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To: vim_dev@googlegroups.com
Subject: Patch 7.3.1150
Fcc: outbox
From: Bram Moolenaar <Bram@moolenaar.net>
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------------

Patch 7.3.1150
Problem:    New regexpengine: Slow when a look-behind match does not have a
	    width specified.
Solution:   Try to compute the maximum width.
Files:	    src/regexp_nfa.c


*** ../vim-7.3.1149/src/regexp_nfa.c	2013-06-08 18:19:39.000000000 +0200
--- src/regexp_nfa.c	2013-06-08 22:29:25.000000000 +0200
***************
*** 38,56 ****
      NFA_START_COLL,		    /* [abc] start */
      NFA_END_COLL,		    /* [abc] end */
      NFA_START_NEG_COLL,		    /* [^abc] start */
!     NFA_END_NEG_COLL,		    /* [^abc] end (only used in postfix) */
!     NFA_RANGE,			    /* range of the two previous items (only
! 				     * used in postfix) */
      NFA_RANGE_MIN,		    /* low end of a range  */
      NFA_RANGE_MAX,		    /* high end of a range  */
  
!     NFA_CONCAT,			    /* concatenate two previous items (only
! 				     * used in postfix) */
!     NFA_OR,
!     NFA_STAR,			    /* greedy * */
!     NFA_STAR_NONGREEDY,		    /* non-greedy * */
!     NFA_QUEST,			    /* greedy \? */
!     NFA_QUEST_NONGREEDY,	    /* non-greedy \? */
  
      NFA_BOL,			    /* ^    Begin line */
      NFA_EOL,			    /* $    End line */
--- 38,56 ----
      NFA_START_COLL,		    /* [abc] start */
      NFA_END_COLL,		    /* [abc] end */
      NFA_START_NEG_COLL,		    /* [^abc] start */
!     NFA_END_NEG_COLL,		    /* [^abc] end (postfix only) */
!     NFA_RANGE,			    /* range of the two previous items
! 				     * (postfix only) */
      NFA_RANGE_MIN,		    /* low end of a range  */
      NFA_RANGE_MAX,		    /* high end of a range  */
  
!     NFA_CONCAT,			    /* concatenate two previous items (postfix
! 				     * only) */
!     NFA_OR,			    /* \| (postfix only) */
!     NFA_STAR,			    /* greedy * (posfix only) */
!     NFA_STAR_NONGREEDY,		    /* non-greedy * (postfix only) */
!     NFA_QUEST,			    /* greedy \? (postfix only) */
!     NFA_QUEST_NONGREEDY,	    /* non-greedy \? (postfix only) */
  
      NFA_BOL,			    /* ^    Begin line */
      NFA_EOL,			    /* $    End line */
***************
*** 153,160 ****
  
      /* NFA_FIRST_NL */
      NFA_ANY,		/*	Match any one character. */
-     NFA_ANYOF,		/*	Match any character in this string. */
-     NFA_ANYBUT,		/*	Match any character not in this string. */
      NFA_IDENT,		/*	Match identifier char */
      NFA_SIDENT,		/*	Match identifier char but no digit */
      NFA_KWORD,		/*	Match keyword char */
--- 153,158 ----
***************
*** 496,503 ****
  
  /*
   * Figure out if the NFA state list contains just literal text and nothing
!  * else.  If so return a string with what must match after regstart.
!  * Otherwise return NULL.
   */
      static char_u *
  nfa_get_match_text(start)
--- 494,501 ----
  
  /*
   * Figure out if the NFA state list contains just literal text and nothing
!  * else.  If so return a string in allocated memory with what must match after
!  * regstart.  Otherwise return NULL.
   */
      static char_u *
  nfa_get_match_text(start)
***************
*** 2578,2583 ****
--- 2576,2800 ----
  }
  
