diff -r bf3695fee719 -r 481802342fdf libidav/utils.c
--- a/libidav/utils.c	Mon Feb 04 14:11:57 2019 +0100
+++ b/libidav/utils.c	Mon Feb 04 17:17:48 2019 +0100
@@ -387,9 +387,9 @@
     return url.ptr;
 }
 
-char* util_get_url(DavSession *sn, char *href) {
-    sstr_t base = sstr(sn->base_url);
-    sstr_t href_str = sstr(href);
+char* util_get_url(DavSession *sn, const char *href) {
+    scstr_t base = scstr(sn->base_url);
+    scstr_t href_str = scstr(href);
     
     char *base_path = util_url_path(sn->base_url);
     base.length -= strlen(base_path);
@@ -398,7 +398,7 @@
     return url.ptr;
 }
 
-void util_set_url(DavSession *sn, char *href) {
+void util_set_url(DavSession *sn, const char *href) {
     char *url = util_get_url(sn, href);
     curl_easy_setopt(sn->handle, CURLOPT_URL, url);
     free(url);
@@ -463,7 +463,7 @@
 }
 
 
-char* util_base64decode(char *in) {
+char* util_base64decode(const char *in) {
     int len = 0;
     return util_base64decode_len(in, &len);
 }
@@ -484,7 +484,7 @@
     66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
     66,66,66,66,66,66
 };
-char* util_base64decode_len(char* in, int *outlen) {
+char* util_base64decode_len(const char* in, int *outlen) {
     /* code is mostly from wikibooks */
     
     size_t inlen = strlen(in);
@@ -494,7 +494,7 @@
     
     unsigned char *out = (unsigned char*)outbuf;
     
-    char *end = in + inlen;
+    const char *end = in + inlen;
     char iter = 0;
     uint32_t buf = 0;
     size_t len = 0;
@@ -559,7 +559,7 @@
 
 
 static char* b64enctable = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-char* util_base64encode(char *in, size_t len) {
+char* util_base64encode(const char *in, size_t len) {
     // calculate length of base64 output and create buffer
     size_t outlen = 4 * ((len + 2) / 3);
     int pad = len % 3;