Move utilities to util/

app/src/util/str_util.h

@@ -0,0 +1,42 @@
+#ifndef STRUTIL_H
+#define STRUTIL_H
+
+#include <stddef.h>
+
+#include "config.h"
+
+// like strncpy, except:
+//  - it copies at most n-1 chars
+//  - the dest string is nul-terminated
+//  - it does not write useless bytes if strlen(src) < n
+//  - it returns the number of chars actually written (max n-1) if src has
+//    been copied completely, or n if src has been truncated
+size_t
+xstrncpy(char *dest, const char *src, size_t n);
+
+// join tokens by sep into dst
+// returns the number of chars actually written (max n-1) if no trucation
+// occurred, or n if truncated
+size_t
+xstrjoin(char *dst, const char *const tokens[], char sep, size_t n);
+
+// quote a string
+// returns the new allocated string, to be freed by the caller
+char *
+strquote(const char *src);
+
+// return the index to truncate a UTF-8 string at a valid position
+size_t
+utf8_truncation_index(const char *utf8, size_t max_len);
+
+#ifdef _WIN32
+// convert a UTF-8 string to a wchar_t string
+// returns the new allocated string, to be freed by the caller
+wchar_t *
+utf8_to_wide_char(const char *utf8);
+
+char *
+utf8_from_wide_char(const wchar_t *s);
+#endif
+
+#endif