/**

 * 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>

/** @brief ring buffer meta data */

struct _RingBuffer {

	size_t initialSize;

	size_t freeSize;

	size_t size;

	size_t readPtr;

	size_t writePtr;

	BYTE *buffer;

};

typedef struct _RingBuffer RingBuffer;

/** @brief a piece of data in the ring buffer, exactly like a glibc iovec */

struct _DataChunk {

	size_t size;

	const BYTE *data;

};

typedef struct _DataChunk DataChunk;

#ifdef __cplusplus

extern "C" {

#endif

/** initialise a ringbuffer

 * @param initialSize the initial capacity of the ringBuffer

 * @return if the initialisation was successful

 */

FREERDP_API BOOL ringbuffer_init(RingBuffer *rb, size_t initialSize);

/** destroys internal data used by this ringbuffer

 * @param ringbuffer

 */

FREERDP_API void ringbuffer_destroy(RingBuffer *ringbuffer);

/** computes the space used in this ringbuffer

 * @param ringbuffer

 * @return the number of bytes stored in that ringbuffer

 */

FREERDP_API size_t ringbuffer_used(const RingBuffer *ringbuffer);

/** returns the capacity of the ring buffer

 * @param ringbuffer

 * @return the capacity of this ring buffer

 */

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 rb 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()

 */

FREERDP_API BOOL ringbuffer_write(RingBuffer *rb, 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 rb the ring buffer

 * @param sz the size to ensure

 * @return a pointer on the write head, or NULL in case of OOM

 */

FREERDP_API BYTE *ringbuffer_ensure_linear_write(RingBuffer *rb, 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 rb 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

 */

FREERDP_API BOOL ringbuffer_commit_written_bytes(RingBuffer *rb, 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 rb 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

 */

FREERDP_API int ringbuffer_peek(const RingBuffer *rb, 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 rb the ring buffer

 * @param sz the

 */

FREERDP_API void ringbuffer_commit_read_bytes(RingBuffer *rb, size_t sz);

#ifdef __cplusplus

}

#endif

#endif /* FREERDP_UTILS_RINGBUFFER_H */