+++ /dev/null
-/* $Cambridge: exim/src/src/pcre/pcre_study.c,v 1.6 2007/11/12 13:02:20 nm4 Exp $ */
-
-/*************************************************
-* Perl-Compatible Regular Expressions *
-*************************************************/
-
-/* PCRE is a library of functions to support regular expressions whose syntax
-and semantics are as close as possible to those of the Perl 5 language.
-
- Written by Philip Hazel
- Copyright (c) 1997-2007 University of Cambridge
-
------------------------------------------------------------------------------
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
- * Redistributions of source code must retain the above copyright notice,
- this list of conditions and the following disclaimer.
-
- * 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.
-
- * Neither the name of the University of Cambridge nor the names of its
- contributors may be used to endorse or promote products derived from
- this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
------------------------------------------------------------------------------
-*/
-
-
-/* This module contains the external function pcre_study(), along with local
-supporting functions. */
-
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include "pcre_internal.h"
-
-
-/* Returns from set_start_bits() */
-
-enum { SSB_FAIL, SSB_DONE, SSB_CONTINUE };
-
-
-/*************************************************
-* Set a bit and maybe its alternate case *
-*************************************************/
-
-/* Given a character, set its bit in the table, and also the bit for the other
-version of a letter if we are caseless.
-
-Arguments:
- start_bits points to the bit map
- c is the character
- caseless the caseless flag
- cd the block with char table pointers
-
-Returns: nothing
-*/
-
-static void
-set_bit(uschar *start_bits, unsigned int c, BOOL caseless, compile_data *cd)
-{
-start_bits[c/8] |= (1 << (c&7));
-if (caseless && (cd->ctypes[c] & ctype_letter) != 0)
- start_bits[cd->fcc[c]/8] |= (1 << (cd->fcc[c]&7));
-}
-
-
-
-/*************************************************
-* Create bitmap of starting bytes *
-*************************************************/
-
-/* This function scans a compiled unanchored expression recursively and
-attempts to build a bitmap of the set of possible starting bytes. As time goes
-by, we may be able to get more clever at doing this. The SSB_CONTINUE return is
-useful for parenthesized groups in patterns such as (a*)b where the group
-provides some optional starting bytes but scanning must continue at the outer
-level to find at least one mandatory byte. At the outermost level, this
-function fails unless the result is SSB_DONE.
-
-Arguments:
- code points to an expression
- start_bits points to a 32-byte table, initialized to 0
- caseless the current state of the caseless flag
- utf8 TRUE if in UTF-8 mode
- cd the block with char table pointers
-
-Returns: SSB_FAIL => Failed to find any starting bytes
- SSB_DONE => Found mandatory starting bytes
- SSB_CONTINUE => Found optional starting bytes
-*/
-
-static int
-set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
- BOOL utf8, compile_data *cd)
-{
-register int c;
-int yield = SSB_DONE;
-
-#if 0
-/* ========================================================================= */
-/* The following comment and code was inserted in January 1999. In May 2006,
-when it was observed to cause compiler warnings about unused values, I took it
-out again. If anybody is still using OS/2, they will have to put it back
-manually. */
-
-/* This next statement and the later reference to dummy are here in order to
-trick the optimizer of the IBM C compiler for OS/2 into generating correct
-code. Apparently IBM isn't going to fix the problem, and we would rather not
-disable optimization (in this module it actually makes a big difference, and
-the pcre module can use all the optimization it can get). */
-
-volatile int dummy;
-/* ========================================================================= */
-#endif
-
-do
- {
- const uschar *tcode = code + (((int)*code == OP_CBRA)? 3:1) + LINK_SIZE;
- BOOL try_next = TRUE;
-
