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