Merge branch 'ks/rfc2047-one-char-at-a-time' into maint

diff --git a/pretty.c b/pretty.c
index eae57ad9d7f3b06a5a76f9d934825f9824def477..41ffbc92404316027490cb36c6c9971fd4074494 100644 (file)
--- a/pretty.c
+++ b/pretty.c
@@ -345,7 +345,7 @@ static int needs_rfc2047_encoding(const char *line, int len,
        return 0;
 }
 
-static void add_rfc2047(struct strbuf *sb, const char *line, int len,
+static void add_rfc2047(struct strbuf *sb, const char *line, size_t len,
                       const char *encoding, enum rfc2047_type type)
 {
        static const int max_encoded_length = 76; /* per rfc2047 */
@@ -355,9 +355,22 @@ static void add_rfc2047(struct strbuf *sb, const char *line, int len,
        strbuf_grow(sb, len * 3 + strlen(encoding) + 100);
        strbuf_addf(sb, "=?%s?q?", encoding);
        line_len += strlen(encoding) + 5; /* 5 for =??q? */
-       for (i = 0; i < len; i++) {
-               unsigned ch = line[i] & 0xFF;
-               int is_special = is_rfc2047_special(ch, type);
+
+       while (len) {
+               /*
+                * RFC 2047, section 5 (3):
+                *
+                * Each 'encoded-word' MUST represent an integral number of
+                * characters.  A multi-octet character may not be split across
+                * adjacent 'encoded- word's.
+                */
+               const unsigned char *p = (const unsigned char *)line;
+               int chrlen = mbs_chrlen(&line, &len, encoding);
+               int is_special = (chrlen > 1) || is_rfc2047_special(*p, type);
+
+               /* "=%02X" * chrlen, or the byte itself */
+               const char *encoded_fmt = is_special ? "=%02X"    : "%c";
+               int         encoded_len = is_special ? 3 * chrlen : 1;
 
                /*
                 * According to RFC 2047, we could encode the special character
@@ -367,18 +380,15 @@ static void add_rfc2047(struct strbuf *sb, const char *line, int len,
                 * causes ' ' to be encoded as '=20', avoiding this problem.
                 */
 
-               if (line_len + 2 + (is_special ? 3 : 1) > max_encoded_length) {
+               if (line_len + encoded_len + 2 > max_encoded_length) {
+                       /* It won't fit with trailing "?=" --- break the line */
                        strbuf_addf(sb, "?=\n =?%s?q?", encoding);
                        line_len = strlen(encoding) + 5 + 1; /* =??q? plus SP */
                }
 
-               if (is_special) {
-                       strbuf_addf(sb, "=%02X", ch);
-                       line_len += 3;
-               } else {
-                       strbuf_addch(sb, ch);
-                       line_len++;
-               }
+               for (i = 0; i < chrlen; i++)
+                       strbuf_addf(sb, encoded_fmt, p[i]);
+               line_len += encoded_len;
        }
        strbuf_addstr(sb, "?=");
 }