106 lines
4.2 KiB
C
106 lines
4.2 KiB
C
/*
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* lib/circ_buf_packet.h
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*
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* Copyright (C) 2012-2017, Samsung Electronics Co., Ltd.
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*
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* Circular buffer packet operations.
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*/
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#ifndef __LIB_CIRC_BUF_PACKET_H__
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#define __LIB_CIRC_BUF_PACKET_H__
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/**
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* Function returns required size of buffer to fit packet's payload of specified size.
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* @param[in] size packet's payload size
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* @return size of buffer sufficient for transmitting of packet
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*/
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size_t circ_buf_size_for_packet(size_t size);
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/**
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* Function writes packet with the specified buffer to circ_buf.
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* Function updates circ_buf write counter.
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* @param[in] circ_buf_desc descriptor of buffer to write buf to
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* @param[in] buf input buf to write to buffer
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* @param[in] length amount of bytes to write
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* @param[in] mode enum indicating whether passed buf
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* belongs to userspace or kernel memory
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* @return number of bytes written on success or error code
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*/
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ssize_t circ_buf_write_packet(struct circ_buf_desc *circ_buf_desc, const char *buf,
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size_t length, enum circ_buf_user_mode mode);
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/**
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* Function writes packet with the specified buffer to circ_buf.
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* Function does not update circ_buf write counter.
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* @param[in] circ_buf_desc descriptor of buffer to write buf to
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* @param[in] buf input buf to write to buffer
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* @param[in] length amount of bytes to write
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* @param[in] mode enum indicating whether passed buf
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* belongs to userspace or kernel memory
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* @return number of bytes written on success or error code
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*/
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ssize_t circ_buf_write_packet_local(struct circ_buf_desc *circ_buf_desc, const char *buf,
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size_t length, enum circ_buf_user_mode mode);
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/**
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* Function reads packet from circ_buf to output buf.
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* Function updates circ_buf read counter.
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* @param[in] circ_buf_desc descriptor of buffer to read from
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* @param[in] buf output buf to read from buffer
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* @param[in] length maximum size of message to read
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* @param[in] mode enum indicating whether passed buf
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* belongs to userspace or kernel memory,
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* or contents of circ_buf must be simply dropped.
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* @return number of bytes read on success or error code
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*/
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ssize_t circ_buf_read_packet(struct circ_buf_desc *circ_buf_desc, char *buf,
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size_t length, enum circ_buf_user_mode mode);
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/**
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* Function reads packet from circ_buf to output buf.
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* Function does not update circ_buf read counter.
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* @param[in] circ_buf_desc descriptor of buffer to read from
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* @param[in] buf output buf to read from buffer
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* @param[in] length maximum size of message to read
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* @param[in] mode enum indicating whether passed buf
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* belongs to userspace or kernel memory,
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* or contents of circ_buf must be simply dropped.
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* @return number of bytes read on success or error code
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*/
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ssize_t circ_buf_read_packet_local(struct circ_buf_desc *circ_buf_desc, char *buf,
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size_t length, enum circ_buf_user_mode mode);
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/**
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* Function drops one packet from the circ_buf.
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* Function updates circ_buf read counter.
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* @param[in] circ_buf_desc descriptor of buffer to drop packet in
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* @return number of bytes dropped on success or error code
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*/
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ssize_t circ_buf_drop_packet(struct circ_buf_desc *circ_buf_desc);
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/**
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* Function drops one packet from the circ_buf.
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* Function does not update circ_buf read counter.
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* @param[in] circ_buf_desc descriptor of buffer to drop packet in
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* @return number of bytes dropped on success or error code
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*/
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ssize_t circ_buf_drop_packet_local(struct circ_buf_desc *circ_buf_desc);
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/**
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* Function checks if there is an available packet in the circ_buf,
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* and copies its contents by specified offset and length. Function does not
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* modify any counters and leaves circ_buf in the state it was before call.
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* @param[in] circ_buf_desc descriptor of buffer to read from
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* @param[in] buf output buf to read from buffer
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* @param[in] length number of bytes to read
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* @param[in] offset offset in packet to read from
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* @param[in] mode enum indicating whether passed buf
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* belongs to userspace or kernel memory,
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* or contents of circ_buf must be simply dropped.
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* @return number of bytes read on success or error code
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*/
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ssize_t circ_buf_peek_packet(struct circ_buf_desc *circ_buf_desc, char *buf,
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size_t length, size_t offset, enum circ_buf_user_mode mode);
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#endif /* __LIB_CIRC_BUF_PACKET_H__ */
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