1 files changed, 123 insertions, 0 deletions
diff --git a/src/fold.c b/src/fold.c
new file mode 100644
index 0000000..64e4534
--- /dev/null
+++ b/src/fold.c
@@ -0,0 +1,123 @@
+/*
+ * fold.c
+ * Implementation of SUSv3 XCU fold utility
+ * Copyright © 2007 Rich Felker
+ * Licensed under the terms of the GNU General Public License, v2 or later
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#include <wchar.h>
+#include <wctype.h>
+#include <unistd.h>
+#include <limits.h>
+#include <locale.h>
+#include <errno.h>
+
+static void my_perror(char *prog, char *msg)
+{
+	char *err = strerror(errno);
+	write(2, prog, strlen(prog));
+	write(2, ": ", 2);
+	write(2, msg, strlen(msg));
+	write(2, ": ", 2);
+	write(2, err, strlen(err));
+	write(2, "\n", 1);
+}
+
+int main(int argc, char *argv[])
+{
+	int b;
+	char *name;
+	char dummy[MB_LEN_MAX];
+	size_t i, j, len=127;
+	wchar_t wc, *buf = malloc(sizeof wc * len);
+	long col, out_col, width=80;
+	int w;
+	int splitable;
+	int byte=0, space=0;
+	FILE *f;
+	
+	if (!setlocale(LC_CTYPE, ""))
+		my_perror(argv[0], "setlocale");
+
+	while ((b = getopt(argc, argv, "bsw:")) != EOF) switch(b) {
+	case 'b': byte=1; break;
+	case 's': space=1; break;
+	case 'w':
+		width=strtoul(optarg, NULL, 10);
+		break;
+	default:
+		return 1;
+	}
+
+	if (optind == argc) {
+		f = stdin;
+		name = "-";
+		goto nofiles;
+	}
+
+	while (optind < argc) {
+		f = fopen(name=argv[optind++], "rb");
+		if (!f) {
+			my_perror(argv[0], name);
+			continue;
+		}
+nofiles:
+		i = col = out_col = 0;
+		splitable = -1;
+		while ((wc = getwc(f))>=0) {
+			if (i == len) {
+				buf = realloc(buf, sizeof wc * (len=len<<1|1));
+				if (!buf) {
+					my_perror(argv[0], "realloc");
+					return 1;
+				}
+			}
+			buf[i++] = wc;
+
+			if (wc == '\n') {
+				col = 0;
+				splitable = -1;
+				goto output;
+			}
+			else if (byte) w = wctomb(dummy, wc);
+			else if (wc == '\t') {
+				w = 8-(col&7);
+				if (w > width - col) w = 8;
+			}
+			else if (wc == '\r') col = w = 0;
+			else if (wc == '\b') {
+				if (col) col--;
+				w = 0;
+			}
+			else w = wcwidth(wc);
+			
+			if (col && w > width - col) {
+				if (putwchar('\n')==WEOF) goto werr;
+				col -= out_col;
+				splitable = -1;
+			}
+			col += w;
+
+			if (space && iswblank(wc))
+				splitable = 1;
+			if (splitable) {
+output:
+				for (j=0; j<i; j++)
+					if (putwchar(buf[j])==WEOF) goto werr;
+				i = 0;
+				out_col = col;
+				splitable >>= 1;
+			}
+		}
+		if (ferror(f)) my_perror(argv[0], name);
+		if (f != stdin) fclose(f);
+	}
+	return 0;
+werr:
+	my_perror(argv[0], "write error");
+	return 1;
+}