add kernel kfifo implementation
This commit is contained in:
parent
64caff6c94
commit
90a17da95c
|
@ -0,0 +1,83 @@
|
|||
/*
|
||||
* A simple kernel FIFO implementation.
|
||||
*
|
||||
* Copyright (C) 2004 Stelian Pop <stelian@popies.net>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*
|
||||
*/
|
||||
#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) */
|
||||
};
|
||||
|
||||
struct kfifo *kfifo_init(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,
|
||||
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
|
||||
|
|
@ -10,6 +10,7 @@ obj-y += parameter.o
|
|||
obj-y += xfuncs.o
|
||||
obj-y += getopt.o
|
||||
obj-y += readkey.o
|
||||
obj-y += kfifo.o
|
||||
obj-$(CONFIG_BZLIB) += bzlib.o bzlib_crctable.o bzlib_decompress.o bzlib_huffman.o bzlib_randtable.o
|
||||
obj-$(CONFIG_ZLIB) += zlib.o gunzip.o
|
||||
obj-$(CONFIG_CRC32) += crc32.o
|
||||
|
|
|
@ -0,0 +1,166 @@
|
|||
/*
|
||||
* A simple kernel FIFO implementation.
|
||||
*
|
||||
* Copyright (C) 2004 Stelian Pop <stelian@popies.net>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <common.h>
|
||||
#include <malloc.h>
|
||||
#include <kfifo.h>
|
||||
#include <errno.h>
|
||||
|
||||
/**
|
||||
* kfifo_init - allocates a new FIFO using a preallocated buffer
|
||||
* @buffer: the preallocated buffer to be used.
|
||||
* @size: the size of the internal buffer, this have to be a power of 2.
|
||||
* @gfp_mask: get_free_pages mask, passed to kmalloc()
|
||||
* @lock: the lock to be used to protect the fifo buffer
|
||||
*
|
||||
* Do NOT pass the kfifo to kfifo_free() after use! Simply free the
|
||||
* &struct kfifo with free().
|
||||
*/
|
||||
struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size)
|
||||
{
|
||||
struct kfifo *fifo;
|
||||
|
||||
fifo = malloc(sizeof(struct kfifo));
|
||||
if (!fifo)
|
||||
return NULL;
|
||||
|
||||
fifo->buffer = buffer;
|
||||
fifo->size = size;
|
||||
fifo->in = fifo->out = 0;
|
||||
|
||||
return fifo;
|
||||
}
|
||||
|
||||
/**
|
||||
* kfifo_alloc - allocates a new FIFO and its internal buffer
|
||||
* @size: the size of the internal buffer to be allocated.
|
||||
* @gfp_mask: get_free_pages mask, passed to kmalloc()
|
||||
* @lock: the lock to be used to protect the fifo buffer
|
||||
*
|
||||
* The size will be rounded-up to a power of 2.
|
||||
*/
|
||||
struct kfifo *kfifo_alloc(unsigned int size)
|
||||
{
|
||||
unsigned char *buffer;
|
||||
struct kfifo *ret;
|
||||
|
||||
buffer = malloc(size);
|
||||
if (!buffer)
|
||||
return NULL;
|
||||
|
||||
ret = kfifo_init(buffer, size);
|
||||
|
||||
if (!ret)
|
||||
free(buffer);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* kfifo_free - frees the FIFO
|
||||
* @fifo: the fifo to be freed.
|
||||
*/
|
||||
void kfifo_free(struct kfifo *fifo)
|
||||
{
|
||||
free(fifo->buffer);
|
||||
free(fifo);
|
||||
}
|
||||
|
||||
/**
|
||||
* kfifo_put - puts some data into the FIFO, no locking version
|
||||
* @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,
|
||||
unsigned char *buffer, unsigned int len)
|
||||
{
|
||||
unsigned int l;
|
||||
|
||||
len = min(len, fifo->size - fifo->in + fifo->out);
|
||||
|
||||
/* first put the data starting from fifo->in to buffer end */
|
||||
l = min(len, fifo->size - (fifo->in & (fifo->size - 1)));
|
||||
memcpy(fifo->buffer + (fifo->in & (fifo->size - 1)), buffer, l);
|
||||
|
||||
/* then put the rest (if any) at the beginning of the buffer */
|
||||
memcpy(fifo->buffer, buffer + l, len - l);
|
||||
|
||||
fifo->in += len;
|
||||
|
||||
return len;
|
||||
}
|
||||
|
||||
/**
|
||||
* kfifo_get - gets some data from the FIFO, no locking version
|
||||
* @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.
|
||||
*
|
||||
* Note that with only one concurrent reader and one concurrent
|
||||
* writer, you don't need extra locking to use these functions.
|
||||
*/
|
||||
unsigned int kfifo_get(struct kfifo *fifo,
|
||||
unsigned char *buffer, unsigned int len)
|
||||
{
|
||||
unsigned int l;
|
||||
|
||||
len = min(len, fifo->in - fifo->out);
|
||||
|
||||
/* first get the data from fifo->out until the end of the buffer */
|
||||
l = min(len, fifo->size - (fifo->out & (fifo->size - 1)));
|
||||
memcpy(buffer, fifo->buffer + (fifo->out & (fifo->size - 1)), l);
|
||||
|
||||
/* then get the rest (if any) from the beginning of the buffer */
|
||||
memcpy(buffer + l, fifo->buffer, len - l);
|
||||
|
||||
fifo->out += len;
|
||||
|
||||
return len;
|
||||
}
|
||||
|
||||
void kfifo_putc(struct kfifo *fifo, unsigned char c)
|
||||
{
|
||||
*(fifo->buffer + (fifo->in & (fifo->size - 1))) = c;
|
||||
fifo->in++;
|
||||
if (fifo->in - fifo->out > fifo->size)
|
||||
fifo->out++;
|
||||
}
|
||||
|
||||
unsigned int kfifo_getc(struct kfifo *fifo, unsigned char *c)
|
||||
{
|
||||
if (fifo->in == fifo->out)
|
||||
return -1;
|
||||
|
||||
*c = *(fifo->buffer + (fifo->out & (fifo->size - 1)));
|
||||
fifo->out++;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
Loading…
Reference in New Issue