Make \=find_limits apply to DFA matching, to find the minimum depth limit.
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Philip.Hazel
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3aeb812180
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@ -84,6 +84,10 @@ pcre2test.
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14. The alternative matching function, pcre2_dfa_match() misbehaved if it
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encountered a character class with a possessive repeat, for example [a-f]{3}+.
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15. The depth (formerly recursion) limit now applies to DFA matching (as
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of 10.23/36); pcre2test has been upgraded so that \=find_limits works with DFA
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matching to find the minimum value for this limit.
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Version 10.23 14-February-2017
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------------------------------
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@ -1,4 +1,4 @@
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.TH PCRE2TEST 1 "21 March 2017" "PCRE 10.30"
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.TH PCRE2TEST 1 "24 March 2017" "PCRE 10.30"
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.SH NAME
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pcre2test - a program for testing Perl-compatible regular expressions.
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.SH SYNOPSIS
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@ -1052,7 +1052,7 @@ pattern.
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copy=<number or name> copy captured substring
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depth_limit=<n> set a depth limit
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dfa use \fBpcre2_dfa_match()\fP
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find_limits find match and recursion limits
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find_limits find match and depth limits
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get=<number or name> extract captured substring
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getall extract all captured substrings
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/g global global matching
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@ -1297,23 +1297,26 @@ limits in the match context. These values are ignored when the
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.SS "Finding minimum limits"
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.rs
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.sp
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If the \fBfind_limits\fP modifier is present, \fBpcre2test\fP calls
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\fBpcre2_match()\fP several times, setting different values in the match
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context via \fBpcre2_set_match_limit()\fP and \fBpcre2_set_depth_limit()\fP
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until it finds the minimum values for each parameter that allow
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\fBpcre2_match()\fP to complete without error.
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If the \fBfind_limits\fP modifier is present on a subject line, \fBpcre2test\fP
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calls the relevant matching function several times, setting different values in
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the match context via \fBpcre2_set_match_limit()\fP or
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\fBpcre2_set_depth_limit()\fP until it finds the minimum values for each
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parameter that allows the match to complete without error.
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.P
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If JIT is being used, only the match limit is relevant. If DFA matching is
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being used, only the depth limit is relevant, but at present this modifier is
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ignored (with a warning message).
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being used, only the depth limit is relevant.
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.P
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The \fImatch_limit\fP number is a measure of the amount of backtracking
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that takes place, and learning the minimum value can be instructive. For most
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simple matches, the number is quite small, but for patterns with very large
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numbers of matching possibilities, it can become large very quickly with
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increasing length of subject string. The \fIdepth_limit\fP number is
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a measure of how much memory for recording backtracking points is needed to
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complete the match attempt.
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increasing length of subject string.
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.P
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For non-DFA matching, the minimum \fIdepth_limit\fP number is a measure of how
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much memory for recording backtracking points is needed to complete the match
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attempt. In the case of DFA matching, \fIdepth_limit\fP controls the depth of
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recursive calls of the internal function that is used for handling pattern
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recursion, lookaround assertions, and atomic groups.
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.
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.
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.SS "Showing MARK names"
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@ -1765,6 +1768,6 @@ Cambridge, England.
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.rs
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.sp
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.nf
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Last updated: 21 March 2017
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Last updated: 24 March 2017
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Copyright (c) 1997-2017 University of Cambridge.
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.fi
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@ -5258,8 +5258,20 @@ return PR_OK;
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* Check match or depth limit *
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*************************************************/
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/* This is used for DFA, normal, and JIT fast matching. For DFA matching it
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should only called with the third argument set to PCRE2_ERROR_DEPTHLIMIT.
