1 files changed, 138 insertions, 0 deletions
diff --git a/rfc822/encodeautodetect.c b/rfc822/encodeautodetect.c
new file mode 100644
index 0000000..ad1ebc6
--- /dev/null
+++ b/rfc822/encodeautodetect.c
@@ -0,0 +1,138 @@
+/*
+** Copyright 2003-2011 Double Precision, Inc.  See COPYING for
+** distribution information.
+*/
+
+/*
+*/
+#include	"encode.h"
+#include	<string.h>
+#include	<stdlib.h>
+#include	"../unicode/unicode.h"
+
+static const char *libmail_encode_autodetect(int use7bit,
+					     int (*func)(void *), void *arg,
+					     int *binaryflag)
+{
+	int	l=0;
+	int	longline=0;
+	int c;
+
+	size_t charcnt=0;
+	size_t bit8cnt=0;
+
+	if (binaryflag)
+		*binaryflag=0;
+
+	while ((c = (*func)(arg)) != EOF)
+	{
+		unsigned char ch= (unsigned char)c;
+
+		++charcnt;
+
+		++l;
+		if (ch < 0x20 || ch >= 0x80)
+		{
+			if (ch != '\t' && ch != '\r' && ch != '\n')
+			{
+				++bit8cnt;
+				l += 2;
+			}
+		}
+
+		if (ch == 0)
+		{
+			if (binaryflag)
+				*binaryflag=1;
+
+			return "base64";
+		}
+
+		if (ch == '\n')	l=0;
+		else if (l > 990)
+		{
+			longline=1;
+		}
+
+	}
+
+	if (use7bit || longline)
+	{
+		if (bit8cnt > charcnt / 10)
+			return "base64";
+
+		return "quoted-printable";
+	}
+
+	return bit8cnt ? "8bit":"7bit";
+}
+
+struct file_info {
+	FILE *fp;
+	off_t pos;
+	off_t end;
+};
+
+static int read_file(void *arg)
+{
+int c;
+struct file_info *fi = (struct file_info *)arg;
+	if (fi->end >= 0 && fi->pos > fi->end)
+		return EOF;
+	c = getc(fi->fp);
+	fi->pos++;
+	return c;
+}
+
+static int read_string(void * arg)
+{
+int c;
+unsigned char **strp = (unsigned char **)arg;
+	if (**strp == 0)
+		return EOF;
+	c = (int)**strp;
+	(*strp)++;
+	return c;
+}
+
+const char *libmail_encode_autodetect_fp(FILE *fp, int use7bit,
+					 int *binaryflag)
+{
+	return libmail_encode_autodetect_fpoff(fp, use7bit, 0, -1,
+					       binaryflag);
+}
+
+const char *libmail_encode_autodetect_fpoff(FILE *fp, int use7bit,
+					    off_t start_pos, off_t end_pos,
+					    int *binaryflag)
+{
+struct file_info fi;
+off_t orig_pos = ftell(fp);
+off_t pos = orig_pos;
+const char *rc;
+
+	if (start_pos >= 0)
+	{
+		if (fseek(fp, start_pos, SEEK_SET) == (off_t)-1)
+			return NULL;
+		else
+			pos = start_pos;
+	}
+
+	fi.fp = fp;
+	fi.pos = pos;
+	fi.end = end_pos;
+
+	rc = libmail_encode_autodetect(use7bit, &read_file, &fi,
+				       binaryflag);
+  
+	if (fseek(fp, orig_pos, SEEK_SET) == (off_t)-1)
+		return NULL;
+	return rc;
+}
+
+const char *libmail_encode_autodetect_buf(const char *str, int use7bit)
+{
+	return libmail_encode_autodetect(use7bit, &read_string, &str,
+					 NULL);
+}