add osmo_use_count_to_str_c()

So far there is only osmo_use_count_name_buf(). Also provide a use count to
string using a talloc context, allowing to use OTC_SELECT.

- instead of foo_name(), rather use foo_to_str().
- osmo_use_count_name_buf() returns the buf and not the chars_needed. So add
  osmo_use_count_to_str_buf() with a signature that is usable by
  OSMO_NAME_C_IMPL().
- provide osmo_use_count_to_str_c() using OSMO_NAME_C_IMPL().

Change-Id: I1d2e7ee979f8c316ef99f7c65675b36d092ddfca

2 files changed, 27 insertions, 1 deletions

diff --git a/include/osmocom/core/use_count.h b/include/osmocom/core/use_count.h
index a0195259..cc5493c7 100644
--- a/include/osmocom/core/use_count.h
+++ b/include/osmocom/core/use_count.h
@@ -216,6 +216,8 @@ int _osmo_use_count_get_put(struct osmo_use_count *uc, const char *use, int32_t
 			    const char *file, int line);
 
 const char *osmo_use_count_name_buf(char *buf, size_t buf_len, const struct osmo_use_count *uc);
+int osmo_use_count_to_str_buf(char *buf, size_t buf_len, const struct osmo_use_count *uc);
+char *osmo_use_count_to_str_c(void *ctx, const struct osmo_use_count *uc);
 
 int32_t osmo_use_count_total(const struct osmo_use_count *uc);
 int32_t osmo_use_count_by(const struct osmo_use_count *uc, const char *use);
diff --git a/src/use_count.c b/src/use_count.c
index 453d2ae8..738cc5da 100644
--- a/src/use_count.c
+++ b/src/use_count.c
@@ -107,6 +107,19 @@ int32_t osmo_use_count_by(const struct osmo_use_count *uc, const char *use)
  */
 const char *osmo_use_count_name_buf(char *buf, size_t buf_len, const struct osmo_use_count *uc)
 {
+	osmo_use_count_to_str_buf(buf, buf_len, uc);
+	return buf;
+}
+
+/*! Write a comprehensive listing of use counts to a string buffer.
+ * Reads like "12 (3*barring,fighting,8*kungfoo)".
+ * \param[inout] buf  Destination buffer.
+ * \param[in] buf_len  sizeof(buf).
+ * \param[in] uc  Use counts to print.
+ * \return number of bytes that would be written, like snprintf().
+ */
+int osmo_use_count_to_str_buf(char *buf, size_t buf_len, const struct osmo_use_count *uc)
+{
 	int32_t count = osmo_use_count_total(uc);
 	struct osmo_strbuf sb = { .buf = buf, .len = buf_len };
 	struct osmo_use_count_entry *e;
@@ -128,7 +141,18 @@ const char *osmo_use_count_name_buf(char *buf, size_t buf_len, const struct osmo
 	if (first)
 		OSMO_STRBUF_PRINTF(sb, "-");
 	OSMO_STRBUF_PRINTF(sb, ")");
-	return buf;
+	return sb.chars_needed;
+}
+
+/*! Write a comprehensive listing of use counts to a talloc allocated string buffer.
+ * Reads like "12 (3*barring,fighting,8*kungfoo)".
+ * \param[in] ctx  talloc pool to allocate from.
+ * \param[in] uc  Use counts to print.
+ * \return buf, always nul-terminated.
+ */
+char *osmo_use_count_to_str_c(void *ctx, const struct osmo_use_count *uc)
+{
+	OSMO_NAME_C_IMPL(ctx, 32, "ERROR", osmo_use_count_to_str_buf, uc)
 }
 
 /* Return a use token's use count entry -- probably you want osmo_use_count_by() instead.