1 files changed, 165 insertions, 0 deletions
diff --git a/src/lib/str-sanitize.c b/src/lib/str-sanitize.c
new file mode 100644
index 0000000..859640a
--- /dev/null
+++ b/src/lib/str-sanitize.c
@@ -0,0 +1,165 @@
+/* Copyright (c) 2004-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "unichar.h"
+#include "str.h"
+#include "str-sanitize.h"
+
+static size_t str_sanitize_skip_start(const char *src, size_t max_bytes)
+{
+	unichar_t chr;
+	size_t i;
+
+	for (i = 0; i < max_bytes && src[i] != '\0'; ) {
+		int len = uni_utf8_get_char_n(src+i, max_bytes-i, &chr);
+		if (len <= 0)
+			break;
+		if ((unsigned char)src[i] < 32)
+			break;
+		i += len;
+	}
+	i_assert(i <= max_bytes);
+	return i;
+}
+
+
+static size_t
+str_sanitize_skip_start_utf8(const char *src, uintmax_t max_chars)
+{
+	unichar_t chr;
+	uintmax_t c;
+	size_t i;
+
+	for (i = 0, c = 0; c < max_chars && src[i] != '\0'; ) {
+		int len = uni_utf8_get_char(src+i, &chr);
+		if (len <= 0)
+			break;
+		if ((unsigned char)src[i] < 32)
+			break;
+		c++;
+		i += len;
+	}
+	i_assert(c <= max_chars);
+	return i;
+}
+
+static void str_sanitize_truncate_char(string_t *dest, unsigned int initial_pos)
+{
+	const unsigned char *data = str_data(dest);
+	size_t len = str_len(dest);
+
+	i_assert(len >= initial_pos);
+	if (len == initial_pos)
+		return;
+
+	data += initial_pos;
+	len -= initial_pos;
+	str_truncate(dest, initial_pos +
+		uni_utf8_data_truncate(data, len, len-1));
+}
+
+void str_sanitize_append(string_t *dest, const char *src, size_t max_bytes)
+{
+	size_t initial_pos = str_len(dest);
+	unichar_t chr;
+	size_t i;
+
+	for (i = 0; i < max_bytes && src[i] != '\0'; ) {
+		int len = uni_utf8_get_char_n(src+i, max_bytes-i, &chr);
+		if (len == 0)
+			break; /* input ended too early */
+
+		if (len < 0) {
+			/* invalid UTF-8 */
+			str_append_c(dest, '?');
+			i++;
+			continue;
+		}
+		if ((unsigned char)src[i] < 32)
+			str_append_c(dest, '?');
+		else
+			str_append_data(dest, src+i, len);
+		i += len;
+	}
+
+	if (src[i] != '\0') {
+		if (max_bytes < 3)
+			str_truncate(dest, initial_pos);
+		else {
+			while (str_len(dest) - initial_pos > max_bytes-3)
+				str_sanitize_truncate_char(dest, initial_pos);
+		}
+		str_append(dest, "...");
+	}
+}
+
+void str_sanitize_append_utf8(string_t *dest, const char *src,
+			      uintmax_t max_cps)
+{
+	size_t last_pos = 0;
+	unichar_t chr;
+	uintmax_t c;
+	size_t i;
+
+	i_assert(max_cps > 0);
+
+	for (i = 0, c = 0; c < max_cps && src[i] != '\0'; ) {
+		int len = uni_utf8_get_char(src+i, &chr);
+		if (len == 0)
+			break; /* input ended too early */
+
+		last_pos = str_len(dest);
+		if (len < 0) {
+			/* invalid UTF-8 */
+			str_append(dest, UNICODE_REPLACEMENT_CHAR_UTF8);
+			i++;
+			continue;
+		}
+		if ((unsigned char)src[i] < 32)
+			str_append(dest, UNICODE_REPLACEMENT_CHAR_UTF8);
+		else
+			str_append_data(dest, src+i, len);
+		i += len;
+		c++;
+	}
+
+	if (src[i] != '\0') {
+		str_truncate(dest, last_pos);
+		str_append(dest, UNICODE_HORIZONTAL_ELLIPSIS_CHAR_UTF8);
+	}
+}
+
+const char *str_sanitize(const char *src, size_t max_bytes)
+{
+	string_t *str;
+	size_t i;
+
+	if (src == NULL)
+		return NULL;
+
+	i = str_sanitize_skip_start(src, max_bytes);
+	if (src[i] == '\0')
+		return src;
+
+	str = t_str_new(I_MIN(max_bytes, 256));
+	str_sanitize_append(str, src, max_bytes);
+	return str_c(str);
+}
+
+const char *str_sanitize_utf8(const char *src, uintmax_t max_cps)
+{
+	string_t *str;
+	size_t i;
+
+	if (src == NULL)
+		return NULL;
+
+	i = str_sanitize_skip_start_utf8(src, max_cps);
+	if (src[i] == '\0')
+		return src;
+
+	str = t_str_new(I_MIN(max_cps, 256));
+	str_sanitize_append_utf8(str, src, max_cps);
+	return str_c(str);
+}
+