+static int base64_append_width(char **prefix, int plen,
+ const char *sep, int indent,
+ const void *p, size_t l,
+ int width) {
+
+ _cleanup_free_ char *x = NULL;
+ char *t, *s;
+ ssize_t slen, len, avail;
+ int line, lines;
+
+ len = base64mem(p, l, &x);
+ if (len <= 0)
+ return len;
+
+ lines = (len + width - 1) / width;
+
+ slen = sep ? strlen(sep) : 0;
+ t = realloc(*prefix, plen + 1 + slen + (indent + width + 1) * lines);
+ if (!t)
+ return -ENOMEM;
+
+ memcpy_safe(t + plen, sep, slen);
+
+ for (line = 0, s = t + plen + slen, avail = len; line < lines; line++) {
+ int act = MIN(width, avail);
+
+ if (line > 0 || sep) {
+ memset(s, ' ', indent);
+ s += indent;
+ }
+
+ memcpy(s, x + width * line, act);
+ s += act;
+ *(s++) = line < lines - 1 ? '\n' : '\0';
+ avail -= act;
+ }
+ assert(avail == 0);
+
+ *prefix = t;
+ return 0;
+}
+
+int base64_append(char **prefix, int plen,
+ const void *p, size_t l,
+ int indent, int width) {
+ if (plen > width / 2 || plen + indent > width)
+ /* leave indent on the left, keep last column free */
+ return base64_append_width(prefix, plen, "\n", indent, p, l, width - indent - 1);
+ else
+ /* leave plen on the left, keep last column free */
+ return base64_append_width(prefix, plen, NULL, plen, p, l, width - plen - 1);
+};
+
+