mirror of git://git.psyced.org/git/psyclpc
473 lines
13 KiB
C
473 lines
13 KiB
C
/*************************************************
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* Perl-Compatible Regular Expressions *
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*************************************************/
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/*
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This is a library of functions to support regular expressions whose syntax
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and semantics are as close as possible to those of the Perl 5 language. See
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the file Tech.Notes for some information on the internals.
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Written by: Philip Hazel <ph10@cam.ac.uk>
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Copyright (c) 1997-2003 University of Cambridge
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-----------------------------------------------------------------------------
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Permission is granted to anyone to use this software for any purpose on any
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computer system, and to redistribute it freely, subject to the following
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restrictions:
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1. This software is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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2. The origin of this software must not be misrepresented, either by
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explicit claim or by omission.
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3. Altered versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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4. If PCRE is embedded in any software that is released under the GNU
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General Purpose Licence (GPL), then the terms of that licence shall
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supersede any condition above with which it is incompatible.
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-----------------------------------------------------------------------------
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*/
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/* Include the internals header, which itself includes Standard C headers plus
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the external pcre header. */
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#include "internal.h"
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/*************************************************
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* Set a bit and maybe its alternate case *
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*************************************************/
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/* Given a character, set its bit in the table, and also the bit for the other
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version of a letter if we are caseless.
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Arguments:
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start_bits points to the bit map
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c is the character
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caseless the caseless flag
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cd the block with char table pointers
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Returns: nothing
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*/
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static void
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set_bit(uschar *start_bits, int c, BOOL caseless, compile_data *cd)
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{
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start_bits[c/8] |= (1 << (c&7));
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if (caseless && (cd->ctypes[c] & ctype_letter) != 0)
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start_bits[cd->fcc[c]/8] |= (1 << (cd->fcc[c]&7));
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}
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/*************************************************
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* Create bitmap of starting chars *
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*************************************************/
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/* This function scans a compiled unanchored expression and attempts to build a
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bitmap of the set of initial characters. If it can't, it returns FALSE. As time
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goes by, we may be able to get more clever at doing this.
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Arguments:
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code points to an expression
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start_bits points to a 32-byte table, initialized to 0
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caseless the current state of the caseless flag
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utf8 TRUE if in UTF-8 mode
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cd the block with char table pointers
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Returns: TRUE if table built, FALSE otherwise
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*/
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static BOOL
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set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
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BOOL utf8, compile_data *cd)
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{
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register int c;
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/* This next statement and the later reference to dummy are here in order to
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trick the optimizer of the IBM C compiler for OS/2 into generating correct
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code. Apparently IBM isn't going to fix the problem, and we would rather not
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disable optimization (in this module it actually makes a big difference, and
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the pcre module can use all the optimization it can get).
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Breaking OS/2 in favor of gcc's paranoia. --lynX 2016
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*/
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do
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{
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const uschar *tcode = code + 1 + LINK_SIZE;
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BOOL try_next = TRUE;
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while (try_next)
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{
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/* If a branch starts with a bracket or a positive lookahead assertion,
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recurse to set bits from within them. That's all for this branch. */
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if ((int)*tcode >= OP_BRA || *tcode == OP_ASSERT)
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{
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if (!set_start_bits(tcode, start_bits, caseless, utf8, cd))
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return FALSE;
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try_next = FALSE;
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}
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else switch(*tcode)
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{
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default:
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return FALSE;
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/* Skip over callout */
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case OP_CALLOUT:
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tcode += 2;
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break;
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/* Skip over extended extraction bracket number */
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case OP_BRANUMBER:
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tcode += 3;
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break;
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/* Skip over lookbehind and negative lookahead assertions */
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case OP_ASSERT_NOT:
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case OP_ASSERTBACK:
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case OP_ASSERTBACK_NOT:
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do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
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tcode += 1+LINK_SIZE;
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break;
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/* Skip over an option setting, changing the caseless flag */
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case OP_OPT:
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caseless = (tcode[1] & PCRE_CASELESS) != 0;
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tcode += 2;
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break;
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/* BRAZERO does the bracket, but carries on. */
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case OP_BRAZERO:
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case OP_BRAMINZERO:
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if (!set_start_bits(++tcode, start_bits, caseless, utf8, cd))
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return FALSE;
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do tcode += GET(tcode,1); while (*tcode == OP_ALT);
