From ff191d4667709b52758fcc5bdc568726d1616be4 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <bonzini@gnu.org>

Date: Tue, 4 May 2010 17:26:09 +0200

Subject: [PATCH] dfa: convert to wide character line-by-line

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This provides a nice speedup for -m in general, but especially

it avoids quadratic complexity in case we have to go to glibc.

Testcases:

   # From upstream backref-multibyte-slow

   yes aba | sed 10000q > aba.txt

   time ./egrep -c '^([a-z]).\1$' aba.txt

   # From rbiba

   time grep '^[a-f][h-j][l-ž]$' cestina-sorted.txt

* src/dfa.c (prepare_wc_buf): Extract out of dfaexec.  Convert

only up to the next newline.

(dfaexec): Exit multibyte processing loop if past buf_end.

Call prepare_wc_buf again after processing a newline.

---

 src/dfa.c |   96 +++++++++++++++++++++++++++++++++++++-----------------------

 1 files changed, 59 insertions(+), 37 deletions(-)

diff --git a/src/dfa.c b/src/dfa.c

index 523fe05..70aa5a8 100644

--- a/src/dfa.c

+++ b/src/dfa.c

@@ -2824,6 +2824,53 @@ transit_state (struct dfa *d, int s, unsigned char const **pp)

 #endif /* MBS_SUPPORT */

+/* Initialize mblen_buf and inputwcs with data from the next line.  */

+

+static void

+prepare_wc_buf (const char *begin, const char *end)

+{

+  unsigned char eol = eolbyte;

+  size_t remain_bytes, i;

+

+  buf_begin = (unsigned char *) begin;

+

+  remain_bytes = 0;

+  for (i = 0; i < end - begin + 1; i++)

+    {

+      if (remain_bytes == 0)

+        {

+          remain_bytes

+            = mbrtowc(inputwcs + i, begin + i, end - begin - i + 1, &mbs);

+          if (remain_bytes < 1

+              || remain_bytes == (size_t) -1

+              || remain_bytes == (size_t) -2

+              || (remain_bytes == 1 && inputwcs[i] == (wchar_t)begin[i]))

+            {

+              remain_bytes = 0;

+              inputwcs[i] = (wchar_t)begin[i];

+              mblen_buf[i] = 0;

+              if (begin[i] == eol)

+                break;

+            }

+          else

+            {

+              mblen_buf[i] = remain_bytes;

+              remain_bytes--;

+            }

+        }

+      else

+        {

+          mblen_buf[i] = remain_bytes;

+          inputwcs[i] = 0;

+          remain_bytes--;

+        }

+    }

+

+  buf_end = (unsigned char *) (begin + i);

+  mblen_buf[i] = 0;

+  inputwcs[i] = 0; /* sentinel */

+}

+

 /* Search through a buffer looking for a match to the given struct dfa.

    Find the first occurrence of a string matching the regexp in the

    buffer, and the shortest possible version thereof.  Return a pointer to

@@ -2870,43 +2917,10 @@ dfaexec (struct dfa *d, char const *begin, char *end,

 #ifdef MBS_SUPPORT

   if (d->mb_cur_max > 1)

     {

-      int remain_bytes, i;

-      buf_begin = (unsigned char *) begin;

-      buf_end = (unsigned char *) end;

-

-      /* initialize mblen_buf, and inputwcs.  */

       MALLOC(mblen_buf, unsigned char, end - begin + 2);

       MALLOC(inputwcs, wchar_t, end - begin + 2);

       memset(&mbs, 0, sizeof(mbstate_t));

-      remain_bytes = 0;

-      for (i = 0; i < end - begin + 1; i++)

-	{

-	  if (remain_bytes == 0)

-	    {

-	      remain_bytes

-		= mbrtowc(inputwcs + i, begin + i, end - begin - i + 1, &mbs);

-	      if (remain_bytes < 1

-		|| (remain_bytes == 1 && inputwcs[i] == (wchar_t)begin[i]))

-		{

-		  remain_bytes = 0;

-		  inputwcs[i] = (wchar_t)begin[i];

-		  mblen_buf[i] = 0;

-		}

-	      else

-		{

-		  mblen_buf[i] = remain_bytes;

-		  remain_bytes--;

-		}

-	    }

-	  else

-	    {

-	      mblen_buf[i] = remain_bytes;

-	      inputwcs[i] = 0;

-	      remain_bytes--;

-	    }

-	}

-      mblen_buf[i] = 0;

-      inputwcs[i] = 0; /* sentinel */

+      prepare_wc_buf (p, end);

     }

 #endif /* MBS_SUPPORT */

@@ -2916,7 +2930,7 @@ dfaexec (struct dfa *d, char const *begin, char *end,

       if (d->mb_cur_max > 1)

 	while ((t = trans[s]))

 	  {

-	    if ((char *) p > end)

+	    if (p > buf_end)

 	      break;

 	    s1 = s;

 	    SKIP_REMAINS_MB_IF_INITIAL_STATE(s, p);

@@ -2985,8 +2999,16 @@ dfaexec (struct dfa *d, char const *begin, char *end,

 	}

       /* If the previous character was a newline, count it. */

-      if (count && (char *) p <= end && p[-1] == eol)

-	++*count;

+      if ((char *) p <= end && p[-1] == eol)

+        {

+          if (count)

+            ++*count;

+

+#ifdef MBS_SUPPORT

+          if (d->mb_cur_max > 1)

+            prepare_wc_buf (p, end);

+#endif

+        }

       /* Check if we've run off the end of the buffer. */

       if ((char *) p > end)

-- 

1.6.6.1