- while (try_next) /* Loop for items in this branch */
- {
- int rc;
- switch(*tcode)
- {
- /* Fail if we reach something we don't understand */
-
- default:
- return SSB_FAIL;
-
- /* If we hit a bracket or a positive lookahead assertion, recurse to set
- bits from within the subpattern. If it can't find anything, we have to
- give up. If it finds some mandatory character(s), we are done for this
- branch. Otherwise, carry on scanning after the subpattern. */
-
- case OP_BRA:
- case OP_SBRA:
- case OP_CBRA:
- case OP_SCBRA:
- case OP_ONCE:
- case OP_ASSERT:
- rc = set_start_bits(tcode, start_bits, caseless, utf8, cd);
- if (rc == SSB_FAIL) return SSB_FAIL;
- if (rc == SSB_DONE) try_next = FALSE; else
- {
- do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
- tcode += 1 + LINK_SIZE;
- }
- break;
-
- /* If we hit ALT or KET, it means we haven't found anything mandatory in
- this branch, though we might have found something optional. For ALT, we
- continue with the next alternative, but we have to arrange that the final
- result from subpattern is SSB_CONTINUE rather than SSB_DONE. For KET,
- return SSB_CONTINUE: if this is the top level, that indicates failure,
- but after a nested subpattern, it causes scanning to continue. */
-
- case OP_ALT:
- yield = SSB_CONTINUE;
- try_next = FALSE;
- break;
-
- case OP_KET:
- case OP_KETRMAX:
- case OP_KETRMIN:
- return SSB_CONTINUE;
-
- /* Skip over callout */
-
- case OP_CALLOUT:
- tcode += 2 + 2*LINK_SIZE;
- break;
-
- /* Skip over lookbehind and negative lookahead assertions */
-
- case OP_ASSERT_NOT:
- case OP_ASSERTBACK:
- case OP_ASSERTBACK_NOT:
- do tcode += GET(tcode, 1); while (*tcode == OP_ALT);
- tcode += 1 + LINK_SIZE;
- break;
-
- /* Skip over an option setting, changing the caseless flag */
-
- case OP_OPT:
- caseless = (tcode[1] & PCRE_CASELESS) != 0;
- tcode += 2;
- break;
-
- /* BRAZERO does the bracket, but carries on. */
-
- case OP_BRAZERO:
- case OP_BRAMINZERO:
- if (set_start_bits(++tcode, start_bits, caseless, utf8, cd) == SSB_FAIL)
- return SSB_FAIL;
-/* =========================================================================
- See the comment at the head of this function concerning the next line,
- which was an old fudge for the benefit of OS/2.
- dummy = 1;
- ========================================================================= */
- do tcode += GET(tcode,1); while (*tcode == OP_ALT);
- tcode += 1 + LINK_SIZE;
- break;
-
- /* Single-char * or ? sets the bit and tries the next item */
-
- case OP_STAR:
- case OP_MINSTAR:
- case OP_POSSTAR:
- case OP_QUERY:
- case OP_MINQUERY:
- case OP_POSQUERY:
- set_bit(start_bits, tcode[1], caseless, cd);
- tcode += 2;
-#ifdef SUPPORT_UTF8
- if (utf8 && tcode[-1] >= 0xc0)
- tcode += _pcre_utf8_table4[tcode[-1] & 0x3f];
-#endif
- break;
-
- /* Single-char upto sets the bit and tries the next */
-
- case OP_UPTO:
- case OP_MINUPTO:
- case OP_POSUPTO:
- set_bit(start_bits, tcode[3], caseless, cd);
- tcode += 4;
-#ifdef SUPPORT_UTF8
- if (utf8 && tcode[-1] >= 0xc0)
- tcode += _pcre_utf8_table4[tcode[-1] & 0x3f];
-#endif
- break;
-
- /* At least one single char sets the bit and stops */
-
- case OP_EXACT: /* Fall through */
- tcode += 2;
-
- case OP_CHAR:
- case OP_CHARNC:
- case OP_PLUS:
- case OP_MINPLUS:
- case OP_POSPLUS:
- set_bit(start_bits, tcode[1], caseless, cd);
- try_next = FALSE;
- break;
-
- /* Single character type sets the bits and stops */
-
- case OP_NOT_DIGIT:
- for (c = 0; c < 32; c++)
- start_bits[c] |= ~cd->cbits[c+cbit_digit];
- try_next = FALSE;
- break;
-
- case OP_DIGIT:
- for (c = 0; c < 32; c++)
- start_bits[c] |= cd->cbits[c+cbit_digit];
- try_next = FALSE;
- break;
-
- /* The cbit_space table has vertical tab as whitespace; we have to
- discard it. */
-
- case OP_NOT_WHITESPACE:
- for (c = 0; c < 32; c++)
- {
- int d = cd->cbits[c+cbit_space];
- if (c == 1) d &= ~0x08;
- start_bits[c] |= ~d;
- }
- try_next = FALSE;
- break;
-
- /* The cbit_space table has vertical tab as whitespace; we have to
- discard it. */
-
- case OP_WHITESPACE:
- for (c = 0; c < 32; c++)
- {
- int d = cd->cbits[c+cbit_space];
- if (c == 1) d &= ~0x08;
- start_bits[c] |= d;
- }
