Differential D52308 Diff 161917 usr.sbin/virtual_oss/virtual_oss/ring.c

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usr.sbin/virtual_oss/virtual_oss/ring.c

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				/*-
				* Copyright (c) 2018 Hans Petter Selasky
				*
				* Redistribution and use in source and binary forms, with or without
				* modification, are permitted provided that the following conditions
				* are met:
				* 1. Redistributions of source code must retain the above copyright
				* notice, this list of conditions and the following disclaimer.
				* 2. Redistributions in binary form must reproduce the above copyright
				* notice, this list of conditions and the following disclaimer in the
				* documentation and/or other materials provided with the distribution.
				*
				* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
				* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
				* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
				* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
				* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
				* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
				* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
				* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
				* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
				* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
				* SUCH DAMAGE.
				*/

				#include <sys/queue.h>
				#include <sys/types.h>

				#include <stdint.h>
				#include <stdlib.h>
				#include <string.h>
				#include <unistd.h>
				#include <errno.h>
				#include <time.h>

				#include "int.h"

				int
				vring_alloc(struct virtual_ring *pvr, size_t size)
				{

				if (pvr->buf_start != NULL)
				return (EBUSY);
				pvr->buf_start = malloc(size);
				if (pvr->buf_start == NULL)
				return (ENOMEM);
				pvr->pos_read = 0;
				pvr->total_size = size;
				pvr->len_write = 0;
				return (0);
				}

				void
				vring_free(struct virtual_ring *pvr)
				{

				if (pvr->buf_start != NULL) {
				free(pvr->buf_start);
				pvr->buf_start = NULL;
				}
				}

				void
				vring_reset(struct virtual_ring *pvr)
				{
				pvr->pos_read = 0;
				pvr->len_write = 0;
				}

				void
				vring_get_read(struct virtual_ring pvr, uint8_t pptr, size_t plen)
				{
				uint32_t delta;

				if (pvr->buf_start == NULL) {
				*pptr = NULL;
				*plen = 0;
				return;
				}
				delta = pvr->total_size - pvr->pos_read;
				if (delta > pvr->len_write)
				delta = pvr->len_write;

				*pptr = pvr->buf_start + pvr->pos_read;
				*plen = delta;
				}

				void
				vring_get_write(struct virtual_ring pvr, uint8_t pptr, size_t plen)
				{
				uint32_t delta;
				uint32_t len_read;
				uint32_t pos_write;

				if (pvr->buf_start == NULL) {
				*pptr = NULL;
				*plen = 0;
				return;
				}
				pos_write = pvr->pos_read + pvr->len_write;
				if (pos_write >= pvr->total_size)
				pos_write -= pvr->total_size;

				len_read = pvr->total_size - pvr->len_write;

				delta = pvr->total_size - pos_write;
				if (delta > len_read)
				delta = len_read;

				*pptr = pvr->buf_start + pos_write;
				*plen = delta;
				}

				void
				vring_inc_read(struct virtual_ring *pvr, size_t len)
				{

				pvr->pos_read += len;
				pvr->len_write -= len;

				/* check for wrap-around */
				if (pvr->pos_read == pvr->total_size)
				pvr->pos_read = 0;
				}

				void
				vring_inc_write(struct virtual_ring *pvr, size_t len)
				{

				pvr->len_write += len;
				}

				size_t
				vring_total_read_len(struct virtual_ring *pvr)
				{

				return (pvr->len_write);
				}

				size_t
				vring_total_write_len(struct virtual_ring *pvr)
				{

				return (pvr->total_size - pvr->len_write);
				}

				size_t
				vring_write_linear(struct virtual_ring pvr, const uint8_t src, size_t total)
				{
				uint8_t *buf_ptr;
				size_t buf_len;
				size_t sum = 0;

				while (total != 0) {
				vring_get_write(pvr, &buf_ptr, &buf_len);
				if (buf_len == 0)
				break;
				if (buf_len > total)
				buf_len = total;
				memcpy(buf_ptr, src, buf_len);
				vring_inc_write(pvr, buf_len);
				src += buf_len;
				sum += buf_len;
				total -= buf_len;
				}
				return (sum);
				}

				size_t
				vring_read_linear(struct virtual_ring pvr, uint8_t dst, size_t total)
				{
				uint8_t *buf_ptr;
				size_t buf_len;
				size_t sum = 0;

				if (total > vring_total_read_len(pvr))
				return (0);

				while (total != 0) {
				vring_get_read(pvr, &buf_ptr, &buf_len);
				if (buf_len == 0)
				break;
				if (buf_len > total)
				buf_len = total;
				memcpy(dst, buf_ptr, buf_len);
				vring_inc_read(pvr, buf_len);
				dst += buf_len;
				sum += buf_len;
				total -= buf_len;
				}
				return (sum);
				}

				size_t
				vring_write_zero(struct virtual_ring *pvr, size_t total)
				{
				uint8_t *buf_ptr;
				size_t buf_len;
				size_t sum = 0;

				while (total != 0) {
				vring_get_write(pvr, &buf_ptr, &buf_len);
				if (buf_len == 0)
				break;
				if (buf_len > total)
				buf_len = total;
				memset(buf_ptr, 0, buf_len);
				vring_inc_write(pvr, buf_len);
				sum += buf_len;
				total -= buf_len;
				}
				return (sum);
				}