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tcode += 1+LINK_SIZE;
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break;
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/* Single-char * or ? sets the bit and tries the next item */
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case OP_STAR:
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case OP_MINSTAR:
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case OP_QUERY:
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case OP_MINQUERY:
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set_bit(start_bits, tcode[1], caseless, cd);
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tcode += 2;
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#ifdef SUPPORT_UTF8
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if (utf8) while ((*tcode & 0xc0) == 0x80) tcode++;
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#endif
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break;
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/* Single-char upto sets the bit and tries the next */
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case OP_UPTO:
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case OP_MINUPTO:
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set_bit(start_bits, tcode[3], caseless, cd);
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tcode += 4;
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#ifdef SUPPORT_UTF8
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if (utf8) while ((*tcode & 0xc0) == 0x80) tcode++;
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#endif
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break;
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/* At least one single char sets the bit and stops */
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case OP_EXACT: /* Fall through */
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tcode++;
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case OP_CHARS: /* Fall through */
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tcode++;
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case OP_PLUS:
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case OP_MINPLUS:
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set_bit(start_bits, tcode[1], caseless, cd);
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try_next = FALSE;
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break;
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/* Single character type sets the bits and stops */
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case OP_NOT_DIGIT:
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for (c = 0; c < 32; c++)
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start_bits[c] |= ~cd->cbits[c+cbit_digit];
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try_next = FALSE;
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break;
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case OP_DIGIT:
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for (c = 0; c < 32; c++)
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start_bits[c] |= cd->cbits[c+cbit_digit];
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try_next = FALSE;
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break;
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case OP_NOT_WHITESPACE:
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for (c = 0; c < 32; c++)
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start_bits[c] |= ~cd->cbits[c+cbit_space];
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try_next = FALSE;
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break;
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case OP_WHITESPACE:
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for (c = 0; c < 32; c++)
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start_bits[c] |= cd->cbits[c+cbit_space];
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try_next = FALSE;
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break;
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case OP_NOT_WORDCHAR:
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for (c = 0; c < 32; c++)
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start_bits[c] |= ~cd->cbits[c+cbit_word];
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try_next = FALSE;
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break;
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case OP_WORDCHAR:
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for (c = 0; c < 32; c++)
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start_bits[c] |= cd->cbits[c+cbit_word];
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try_next = FALSE;
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break;
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/* One or more character type fudges the pointer and restarts, knowing
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it will hit a single character type and stop there. */
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case OP_TYPEPLUS:
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case OP_TYPEMINPLUS:
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tcode++;
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break;
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case OP_TYPEEXACT:
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tcode += 3;
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break;
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/* Zero or more repeats of character types set the bits and then
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try again. */
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case OP_TYPEUPTO:
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case OP_TYPEMINUPTO:
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tcode += 2; /* Fall through */
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case OP_TYPESTAR:
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case OP_TYPEMINSTAR:
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case OP_TYPEQUERY:
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case OP_TYPEMINQUERY:
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switch(tcode[1])
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{
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case OP_ANY:
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return FALSE;
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case OP_NOT_DIGIT:
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for (c = 0; c < 32; c++)
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start_bits[c] |= ~cd->cbits[c+cbit_digit];
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break;
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case OP_DIGIT:
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for (c = 0; c < 32; c++)
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start_bits[c] |= cd->cbits[c+cbit_digit];
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break;
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case OP_NOT_WHITESPACE:
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for (c = 0; c < 32; c++)
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start_bits[c] |= ~cd->cbits[c+cbit_space];
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break;
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case OP_WHITESPACE:
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for (c = 0; c < 32; c++)
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start_bits[c] |= cd->cbits[c+cbit_space];
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break;
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case OP_NOT_WORDCHAR:
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for (c = 0; c < 32; c++)
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start_bits[c] |= ~cd->cbits[c+cbit_word];
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break;
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case OP_WORDCHAR:
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for (c = 0; c < 32; c++)
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start_bits[c] |= cd->cbits[c+cbit_word];
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break;
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}
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tcode += 2;
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break;
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/* Character class where all the information is in a bit map: set the
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bits and either carry on or not, according to the repeat count. If it was
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a negative class, and we are operating with UTF-8 characters, any byte
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with a value >= 0xc4 is a potentially valid starter because it starts a
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character with a value > 255. */
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case OP_NCLASS:
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if (utf8)
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{
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start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
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memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
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}
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/* Fall through */
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case OP_CLASS:
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{
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tcode++;
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/* In UTF-8 mode, the bits in a bit map correspond to character
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values, not to byte values. However, the bit map we are constructing is
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for byte values. So we have to do a conversion for characters whose
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value is > 127. In fact, there are only two possible starting bytes for
