1 files changed, 130 insertions, 0 deletions
diff --git a/util/sbase/fold.c b/util/sbase/fold.c
new file mode 100644
index 00000000..6c7b9e7b
--- /dev/null
+++ b/util/sbase/fold.c
@@ -0,0 +1,130 @@
+/* See LICENSE file for copyright and license details. */
+#include <ctype.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "text.h"
+#include "util.h"
+#include "utf.h"
+
+static int    bflag = 0;
+static int    sflag = 0;
+static size_t width = 80;
+
+static void
+foldline(struct line *l, const char *fname) {
+	size_t i, col, last, spacesect, len;
+	Rune r;
+	int runelen;
+
+	for (i = 0, last = 0, col = 0, spacesect = 0; i < l->len; i += runelen) {
+		if (col >= width && ((l->data[i] != '\r' && l->data[i] != '\b') || bflag)) {
+			if (bflag && col > width)
+				i -= runelen;	/* never split a character */
+			len = ((sflag && spacesect) ? spacesect : i) - last;
+			if (fwrite(l->data + last, 1, len, stdout) != len)
+				eprintf("fwrite <stdout>:");
+			if (l->data[i] != '\n')
+				putchar('\n');
+			if (sflag && spacesect)
+				i = spacesect;
+			last = i;
+			col = 0;
+			spacesect = 0;
+		}
+		runelen = charntorune(&r, l->data + i, l->len - i);
+		if (!runelen || r == Runeerror)
+			eprintf("charntorune: %s: invalid utf\n", fname);
+		if (sflag && isblankrune(r))
+			spacesect = i + runelen;
+		if (!bflag && iscntrl(l->data[i])) {
+			switch(l->data[i]) {
+			case '\b':
+				col -= (col > 0);
+				break;
+			case '\r':
+				col = 0;
+				break;
+			case '\t':
+				col += (8 - (col % 8));
+				if (col >= width)
+					i--;
+				break;
+			}
+		} else {
+			col += bflag ? runelen : 1;
+		}
+	}
+	if (l->len - last)
+		fwrite(l->data + last, 1, l->len - last, stdout);
+}
+
+static void
+fold(FILE *fp, const char *fname)
+{
+	static struct line line;
+	static size_t size = 0;
+	ssize_t len;
+
+	while ((len = getline(&line.data, &size, fp)) > 0) {
+		line.len = len;
+		foldline(&line, fname);
+	}
+	if (ferror(fp))
+		eprintf("getline %s:", fname);
+}
+
+static void
+usage(void)
+{
+	eprintf("usage: %s [-bs] [-w num | -num] [FILE ...]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	FILE *fp;
+	int ret = 0;
+
+	ARGBEGIN {
+	case 'b':
+		bflag = 1;
+		break;
+	case 's':
+		sflag = 1;
+		break;
+	case 'w':
+		width = estrtonum(EARGF(usage()), 1, MIN(LLONG_MAX, SIZE_MAX));
+		break;
+	ARGNUM:
+		if (!(width = ARGNUMF()))
+			eprintf("illegal width value, too small\n");
+		break;
+	default:
+		usage();
+	} ARGEND
+
+	if (!argc) {
+		fold(stdin, "<stdin>");
+	} else {
+		for (; *argv; argc--, argv++) {
+			if (!strcmp(*argv, "-")) {
+				*argv = "<stdin>";
+				fp = stdin;
+			} else if (!(fp = fopen(*argv, "r"))) {
+				weprintf("fopen %s:", *argv);
+				ret = 1;
+				continue;
+			}
+			fold(fp, *argv);
+			if (fp != stdin && fshut(fp, *argv))
+				ret = 1;
+		}
+	}
+
+	ret |= fshut(stdin, "<stdin>") | fshut(stdout, "<stdout>");
+
+	return ret;
+}