  /*
+  * Estimate the maximum byte length of anything matching "state".
+  * When unknown or unlimited return -1.
+  */
+     static int
+ nfa_max_width(startstate, depth)
+     nfa_state_T *startstate;
+     int		depth;
+ {
+     int		    l, r;
+     nfa_state_T	    *state = startstate;
+     int		    len = 0;
+ 
+     /* detect looping in a NFA_SPLIT */
+     if (depth > 4)
+ 	return -1;
+ 
+     for (;;)
+     {
+ 	switch (state->c)
+ 	{
+ 	    case NFA_END_INVISIBLE:
+ 	    case NFA_END_INVISIBLE_NEG:
+ 		/* the end, return what we have */
+ 		return len;
+ 
+ 	    case NFA_SPLIT:
+ 		/* two alternatives, use the maximum */
+ 		l = nfa_max_width(state->out, depth + 1);
+ 		r = nfa_max_width(state->out1, depth + 1);
+ 		if (l < 0 || r < 0)
+ 		    return -1;
+ 		return len + (l > r ? l : r);
+ 
+ 	    case NFA_ANY:
+ 	    case NFA_START_COLL:
+ 	    case NFA_START_NEG_COLL:
+ 		/* matches some character, including composing chars */
+ #ifdef FEAT_MBYTE
+ 		if (enc_utf8)
+ 		    len += MB_MAXBYTES;
+ 		else if (has_mbyte)
+ 		    len += 2;
+ 		else
+ #endif
+ 		    ++len;
+ 		if (state->c != NFA_ANY)
+ 		{
+ 		    /* skip over the characters */
+ 		    state = state->out1->out;
+ 		    continue;
+ 		}
+ 		break;
+ 
+ 	    case NFA_DIGIT:
+ 	    case NFA_WHITE:
+ 	    case NFA_HEX:
+ 	    case NFA_OCTAL:
+ 		/* ascii */
+ 		++len;
+ 		break;
+ 
+ 	    case NFA_IDENT:
+ 	    case NFA_SIDENT:
+ 	    case NFA_KWORD:
+ 	    case NFA_SKWORD:
+ 	    case NFA_FNAME:
+ 	    case NFA_SFNAME:
+ 	    case NFA_PRINT:
+ 	    case NFA_SPRINT:
+ 	    case NFA_NWHITE:
+ 	    case NFA_NDIGIT:
+ 	    case NFA_NHEX:
+ 	    case NFA_NOCTAL:
+ 	    case NFA_WORD:
+ 	    case NFA_NWORD:
+ 	    case NFA_HEAD:
+ 	    case NFA_NHEAD:
+ 	    case NFA_ALPHA:
+ 	    case NFA_NALPHA:
+ 	    case NFA_LOWER:
+ 	    case NFA_NLOWER:
+ 	    case NFA_UPPER:
+ 	    case NFA_NUPPER:
+ 		/* possibly non-ascii */
+ #ifdef FEAT_MBYTE
+ 		if (has_mbyte)
+ 		    len += 3;
+ 		else
+ #endif
+ 		    ++len;
+ 		break;
+ 
+ 	    case NFA_START_INVISIBLE:
+ 	    case NFA_START_INVISIBLE_NEG:
+ 	    case NFA_START_INVISIBLE_BEFORE:
+ 	    case NFA_START_INVISIBLE_BEFORE_NEG:
+ 		/* zero-width, out1 points to the END state */
+ 		state = state->out1->out;
+ 		continue;
+ 
+ 	    case NFA_BACKREF1:
+ 	    case NFA_BACKREF2:
+ 	    case NFA_BACKREF3:
+ 	    case NFA_BACKREF4:
+ 	    case NFA_BACKREF5:
+ 	    case NFA_BACKREF6:
+ 	    case NFA_BACKREF7:
+ 	    case NFA_BACKREF8:
+ 	    case NFA_BACKREF9:
+ #ifdef FEAT_SYN_HL
+ 	    case NFA_ZREF1:
+ 	    case NFA_ZREF2:
+ 	    case NFA_ZREF3:
+ 	    case NFA_ZREF4:
+ 	    case NFA_ZREF5:
+ 	    case NFA_ZREF6:
+ 	    case NFA_ZREF7:
+ 	    case NFA_ZREF8:
+ 	    case NFA_ZREF9:
+ #endif
+ 	    case NFA_NEWL:
+ 	    case NFA_SKIP:
+ 		/* unknown width */
+ 		return -1;
+ 
+ 	    case NFA_BOL:
+ 	    case NFA_EOL:
+ 	    case NFA_BOF:
+ 	    case NFA_EOF:
+ 	    case NFA_BOW:
+ 	    case NFA_EOW:
+ 	    case NFA_MOPEN:
+ 	    case NFA_MOPEN1:
+ 	    case NFA_MOPEN2:
+ 	    case NFA_MOPEN3:
+ 	    case NFA_MOPEN4:
+ 	    case NFA_MOPEN5:
+ 	    case NFA_MOPEN6:
+ 	    case NFA_MOPEN7:
+ 	    case NFA_MOPEN8:
+ 	    case NFA_MOPEN9:
+ #ifdef FEAT_SYN_HL
+ 	    case NFA_ZOPEN:
+ 	    case NFA_ZOPEN1:
+ 	    case NFA_ZOPEN2:
+ 	    case NFA_ZOPEN3:
+ 	    case NFA_ZOPEN4:
+ 	    case NFA_ZOPEN5:
+ 	    case NFA_ZOPEN6:
+ 	    case NFA_ZOPEN7:
+ 	    case NFA_ZOPEN8:
+ 	    case NFA_ZOPEN9:
+ 	    case NFA_ZCLOSE:
+ 	    case NFA_ZCLOSE1:
+ 	    case NFA_ZCLOSE2:
+ 	    case NFA_ZCLOSE3:
+ 	    case NFA_ZCLOSE4:
+ 	    case NFA_ZCLOSE5:
+ 	    case NFA_ZCLOSE6:
+ 	    case NFA_ZCLOSE7:
+ 	    case NFA_ZCLOSE8:
+ 	    case NFA_ZCLOSE9:
+ #endif
+ 	    case NFA_MCLOSE:
+ 	    case NFA_MCLOSE1:
+ 	    case NFA_MCLOSE2:
+ 	    case NFA_MCLOSE3:
+ 	    case NFA_MCLOSE4:
+ 	    case NFA_MCLOSE5:
+ 	    case NFA_MCLOSE6:
+ 	    case NFA_MCLOSE7:
+ 	    case NFA_MCLOSE8:
+ 	    case NFA_MCLOSE9:
+ 	    case NFA_NOPEN:
+ 	    case NFA_NCLOSE:
+ 
+ 	    case NFA_LNUM_GT:
+ 	    case NFA_LNUM_LT:
+ 	    case NFA_COL_GT:
+ 	    case NFA_COL_LT:
+ 	    case NFA_VCOL_GT:
+ 	    case NFA_VCOL_LT:
+ 	    case NFA_MARK_GT:
+ 	    case NFA_MARK_LT:
+ 	    case NFA_VISUAL:
+ 	    case NFA_LNUM:
+ 	    case NFA_CURSOR:
+ 	    case NFA_COL:
+ 	    case NFA_VCOL:
+ 	    case NFA_MARK:
+ 
+ 	    case NFA_ZSTART:
+ 	    case NFA_ZEND:
+ 	    case NFA_OPT_CHARS:
+ 	    case NFA_SKIP_CHAR:
+ 	    case NFA_START_PATTERN:
+ 	    case NFA_END_PATTERN:
+ 	    case NFA_COMPOSING:
+ 	    case NFA_END_COMPOSING:
+ 		/* zero-width */
+ 		break;
+ 
+ 	    default:
+ 		if (state->c < 0)
+ 		    /* don't know what this is */
+ 		    return -1;
+ 		/* normal character */
+ 		len += MB_CHAR2LEN(state->c);
+ 		break;
+ 	}
+ 
+ 	/* normal way to continue */
+ 	state = state->out;
+     }
+ 
+     /* unrecognized */
+     return -1;
+ }
+ /*
   * Convert a postfix form into its equivalent NFA.
   * Return the NFA start state on success, NULL otherwise.
   */
***************
*** 2856,2863 ****
  	    s = alloc_state(start_state, e.start, s1);
  	    if (s == NULL)
  		goto theend;
- 	    if (before)
- 		s->val = n; /* store the count */
  	    if (pattern)
  	    {
  		/* NFA_ZEND -> NFA_END_PATTERN -> NFA_SKIP -> what follows. */
--- 3073,3078 ----
***************
*** 2871,2876 ****
--- 3086,3099 ----
  	    {
  		patch(e.out, s1);
  		PUSH(frag(s, list1(&s1->out)));
+ 		if (before)
+ 		{
+ 		    if (n <= 0)
+ 			/* See if we can guess the maximum width, it avoids a
+ 			 * lot of pointless tries. */
+ 			n = nfa_max_width(e.start, 0);
+ 		    s->val = n; /* store the count */
+ 		}
  	    }
  	    break;
  	  }
***************
*** 4088,4096 ****
  
