--- /dev/null
+/*************************************************
+* Perl-Compatible Regular Expressions *
+*************************************************/
+
+/*
+This 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. See
+the file Tech.Notes for some information on the internals.
+
+Written by: Philip Hazel <ph10@cam.ac.uk>
+
+ Copyright (c) 1997-2004 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.
+-----------------------------------------------------------------------------
+*/
+
+
+/* Include the internals header, which itself includes Standard C headers plus
+the external pcre header. */
+
+#include "internal.h"
+
+
+
+/*************************************************
+* 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 chars *
+*************************************************/
+
+/* This function scans a compiled unanchored expression and attempts to build a
+bitmap of the set of initial characters. If it can't, it returns FALSE. As time
+goes by, we may be able to get more clever at doing this.
+
+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: TRUE if table built, FALSE otherwise
+*/
+
+static BOOL
+set_start_bits(const uschar *code, uschar *start_bits, BOOL caseless,
+ BOOL utf8, compile_data *cd)
+{
+register int c;
+
+/* 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;
+
+do
+ {
+ const uschar *tcode = code + 1 + LINK_SIZE;
+ BOOL try_next = TRUE;
+
+ while (try_next)
+ {
+ /* If a branch starts with a bracket or a positive lookahead assertion,
+ recurse to set bits from within them. That's all for this branch. */
+
+ if ((int)*tcode >= OP_BRA || *tcode == OP_ASSERT)
+ {
+ if (!set_start_bits(tcode, start_bits, caseless, utf8, cd))
+ return FALSE;
+ try_next = FALSE;
+ }
+
+ else switch(*tcode)
+ {
+ default:
+ return FALSE;
+
+ /* Skip over callout */
+
+ case OP_CALLOUT:
+ tcode += 2 + 2*LINK_SIZE;
+ break;
+
+ /* Skip over extended extraction bracket number */
+
+ case OP_BRANUMBER:
+ tcode += 3;
+ 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))
+ return FALSE;
+ 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_QUERY:
+ case OP_MINQUERY:
+ set_bit(start_bits, tcode[1], caseless, cd);
+ tcode += 2;
+#ifdef SUPPORT_UTF8
+ if (utf8) while ((*tcode & 0xc0) == 0x80) tcode++;
+#endif
+ break;
+
+ /* Single-char upto sets the bit and tries the next */
+
+ case OP_UPTO:
+ case OP_MINUPTO:
+ set_bit(start_bits, tcode[3], caseless, cd);
+ tcode += 4;
+#ifdef SUPPORT_UTF8
+ if (utf8) while ((*tcode & 0xc0) == 0x80) tcode++;
+#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:
+ 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;
+
+ case OP_NOT_WHITESPACE:
+ for (c = 0; c < 32; c++)
+ start_bits[c] |= ~cd->cbits[c+cbit_space];
+ try_next = FALSE;
+ break;
+
+ case OP_WHITESPACE:
+ for (c = 0; c < 32; c++)
+ start_bits[c] |= cd->cbits[c+cbit_space];
+ 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:
+ tcode += 2; /* Fall through */
+
+ case OP_TYPESTAR:
+ case OP_TYPEMINSTAR:
+ case OP_TYPEQUERY:
+ case OP_TYPEMINQUERY:
+ switch(tcode[1])
+ {
+ case OP_ANY:
+ return FALSE;
+
+ 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;
+
+ case OP_NOT_WHITESPACE:
+ for (c = 0; c < 32; c++)
+ start_bits[c] |= ~cd->cbits[c+cbit_space];
+ break;
+
+ case OP_WHITESPACE:
+ for (c = 0; c < 32; c++)
+ start_bits[c] |= cd->cbits[c+cbit_space];
+ 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:
+ if (utf8)
+ {
+ start_bits[24] |= 0xf0; /* Bits for 0xc4 - 0xc8 */
+ memset(start_bits+25, 0xff, 7); /* Bits for 0xc9 - 0xff */
+ }
+ /* 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. */
+
+ 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
+ {
+ 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 TRUE;
+}
+
+
+
+/*************************************************
+* 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
+*/
+
+EXPORT 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;
+const real_pcre *re = (const real_pcre *)external_re;
+uschar *code = (uschar *)re + re->name_table_offset +
+ (re->name_count * re->name_entry_size);
+compile_data compile_block;
+
+*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;
+ }
+
+/* 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|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, &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)) 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 study.c */
projects / exim.git / blobdiff