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characters in the range 128 - 255. */
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if (utf8)
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{
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for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
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for (c = 128; c < 256; c++)
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{
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if ((tcode[c/8] && (1 << (c&7))) != 0)
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{
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int d = (c >> 6) | 0xc0; /* Set bit for this starter */
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start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
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c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
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}
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}
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}
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/* In non-UTF-8 mode, the two bit maps are completely compatible. */
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else
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{
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for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
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}
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/* Advance past the bit map, and act on what follows */
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tcode += 32;
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switch (*tcode)
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{
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case OP_CRSTAR:
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case OP_CRMINSTAR:
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case OP_CRQUERY:
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case OP_CRMINQUERY:
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tcode++;
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break;
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case OP_CRRANGE:
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case OP_CRMINRANGE:
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if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
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else try_next = FALSE;
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break;
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default:
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try_next = FALSE;
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break;
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}
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}
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break; /* End of bitmap class handling */
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} /* End of switch */
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} /* End of try_next loop */
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code += GET(code, 1); /* Advance to next branch */
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}
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while (*code == OP_ALT);
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return TRUE;
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}
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/*************************************************
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* Study a compiled expression *
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*************************************************/
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/* This function is handed a compiled expression that it must study to produce
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information that will speed up the matching. It returns a pcre_extra block
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which then gets handed back to pcre_exec().
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Arguments:
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re points to the compiled expression
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options contains option bits
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errorptr points to where to place error messages;
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set NULL unless error
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Returns: pointer to a pcre_extra block, with study_data filled in and the
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appropriate flag set;
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NULL on error or if no optimization possible
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*/
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EXPORT pcre_extra *
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pcre_study(const pcre *external_re, int options, const char **errorptr)
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{
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uschar start_bits[32];
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pcre_extra *extra;
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pcre_study_data *study;
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const real_pcre *re = (const real_pcre *)external_re;
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uschar *code = (uschar *)re + sizeof(real_pcre) +
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(re->name_count * re->name_entry_size);
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compile_data compile_block;
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*errorptr = NULL;
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if (re == NULL || re->magic_number != MAGIC_NUMBER)
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{
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*errorptr = "argument is not a compiled regular expression";
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return NULL;
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}
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if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
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{
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*errorptr = "unknown or incorrect option bit(s) set";
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return NULL;
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}
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/* For an anchored pattern, or an unanchored pattern that has a first char, or
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a multiline pattern that matches only at "line starts", no further processing
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at present. */
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if ((re->options & (PCRE_ANCHORED|PCRE_FIRSTSET|PCRE_STARTLINE)) != 0)
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return NULL;
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/* Set the character tables in the block which is passed around */
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compile_block.lcc = re->tables + lcc_offset;
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compile_block.fcc = re->tables + fcc_offset;
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compile_block.cbits = re->tables + cbits_offset;
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compile_block.ctypes = re->tables + ctypes_offset;
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/* See if we can find a fixed set of initial characters for the pattern. */
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memset(start_bits, 0, 32 * sizeof(uschar));
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if (!set_start_bits(code, start_bits, (re->options & PCRE_CASELESS) != 0,
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(re->options & PCRE_UTF8) != 0, &compile_block)) return NULL;
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/* Get a pcre_extra block and a pcre_study_data block. The study data is put in
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the latter, which is pointed to by the former, which may also get additional
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data set later by the calling program. At the moment, the size of
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pcre_study_data is fixed. We nevertheless save it in a field for returning via
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the pcre_fullinfo() function so that if it becomes variable in the future, we
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don't have to change that code. */
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extra = (pcre_extra *)(pcre_malloc)
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(sizeof(pcre_extra) + sizeof(pcre_study_data));
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if (extra == NULL)
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{
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*errorptr = "failed to get memory";
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return NULL;
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}
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study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
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extra->flags = PCRE_EXTRA_STUDY_DATA;
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extra->study_data = study;
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study->size = sizeof(pcre_study_data);
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study->options = PCRE_STUDY_MAPPED;
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memcpy(study->start_bits, start_bits, sizeof(start_bits));
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return extra;
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}
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/* End of study.c */
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