Copyright (c) Ian F. Darwin 1986-1995. + * Software written by Ian F. Darwin and others; + * maintained 1995-present by Christos Zoulas and others. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice immediately at the beginning of the file, without modification, + * this list of conditions, and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR + * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ +/* + * Encoding -- determine the character encoding of a text file. + * + * Joerg Wunsch <joerg@freebsd.org> wrote the original support for 8-bit + * international characters. + */ + +#include "file.h" + +#ifndef lint +FILE_RCSID("@(#)$File: encoding.c,v 1.9 2013/11/19 20:45:50 christos Exp $") +#endif /* lint */ + +#include "magic.h" +#include <string.h> +#include <memory.h> +#include <stdlib.h> + + +private int looks_ascii(const unsigned char *, size_t, unichar *, size_t *); +private int looks_utf8_with_BOM(const unsigned char *, size_t, unichar *, + size_t *); +private int looks_ucs16(const unsigned char *, size_t, unichar *, size_t *); +private int looks_latin1(const unsigned char *, size_t, unichar *, size_t *); +private int looks_extended(const unsigned char *, size_t, unichar *, size_t *); +private void from_ebcdic(const unsigned char *, size_t, unsigned char *); + +#ifdef DEBUG_ENCODING +#define DPRINTF(a) printf a +#else +#define DPRINTF(a) +#endif + +/* + * Try to determine whether text is in some character code we can + * identify. Each of these tests, if it succeeds, will leave + * the text converted into one-unichar-per-character Unicode in + * ubuf, and the number of characters converted in ulen. + */ +protected int +file_encoding(struct magic_set *ms, const unsigned char *buf, size_t nbytes, unichar **ubuf, size_t *ulen, const char **code, const char **code_mime, const char **type) +{ + size_t mlen; + int rv = 1, ucs_type; + unsigned char *nbuf = NULL; + + *type = "text"; + *ulen = 0; + *code = "unknown"; + *code_mime = "binary"; + + mlen = (nbytes + 1) * sizeof((*ubuf)[0]); + if ((*ubuf = CAST(unichar *, calloc((size_t)1, mlen))) == NULL) { + file_oomem(ms, mlen); + goto done; + } + mlen = (nbytes + 1) * sizeof(nbuf[0]); + if ((nbuf = CAST(unsigned char *, calloc((size_t)1, mlen))) == NULL) { + file_oomem(ms, mlen); + goto done; + } + + if (looks_ascii(buf, nbytes, *ubuf, ulen)) { + DPRINTF(("ascii %" SIZE_T_FORMAT "u\n", *ulen)); + *code = "ASCII"; + *code_mime = "us-ascii"; + } else if (looks_utf8_with_BOM(buf, nbytes, *ubuf, ulen) > 0) { + DPRINTF(("utf8/bom %" SIZE_T_FORMAT "u\n", *ulen)); + *code = "UTF-8 Unicode (with BOM)"; + *code_mime = "utf-8"; + } else if (file_looks_utf8(buf, nbytes, *ubuf, ulen) > 1) { + DPRINTF(("utf8 %" SIZE_T_FORMAT "u\n", *ulen)); + *code = "UTF-8 Unicode (with BOM)"; + *code = "UTF-8 Unicode"; + *code_mime = "utf-8"; + } else if ((ucs_type = looks_ucs16(buf, nbytes, *ubuf, ulen)) != 0) { + if (ucs_type == 1) { + *code = "Little-endian UTF-16 Unicode"; + *code_mime = "utf-16le"; + } else { + *code = "Big-endian UTF-16 Unicode"; + *code_mime = "utf-16be"; + } + DPRINTF(("ucs16 %" SIZE_T_FORMAT "u\n", *ulen)); + } else if (looks_latin1(buf, nbytes, *ubuf, ulen)) { + DPRINTF(("latin1 %" SIZE_T_FORMAT "u\n", *ulen)); + *code = "ISO-8859"; + *code_mime = "iso-8859-1"; + } else if (looks_extended(buf, nbytes, *ubuf, ulen)) { + DPRINTF(("extended %" SIZE_T_FORMAT "u\n", *ulen)); + *code = "Non-ISO extended-ASCII"; + *code_mime = "unknown-8bit"; + } else { + from_ebcdic(buf, nbytes, nbuf); + + if (looks_ascii(nbuf, nbytes, *ubuf, ulen)) { + DPRINTF(("ebcdic %" SIZE_T_FORMAT "u\n", *ulen)); + *code = "EBCDIC"; + *code_mime = "ebcdic"; + } else if (looks_latin1(nbuf, nbytes, *ubuf, ulen)) { + DPRINTF(("ebcdic/international %" SIZE_T_FORMAT "u\n", + *ulen)); + *code = "International EBCDIC"; + *code_mime = "ebcdic"; + } else { /* Doesn't look like text at all */ + DPRINTF(("binary\n")); + rv = 0; + *type = "binary"; + } + } + + done: + free(nbuf); + + return rv; +} + +/* + * This table reflects a particular philosophy about what constitutes + * "text," and there is room for disagreement about it. + * + * Version 3.31 of the file command considered a file to be ASCII if + * each of its characters was approved by either the isascii() or + * isalpha() function. On most systems, this would mean that any + * file consisting only of characters in the range 0x00 ... 