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Diffstat (limited to 'src/grep/lib/localeinfo.c')
| -rw-r--r-- | src/grep/lib/localeinfo.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/grep/lib/localeinfo.c b/src/grep/lib/localeinfo.c new file mode 100644 index 0000000..4996018 --- /dev/null +++ b/src/grep/lib/localeinfo.c @@ -0,0 +1,151 @@ +/* locale information + + Copyright 2016-2021 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA + 02110-1301, USA. */ + +/* Written by Paul Eggert. */ + +#include <config.h> + +#include <localeinfo.h> + +#include <verify.h> + +#include <limits.h> +#include <locale.h> +#include <stdlib.h> +#include <string.h> +#include <wctype.h> + +/* The sbclen implementation relies on this. */ +verify (MB_LEN_MAX <= SCHAR_MAX); + +/* Return true if the locale uses UTF-8. */ + +static bool +is_using_utf8 (void) +{ + wchar_t wc; + mbstate_t mbs = {0}; + return mbrtowc (&wc, "\xc4\x80", 2, &mbs) == 2 && wc == 0x100; +} + +/* Return true if the locale is compatible enough with the C locale so + that the locale is single-byte, bytes are in collating-sequence + order, and there are no multi-character collating elements. */ + +static bool +using_simple_locale (bool multibyte) +{ + /* The native character set is known to be compatible with + the C locale. The following test isn't perfect, but it's good + enough in practice, as only ASCII and EBCDIC are in common use + and this test correctly accepts ASCII and rejects EBCDIC. */ + enum { native_c_charset = + ('\b' == 8 && '\t' == 9 && '\n' == 10 && '\v' == 11 && '\f' == 12 + && '\r' == 13 && ' ' == 32 && '!' == 33 && '"' == 34 && '#' == 35 + && '%' == 37 && '&' == 38 && '\'' == 39 && '(' == 40 && ')' == 41 + && '*' == 42 && '+' == 43 && ',' == 44 && '-' == 45 && '.' == 46 + && '/' == 47 && '0' == 48 && '9' == 57 && ':' == 58 && ';' == 59 + && '<' == 60 && '=' == 61 && '>' == 62 && '?' == 63 && 'A' == 65 + && 'Z' == 90 && '[' == 91 && '\\' == 92 && ']' == 93 && '^' == 94 + && '_' == 95 && 'a' == 97 && 'z' == 122 && '{' == 123 && '|' == 124 + && '}' == 125 && '~' == 126) + }; + + if (!native_c_charset || multibyte) + return false; + + /* As a heuristic, use strcoll to compare native character order. + If this agrees with byte order the locale should be simple. + This heuristic should work for all known practical locales, + although it would be invalid for artificially-constructed locales + where the native order is the collating-sequence order but there + are multi-character collating elements. */ + for (int i = 0; i < UCHAR_MAX; i++) + if (0 <= strcoll (((char []) {i, 0}), ((char []) {i + 1, 0}))) + return false; + + return true; +} + +/* Initialize *LOCALEINFO from the current locale. */ + +void +init_localeinfo (struct localeinfo *localeinfo) +{ + localeinfo->multibyte = MB_CUR_MAX > 1; + localeinfo->simple = using_simple_locale (localeinfo->multibyte); + localeinfo->using_utf8 = is_using_utf8 (); + + for (int i = CHAR_MIN; i <= CHAR_MAX; i++) + { + char c = i; + unsigned char uc = i; + mbstate_t s = {0}; + wchar_t wc; + size_t len = mbrtowc (&wc, &c, 1, &s); + localeinfo->sbclen[uc] = len <= 1 ? 1 : - (int) - len; + localeinfo->sbctowc[uc] = len <= 1 ? wc : WEOF; + } +} + +/* The set of wchar_t values C such that there's a useful locale + somewhere where C != towupper (C) && C != towlower (towupper (C)). + For example, 0x00B5 (U+00B5 MICRO SIGN) is in this table, because + towupper (0x00B5) == 0x039C (U+039C GREEK CAPITAL LETTER MU), and + towlower (0x039C) == 0x03BC (U+03BC GREEK SMALL LETTER MU). */ +static short const lonesome_lower[] = + { + 0x00B5, 0x0131, 0x017F, 0x01C5, 0x01C8, 0x01CB, 0x01F2, 0x0345, + 0x03C2, 0x03D0, 0x03D1, 0x03D5, 0x03D6, 0x03F0, 0x03F1, + + /* U+03F2 GREEK LUNATE SIGMA SYMBOL lacks a specific uppercase + counterpart in locales predating Unicode 4.0.0 (April 2003). */ + 0x03F2, + + 0x03F5, 0x1E9B, 0x1FBE, + }; + +/* Verify that the worst case fits. This is 1 for towupper, 1 for + towlower, and 1 for each entry in LONESOME_LOWER. */ +verify (1 + 1 + sizeof lonesome_lower / sizeof *lonesome_lower + <= CASE_FOLDED_BUFSIZE); + +/* Find the characters equal to C after case-folding, other than C + itself, and store them into FOLDED. Return the number of characters + stored; this is zero if C is WEOF. */ + +int +case_folded_counterparts (wint_t c, wchar_t folded[CASE_FOLDED_BUFSIZE]) +{ + int i; + int n = 0; + wint_t uc = towupper (c); + wint_t lc = towlower (uc); + if (uc != c) + folded[n++] = uc; + if (lc != uc && lc != c && towupper (lc) == uc) + folded[n++] = lc; + for (i = 0; i < sizeof lonesome_lower / sizeof *lonesome_lower; i++) + { + wint_t li = lonesome_lower[i]; + if (li != lc && li != uc && li != c && towupper (li) == uc) + folded[n++] = li; + } + return n; +} |