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/* pcresearch.c - searching subroutines using PCRE for grep.
Copyright 2000, 2007, 2009-2012 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 August 1992 by Mike Haertel. */
#include <config.h>
#include "search.h"
#if HAVE_PCRE_H
# include <pcre.h>
#elif HAVE_PCRE_PCRE_H
# include <pcre/pcre.h>
#endif
#if HAVE_LIBPCRE
/* Compiled internal form of a Perl regular expression. */
static pcre *cre;
/* Additional information about the pattern. */
static pcre_extra *extra;
#endif
void
Pcompile (char const *pattern, size_t size)
{
#if !HAVE_LIBPCRE
error (EXIT_TROUBLE, 0, "%s",
_("support for the -P option is not compiled into "
"this --disable-perl-regexp binary"));
#else
int e;
char const *ep;
char *re = xnmalloc (4, size + 7);
int flags = PCRE_MULTILINE | (match_icase ? PCRE_CASELESS : 0);
char const *patlim = pattern + size;
char *n = re;
char const *p;
char const *pnul;
/* FIXME: Remove these restrictions. */
if (memchr(pattern, '\n', size))
error (EXIT_TROUBLE, 0, _("the -P option only supports a single pattern"));
*n = '\0';
if (match_lines)
strcpy (n, "^(");
if (match_words)
strcpy (n, "\\b(");
n += strlen (n);
/* The PCRE interface doesn't allow NUL bytes in the pattern, so
replace each NUL byte in the pattern with the four characters
"\000", removing a preceding backslash if there are an odd
number of backslashes before the NUL.
FIXME: This method does not work with some multibyte character
encodings, notably Shift-JIS, where a multibyte character can end
in a backslash byte. */
for (p = pattern; (pnul = memchr (p, '\0', patlim - p)); p = pnul + 1)
{
memcpy (n, p, pnul - p);
n += pnul - p;
for (p = pnul; pattern < p && p[-1] == '\\'; p--)
continue;
n -= (pnul - p) & 1;
strcpy (n, "\\000");
n += 4;
}
memcpy (n, p, patlim - p);
n += patlim - p;
*n = '\0';
if (match_words)
strcpy (n, ")\\b");
if (match_lines)
strcpy (n, ")$");
cre = pcre_compile (re, flags, &ep, &e, pcre_maketables ());
if (!cre)
error (EXIT_TROUBLE, 0, "%s", ep);
extra = pcre_study (cre, 0, &ep);
if (ep)
error (EXIT_TROUBLE, 0, "%s", ep);
free (re);
#endif
}
size_t
Pexecute (char const *buf, size_t size, size_t *match_size,
char const *start_ptr)
{
#if !HAVE_LIBPCRE
/* We can't get here, because Pcompile would have been called earlier. */
error (EXIT_TROUBLE, 0, _("internal error"));
return -1;
#else
/* This array must have at least two elements; everything after that
is just for performance improvement in pcre_exec. */
int sub[300];
const char *line_buf, *line_end, *line_next;
int e = PCRE_ERROR_NOMATCH;
ptrdiff_t start_ofs = start_ptr ? start_ptr - buf : 0;
/* PCRE can't limit the matching to single lines, therefore we have to
match each line in the buffer separately. */
for (line_next = buf;
e == PCRE_ERROR_NOMATCH && line_next < buf + size;
start_ofs -= line_next - line_buf)
{
line_buf = line_next;
line_end = memchr (line_buf, eolbyte, (buf + size) - line_buf);
if (line_end == NULL)
line_next = line_end = buf + size;
else
line_next = line_end + 1;
if (start_ptr && start_ptr >= line_end)
continue;
e = pcre_exec (cre, extra, line_buf, line_end - line_buf,
start_ofs < 0 ? 0 : start_ofs, 0,
sub, sizeof sub / sizeof *sub);
}
if (e <= 0)
{
switch (e)
{
case PCRE_ERROR_NOMATCH:
return -1;
case PCRE_ERROR_NOMEMORY:
error (EXIT_TROUBLE, 0, _("memory exhausted"));
case PCRE_ERROR_MATCHLIMIT:
error (EXIT_TROUBLE, 0,
_("exceeded PCRE's backtracking limit"));
default:
abort ();
}
}
else
{
/* Narrow down to the line we've found. */
char const *beg = line_buf + sub[0];
char const *end = line_buf + sub[1];
char const *buflim = buf + size;
char eol = eolbyte;
if (!start_ptr)
{
/* FIXME: The case when '\n' is not found indicates a bug:
Since grep is line oriented, the match should never contain
a newline, so there _must_ be a newline following.
*/
if (!(end = memchr (end, eol, buflim - end)))
end = buflim;
else
end++;
while (buf < beg && beg[-1] != eol)
--beg;
}
*match_size = end - beg;
return beg - buf;
}
#endif
}
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