  	/* Go back the specified number of bytes, or as far as the
  	 * start of the previous line, to try matching "\@<=" or
! 	 * not matching "\@<!".
! 	 * TODO: This is very inefficient! Would be better to
! 	 * first check for a match with what follows. */
  	if (state->val <= 0)
  	{
  	    if (REG_MULTI)
--- 4311,4318 ----
  
  	/* Go back the specified number of bytes, or as far as the
  	 * start of the previous line, to try matching "\@<=" or
! 	 * not matching "\@<!". This is very ineffecient, limit the number of
! 	 * bytes if possible. */
  	if (state->val <= 0)
  	{
  	    if (REG_MULTI)
***************
*** 4386,4392 ****
  
  /*
   * Check for a match with match_text.
!  * Called after skip_to_start() has find regstart.
   * Returns zero for no match, 1 for a match.
   */
      static long
--- 4608,4614 ----
  
  /*
   * Check for a match with match_text.
!  * Called after skip_to_start() has found regstart.
   * Returns zero for no match, 1 for a match.
   */
      static long
***************
*** 4736,4742 ****
  #ifdef FEAT_SYN_HL
  			    || (cout >= NFA_ZCLOSE && cout <= NFA_ZCLOSE9)
  #endif
- 			    || cout == NFA_NCLOSE
  			    || t->pim != NULL
  			    || (t->state->c != NFA_START_INVISIBLE_BEFORE
  			        && t->state->c != NFA_START_INVISIBLE_BEFORE_NEG
--- 4958,4963 ----
*** ../vim-7.3.1149/src/version.c	2013-06-08 18:19:40.000000000 +0200
--- src/version.c	2013-06-08 22:15:27.000000000 +0200
***************
*** 730,731 ****
--- 730,733 ----
  {   /* Add new patch number below this line */
+ /**/
+     1150,
  /**/

-- 
Amnesia is one of my favorite words, but I forgot what it means.

 /// Bram Moolenaar -- Bram@Moolenaar.net -- http://www.Moolenaar.net   \\\
///        sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\  an exciting new programming language -- http://www.Zimbu.org        ///
 \\\            help me help AIDS victims -- http://ICCF-Holland.org    ///