NetBSD/lib/libevent/buffer.c

320 lines
7.0 KiB
C

/* $NetBSD: buffer.c,v 1.3 2005/04/17 07:20:00 provos Exp $ */
/*
* Copyright (c) 2002, 2003 Niels Provos <provos@citi.umich.edu>
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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/types.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include "event.h"
struct evbuffer *
evbuffer_new(void)
{
struct evbuffer *buffer;
buffer = calloc(1, sizeof(struct evbuffer));
return (buffer);
}
void
evbuffer_free(struct evbuffer *buffer)
{
if (buffer->orig_buffer != NULL)
free(buffer->orig_buffer);
free(buffer);
}
/*
* This is a destructive add. The data from one buffer moves into
* the other buffer.
*/
#define SWAP(x,y) do { \
(x)->buffer = (y)->buffer; \
(x)->orig_buffer = (y)->orig_buffer; \
(x)->misalign = (y)->misalign; \
(x)->totallen = (y)->totallen; \
(x)->off = (y)->off; \
} while (0)
int
evbuffer_add_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
{
int res;
/* Short cut for better performance */
if (outbuf->off == 0) {
struct evbuffer tmp;
size_t oldoff = inbuf->off;
/* Swap them directly */
SWAP(&tmp, outbuf);
SWAP(outbuf, inbuf);
SWAP(inbuf, &tmp);
/*
* Optimization comes with a price; we need to notify the
* buffer if necessary of the changes. oldoff is the amount
* of data that we tranfered from inbuf to outbuf
*/
if (inbuf->off != oldoff && inbuf->cb != NULL)
(*inbuf->cb)(inbuf, oldoff, inbuf->off, inbuf->cbarg);
if (oldoff && outbuf->cb != NULL)
(*outbuf->cb)(outbuf, 0, oldoff, outbuf->cbarg);
return (0);
}
res = evbuffer_add(outbuf, inbuf->buffer, inbuf->off);
if (res == 0)
evbuffer_drain(inbuf, inbuf->off);
return (res);
}
int
evbuffer_add_printf(struct evbuffer *buf, char *fmt, ...)
{
int res = -1;
char *msg;
va_list ap;
va_start(ap, fmt);
if (vasprintf(&msg, fmt, ap) == -1)
goto end;
res = strlen(msg);
if (evbuffer_add(buf, msg, res) == -1)
res = -1;
free(msg);
end:
va_end(ap);
return (res);
}
/* Reads data from an event buffer and drains the bytes read */
int
evbuffer_remove(struct evbuffer *buf, void *data, size_t datlen)
{
size_t nread = datlen;
if (nread >= buf->off)
nread = buf->off;
memcpy(data, buf->buffer, nread);
evbuffer_drain(buf, nread);
return (nread);
}
/* Adds data to an event buffer */
static inline void
evbuffer_align(struct evbuffer *buf)
{
memmove(buf->orig_buffer, buf->buffer, buf->off);
buf->buffer = buf->orig_buffer;
buf->misalign = 0;
}
/* Expands the available space in the event buffer to at least datlen */
int
evbuffer_expand(struct evbuffer *buf, size_t datlen)
{
size_t need = buf->misalign + buf->off + datlen;
/* If we can fit all the data, then we don't have to do anything */
if (buf->totallen >= need)
return (0);
/*
* If the misalignment fulfills our data needs, we just force an
* alignment to happen. Afterwards, we have enough space.
*/
if (buf->misalign >= datlen) {
evbuffer_align(buf);
} else {
void *newbuf;
size_t length = buf->totallen;
if (length < 256)
length = 256;
while (length < need)
length <<= 1;
if (buf->orig_buffer != buf->buffer)
evbuffer_align(buf);
if ((newbuf = realloc(buf->buffer, length)) == NULL)
return (-1);
buf->orig_buffer = buf->buffer = newbuf;
buf->totallen = length;
}
return (0);
}
int
evbuffer_add(struct evbuffer *buf, void *data, size_t datlen)
{
size_t need = buf->misalign + buf->off + datlen;
size_t oldoff = buf->off;
if (buf->totallen < need) {
if (evbuffer_expand(buf, datlen) == -1)
return (-1);
}
memcpy(buf->buffer + buf->off, data, datlen);
buf->off += datlen;
if (datlen && buf->cb != NULL)
(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
return (0);
}
void
evbuffer_drain(struct evbuffer *buf, size_t len)
{
size_t oldoff = buf->off;
if (len >= buf->off) {
buf->off = 0;
buf->buffer = buf->orig_buffer;
buf->misalign = 0;
goto done;
}
buf->buffer += len;
buf->misalign += len;
buf->off -= len;
done:
/* Tell someone about changes in this buffer */
if (buf->off != oldoff && buf->cb != NULL)
(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
}
/*
* Reads data from a file descriptor into a buffer.
*/
#define EVBUFFER_MAX_READ 4096
int
evbuffer_read(struct evbuffer *buf, int fd, int howmuch)
{
u_char *p;
size_t oldoff = buf->off;
int n = EVBUFFER_MAX_READ;
if (ioctl(fd, FIONREAD, &n) == -1)
n = EVBUFFER_MAX_READ;
if (howmuch < 0 || howmuch > n)
howmuch = n;
/* If we don't have FIONREAD, we might waste some space here */
if (evbuffer_expand(buf, howmuch) == -1)
return (-1);
/* We can append new data at this point */
p = buf->buffer + buf->off;
n = read(fd, p, howmuch);
if (n == -1)
return (-1);
if (n == 0)
return (0);
buf->off += n;
/* Tell someone about changes in this buffer */
if (buf->off != oldoff && buf->cb != NULL)
(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
return (n);
}
int
evbuffer_write(struct evbuffer *buffer, int fd)
{
int n;
n = write(fd, buffer->buffer, buffer->off);
if (n == -1)
return (-1);
if (n == 0)
return (0);
evbuffer_drain(buffer, n);
return (n);
}
u_char *
evbuffer_find(struct evbuffer *buffer, u_char *what, size_t len)
{
size_t remain = buffer->off;
u_char *search = buffer->buffer;
u_char *p;
while ((p = memchr(search, *what, remain)) != NULL && remain >= len) {
if (memcmp(p, what, len) == 0)
return (p);
search = p + 1;
remain = buffer->off - (size_t)(search - buffer->buffer);
}
return (NULL);
}
void evbuffer_setcb(struct evbuffer *buffer,
void (*cb)(struct evbuffer *, size_t, size_t, void *),
void *cbarg)
{
buffer->cb = cb;
buffer->cbarg = cbarg;
}