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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* A simple kernel FIFO implementation.
*
* Copyright (C) 2004 Stelian Pop <stelian@popies.net>
*/
#ifndef _LINUX_KFIFO_H
#define _LINUX_KFIFO_H
struct kfifo {
unsigned char *buffer; /* the buffer holding the data */
unsigned int size; /* the size of the allocated buffer */
unsigned int in; /* data is added at offset (in % size) */
unsigned int out; /* data is extracted from off. (out % size) */
};
void kfifo_init(struct kfifo *fifo, unsigned char *buffer, unsigned int size);
struct kfifo *kfifo_alloc(unsigned int size);
void kfifo_free(struct kfifo *fifo);
/**
* kfifo_put - puts some data into the FIFO
* @fifo: the fifo to be used.
* @buffer: the data to be added.
* @len: the length of the data to be added.
*
* This function copies at most @len bytes from the @buffer into
* the FIFO depending on the free space, and returns the number of
* bytes copied.
*/
unsigned int kfifo_put(struct kfifo *fifo,
const unsigned char *buffer, unsigned int len);
/**
* kfifo_get - gets some data from the FIFO
* @fifo: the fifo to be used.
* @buffer: where the data must be copied.
* @len: the size of the destination buffer.
*
* This function copies at most @len bytes from the FIFO into the
* @buffer and returns the number of copied bytes.
*/
unsigned int kfifo_get(struct kfifo *fifo,
unsigned char *buffer, unsigned int len);
/**
* kfifo_reset - removes the entire FIFO contents
* @fifo: the fifo to be emptied.
*/
static inline void kfifo_reset(struct kfifo *fifo)
{
fifo->in = fifo->out = 0;
}
/**
* kfifo_len - returns the number of bytes available in the FIFO.
* @fifo: the fifo to be used.
*/
static inline unsigned int kfifo_len(struct kfifo *fifo)
{
return fifo->in - fifo->out;
}
void kfifo_putc(struct kfifo *fifo, unsigned char c);
unsigned int kfifo_getc(struct kfifo *fifo, unsigned char *c);
#endif
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