Milestone 5: deliver embedded RDP sessions and lifecycle hardening

third_party/FreeRDP/include/freerdp/utils/ringbuffer.h

@@ -0,0 +1,138 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Implementation
+ *
+ * Copyright 2014 Thincast Technologies GmbH
+ * Copyright 2014 Hardening <contact@hardening-consulting.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FREERDP_UTILS_RINGBUFFER_H
+#define FREERDP_UTILS_RINGBUFFER_H
+
+#include <winpr/wtypes.h>
+#include <freerdp/api.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+	/** @brief ring buffer meta data */
+	typedef struct
+	{
+		size_t initialSize;
+		size_t freeSize;
+		size_t size;
+		size_t readPtr;
+		size_t writePtr;
+		BYTE* buffer;
+	} RingBuffer;
+
+	/** @brief a piece of data in the ring buffer, exactly like a glibc iovec */
+	typedef struct
+	{
+		size_t size;
+		const BYTE* data;
+	} DataChunk;
+
+	/**
+	 * initialise a ringbuffer
+	 *
+	 * @param initialSize the initial capacity of the ringBuffer
+	 * @return if the initialisation was successful
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API BOOL ringbuffer_init(RingBuffer* ringbuffer, size_t initialSize);
+
+	/**
+	 * destroys internal data used by this ringbuffer
+	 *
+	 * @param ringbuffer A pointer to the ringbuffer
+	 */
+	FREERDP_API void ringbuffer_destroy(RingBuffer* ringbuffer);
+
+	/**
+	 * computes the space used in this ringbuffer
+	 *
+	 * @param ringbuffer A pointer to the ringbuffer
+	 * @return the number of bytes stored in that ringbuffer
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API size_t ringbuffer_used(const RingBuffer* ringbuffer);
+
+	/** returns the capacity of the ring buffer
+	 *
+	 * @param ringbuffer A pointer to the ringbuffer
+	 * @return the capacity of this ring buffer
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API size_t ringbuffer_capacity(const RingBuffer* ringbuffer);
+
+	/** writes some bytes in the ringbuffer, if the data doesn't fit, the ringbuffer
+	 * is resized automatically
+	 *
+	 * @param ringbuffer the ringbuffer
+	 * @param ptr a pointer on the data to add
+	 * @param sz the size of the data to add
+	 * @return if the operation was successful, it could fail in case of OOM during realloc()
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API BOOL ringbuffer_write(RingBuffer* ringbuffer, const BYTE* ptr, size_t sz);
+
+	/** ensures that we have sz bytes available at the write head, and return a pointer
+	 * on the write head
+	 *
+	 * @param ringbuffer the ring buffer
+	 * @param sz the size to ensure
+	 * @return a pointer on the write head, or nullptr in case of OOM
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API BYTE* ringbuffer_ensure_linear_write(RingBuffer* ringbuffer, size_t sz);
+
+	/** move ahead the write head in case some byte were written directly by using
+	 * a pointer retrieved via ringbuffer_ensure_linear_write(). This function is
+	 * used to commit the written bytes. The provided size should not exceed the
+	 * size ensured by ringbuffer_ensure_linear_write()
+	 *
+	 * @param ringbuffer the ring buffer
+	 * @param sz the number of bytes that have been written
+	 * @return if the operation was successful, FALSE is sz is too big
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API BOOL ringbuffer_commit_written_bytes(RingBuffer* ringbuffer, size_t sz);
+
+	/** peeks the buffer chunks for sz bytes and returns how many chunks are filled.
+	 * Note that the sum of the resulting chunks may be smaller than sz.
+	 *
+	 * @param ringbuffer the ringbuffer
+	 * @param chunks an array of data chunks that will contain data / size of chunks
+	 * @param sz the requested size
+	 * @return the number of chunks used for reading sz bytes
+	 */
+	WINPR_ATTR_NODISCARD
+	FREERDP_API int ringbuffer_peek(const RingBuffer* ringbuffer, DataChunk chunks[2], size_t sz);
+
+	/** move ahead the read head in case some byte were read using ringbuffer_peek()
+	 * This function is used to commit the bytes that were effectively consumed.
+	 *
+	 * @param ringbuffer the ring buffer
+	 * @param sz the number of bytes to read
+	 */
+	FREERDP_API void ringbuffer_commit_read_bytes(RingBuffer* ringbuffer, size_t sz);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* FREERDP_UTILS_RINGBUFFER_H */