0x7F + * would be called ASCII text, but many systems might reasonably + * consider some characters outside this range to be alphabetic, + * so the file command would call such characters ASCII. It might + * have been more accurate to call this "considered textual on the + * local system" than "ASCII." + * + * It considered a file to be "International language text" if each + * of its characters was either an ASCII printing character (according + * to the real ASCII standard, not the above test), a character in + * the range 0x80 ... 0xFF, or one of the following control characters: + * backspace, tab, line feed, vertical tab, form feed, carriage return, + * escape. No attempt was made to determine the language in which files + * of this type were written. + * + * + * The table below considers a file to be ASCII if all of its characters + * are either ASCII printing characters (again, according to the X3.4 + * standard, not isascii()) or any of the following controls: bell, + * backspace, tab, line feed, form feed, carriage return, esc, nextline. + * + * I include bell because some programs (particularly shell scripts) + * use it literally, even though it is rare in normal text. I exclude + * vertical tab because it never seems to be used in real text. I also + * include, with hesitation, the X3.64/ECMA-43 control nextline (0x85), + * because that's what the dd EBCDIC->ASCII table maps the EBCDIC newline + * character to. It might be more appropriate to include it in the 8859 + * set instead of the ASCII set, but it's got to be included in *something* + * we recognize or EBCDIC files aren't going to be considered textual. + * Some old Unix source files use SO/SI (^N/^O) to shift between Greek + * and Latin characters, so these should possibly be allowed. But they + * make a real mess on VT100-style displays if they're not paired properly, + * so we are probably better off not calling them text. + * + * A file is considered to be ISO-8859 text if its characters are all + * either ASCII, according to the above definition, or printing characters + * from the ISO-8859 8-bit extension, characters 0xA0 ... 0xFF. + * + * Finally, a file is considered to be international text from some other + * character code if its characters are all either ISO-8859 (according to + * the above definition) or characters in the range 0x80 ... 0x9F, which + * ISO-8859 considers to be control characters but the IBM PC and Macintosh + * consider to be printing characters. + */ + +#define F 0 /* character never appears in text */ +#define T 1 /* character appears in plain ASCII text */ +#define I 2 /* character appears in ISO-8859 text */ +#define X 3 /* character appears in non-ISO extended ASCII (Mac, IBM PC) */ + +private char text_chars[256] = { + /* BEL BS HT LF FF CR */ + F, F, F, F, F, F, F, T, T, T, T, F, T, T, F, F, /* 0x0X */ + /* ESC */ + F, F, F, F, F, F, F, F, F, F, F, T, F, F, F, F, /* 0x1X */ + T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x2X */ + T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x3X */ + T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x4X */ + T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x5X */ + T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, /* 0x6X */ + T, T, T, T, T, T, T, T, T, T, T, T, T, T, T, F, /* 0x7X */ + /* NEL */ + X, X, X, X, X, T, X, X, X, X, X, X, X, X, X, X, /* 0x8X */ + X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, X, /* 0x9X */ + I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xaX */ + I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xbX */ + I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xcX */ + I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xdX */ + I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, /* 0xeX */ + I, I, I, I, I, I, I, I, I, I, I, I, I, I, I, I /* 0xfX */ +}; + +private int +looks_ascii(const unsigned char *buf, size_t nbytes, unichar *ubuf, + size_t *ulen) +{ + size_t i; + + *ulen = 0; + + for (i = 0; i < nbytes; i++) { + int t = text_chars[buf[i]]; + + if (t != T) + return 0; + + ubuf[(*ulen)++] = buf[i]; + } + + return 1; +} + +private int +looks_latin1(const unsigned char *buf, size_t nbytes, unichar *ubuf, size_t *ulen) +{ + size_t i; + + *ulen = 0; + + for (i = 0; i < nbytes; i++) { + int t = text_chars[buf[i]]; + + if (t != T && t != I) + return 0; + + ubuf[(*ulen)++] = buf[i]; + } + + return 1; +} + +private int +looks_extended(const unsigned char *buf, size_t nbytes, unichar *ubuf, + size_t *ulen) +{ + size_t i; + + *ulen = 0; + + for (i = 0; i < nbytes; i++) { + int t = text_chars[buf[i]]; + + if (t != T && t != I && t != X) + return 0; + + ubuf[(*ulen)++] = buf[i]; + } + + return 1; +} + +/* + * Decide whether some text looks like UTF-8. Returns: + * + * -1: invalid UTF-8 + * 0: uses odd control characters, so doesn't look like text + * 1: 7-bit text + * 2: definitely UTF-8 text (valid high-bit set bytes) + * + * If ubuf is non-NULL on entry, text is decoded into ubuf, *ulen; + * ubuf must be big enough! + */ +protected int +file_looks_utf8(const unsigned char *buf, size_t nbytes, unichar *ubuf, size_t *ulen) +{ + size_t i; + int n; + unichar c; + int gotone = 0, ctrl = 0; + + if (ubuf) + *ulen = 0; + + for (i = 0; i < nbytes; i++) { + if ((buf[i] & 0x80) == 0) { /* 0xxxxxxx is plain ASCII */ + /* + * Even if the whole file is valid UTF-8 sequences, + * still reject it if it uses weird control characters. + */ + + if (text_chars[buf[i]] != T) + ctrl = 1; + + if (ubuf) + ubuf[(*ulen)++] = buf[i]; + } else if ((buf[i] & 0x40) == 0) { /* 10xxxxxx never 1st byte */ + return -1; + } else { /* 11xxxxxx begins UTF-8 */ + int following; + + if ((buf[i] & 0x20) == 0) { /* 110xxxxx */ + c = buf[i] & 0x1f; + following = 1; + } else if ((buf[i] & 0x10) == 0) { /* 1110xxxx */ + c = buf[i] & 0x0f; + following = 2; + } else if ((buf[i] & 0x08) == 0) { /* 11110xxx */ + c = buf[i] & 0x07; + following = 3; + } else if ((buf[i] & 0x04) == 0) { /* 111110xx */ + c = buf[i] & 0x03; + following = 4; + } else if ((buf[i] & 0x02) == 0) { /* 1111110x */ + c = buf[i] & 0x01; + following = 5; + } else + return -1; + + for (n = 0; n < following; n++) { + i++; + if (i >= nbytes) + goto done; + + if ((buf[i] & 0x80) == 0 || (buf[i] & 0x40)) + return -1; + + c = (c << 6) + (buf[i] & 0x3f); + } + + if (ubuf) + ubuf[(*ulen)++] = c; + gotone = 1; + } + } +done: + return ctrl ? 0 : (gotone ? 2 : 1); +} + +/* + * Decide whether some text looks like UTF-8 with BOM. If there is no + * BOM, return -1; otherwise return the result of looks_utf8 on the + * rest of the text. + */ +private int +looks_utf8_with_BOM(const unsigned char *buf, size_t nbytes, unichar *ubuf, + size_t *ulen) +{ + if (nbytes > 3 && buf[0] == 0xef && buf[1] == 0xbb && buf[2] == 0xbf) + return file_looks_utf8(buf + 3, nbytes - 3, ubuf, ulen); + else + return -1; +} + +private int +looks_ucs16(const unsigned char *buf, size_t nbytes, unichar *ubuf, + size_t *ulen) +{ + int bigend; + size_t i; + + if (nbytes < 2) + return 0; + + if (buf[0] == 0xff && buf[1] == 0xfe) + bigend = 0; + else if (buf[0] == 0xfe && buf[1] == 0xff) + bigend = 1; + else + return 0; + + *ulen = 0; + + for (i = 2; i + 1 < nbytes; i += 2) { + /* XXX fix to properly handle chars > 65536 */ + + if (bigend) + ubuf[(*ulen)++] = buf[i + 1] + 256 * buf[i]; + else + ubuf[(*ulen)++] = buf[i] + 256 * buf[i + 1]; + + if (ubuf[*ulen - 1] == 0xfffe) + return 0; + if (ubuf[*ulen - 1] < 128 && + text_chars[(size_t)ubuf[*ulen - 1]] != T) + return 0; + } + + return 1 + bigend; +} + +#undef F +#undef T +#undef I +#undef X + +/* + * This table maps each EBCDIC character to an (8-bit extended) ASCII + * character, as specified in the rationale for the dd(1) command in + * draft 11.2 (September, 1991) of the POSIX P1003.2 standard. + * + * Unfortunately it does not seem to correspond exactly to any of the + * five variants