- try_next = FALSE;
- break;
-
- case OP_NOT_WORDCHAR:
- for (c = 0; c < 32; c++)
- start_bits[c] |= ~cd->cbits[c+cbit_word];
- try_next = FALSE;
- break;
-
- case OP_WORDCHAR:
- for (c = 0; c < 32; c++)
- start_bits[c] |= cd->cbits[c+cbit_word];
- try_next = FALSE;
- break;
-
- /* One or more character type fudges the pointer and restarts, knowing
- it will hit a single character type and stop there. */
-
- case OP_TYPEPLUS:
- case OP_TYPEMINPLUS:
- tcode++;
- break;
-
- case OP_TYPEEXACT:
- tcode += 3;
- break;
-
- /* Zero or more repeats of character types set the bits and then
- try again. */
-
- case OP_TYPEUPTO:
- case OP_TYPEMINUPTO:
- case OP_TYPEPOSUPTO:
- tcode += 2; /* Fall through */
-
- case OP_TYPESTAR:
- case OP_TYPEMINSTAR:
- case OP_TYPEPOSSTAR:
- case OP_TYPEQUERY:
- case OP_TYPEMINQUERY:
- case OP_TYPEPOSQUERY:
- switch(tcode[1])
- {
- case OP_ANY:
- return SSB_FAIL;
-
- case OP_NOT_DIGIT:
- for (c = 0; c < 32; c++)
- start_bits[c] |= ~cd->cbits[c+cbit_digit];
- break;
-
- case OP_DIGIT:
- for (c = 0; c < 32; c++)
- start_bits[c] |= cd->cbits[c+cbit_digit];
- break;
-
- /* The cbit_space table has vertical tab as whitespace; we have to
- discard it. */
-
- case OP_NOT_WHITESPACE:
- for (c = 0; c < 32; c++)
- {
- int d = cd->cbits[c+cbit_space];
- if (c == 1) d &= ~0x08;
- start_bits[c] |= ~d;
- }
- break;
-
- /* The cbit_space table has vertical tab as whitespace; we have to
- discard it. */
-
- case OP_WHITESPACE:
- for (c = 0; c < 32; c++)
- {
- int d = cd->cbits[c+cbit_space];
- if (c == 1) d &= ~0x08;
- start_bits[c] |= d;
- }
- break;
-
- case OP_NOT_WORDCHAR:
- for (c = 0; c < 32; c++)
- start_bits[c] |= ~cd->cbits[c+cbit_word];
- break;
-
- case OP_WORDCHAR:
- for (c = 0; c < 32; c++)
- start_bits[c] |= cd->cbits[c+cbit_word];
- break;
- }
-
- tcode += 2;
- break;
-
- /* Character class where all the information is in a bit map: set the
- bits and either carry on or not, according to the repeat count. If it was
- a negative class, and we are operating with UTF-8 characters, any byte
- with a value >= 0xc4 is a potentially valid starter because it starts a
- character with a value > 255. */
-
- case OP_NCLASS:
-#ifdef SUPPORT_UTF8
- if (utf8)
- {
- start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
- memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
- }
-#endif
- /* Fall through */
-
- case OP_CLASS:
- {
- tcode++;
-
- /* In UTF-8 mode, the bits in a bit map correspond to character
- values, not to byte values. However, the bit map we are constructing is
- for byte values. So we have to do a conversion for characters whose
- value is > 127. In fact, there are only two possible starting bytes for
- characters in the range 128 - 255. */
-
-#ifdef SUPPORT_UTF8
- if (utf8)
- {
- for (c = 0; c < 16; c++) start_bits[c] |= tcode[c];
- for (c = 128; c < 256; c++)
- {
- if ((tcode[c/8] && (1 << (c&7))) != 0)
- {
- int d = (c >> 6) | 0xc0; /* Set bit for this starter */
- start_bits[d/8] |= (1 << (d&7)); /* and then skip on to the */
- c = (c & 0xc0) + 0x40 - 1; /* next relevant character. */
- }
- }
- }
-
- /* In non-UTF-8 mode, the two bit maps are completely compatible. */
-
- else
-#endif
- {
- for (c = 0; c < 32; c++) start_bits[c] |= tcode[c];
- }
-
- /* Advance past the bit map, and act on what follows */
-
- tcode += 32;
- switch (*tcode)
- {
- case OP_CRSTAR:
- case OP_CRMINSTAR:
- case OP_CRQUERY:
- case OP_CRMINQUERY:
- tcode++;
- break;
-
- case OP_CRRANGE:
- case OP_CRMINRANGE:
- if (((tcode[1] << 8) + tcode[2]) == 0) tcode += 5;
- else try_next = FALSE;
- break;
-
- default:
- try_next = FALSE;
- break;
- }
- }
- break; /* End of bitmap class handling */
-
- } /* End of switch */
- } /* End of try_next loop */
-
- code += GET(code, 1); /* Advance to next branch */
- }
-while (*code == OP_ALT);
-return yield;
-}
-
-
-
-/*************************************************
-* Study a compiled expression *
-*************************************************/
-
-/* This function is handed a compiled expression that it must study to produce
-information that will speed up the matching. It returns a pcre_extra block
-which then gets handed back to pcre_exec().