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Arguments:
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pp the subject string
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ulen length of subject or PCRE2_ZERO_TERMINATED
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errnumber defines which limit to test
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msg string to include in final message
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Returns: the return from the final match function call
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*/
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static int
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check_match_limit(uint8_t *pp, size_t ulen, int errnumber, const char *msg)
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check_match_limit(uint8_t *pp, PCRE2_SIZE ulen, int errnumber, const char *msg)
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{
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int capcount;
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uint32_t min = 0;
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@ -5280,9 +5292,21 @@ for (;;)
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PCRE2_SET_DEPTH_LIMIT(dat_context, mid);
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}
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if ((pat_patctl.control & CTL_JITFAST) != 0)
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if ((dat_datctl.control & CTL_DFA) != 0)
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{
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if (dfa_workspace == NULL)
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dfa_workspace = (int *)malloc(DFA_WS_DIMENSION*sizeof(int));
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if (dfa_matched++ == 0)
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dfa_workspace[0] = -1; /* To catch bad restart */
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PCRE2_DFA_MATCH(capcount, compiled_code, pp, ulen, dat_datctl.offset,
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dat_datctl.options, match_data,
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PTR(dat_context), dfa_workspace, DFA_WS_DIMENSION);
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}
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else if ((pat_patctl.control & CTL_JITFAST) != 0)
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PCRE2_JIT_MATCH(capcount, compiled_code, pp, ulen, dat_datctl.offset,
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dat_datctl.options, match_data, PTR(dat_context));
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else
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PCRE2_MATCH(capcount, compiled_code, pp, ulen, dat_datctl.offset,
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dat_datctl.options, match_data, PTR(dat_context));
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@ -6243,12 +6267,6 @@ if ((pat_patctl.control & CTL_POSIX) != 0)
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/* Handle matching via the native interface. Check for consistency of
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modifiers. */
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if ((dat_datctl.control & (CTL_DFA|CTL_FINDLIMITS)) == (CTL_DFA|CTL_FINDLIMITS))
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{
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fprintf(outfile, "** Finding match limits is not relevant for DFA matching: ignored\n");
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dat_datctl.control &= ~CTL_FINDLIMITS;
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}
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/* ALLUSEDTEXT is not supported with JIT, but JIT is not used with DFA
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matching, even if the JIT compiler was used. */
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@ -6579,14 +6597,19 @@ else for (gmatched = 0;; gmatched++)
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(double)CLOCKS_PER_SEC);
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}
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/* Find the match and depth limits if requested. The depth limit
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is not relevant for JIT. */
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/* Find the match and depth limits if requested. The match limit is not
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relevant for DFA matching and the depth limit is not relevant for JIT. */
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if ((dat_datctl.control & CTL_FINDLIMITS) != 0)
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{
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capcount = check_match_limit(pp, arg_ulen, PCRE2_ERROR_MATCHLIMIT, "match");
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if (FLD(compiled_code, executable_jit) == NULL)
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(void)check_match_limit(pp, arg_ulen, PCRE2_ERROR_DEPTHLIMIT,
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if ((dat_datctl.control & CTL_DFA) == 0)
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capcount = check_match_limit(pp, arg_ulen, PCRE2_ERROR_MATCHLIMIT,
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"match");
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else capcount = 0;
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if (FLD(compiled_code, executable_jit) == NULL ||
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(dat_datctl.options & PCRE2_NO_JIT) != 0 ||
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(dat_datctl.control & CTL_DFA) != 0)
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capcount = check_match_limit(pp, arg_ulen, PCRE2_ERROR_DEPTHLIMIT,
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"depth");
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}
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@ -4889,4 +4889,7 @@
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/(02-)?[0-9]{3}-[0-9]{3}/
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02-123-123
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/^(a(?2))(b)(?1)/
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abbab\=find_limits
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# End of testinput6
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@ -7689,4 +7689,9 @@ Failed: error -53: matching depth limit exceeded
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02-123-123
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0: 02-123-123
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/^(a(?2))(b)(?1)/
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abbab\=find_limits
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Minimum depth limit = 2
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0: abbab
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# End of testinput6
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