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miguel's rewrite of fnematch

--- a/b.c

+++ b/b.c

@@ -759,59 +759,6 @@

 #define MAX_UTF_BYTES	4	// UTF-8 is up to 4 bytes long

-// Read one rune at a time from the given FILE*. Return both

-// the bytes and the actual rune.

-

-struct runedata {

-	int rune;

-	size_t len;

-	char bytes[6];

-};

-

-struct runedata getrune(FILE *fp)

-{

-	struct runedata result;

-	int c, next;

-

-	memset(&result, 0, sizeof(result));

-

-	c = getc(fp);

-	if (c == EOF)

-		return result;	// result.rune == 0 --> EOF

-	else if (c < 128 || awk_mb_cur_max == 1) {

-		result.bytes[0] = c;

-		result.len = 1;

-		result.rune = c;

-

-		return result;

-	}

-

-	// need to get bytes and fill things in

-	result.bytes[0] = c;

-	result.len = 1;

-

-	next = 1;

-	for (int i = 1; i < MAX_UTF_BYTES; i++) {

-		c = getc(fp);

-		if (c == EOF)

-			break;

-		result.bytes[next++] = c;

-		result.len++;

-	}

-

-	// put back any extra input bytes

-	int actual_len = u8_nextlen(result.bytes);

-	while (result.len > actual_len) {

-		ungetc(result.bytes[--result.len], fp);

-	}

-

-	result.bytes[result.len] = '\0';

-	(void) u8_rune(& result.rune, (uschar *) result.bytes);

-

-	return result;

-}

-

-

 /*

  * NAME

  *     fnematch

@@ -829,51 +776,70 @@

 bool fnematch(fa *pfa, FILE *f, char **pbuf, int *pbufsize, int quantum)

 {

-	char *buf = *pbuf;

+	char *i, *j, *k, *buf = *pbuf;

 	int bufsize = *pbufsize;

-	int i, j, k, ns, s;

-	struct runedata r;

+	int c, n, ns, s;

 	s = pfa->initstat;

 	patlen = 0;

 	/*

-	 * All indices relative to buf.

-	 * i <= j <= k <= bufsize

+	 * buf <= i <= j <= k <= buf+bufsize

 	 *

-	 * i: origin of active substring (first byte of first character)

-	 * j: current character		(last byte of current character)

-	 * k: destination of next getc()

+	 * i: origin of active substring

+	 * j: current character

+	 * k: destination of the next getc

 	 */

-	i = -1, k = 0;

-        do {

-		j = i++;

-		do {

-			r = getrune(f);

-			if ((++j + r.len) >= k) {

-				if (k >= bufsize)

-					if (!adjbuf((char **) &buf, &bufsize, bufsize+1, quantum, 0, "fnematch"))

-						FATAL("stream '%.30s...' too long", buf);

-			}

-			memcpy(buf + k, r.bytes, r.len);

-			j += r.len - 1;	// incremented next time around the loop

-			k += r.len;

-			if ((ns = get_gototab(pfa, s, r.rune)) != 0)

-				s = ns;

-			else

-				s = cgoto(pfa, s, r.rune);

+	i = j = k = buf;

-			if (pfa->out[s]) {	/* final state */

-				patlen = j - i + 1;

-				if (r.rune == 0)	/* don't count $ */

-					patlen--;

+	do {

+		/*

+		 * Call u8_rune with at least MAX_UTF_BYTES ahead in

+		 * the buffer until EOF interferes.

+		 */

+		if (k - j < MAX_UTF_BYTES) {

+			if (k + MAX_UTF_BYTES > buf + bufsize) {

+				adjbuf((char **) &buf, &bufsize,

+				    bufsize + MAX_UTF_BYTES,

+				    quantum, 0, "fnematch");

 			}

-		} while (buf[j] && s != 1);

+			for (n = MAX_UTF_BYTES ; n > 0; n--) {

+				*k++ = (c = getc(f)) != EOF ? c : 0;

+				if (c == EOF) {

+					if (ferror(f))

+						FATAL("fnematch: getc error");

+					break;

+				}

+			}

+		}

+

+		j += u8_rune(&c, (uschar *)j);

+

+		if ((ns = get_gototab(pfa, s, c)) != 0)

+			s = ns;

+		else

+			s = cgoto(pfa, s, c);

+

+		if (pfa->out[s]) {	/* final state */

+			patbeg = i;

+			patlen = j - i;

+			if (c == 0)	/* don't count $ */

+				patlen--;

+		}

+

+		if (c && s != 1)

+			continue;  /* origin i still viable, next j */

+		if (patlen)

+			break;     /* best match found */

+

+		/* no match at origin i, next i and start over */

+		i += u8_rune(&c, (uschar *)i);

+		if (c == 0)

+			break;    /* no match */

+		j = i;

 		s = 2;

-		if (r.len > 1)

-			i += r.len - 1;	// i incremented around the loop

-	} while (buf[i] && !patlen);

+	} while (1);

 	/* adjbuf() may have relocated a resized buffer. Inform the world. */

 	*pbuf = buf;

@@ -880,7 +846,6 @@

 	*pbufsize = bufsize;

 	if (patlen) {

-		patbeg = (char *) buf + i;

 		/*

 		 * Under no circumstances is the last character fed to

 		 * the automaton part of the match. It is EOF's nullbyte,

@@ -893,11 +858,10 @@

 		 * terminate the buffer.

 		 */

 		do

-			for (int ii = r.len; ii > 0; ii--)

-				if (buf[--k] && ungetc(buf[k], f) == EOF)

-					FATAL("unable to ungetc '%c'", buf[k]);

-		while (k > i + patlen);

-		buf[k] = '\0';

+			if (*--k && ungetc(*k, f) == EOF)

+				FATAL("unable to ungetc '%c'", *k);

+		while (k > patbeg + patlen);

+		*k = '\0';

 		return true;

 	}

 	else

-- 

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