From f98c6554b0e1dd37e0f992f7b5e67c4431f911a6 Mon Sep 17 00:00:00 2001
From: Philippe Proulx <eeppeliteloop@gmail.com>
Date: Wed, 15 Apr 2015 17:20:25 -0400
Subject: [PATCH] ir: add bt_ctf_field_string_append_len()
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Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---
 formats/ctf/ir/event-fields.c            | 39 ++++++++++++++++++++++++
 include/babeltrace/ctf-ir/event-fields.h | 22 +++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/formats/ctf/ir/event-fields.c b/formats/ctf/ir/event-fields.c
index 92c06da8..c80c12fe 100644
--- a/formats/ctf/ir/event-fields.c
+++ b/formats/ctf/ir/event-fields.c
@@ -946,6 +946,45 @@ end:
 	return ret;
 }
 
+int bt_ctf_field_string_append_len(struct bt_ctf_field *field,
+		const char *value, unsigned int length)
+{
+	int i;
+	int ret = 0;
+	unsigned int effective_length = length;
+	struct bt_ctf_field_string *string_field;
+
+	if (!field || !value ||
+		bt_ctf_field_type_get_type_id(field->type) !=
+			CTF_TYPE_STRING) {
+		ret = -1;
+		goto end;
+	}
+
+	string_field = container_of(field, struct bt_ctf_field_string, parent);
+
+	/* make sure no null bytes are appended */
+	for (i = 0; i < length; ++i) {
+		if (value[i] == '\0') {
+			effective_length = i;
+			break;
+		}
+	}
+
+	if (string_field->payload) {
+		g_string_insert_len(string_field->payload, -1, value,
+			effective_length);
+	} else {
+		string_field->payload = g_string_new_len(value,
+			effective_length);
+	}
+
+	string_field->parent.payload_set = 1;
+
+end:
+	return ret;
+}
+
 BT_HIDDEN
 int bt_ctf_field_validate(struct bt_ctf_field *field)
 {
diff --git a/include/babeltrace/ctf-ir/event-fields.h b/include/babeltrace/ctf-ir/event-fields.h
index 489c2bf8..b102d632 100644
--- a/include/babeltrace/ctf-ir/event-fields.h
+++ b/include/babeltrace/ctf-ir/event-fields.h
@@ -304,6 +304,28 @@ extern int bt_ctf_field_string_set_value(struct bt_ctf_field *string_field,
 extern int bt_ctf_field_string_append(struct bt_ctf_field *string_field,
 		const char *value);
 
+/*
+ * bt_ctf_field_string_append_len: append a string of a given length to
+ * a string field's current value.
+ *
+ * Append a string of a given length to the current value of a string
+ * field. If the string field was never set using
+ * bt_ctf_field_string_set_value(), it is first set to an empty string,
+ * and then the concatenation happens.
+ *
+ * If a null byte is encountered before the given length, only the
+ * substring before the first null byte is appended.
+ *
+ * @param string_field String field instance.
+ * @param value String to append to the current string field's value.
+ * @param length Length of string value to append.
+ *
+ * Returns 0 on success, a negative value on error.
+ */
+extern int bt_ctf_field_string_append_len(
+		struct bt_ctf_field *string_field, const char *value,
+		unsigned int length);
+
 /*
  * bt_ctf_field_get_type: get a field's type
  *
-- 
2.34.1