| 1 | /* pcresearch.c - searching subroutines using PCRE for grep.
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| 2 | Copyright 2000, 2007, 2009-2012 Free Software Foundation, Inc.
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| 3 |
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| 4 | This program is free software; you can redistribute it and/or modify
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| 5 | it under the terms of the GNU General Public License as published by
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| 6 | the Free Software Foundation; either version 3, or (at your option)
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| 7 | any later version.
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| 8 |
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| 9 | This program is distributed in the hope that it will be useful,
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | GNU General Public License for more details.
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| 13 |
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| 14 | You should have received a copy of the GNU General Public License
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| 15 | along with this program; if not, write to the Free Software
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| 16 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
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| 17 | 02110-1301, USA. */
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| 18 |
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| 19 | /* Written August 1992 by Mike Haertel. */
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| 20 |
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| 21 | #include <config.h>
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| 22 | #include "search.h"
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| 23 | #if HAVE_PCRE_H
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| 24 | # include <pcre.h>
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| 25 | #elif HAVE_PCRE_PCRE_H
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| 26 | # include <pcre/pcre.h>
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| 27 | #endif
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| 28 |
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| 29 | #if HAVE_LIBPCRE
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| 30 | /* Compiled internal form of a Perl regular expression. */
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| 31 | static pcre *cre;
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| 32 |
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| 33 | /* Additional information about the pattern. */
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| 34 | static pcre_extra *extra;
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| 35 | #endif
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| 36 |
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| 37 | void
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| 38 | Pcompile (char const *pattern, size_t size)
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| 39 | {
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| 40 | #if !HAVE_LIBPCRE
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| 41 | error (EXIT_TROUBLE, 0, "%s",
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| 42 | _("support for the -P option is not compiled into "
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| 43 | "this --disable-perl-regexp binary"));
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| 44 | #else
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| 45 | int e;
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| 46 | char const *ep;
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| 47 | char *re = xnmalloc (4, size + 7);
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| 48 | int flags = PCRE_MULTILINE | (match_icase ? PCRE_CASELESS : 0);
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| 49 | char const *patlim = pattern + size;
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| 50 | char *n = re;
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| 51 | char const *p;
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| 52 | char const *pnul;
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| 53 |
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| 54 | /* FIXME: Remove these restrictions. */
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| 55 | if (memchr(pattern, '\n', size))
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| 56 | error (EXIT_TROUBLE, 0, _("the -P option only supports a single pattern"));
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| 57 |
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| 58 | *n = '\0';
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| 59 | if (match_lines)
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| 60 | strcpy (n, "^(");
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| 61 | if (match_words)
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| 62 | strcpy (n, "\\b(");
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| 63 | n += strlen (n);
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| 64 |
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| 65 | /* The PCRE interface doesn't allow NUL bytes in the pattern, so
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| 66 | replace each NUL byte in the pattern with the four characters
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| 67 | "\000", removing a preceding backslash if there are an odd
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| 68 | number of backslashes before the NUL.
