/*
* Empire - A multi-player, client/server Internet based war game.
- * Copyright (C) 1986-2007, Dave Pare, Jeff Bailey, Thomas Ruschak,
- * Ken Stevens, Steve McClure
+ * Copyright (C) 1986-2020, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ * Ken Stevens, Steve McClure, Markus Armbruster
*
- * This program is free software; you can redistribute it and/or modify
+ * Empire 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
+ * the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* ---
*
* ---
*
* ringbuf.c: Simple ring buffer
- *
+ *
* Known contributors to this file:
- * Markus Armbruster, 2007
+ * Markus Armbruster, 2007-2017
*/
#include <config.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
-#ifndef _WIN32
-#include <sys/uio.h>
-#include <unistd.h>
-#else
-#define readv(fd, iov, iovcnt) \
- w32_readv_handle((fd), (iov), (iovcnt))
-#define writev(fd, iov, iovcnt) \
- w32_writev_socket((fd), (iov), (iovcnt))
-#endif
-#include "misc.h"
#include "ringbuf.h"
/*
* Initialize empty ring buffer.
- * Not necessary if *R is already zeroed.
+ * Not necessary if *@r is already zeroed.
*/
void
ring_init(struct ring *r)
/*
* Peek at ring buffer contents.
- * N must be between -RING_SIZE-1 and RING_SIZE.
- * If N>=0, peek at the (N+1)-th byte to be gotten.
- * If N<0, peek at the -N-th byte that has been put in.
+ * @n must be between -RING_SIZE-1 and RING_SIZE.
+ * If @n>=0, peek at the (@n+1)-th byte to be gotten.
+ * If @n<0, peek at the -@n-th byte that has been put in.
* Return the byte as unsigned char coverted to int, or EOF if there
* aren't that many bytes in the ring buffer.
*/
assert(-RING_SIZE - 1 <= n && n <= RING_SIZE);
- idx = n >= 0 ? r->cons + n : r->prod - -n;
- if (idx < r->cons && idx >= r->prod)
- return EOF;
+ if (n >= 0) {
+ idx = r->cons + n;
+ if (idx >= r->prod)
+ return EOF;
+ } else {
+ /* Beware, r->prod - -n can wrap around, avoid that */
+ if (r->prod < r->cons + -n)
+ return EOF;
+ idx = r->prod - -n;
+ }
+
return r->buf[idx % RING_SIZE];
}
/*
* Get and remove the oldest byte from the ring buffer.
- * Return it as unsigned char coverted to int, or EOF if the buffer was
+ * Return it as unsigned char converted to int, or EOF if the buffer was
* empty.
*/
int
}
/*
- * Attempt to put byte C into the ring buffer.
- * Return EOF when the buffer is full, else C.
+ * Attempt to put byte @c into the ring buffer.
+ * Return EOF when the buffer is full, else @c.
*/
int
ring_putc(struct ring *r, unsigned char c)
}
/*
- * Attempt to put SZ bytes from BUF into the ring buffer.
+ * Attempt to put @sz bytes from @buf into the ring buffer.
* Return space left in ring buffer when it fits, else don't change
* the ring buffer and return how much space is missing times -1.
*/
}
/*
- * Discard the N oldest bytes from the ring buffer.
+ * Discard the @n oldest bytes from the ring buffer.
* It must hold at least that many.
*/
void
}
/*
- * Search the ring buffer for zero-terminated string S.
- * If found, return a non-negative value referring to the beginning of
- * S in the buffer when passed to ring_peek(). Else return -1.
+ * Search the ring buffer for zero-terminated string @s.
+ * Start at the (@n+1)-th byte to be gotten.
+ * If found, return the number of bytes in the buffer before @s.
+ * Else return -1.
*/
int
-ring_search(struct ring *r, char *s)
+ring_search(struct ring *r, char *s, int n)
{
size_t len = strlen(s);
size_t i, j;
- for (i = r->cons; i + len <= r->prod; i++) {
- for (j = 0; j < len && s[j] == r->buf[(i + j) % RING_SIZE]; j++) ;
+ for (i = r->cons + n; i + len <= r->prod; i++) {
+ for (j = 0; s[j] && s[j] == (char)r->buf[(i + j) % RING_SIZE]; j++)
+ ;
if (!s[j])
return i - r->cons;
}
}
/*
- * Fill ring buffer from file referred by file descriptor FD.
+ * Fill ring buffer from file referred by file descriptor @fd.
* If ring buffer is already full, do nothing and return 0.
* Else attempt to read as many bytes as space permits, with readv(),
* and return its value.
}
/*
- * Drain ring buffer to file referred by file descriptor FD.
- * If ring buffer is already empty, do nothing and return 0.
- * Else attempt to write complete contents with writev(), and return
- * its value.
+ * Set up @iov[] to describe complete contents of ring buffer.
+ * @iov[] must have at least two elements.
+ * Return number of elements used (zero for an empty ring buffer).
*/
int
-ring_to_file(struct ring *r, int fd)
+ring_to_iovec(struct ring *r, struct iovec iov[])
{
unsigned cons = r->cons % RING_SIZE;
unsigned prod = r->prod % RING_SIZE;
- struct iovec iov[2];
- int cnt;
- ssize_t res;
if (r->cons == r->prod)
return 0;
iov[0].iov_base = r->buf + cons;
- if (prod <= cons) {
- /* r->buf[cons..] */
- iov[0].iov_len = RING_SIZE - cons;
- /* r->buf[..prod-1] */
- iov[1].iov_base = r->buf;
- iov[1].iov_len = prod;
- cnt = 2;
- } else {
+ if (prod > cons) {
/* r->buf[cons..prod-1] */
iov[0].iov_len = prod - cons;
- cnt = 1;
+ return 1;
}
- res = writev(fd, iov, cnt);
- if (res < 0)
- return res;
- r->cons += res;
- return res;
+ /* r->buf[cons..] */
+ iov[0].iov_len = RING_SIZE - cons;
+ /* r->buf[..prod-1] */
+ iov[1].iov_base = r->buf;
+ iov[1].iov_len = prod;
+ return 2;
}
projects / empserver / blobdiff