tweak OSMO_STRBUF_APPEND(), add OSMO_STRBUF_APPEND_NOLEN()
In OSMO_STRBUF_APPEND, use local variable names that are less likely to shadow
other local variables: prefix with _sb_.
In OSMO_STRBUF_APPEND, add a check to add to .pos only if it is not NULL.
Add OSMO_STRBUF_APPEND_NOLEN(), which works for function signatures that don't
return a length. This is useful for any osmo_*_buf() string writing functions,
so that these write directly to the strbuf.
Change-Id: I108cadf72deb3a3bcab9a07e50572d9da1ab0359
diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 474e36c..f13c1e4 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -205,14 +205,14 @@
#define OSMO_STRBUF_APPEND(STRBUF, func, args...) do { \
if (!(STRBUF).pos) \
(STRBUF).pos = (STRBUF).buf; \
- size_t remain = (STRBUF).buf ? (STRBUF).len - ((STRBUF).pos - (STRBUF).buf) : 0; \
- int l = func((STRBUF).pos, remain, ##args); \
- if (l < 0 || l > remain) \
+ size_t _sb_remain = (STRBUF).buf ? (STRBUF).len - ((STRBUF).pos - (STRBUF).buf) : 0; \
+ int _sb_l = func((STRBUF).pos, _sb_remain, ##args); \
+ if (_sb_l < 0 || _sb_l > _sb_remain) \
(STRBUF).pos = (STRBUF).buf + (STRBUF).len; \
- else \
- (STRBUF).pos += l; \
- if (l > 0) \
- (STRBUF).chars_needed += l; \
+ else if ((STRBUF).pos) \
+ (STRBUF).pos += _sb_l; \
+ if (_sb_l > 0) \
+ (STRBUF).chars_needed += _sb_l; \
} while(0)
/*! Shortcut for OSMO_STRBUF_APPEND() invocation using snprintf().
@@ -237,6 +237,29 @@
#define OSMO_STRBUF_PRINTF(STRBUF, fmt, args...) \
OSMO_STRBUF_APPEND(STRBUF, snprintf, fmt, ##args)
+/*! Like OSMO_STRBUF_APPEND(), but for function signatures that return the char* buffer instead of a length.
+ * When using this function, the final STRBUF.chars_needed may not reflect the actual number of characters needed, since
+ * that number cannot be obtained from this kind of function signature.
+ * \param[inout] STRBUF A struct osmo_strbuf instance.
+ * \param[in] func A function with a signature of char *func(char *dst, size_t dst_len [, args]) where
+ * the returned string is always written to dst.
+ * \param[in] args Arguments passed to func, if any.
+ */
+#define OSMO_STRBUF_APPEND_NOLEN(STRBUF, func, args...) do { \
+ if (!(STRBUF).pos) \
+ (STRBUF).pos = (STRBUF).buf; \
+ size_t _sb_remain = (STRBUF).buf ? (STRBUF).len - ((STRBUF).pos - (STRBUF).buf) : 0; \
+ if (_sb_remain) { \
+ func((STRBUF).pos, _sb_remain, ##args); \
+ } \
+ size_t _sb_l = (STRBUF).pos ? strnlen((STRBUF).pos, _sb_remain) : 0; \
+ if (_sb_l > _sb_remain) \
+ (STRBUF).pos = (STRBUF).buf + (STRBUF).len; \
+ else if ((STRBUF).pos) \
+ (STRBUF).pos += _sb_l; \
+ (STRBUF).chars_needed += _sb_l; \
+ } while(0)
+
bool osmo_str_startswith(const char *str, const char *startswith_str);
/*! @} */