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| 69 |
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| 70 | FIXME: This method does not work with some multibyte character
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| 71 | encodings, notably Shift-JIS, where a multibyte character can end
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| 72 | in a backslash byte. */
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| 73 | for (p = pattern; (pnul = memchr (p, '\0', patlim - p)); p = pnul + 1)
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| 74 | {
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| 75 | memcpy (n, p, pnul - p);
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| 76 | n += pnul - p;
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| 77 | for (p = pnul; pattern < p && p[-1] == '\\'; p--)
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| 78 | continue;
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| 79 | n -= (pnul - p) & 1;
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| 80 | strcpy (n, "\\000");
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| 81 | n += 4;
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| 82 | }
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| 83 |
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| 84 | memcpy (n, p, patlim - p);
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| 85 | n += patlim - p;
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| 86 | *n = '\0';
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| 87 | if (match_words)
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| 88 | strcpy (n, ")\\b");
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| 89 | if (match_lines)
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| 90 | strcpy (n, ")$");
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| 91 |
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| 92 | cre = pcre_compile (re, flags, &ep, &e, pcre_maketables ());
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| 93 | if (!cre)
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| 94 | error (EXIT_TROUBLE, 0, "%s", ep);
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| 95 |
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| 96 | extra = pcre_study (cre, 0, &ep);
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| 97 | if (ep)
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| 98 | error (EXIT_TROUBLE, 0, "%s", ep);
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| 99 |
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| 100 | free (re);
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| 101 | #endif
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| 102 | }
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| 103 |
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| 104 | size_t
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| 105 | Pexecute (char const *buf, size_t size, size_t *match_size,
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| 106 | char const *start_ptr)
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| 107 | {
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| 108 | #if !HAVE_LIBPCRE
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| 109 | /* We can't get here, because Pcompile would have been called earlier. */
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| 110 | error (EXIT_TROUBLE, 0, _("internal error"));
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| 111 | return -1;
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| 112 | #else
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| 113 | /* This array must have at least two elements; everything after that
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| 114 | is just for performance improvement in pcre_exec. */
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| 115 | int sub[300];
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| 116 |
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| 117 | const char *line_buf, *line_end, *line_next;
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| 118 | int e = PCRE_ERROR_NOMATCH;
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| 119 | ptrdiff_t start_ofs = start_ptr ? start_ptr - buf : 0;
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| 120 |
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| 121 | /* PCRE can't limit the matching to single lines, therefore we have to
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| 122 | match each line in the buffer separately. */
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| 123 | for (line_next = buf;
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| 124 | e == PCRE_ERROR_NOMATCH && line_next < buf + size;
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| 125 | start_ofs -= line_next - line_buf)
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| 126 | {
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| 127 | line_buf = line_next;
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| 128 | line_end = memchr (line_buf, eolbyte, (buf + size) - line_buf);
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| 129 | if (line_end == NULL)
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| 130 | line_next = line_end = buf + size;
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| 131 | else
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| 132 | line_next = line_end + 1;
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| 133 |
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| 134 | if (start_ptr && start_ptr >= line_end)
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| 135 | continue;
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| 136 |
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| 137 | if (INT_MAX < line_end - line_buf)
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| 138 | error (EXIT_TROUBLE, 0, _("exceeded PCRE's line length limit"));
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| 139 |
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| 140 | e = pcre_exec (cre, extra, line_buf, line_end - line_buf,
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| 141 | start_ofs < 0 ? 0 : start_ofs, 0,
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| 142 | sub, sizeof sub / sizeof *sub);
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| 143 | }
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| 144 |
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| 145 | if (e <= 0)
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| 146 | {
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| 147 | switch (e)
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| 148 | {
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| 149 | case PCRE_ERROR_NOMATCH:
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| 150 | return -1;
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| 151 |
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| 152 | case PCRE_ERROR_NOMEMORY:
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| 153 | error (EXIT_TROUBLE, 0, _("memory exhausted"));
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| 154 |
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| 155 | case PCRE_ERROR_MATCHLIMIT:
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| 156 | error (EXIT_TROUBLE, 0,
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| 157 | _("exceeded PCRE's backtracking limit"));
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| 158 |
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| 159 | default:
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| 160 | abort ();
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| 161 | }
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| 162 | }
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| 163 | else
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| 164 | {
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| 165 | /* Narrow down to the line we've found. */
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| 166 | char const *beg = line_buf + sub[0];
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| 167 | char const *end = line_buf + sub[1];
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| 168 | char const *buflim = buf + size;
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| 169 | char eol = eolbyte;
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| 170 | if (!start_ptr)
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| 171 | {
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| 172 | /* FIXME: The case when '\n' is not found indicates a bug:
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| 173 | Since grep is line oriented, the match should never contain
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| 174 | a newline, so there _must_ be a newline following.
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| 175 | */
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| 176 | if (!(end = memchr (end, eol, buflim - end)))
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| 177 | end = buflim;
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| 178 | else
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| 179 | end++;
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| 180 | while (buf < beg && beg[-1] != eol)
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| 181 | --beg;
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| 182 | }
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| 183 |
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| 184 | *match_size = end - beg;
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| 185 | return beg - buf;
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| 186 | }
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| 187 | #endif
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| 188 | }
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