Added a method to bio_writer_t that allows to extract the internal buffer

src/libstrongswan/bio/bio_writer.c

@@ -1,4 +1,7 @@
 /*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
  * Copyright (C) 2010 Martin Willi
  * Copyright (C) 2010 revosec AG
  *
@@ -205,6 +208,15 @@ METHOD(bio_writer_t, get_buf, chunk_t,
 	return chunk_create(this->buf.ptr, this->used);
 }
 
+METHOD(bio_writer_t, extract_buf, chunk_t,
+	private_bio_writer_t *this)
+{
+	chunk_t buf = get_buf(this);
+	this->buf = chunk_empty;
+	this->used = 0;
+	return buf;
+}
+
 METHOD(bio_writer_t, destroy, void,
 	private_bio_writer_t *this)
 {
@@ -236,6 +248,7 @@ bio_writer_t *bio_writer_create(u_int32_t bufsize)
 			.wrap24 = _wrap24,
 			.wrap32 = _wrap32,
 			.get_buf = _get_buf,
+			.extract_buf = _extract_buf,
 			.destroy = _destroy,
 		},
 		.increase = bufsize ? max(bufsize, 4) : 32,

src/libstrongswan/bio/bio_writer.h

@@ -1,4 +1,7 @@
 /*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
  * Copyright (C) 2010 Martin Willi
  * Copyright (C) 2010 revosec AG
  *
@@ -27,6 +30,8 @@ typedef struct bio_writer_t bio_writer_t;
 
 /**
  * Buffered output generator.
+ *
+ * @note Integers are converted to network byte order before writing.
  */
 struct bio_writer_t {
 
@@ -127,6 +132,14 @@ struct bio_writer_t {
 	 */
 	chunk_t (*get_buf)(bio_writer_t *this);
 
+	/**
+	 * Return the encoded data buffer and detach it from the writer (resets
+	 * the internal buffer).
+	 *
+	 * @return			chunk to internal buffer (has to be freed)
+	 */
+	chunk_t (*extract_buf)(bio_writer_t *this);
+
 	/**
 	 * Destroy a bio_writer_t.
 	 */
@@ -136,6 +149,9 @@ struct bio_writer_t {
 /**
  * Create a bio_writer instance.
  *
+ * The size of the internal buffer is increased automatically by bufsize (or a
+ * default if not given) if the initial size does not suffice.
+ *
  * @param bufsize		initially allocated buffer size
  */
 bio_writer_t *bio_writer_create(u_int32_t bufsize);