libtraceevent: Add kbuffer_create()

The kbuffer_alloc() is awkward to use as the size and endianess needs to
be passed in by enum values. Add a kbuffer_create() that only takes a tep
handle, and it determines these values via the handle instead.

Link: https://lore.kernel.org/linux-trace-devel/20221202123854.5761a742@gandalf.local.home

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

2 files changed, 27 insertions, 0 deletions

diff --git a/include/traceevent/kbuffer.h b/include/traceevent/kbuffer.h
index a2b5220..66b0958 100644
--- a/include/traceevent/kbuffer.h
+++ b/include/traceevent/kbuffer.h
@@ -29,6 +29,7 @@ enum {
 struct kbuffer;
 
 struct kbuffer *kbuffer_alloc(enum kbuffer_long_size size, enum kbuffer_endian endian);
+struct kbuffer *kbuffer_create(struct tep_handle *tep);
 void kbuffer_free(struct kbuffer *kbuf);
 int kbuffer_load_subbuffer(struct kbuffer *kbuf, void *subbuffer);
 void *kbuffer_read_event(struct kbuffer *kbuf, unsigned long long *ts);
diff --git a/src/parse-utils.c b/src/parse-utils.c
index 09059ed..ffa6c58 100644
--- a/src/parse-utils.c
+++ b/src/parse-utils.c
@@ -11,6 +11,7 @@
 
 #include "event-utils.h"
 #include "event-parse.h"
+#include "kbuffer.h"
 
 #define __weak __attribute__((weak))
 
@@ -122,3 +123,28 @@ void __weak __vpr_stat(const char *fmt, va_list ap)
 }
 
 void vpr_stat(const char *fmt, va_list ap) __attribute__((weak, alias("__vpr_stat")));
+
+/**
+ * kbuffer_create - create and allocate a new kbuffer
+ * @tep: the data to get the long size and endianess from
+ *
+ * Allocates and returns a new kbuffer.
+ */
+struct kbuffer *kbuffer_create(struct tep_handle *tep)
+{
+	enum kbuffer_endian endian;
+	int long_size;
+
+	long_size = tep_get_long_size(tep);
+	if (long_size == 8)
+		long_size = KBUFFER_LSIZE_8;
+	else
+		long_size = KBUFFER_LSIZE_4;
+
+	if (tep_is_file_bigendian(tep))
+		endian = KBUFFER_ENDIAN_BIG;
+	else
+		endian = KBUFFER_ENDIAN_LITTLE;
+
+	return kbuffer_alloc(long_size, endian);
+}