ed

commit 87c56d264c0f11c17339bf751e16a5d4020ecb71
parent 43caad39eb764d7de73bf651e97619afe339ceee
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Tue,  8 Dec 2015 21:21:29 +0100

Change getlst() to a getchar() parser alike function

We need this change, because the behaviour of readcmd()
depends on which part of the command we are, so it is
a very bad idea to read the full line at the beginning.
This commit is going to break a lot of things, for sure,
even when the last patch serie try to minimize it, but
it is a big change. Regular expression in address
were disabled, because they were also used in commands,
and since we didn't want to modify them, it was needed
this small inconvenience.

Diffstat:
M
ed.c
 | 
101
++++++++++++++++++++++++++++++++++++++++++++++---------------------------------

1 file changed, 59 insertions(+), 42 deletions(-)
diff --git a/ed.c b/ed.c
@@ -310,22 +310,41 @@ invalid:
 }
 
 static int
+xgetnum(void)
+{
+	int ln, n, c;
+
+	for (ln = 0; isdigit(c = getchar()); ln += n) {
+		if (ln > INT_MAX/10)
+			goto invalid;
+		n = c - '0';
+		ln *= 10;
+		if (INT_MAX - ln < n)
+			goto invalid;
+	}
+	ungetc(c, stdin);
+	return ln;
+
+invalid:
+	error("invalid address");
+}
+
+static int
 linenum(int *line)
 {
-	int ln, c, sign = 1;
+	int ln, c, sign = 1, ret = 1;
 
-	while (isspace(*cmdp))
-		++cmdp;
+	while (isspace(c = getchar()))
+		/* nothing */;
 
-	switch (*cmdp) {
+	switch (c) {
 	case '.':
 		ln = curln;
 		break;
 	case '\'':
-		++cmdp;
-		while (isspace(*cmdp))
-			++cmdp;
-		if (!isalpha(c = *cmdp))
+		while (isspace(c = getchar()))
+			/* nothing */;
+		if (!isalpha(c))
 			error("invalid mark character");
 		if (!(ln = marks[c]))
 			error("invalid address");
@@ -336,21 +355,24 @@ linenum(int *line)
 	case '?':
 		sign = -sign;
 	case '/':
-		c = *cmdp;
-		compile();
-		ln = match(c);
+		// compile();
+		// ln = match(c);
 		break;
-	default:
-		if (!isdigit(*cmdp))
-			return 0;
-		*line = getnum();
 	case '-':
 	case '+':
-		return 1;
+		ln = curln;
+		ungetc(c, stdin);
+		break;
+	default:
+		ungetc(c, stdin);
+		if (isdigit(c))
+			ln = xgetnum();
+		else
+			ret = 0;
+		break;
 	}
-	++cmdp;
 	*line = ln;
-	return 1;
+	return ret;
 }
 
 static int
@@ -358,62 +380,57 @@ address(int *line)
 {
 	int ln, sign, c, num;
 
-	/*
-	 * FIXME:we are getting the full line using
-	 *       a function that deals with escape
-	 *       character, and it means that it
-	 *       will remove the escape characters
-	 *       in the address, transforming
-	 *       /\// into ///, which will produce an
-	 *       error.
-	 */
 	if (!linenum(&ln))
 		return 0;
 
 	for (;;) {
-		while (isspace(*cmdp))
-			++cmdp;
-		c = *cmdp++;
+		while (isspace(c = getchar()))
+			/* nothing */;
 		if (c != '+' && c != '-')
 			break;
 		sign = c == '+';
-		if (!linenum(&num))
-			num = 1;
-		/* FIXME: detect integer overflow here */
+		num = isdigit(ungetc(getchar(), stdin)) ? xgetnum() : 1;
+		num *= sign;
+		if (INT_MAX - ln < num)
+			goto invalid;
 		ln += sign * num;
 	}
-	--cmdp;
+	ungetc(c, stdin);
 
 	if (ln < 0 || ln > lastln)
 		error("invalid address");
 	*line = ln;
 	return 1;
+
+invalid:
+	error("invalid address");
 }
 
 static void
 getlst()
 {
-	int ln;
+	int ln, c;
 
-	if (*cmdp == ',') {
-		++cmdp;
+	if ((c = getchar()) == ',') {
 		line1 = 1;
 		line2 = lastln;
 		nlines = lastln;
 		return;
 	}
+	ungetc(c, stdin);
 	line2 = curln;
 	for (nlines = 0; address(&ln); ) {
 		line1 = line2;
 		line2 = ln;
 		++nlines;
-		while (isspace(*cmdp))
-			++cmdp;
-		if (*cmdp != ',' && *cmdp != ';')
+		while (isspace(c = getchar()))
+			/* nothing */;
+		if (c != ',' && c != ';')
 			break;
-		if (*cmdp++ == ';')
+		if (c == ';')
 			curln = line2;
 	}
+	ungetc(c, stdin);
 	if (nlines > 2)
 		nlines = 2;
 	else if (nlines <= 1)
@@ -1066,8 +1083,8 @@ main(int argc, char *argv[])
 	for (;;) {
 		if (optprompt)
 			fputs(prompt, stdout);
-		readcmd();
 		getlst();
+		readcmd();
 		if (chkglobal())
 			doglobal();
 		else