ring.c
资源名称:socks5.zip [点击查看]
上传用户:sddyfurun
上传日期:2007-01-04
资源大小:525k
文件大小:8k
源码类别:
代理服务器
开发平台:
Unix_Linux
- /*
- * Copyright (c) 1988, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * 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.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
- */
- #ifdef SHOW_SCCSIDS
- static char sccsid[] = "@(#)ring.c 8.2 (Berkeley) 5/30/95";
- #endif
- /*
- * This defines a structure for a ring buffer.
- *
- * The circular buffer has two parts:
- *(((
- * full: [consume, supply)
- * empty: [supply, consume)
- *]]]
- *
- */
- #include <stdio.h>
- #include <errno.h>
- #ifdef size_t
- #undef size_t
- #endif
- #include "config.h"
- #ifdef HAVE_STRING_H
- #include <string.h>
- #endif
- #if !defined(STDC_HEADERS) && defined(HAVE_MEMORY_H)
- #include <memory.h>
- #endif
- #ifdef HAVE_STRINGS_H
- #include <strings.h>
- #endif
- #include <sys/types.h>
- #ifndef FILIO_H
- #include <sys/ioctl.h>
- #endif
- #include <sys/socket.h>
- #include "ring.h"
- #include "general.h"
- /* Internal macros */
- #ifndef MIN
- #define MIN(a,b) (((a)<(b))? (a):(b))
- #endif /* !defined(MIN) */
- #define ring_subtract(d,a,b) (((a)-(b) >= 0)?
- (a)-(b): (((a)-(b))+(d)->size))
- #define ring_increment(d,a,c) (((a)+(c) < (d)->top)?
- (a)+(c) : (((a)+(c))-(d)->size))
- #define ring_decrement(d,a,c) (((a)-(c) >= (d)->bottom)?
- (a)-(c) : (((a)-(c))-(d)->size))
- /*
- * The following is a clock, used to determine full, empty, etc.
- *
- * There is some trickiness here. Since the ring buffers are initialized
- * to ZERO on allocation, we need to make sure, when interpreting the
- * clock, that when the times are EQUAL, then the buffer is FULL.
- */
- static u_long ring_clock = 0;
- #define ring_empty(d) (((d)->consume == (d)->supply) &&
- ((d)->consumetime >= (d)->supplytime))
- #define ring_full(d) (((d)->supply == (d)->consume) &&
- ((d)->supplytime > (d)->consumetime))
- /* Buffer state transition routines */
- int
- ring_init(ring, buffer, count)
- Ring *ring;
- unsigned char *buffer;
- int count;
- {
- memset((char *)ring, 0, sizeof *ring);
- ring->size = count;
- ring->supply = ring->consume = ring->bottom = buffer;
- ring->top = ring->bottom+ring->size;
- return 1;
- }
- /* Mark routines */
- /*
- * Mark the most recently supplied byte.
- */
- void
- ring_mark(ring)
- Ring *ring;
- {
- ring->mark = ring_decrement(ring, ring->supply, 1);
- }
- /*
- * Is the ring pointing to the mark?
- */
- int
- ring_at_mark(ring)
- Ring *ring;
- {
- if (ring->mark == ring->consume) {
- return 1;
- } else {
- return 0;
- }
- }
- /*
- * Clear any mark set on the ring.
- */
- void
- ring_clear_mark(ring)
- Ring *ring;
- {
- ring->mark = 0;
- }
- /*
- * Add characters from current segment to ring buffer.
- */
- void
- ring_supplied(ring, count)
- Ring *ring;
- int count;
- {
- ring->supply = ring_increment(ring, ring->supply, count);
- ring->supplytime = ++ring_clock;
- }
- /*
- * We have just consumed "c" bytes.
- */
- void
- ring_consumed(ring, count)
- Ring *ring;
- int count;
- {
- if (count == 0) /* don't update anything */
- return;
- if (ring->mark &&
- (ring_subtract(ring, ring->mark, ring->consume) < count)) {
- ring->mark = 0;
- }
- ring->consume = ring_increment(ring, ring->consume, count);
- ring->consumetime = ++ring_clock;
- /*
- * Try to encourage "ring_empty_consecutive()" to be large.
- */
- if (ring_empty(ring)) {
- ring->consume = ring->supply = ring->bottom;
- }
- }
- /* Buffer state query routines */
- /* Number of bytes that may be supplied */
- int
- ring_empty_count(ring)
- Ring *ring;
- {
- if (ring_empty(ring)) { /* if empty */
- return ring->size;
- } else {
- return ring_subtract(ring, ring->consume, ring->supply);
- }
- }
- /* number of CONSECUTIVE bytes that may be supplied */
- int
- ring_empty_consecutive(ring)
- Ring *ring;
- {
- if ((ring->consume < ring->supply) || ring_empty(ring)) {
- /*
- * if consume is "below" supply, or empty, then
- * return distance to the top
- */
- return ring_subtract(ring, ring->top, ring->supply);
- } else {
- /*
- * else, return what we may.
- */
- return ring_subtract(ring, ring->consume, ring->supply);
- }
- }
- /* Return the number of bytes that are available for consuming
- * (but don't give more than enough to get to cross over set mark)
- */
- int
- ring_full_count(ring)
- Ring *ring;
- {
- if ((ring->mark == 0) || (ring->mark == ring->consume)) {
- if (ring_full(ring)) {
- return ring->size; /* nothing consumed, but full */
- } else {
- return ring_subtract(ring, ring->supply, ring->consume);
- }
- } else {
- return ring_subtract(ring, ring->mark, ring->consume);
- }
- }
- /*
- * Return the number of CONSECUTIVE bytes available for consuming.
- * However, don't return more than enough to cross over set mark.
- */
- int
- ring_full_consecutive(ring)
- Ring *ring;
- {
- if ((ring->mark == 0) || (ring->mark == ring->consume)) {
- if ((ring->supply < ring->consume) || ring_full(ring)) {
- return ring_subtract(ring, ring->top, ring->consume);
- } else {
- return ring_subtract(ring, ring->supply, ring->consume);
- }
- } else {
- if (ring->mark < ring->consume) {
- return ring_subtract(ring, ring->top, ring->consume);
- } else { /* Else, distance to mark */
- return ring_subtract(ring, ring->mark, ring->consume);
- }
- }
- }
- /*
- * Move data into the "supply" portion of of the ring buffer.
- */
- void
- ring_supply_data(ring, buffer, count)
- Ring *ring;
- unsigned char *buffer;
- int count;
- {
- int i;
- while (count) {
- i = MIN(count, ring_empty_consecutive(ring));
- memmove(ring->supply, buffer, i);
- ring_supplied(ring, i);
- count -= i;
- buffer += i;
- }
- }
- #ifdef notdef
- /*
- * Move data from the "consume" portion of the ring buffer
- */
- void
- ring_consume_data(ring, buffer, count)
- Ring *ring;
- unsigned char *buffer;
- int count;
- {
- int i;
- while (count) {
- i = MIN(count, ring_full_consecutive(ring));
- memmove(buffer, ring->consume, i);
- ring_consumed(ring, i);
- count -= i;
- buffer += i;
- }
- }
- #endif