To: vim-dev@vim.org
Subject: Patch 7.1.235
Fcc: outbox
From: Bram Moolenaar <Bram@moolenaar.net>
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------------
 
Patch 7.1.235
Problem:    Pattern matching is slow when using a lot of simple patterns.
Solution:   Avoid allocating memory by not freeing it when it's not so much.
	    (Alexei Alexandrov)
Files:	    src/regexp.c
 
 
*** ../vim-7.1.234/src/regexp.c	Wed Jan  2 15:34:48 2008
--- src/regexp.c	Fri Jan 18 20:35:21 2008
***************
*** 378,391 ****
  
  static char_u		*reg_prev_sub = NULL;
  
- #if defined(EXITFREE) || defined(PROTO)
-     void
- free_regexp_stuff()
- {
-     vim_free(reg_prev_sub);
- }
- #endif
- 
  /*
   * REGEXP_INRANGE contains all characters which are always special in a []
   * range after '\'.
--- 378,383 ----
***************
*** 3206,3217 ****
  } backpos_T;
  
  /*
!  * regstack and backpos are used by regmatch().  They are kept over calls to
!  * avoid invoking malloc() and free() often.
   */
! static garray_T	regstack;	/* stack with regitem_T items, sometimes
! 				   preceded by regstar_T or regbehind_T. */
! static garray_T	backpos;	/* table with backpos_T for BACK */
  
  /*
   * Get pointer to the line "lnum", which is relative to "reg_firstlnum".
--- 3198,3236 ----
  } backpos_T;
  
  /*
!  * "regstack" and "backpos" are used by regmatch().  They are kept over calls
!  * to avoid invoking malloc() and free() often.
!  * "regstack" is a stack with regitem_T items, sometimes preceded by regstar_T
!  * or regbehind_T.
!  * "backpos_T" is a table with backpos_T for BACK
!  */
! static garray_T	regstack = {0, 0, 0, 0, NULL};
! static garray_T	backpos = {0, 0, 0, 0, NULL};
! 
! /*
!  * Both for regstack and backpos tables we use the following strategy of
!  * allocation (to reduce malloc/free calls):
!  * - Initial size is fairly small.
!  * - When needed, the tables are grown bigger (8 times at first, double after
!  *   that).
!  * - After executing the match we free the memory only if the array has grown.
!  *   Thus the memory is kept allocated when it's at the initial size.
!  * This makes it fast while not keeping a lot of memory allocated.
!  * A three times speed increase was observed when using many simple patterns.
   */
! #define REGSTACK_INITIAL	2048
! #define BACKPOS_INITIAL		64
! 
! #if defined(EXITFREE) || defined(PROTO)
!     void
! free_regexp_stuff()
! {
!     ga_clear(&regstack);
!     ga_clear(&backpos);
!     vim_free(reg_tofree);
!     vim_free(reg_prev_sub);
! }
! #endif
  
  /*
   * Get pointer to the line "lnum", which is relative to "reg_firstlnum".
***************
*** 3346,3360 ****
      char_u	*s;
      long	retval = 0L;
  
!     reg_tofree = NULL;
! 
!     /* Init the regstack empty.  Use an item size of 1 byte, since we push
!      * different things onto it.  Use a large grow size to avoid reallocating
!      * it too often. */
!     ga_init2(&regstack, 1, 10000);
! 
!     /* Init the backpos table empty. */
!     ga_init2(&backpos, sizeof(backpos_T), 10);
  
      if (REG_MULTI)
      {
--- 3365,3389 ----
      char_u	*s;
      long	retval = 0L;
  
!     /* Create "regstack" and "backpos" if they are not allocated yet.
!      * We allocate *_INITIAL amount of bytes first and then set the grow size
!      * to much bigger value to avoid many malloc calls in case of deep regular
!      * expressions.  */
!     if (regstack.ga_data == NULL)
!     {
! 	/* Use an item size of 1 byte, since we push different things
! 	 * onto the regstack. */
! 	ga_init2(&regstack, 1, REGSTACK_INITIAL);
! 	ga_grow(&regstack, REGSTACK_INITIAL);
! 	regstack.ga_growsize = REGSTACK_INITIAL * 8;
!     }
! 
!     if (backpos.ga_data == NULL)
!     {
! 	ga_init2(&backpos, sizeof(backpos_T), BACKPOS_INITIAL);
! 	ga_grow(&backpos, BACKPOS_INITIAL);
! 	backpos.ga_growsize = BACKPOS_INITIAL * 8;
!     }
  
      if (REG_MULTI)
      {
***************
*** 3525,3533 ****
      }
  
  theend:
!     vim_free(reg_tofree);
!     ga_clear(&regstack);
!     ga_clear(&backpos);
  
      return retval;
  }
--- 3554,3570 ----
      }
  
  theend:
!     /* Free "reg_tofree" when it's a bit big.
!      * Free regstack and backpos if they are bigger than their initial size. */
!     if (reg_tofreelen > 400)
!     {
! 	vim_free(reg_tofree);
! 	reg_tofree = NULL;
!     }
!     if (regstack.ga_maxlen > REGSTACK_INITIAL)
! 	ga_clear(&regstack);
!     if (backpos.ga_maxlen > BACKPOS_INITIAL)
! 	ga_clear(&backpos);
  
      return retval;
  }
***************
*** 3717,3724 ****
  #define RA_MATCH	4	/* successful match */
  #define RA_NOMATCH	5	/* didn't match */
  
!   /* Init the regstack and backpos table empty.  They are initialized and
!    * freed in vim_regexec_both() to reduce malloc()/free() calls. */
    regstack.ga_len = 0;
    backpos.ga_len = 0;
  
--- 3754,3761 ----
  #define RA_MATCH	4	/* successful match */
  #define RA_NOMATCH	5	/* didn't match */
  
!   /* Make "regstack" and "backpos" empty.  They are allocated and freed in
!    * vim_regexec_both() to reduce malloc()/free() calls. */
    regstack.ga_len = 0;
    backpos.ga_len = 0;
  
*** ../vim-7.1.234/src/version.c	Fri Jan 18 17:39:10 2008
--- src/version.c	Fri Jan 18 20:33:26 2008
***************
*** 668,669 ****
--- 668,671 ----
  {   /* Add new patch number below this line */
+ /**/
+     235,
  /**/
 
-- 
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 /// Bram Moolenaar -- Bram@Moolenaar.net -- http://www.Moolenaar.net   \\\
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