add mflow

1 files changed, 187 insertions, 0 deletions

diff --git a/mflow.c b/mflow.c
new file mode 100644
index 0000000..56af515
--- /dev/null
+++ b/mflow.c
@@ -0,0 +1,187 @@
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "blaze822.h"
+
+int column = 0;
+int maxcolumn = 80;
+
+void
+chgquote(int quotes)
+{
+	static int oquotes;
+
+	if (quotes != oquotes) {
+		if (column)
+			putchar('\n');
+		column = 0;
+		oquotes = quotes;
+	}
+}
+
+void
+fixed(int quotes, char *line, size_t linelen)
+{
+	chgquote(quotes);
+
+	if (linelen > (size_t)(maxcolumn - column)) {
+		putchar('\n');
+		column = 0;
+	}
+
+	if (column == 0) {
+		for (; column < quotes; column++)
+			putchar('>');
+		if (quotes)
+			putchar(' ');
+	}
+
+	fwrite(line, 1, linelen, stdout);
+	putchar('\n');
+	column = 0;
+}
+
+void
+flowed(int quotes, char *line, ssize_t linelen)
+{
+	chgquote(quotes);
+	int done = 0;
+
+	while (!done) {
+		if (column == 0) {
+			for (; column < quotes; column++)
+				putchar('>');
+			column++;
+			if (quotes)
+				putchar(' ');
+		}
+
+		char *eow;
+		if (*line == ' ')
+			eow = memchr(line + 1, ' ', linelen - 1);
+		else
+			eow = memchr(line, ' ', linelen);
+
+		if (!eow) {
+			eow = line + linelen;
+			done = 1;
+		}
+
+		if (column + (eow - line) > maxcolumn) {
+			putchar('\n');
+			column = 0;
+			if (*line == ' ') {
+				line++;
+				linelen--;
+			}
+		} else {
+			fwrite(line, 1, eow - line, stdout);
+			column += eow - line;
+			linelen -= eow - line;
+			line = eow;
+		}
+	}
+}
+
+int
+main()
+{
+	char *linebuf = 0;
+	char *line;
+	size_t linelen = 0;
+	int quotes = 0;
+
+	int reflow = 1;  // re-evaluated on $PIPE_CONTENTTYPE
+	int delsp = 0;
+
+	char *ct = getenv("PIPE_CONTENTTYPE");
+	if (ct) {
+		char *s, *se;
+		blaze822_mime_parameter(ct, "format", &s, &se);
+		reflow = s && (strncasecmp(s, "flowed", 6) == 0);
+		blaze822_mime_parameter(ct, "delsp", &s, &se);
+		delsp = s && (strncasecmp(s, "yes", 3) == 0);
+	}
+
+	char *cols = getenv("COLUMNS");
+	if (cols && isdigit(*cols)) {
+		maxcolumn = atoi(cols);
+	} else {
+		struct winsize w;
+		int fd = open("/dev/tty", O_RDONLY | O_NOCTTY);
+		if (fd >= 0) {
+			if (ioctl(fd, TIOCGWINSZ, &w) == 0)
+				maxcolumn = w.ws_col;
+			close(fd);
+		}
+	}
+
+	char *maxcols = getenv("MAXCOLUMNS");
+	if (maxcols && isdigit(*maxcols)) {
+		int m = atoi(maxcols);
+		if (maxcolumn > m)
+			maxcolumn = m;
+	}
+
+	while (1) {
+		errno = 0;
+		ssize_t rd = getdelim(&linebuf, &linelen, '\n', stdin);
+		if (rd == -1) {
+			if (errno == 0)
+				break;
+			fprintf(stderr, "mflow: error reading: %s\n",
+			    strerror(errno));
+			exit(1);
+		}
+
+		line = linebuf;
+
+		if (!reflow) {
+			fwrite(line, 1, rd, stdout);
+			continue;
+		}
+
+		if (rd > 0 && line[rd-1] == '\n')
+                        line[--rd] = 0;
+		if (rd > 0 && line[rd-1] == '\r')
+                        line[--rd] = 0;
+		
+		quotes = 0;
+		while (*line == '>') {  // measure quote depth
+			line++;
+			quotes++;
+			rd--;
+		}
+
+		if (*line == ' ') {  // space stuffing
+			line++;
+			rd--;
+		}
+
+		if (strcmp(line, "-- ") == 0) {  // usenet signature convention
+			if (column)
+				fixed(quotes, "", 0);  // flush paragraph
+			fixed(quotes, line, rd);
+			continue;
+		}
+
+		if (rd > 0 && line[rd-1] == ' ') {  // flowed line
+			if (delsp)
+				line[--rd] = 0;
+			flowed(quotes, line, rd);
+		} else {
+			fixed(quotes, line, rd);
+		}
+	}
+
+	if (reflow && column != 0)
+		putchar('\n');
+}