1 files changed, 72 insertions, 0 deletions
diff --git a/src/lib-mail/message-header-hash.c b/src/lib-mail/message-header-hash.c
new file mode 100644
index 0000000..05eb791
--- /dev/null
+++ b/src/lib-mail/message-header-hash.c
@@ -0,0 +1,72 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "hash-method.h"
+#include "message-header-hash.h"
+
+void message_header_hash_more(struct message_header_hash_context *ctx,
+			      const struct hash_method *method, void *context,
+			      unsigned int version,
+			      const unsigned char *data, size_t size)
+{
+	size_t i, start;
+
+	i_assert(version >= 1 && version <= MESSAGE_HEADER_HASH_MAX_VERSION);
+
+	if (version == 1) {
+		method->loop(context, data, size);
+		return;
+	}
+	/* - Dovecot IMAP replaces NULs with 0x80 character.
+	   - Dovecot POP3 with outlook-no-nuls workaround replaces NULs
+	   with 0x80 character.
+	   - Zimbra replaces 8bit chars with '?' in header fetches,
+	   but not body fetches.
+	   - Yahoo replaces 8bit chars with '?' in partial header
+	   fetches, but not POP3 TOP. UTF-8 character sequence writes only a
+	   single '?'
+
+	   So we'll just replace all control and 8bit chars with '?' and
+	   remove any repeated '?', which hopefully will satisfy everybody.
+
+	   Also:
+	   - Zimbra removes trailing spaces and tabs from IMAP BODY[HEADER],
+	   but not IMAP BODY[] or POP3 TOP. Just strip away all spaces with
+	   version 3 and tabs also with version 4.
+	*/
+	for (i = start = 0; i < size; i++) {
+		bool cur_is_questionmark = FALSE;
+
+		switch (data[i]) {
+		case ' ':
+			if (version >= 3) {
+				/* strip away spaces */
+				method->loop(context, data + start, i-start);
+				start = i+1;
+			}
+			break;
+		case '\t':
+			if (version >= 4) {
+				/* strip away tabs */
+				method->loop(context, data + start, i-start);
+				start = i+1;
+			}
+			break;
+		case '\n':
+			break;
+		default:
+			if (data[i] < 0x20 || data[i] >= 0x7f || data[i] == '?') {
+				/* remove repeated '?' */
+				if (start < i || !ctx->prev_was_questionmark) {
+					method->loop(context, data + start, i-start);
+					method->loop(context, "?", 1);
+				}
+				start = i+1;
+				cur_is_questionmark = TRUE;
+			}
+			break;
+		}
+		ctx->prev_was_questionmark = cur_is_questionmark;
+	}
+	method->loop(context, data + start, i-start);
+}