of EBCDIC documented in IBM's _Enterprise Systems + * Architecture/390: Principles of Operation_, SA22-7201-06, Seventh + * Edition, July, 1999, pp. I-1 - I-4. + * + * Fortunately, though, all versions of EBCDIC, including this one, agree + * on most of the printing characters that also appear in (7-bit) ASCII. + * Of these, only '|', '!', '~', '^', '[', and ']' are in question at all. + * + * Fortunately too, there is general agreement that codes 0x00 through + * 0x3F represent control characters, 0x41 a nonbreaking space, and the + * remainder printing characters. + * + * This is sufficient to allow us to identify EBCDIC text and to distinguish + * between old-style and internationalized examples of text. + */ + +private unsigned char ebcdic_to_ascii[] = { + 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, +' ', 160, 161, 162, 163, 164, 165, 166, 167, 168, 213, '.', '<', '(', '+', '|', +'&', 169, 170, 171, 172, 173, 174, 175, 176, 177, '!', '$', '*', ')', ';', '~', +'-', '/', 178, 179, 180, 181, 182, 183, 184, 185, 203, ',', '%', '_', '>', '?', +186, 187, 188, 189, 190, 191, 192, 193, 194, '`', ':', '#', '@', '\'','=', '"', +195, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 196, 197, 198, 199, 200, 201, +202, 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', '^', 204, 205, 206, 207, 208, +209, 229, 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 210, 211, 212, '[', 214, 215, +216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, ']', 230, 231, +'{', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 232, 233, 234, 235, 236, 237, +'}', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 238, 239, 240, 241, 242, 243, +'\\',159, 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 244, 245, 246, 247, 248, 249, +'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 250, 251, 252, 253, 254, 255 +}; + +#ifdef notdef +/* + * The following EBCDIC-to-ASCII table may relate more closely to reality, + * or at least to modern reality. It comes from + * + * http://ftp.s390.ibm.com/products/oe/bpxqp9.html + * + * and maps the characters of EBCDIC code page 1047 (the code used for + * Unix-derived software on IBM's 390 systems) to the corresponding + * characters from ISO 8859-1. + * + * If this table is used instead of the above one, some of the special + * cases for the NEL character can be taken out of the code. + */ + +private unsigned char ebcdic_1047_to_8859[] = { +0x00,0x01,0x02,0x03,0x9C,0x09,0x86,0x7F,0x97,0x8D,0x8E,0x0B,0x0C,0x0D,0x0E,0x0F, +0x10,0x11,0x12,0x13,0x9D,0x0A,0x08,0x87,0x18,0x19,0x92,0x8F,0x1C,0x1D,0x1E,0x1F, +0x80,0x81,0x82,0x83,0x84,0x85,0x17,0x1B,0x88,0x89,0x8A,0x8B,0x8C,0x05,0x06,0x07, +0x90,0x91,0x16,0x93,0x94,0x95,0x96,0x04,0x98,0x99,0x9A,0x9B,0x14,0x15,0x9E,0x1A, +0x20,0xA0,0xE2,0xE4,0xE0,0xE1,0xE3,0xE5,0xE7,0xF1,0xA2,0x2E,0x3C,0x28,0x2B,0x7C, +0x26,0xE9,0xEA,0xEB,0xE8,0xED,0xEE,0xEF,0xEC,0xDF,0x21,0x24,0x2A,0x29,0x3B,0x5E, +0x2D,0x2F,0xC2,0xC4,0xC0,0xC1,0xC3,0xC5,0xC7,0xD1,0xA6,0x2C,0x25,0x5F,0x3E,0x3F, +0xF8,0xC9,0xCA,0xCB,0xC8,0xCD,0xCE,0xCF,0xCC,0x60,0x3A,0x23,0x40,0x27,0x3D,0x22, +0xD8,0x61,0x62,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0xAB,0xBB,0xF0,0xFD,0xFE,0xB1, +0xB0,0x6A,0x6B,0x6C,0x6D,0x6E,0x6F,0x70,0x71,0x72,0xAA,0xBA,0xE6,0xB8,0xC6,0xA4, +0xB5,0x7E,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0xA1,0xBF,0xD0,0x5B,0xDE,0xAE, +0xAC,0xA3,0xA5,0xB7,0xA9,0xA7,0xB6,0xBC,0xBD,0xBE,0xDD,0xA8,0xAF,0x5D,0xB4,0xD7, +0x7B,0x41,0x42,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0xAD,0xF4,0xF6,0xF2,0xF3,0xF5, +0x7D,0x4A,0x4B,0x4C,0x4D,0x4E,0x4F,0x50,0x51,0x52,0xB9,0xFB,0xFC,0xF9,0xFA,0xFF, +0x5C,0xF7,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0xB2,0xD4,0xD6,0xD2,0xD3,0xD5, +0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,0xB3,0xDB,0xDC,0xD9,0xDA,0x9F +}; +#endif + +/* + * Copy buf[0 ... nbytes-1] into out[], translating EBCDIC to ASCII. + */ +private void +from_ebcdic(const unsigned char *buf, size_t nbytes, unsigned char *out) +{ + size_t i; + + for (i = 0; i < nbytes; i++) { + out[i] = ebcdic_to_ascii[buf[i]]; + } +} |