add osmo_quote_str_buf3, osmo_escape_str_buf3

There already are osmo_quote_str_buf() and osmo_quote_str_buf2(), same
for _escape_, but none of them return the snprintf() like string length.
A private function does, publish this in the API.

The returned chars_needed is required to accurately allocate sufficient
size in string functions that call osmo_quote_str/osmo_escape_str. I am
adding such in osmo-upf.git.

Related: SYS#5599
Change-Id: I05d75a40599e3133da099a11e8babaaad0e9493a
diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 327aa3d..eda0e39 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -157,10 +157,12 @@
 char *osmo_quote_cstr_c(void *ctx, const char *str, int in_len);
 
 const char *osmo_escape_str(const char *str, int len);
+int osmo_escape_str_buf3(char *buf, size_t bufsize, const char *str, int in_len);
 char *osmo_escape_str_buf2(char *buf, size_t bufsize, const char *str, int in_len);
 const char *osmo_escape_str_buf(const char *str, int in_len, char *buf, size_t bufsize);
 char *osmo_escape_str_c(const void *ctx, const char *str, int in_len);
 const char *osmo_quote_str(const char *str, int in_len);
+int osmo_quote_str_buf3(char *buf, size_t bufsize, const char *str, int in_len);
 char *osmo_quote_str_buf2(char *buf, size_t bufsize, const char *str, int in_len);
 const char *osmo_quote_str_buf(const char *str, int in_len, char *buf, size_t bufsize);
 char *osmo_quote_str_c(const void *ctx, const char *str, int in_len);
diff --git a/src/utils.c b/src/utils.c
index 357ed53..2012b74 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -754,7 +754,7 @@
  *                           the non-legacy format also escapes those as "\xNN" sequences.
  * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
  */
-static size_t _osmo_escape_str_buf(char *buf, size_t bufsize, const char *str, int in_len, bool legacy_format)
+static int _osmo_escape_str_buf(char *buf, size_t bufsize, const char *str, int in_len, bool legacy_format)
 {
 	struct osmo_strbuf sb = { .buf = buf, .len = bufsize };
 	int in_pos = 0;
@@ -826,6 +826,18 @@
  * \param[in] bufsize  sizeof(buf).
  * \param[in] str  A string that may contain any characters.
  * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length (also past nul chars).
+ * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
+ */
+int osmo_escape_str_buf3(char *buf, size_t bufsize, const char *str, int in_len)
+{
+	return _osmo_escape_str_buf(buf, bufsize, str, in_len, false);
+}
+
+/*! Return the string with all non-printable characters escaped.
+ * \param[out] buf  string buffer to write escaped characters to.
+ * \param[in] bufsize  sizeof(buf).
+ * \param[in] str  A string that may contain any characters.
+ * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length (also past nul chars).
  * \return The output buffer (buf).
  */
 char *osmo_escape_str_buf2(char *buf, size_t bufsize, const char *str, int in_len)
@@ -883,6 +895,20 @@
 	return sb.chars_needed;
 }
 
+/*! Like osmo_escape_str_buf3(), but returns double-quotes around a string, or "NULL" for a NULL string.
+ * This allows passing any char* value and get its C representation as string.
+ * The function signature is suitable for OSMO_STRBUF_APPEND_NOLEN().
+ * \param[out] buf  string buffer to write escaped characters to.
+ * \param[in] bufsize  sizeof(buf).
+ * \param[in] str  A string that may contain any characters.
+ * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length.
+ * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
+ */
+int osmo_quote_str_buf3(char *buf, size_t bufsize, const char *str, int in_len)
+{
+	return _osmo_quote_str_buf(buf, bufsize, str, in_len, false);
+}
+
 /*! Like osmo_escape_str_buf2(), but returns double-quotes around a string, or "NULL" for a NULL string.
  * This allows passing any char* value and get its C representation as string.
  * The function signature is suitable for OSMO_STRBUF_APPEND_NOLEN().