ed

commit 13aeb0226d445fbf9e821699ae8ab67fd624489f
parent ee3e77b402e49dba4684f245ffd2094c57554eb1
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sun, 13 Dec 2015 11:23:25 +0100

First functional version of 's' command

This version tries to hide the use of regexec
as much as possible. All the work is done in
3 functions, addpre, addsub and addpost,
which copy the text before the match,
the text of the substitution and the text
after the match.

Diffstat:
M
ed.c
 | 
106
++++++++++++++++++++++++++++++++++++++++++++++---------------------------------

1 file changed, 62 insertions(+), 44 deletions(-)
diff --git a/ed.c b/ed.c
@@ -49,6 +49,7 @@ char *ocmdline;
 size_t cmdsiz, cmdcap;
 int repidx;
 char *rhs;
+char *lastmatch;
 
 static void
 error(char *msg)
@@ -319,9 +320,17 @@ compile(int delim)
 }
 
 static int
-match(int num, int flags)
+match(int num)
 {
-	return !regexec(pattern, gettxt(num), 10, matchs, flags);
+	lastmatch = gettxt(num);
+	return !regexec(pattern, lastmatch, 10, matchs, 0);
+}
+
+static int
+rematch(int num)
+{
+	lastmatch += matchs[0].rm_eo;
+	return !regexec(pattern, lastmatch, 10, matchs, 0);
 }
 
 static int
@@ -332,7 +341,7 @@ search(int way)
 	i = curln;
 	do {
 		i = (way == '?') ? prevln(i) : nextln(i);
-		if (match(i, 0))
+		if (match(i))
 			return i;
 	} while (i != curln);
 
@@ -841,6 +850,8 @@ getnth(void)
 	if ((c = input()) == 'g') {
 		return -1;
 	} else if (isdigit(c)) {
+		if (c == '0')
+			return -1;
 		return c - '0';
 	} else {
 		back(c);
@@ -849,60 +860,67 @@ getnth(void)
 }
 
 static void
+addpre(char **s, size_t *cap, size_t *siz)
+{
+	char *p;
+
+	for (p = lastmatch; p < lastmatch + matchs[0].rm_so; ++p)
+		*s = addchar(*p, *s, cap, siz);
+}
+
+static void
+addpost(char **s, size_t *cap, size_t *siz)
+{
+	char c, *p;
+
+	for (p = lastmatch + matchs[0].rm_eo; c = *p; ++p)
+		*s = addchar(c, *s, cap, siz);
+	*s = addchar('\0', *s, cap, siz);
+}
+
+static void
+addsub(char **s, size_t *cap, size_t *siz)
+{
+	char *p, c;
+
+	for (p = rhs; c = *p; ++p)
+		*s = addchar(c, *s, cap, siz);
+}
+
+static void
 subline(int num, int nth)
 {
-	char *s, *p, *t, c, *q;
-	size_t siz, cap;
-	static char *line;
-	regmatch_t m[10], *mp;
-
-	free(line);
-	line = NULL;
-
-	p = s = gettxt(num);
-	while (nth--) {
-		if (!regexec(pattern, s, 10, m, 0))
-			return;
-		p += m[0].rm_eo;
-		if (nth <= 0)
-			break;
-	}
+	int m, changed;
+	static char *s;
+	static size_t siz, cap;
 
-	siz = cap = 0;
-	for (t = s; p > t; ++t)
-		line = addchar(*t++, line, &cap, &siz);
-
-	for (t = rhs; c = *t; ++t) {
-		switch (c) {
-		case '\\':
-			if (!isdigit(*t))
-				goto add_char;
-			mp = &m[*t++ - '0'];
-			goto add_string;
-		case '&':
-			mp = &m[0];
-		add_string:
-			for (q = s + mp->rm_so; q < s + mp->rm_eo; ++q)
-				line = addchar(*q, line, &cap, &siz);
-			break;
-		default:
-		add_char:
-			line = addchar(c, line, &cap, &siz);
+	siz = 0;
+	for (m = match(num); m; m = rematch(num)) {
+		if (--nth > 0)
+			continue;
+		changed = 1;
+		addpre(&s, &cap, &siz);
+		addsub(&s, &cap, &siz);
+		if (nth == 0)
 			break;
-		}
 	}
+	if (!changed)
+		return;
+	addpost(&s, &cap, &siz);
+	delete(num, num);
+	curln = prevln(num);
+	inject(s);
 }
 
 static void
 subst(void)
 {
-	int delim, nth, i;
-	char *s;
+	int nth, i;
 
 	nth = getnth();
-
 	for (i = line1; i <= line2; i = nextln(i))
 		subline(i, nth);
+	curln = line2;
 }
 
 static void
@@ -1152,7 +1170,7 @@ chkglobal(void)
 		if (i >= line1 && i <= line2)
 			v = 0;
 		else
-			v = match(i, 0) == dir;
+			v = match(i) == dir;
 		setglobal(i, v);
 	}