-
-Arguments:
- re points to the compiled expression
- options contains option bits
- errorptr points to where to place error messages;
- set NULL unless error
-
-Returns: pointer to a pcre_extra block, with study_data filled in and the
- appropriate flag set;
- NULL on error or if no optimization possible
-*/
-
-PCRE_EXP_DEFN pcre_extra *
-pcre_study(const pcre *external_re, int options, const char **errorptr)
-{
-uschar start_bits[32];
-pcre_extra *extra;
-pcre_study_data *study;
-const uschar *tables;
-uschar *code;
-compile_data compile_block;
-const real_pcre *re = (const real_pcre *)external_re;
-
-*errorptr = NULL;
-
-if (re == NULL || re->magic_number != MAGIC_NUMBER)
- {
- *errorptr = "argument is not a compiled regular expression";
- return NULL;
- }
-
-if ((options & ~PUBLIC_STUDY_OPTIONS) != 0)
- {
- *errorptr = "unknown or incorrect option bit(s) set";
- return NULL;
- }
-
-code = (uschar *)re + re->name_table_offset +
- (re->name_count * re->name_entry_size);
-
-/* For an anchored pattern, or an unanchored pattern that has a first char, or
-a multiline pattern that matches only at "line starts", no further processing
-at present. */
-
-if ((re->options & PCRE_ANCHORED) != 0 ||
- (re->flags & (PCRE_FIRSTSET|PCRE_STARTLINE)) != 0)
- return NULL;
-
-/* Set the character tables in the block that is passed around */
-
-tables = re->tables;
-if (tables == NULL)
- (void)pcre_fullinfo(external_re, NULL, PCRE_INFO_DEFAULT_TABLES,
- (void *)(&tables));
-
-compile_block.lcc = tables + lcc_offset;
-compile_block.fcc = tables + fcc_offset;
-compile_block.cbits = tables + cbits_offset;
-compile_block.ctypes = tables + ctypes_offset;
-
-/* See if we can find a fixed set of initial characters for the pattern. */
-
-memset(start_bits, 0, 32 * sizeof(uschar));
-if (set_start_bits(code, start_bits, (re->options & PCRE_CASELESS) != 0,
- (re->options & PCRE_UTF8) != 0, &compile_block) != SSB_DONE) return NULL;
-
-/* Get a pcre_extra block and a pcre_study_data block. The study data is put in
-the latter, which is pointed to by the former, which may also get additional
-data set later by the calling program. At the moment, the size of
-pcre_study_data is fixed. We nevertheless save it in a field for returning via
-the pcre_fullinfo() function so that if it becomes variable in the future, we
-don't have to change that code. */
-
-extra = (pcre_extra *)(pcre_malloc)
- (sizeof(pcre_extra) + sizeof(pcre_study_data));
-
-if (extra == NULL)
- {
- *errorptr = "failed to get memory";
- return NULL;
- }
-
-study = (pcre_study_data *)((char *)extra + sizeof(pcre_extra));
-extra->flags = PCRE_EXTRA_STUDY_DATA;
-extra->study_data = study;
-
-study->size = sizeof(pcre_study_data);
-study->options = PCRE_STUDY_MAPPED;
-memcpy(study->start_bits, start_bits, sizeof(start_bits));
-
-return extra;
-}
-
-/* End of pcre_study.c */
git://git.exim.org / exim.git / blobdiff