Add libString.

src/libString/s_getline.c

@@ -0,0 +1,72 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include "libString.h"
+
+/* Append an input line to a String.
+ *
+ * Returns a pointer to the character string (or 0).
+ * Leading whitespace and newlines are removed.
+ *
+ * Empty lines and lines starting with '#' are ignored.
+ */ 
+extern char *
+s_getline(Biobuf *fp, String *to)
+{
+	int c;
+	int len=0;
+
+	s_terminate(to);
+
+	/* end of input */
+	if ((c = Bgetc(fp)) < 0)
+		return 0;
+
+	/* take care of inconsequentials */
+	for(;;) {
+		/* eat leading white */
+		while(c==' ' || c=='\t' || c=='\n' || c=='\r')
+			c = Bgetc(fp);
+
+		if(c < 0)
+			return 0;
+
+		/* take care of comments */
+		if(c == '#'){
+			do {
+				c = Bgetc(fp);
+				if(c < 0)
+					return 0;
+			} while(c != '\n');
+			continue;
+		}
+
+		/* if we got here, we've gotten something useful */
+		break;
+	}
+
+	/* gather up a line */
+	for(;;) {
+		len++;
+		switch(c) {
+		case -1:
+			s_terminate(to);
+			return len ? to->ptr-len : 0;
+		case '\\':
+			c = Bgetc(fp);
+			if (c != '\n') {
+				s_putc(to, '\\');
+				s_putc(to, c);
+			}
+			break;
+		case '\n':
+			s_terminate(to);
+			return len ? to->ptr-len : 0;
+		default:
+			s_putc(to, c);
+			break;
+		}
+		c = Bgetc(fp);
+	}
+	return 0;
+}