320 lines
7.0 KiB
C
320 lines
7.0 KiB
C
/* $NetBSD: buffer.c,v 1.3 2005/04/17 07:20:00 provos Exp $ */
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/*
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* Copyright (c) 2002, 2003 Niels Provos <provos@citi.umich.edu>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/ioctl.h>
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#include <err.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#include <unistd.h>
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#include "event.h"
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struct evbuffer *
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evbuffer_new(void)
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{
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struct evbuffer *buffer;
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buffer = calloc(1, sizeof(struct evbuffer));
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return (buffer);
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}
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void
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evbuffer_free(struct evbuffer *buffer)
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{
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if (buffer->orig_buffer != NULL)
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free(buffer->orig_buffer);
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free(buffer);
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}
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/*
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* This is a destructive add. The data from one buffer moves into
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* the other buffer.
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*/
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#define SWAP(x,y) do { \
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(x)->buffer = (y)->buffer; \
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(x)->orig_buffer = (y)->orig_buffer; \
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(x)->misalign = (y)->misalign; \
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(x)->totallen = (y)->totallen; \
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(x)->off = (y)->off; \
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} while (0)
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int
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evbuffer_add_buffer(struct evbuffer *outbuf, struct evbuffer *inbuf)
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{
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int res;
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/* Short cut for better performance */
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if (outbuf->off == 0) {
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struct evbuffer tmp;
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size_t oldoff = inbuf->off;
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/* Swap them directly */
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SWAP(&tmp, outbuf);
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SWAP(outbuf, inbuf);
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SWAP(inbuf, &tmp);
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/*
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* Optimization comes with a price; we need to notify the
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* buffer if necessary of the changes. oldoff is the amount
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* of data that we tranfered from inbuf to outbuf
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*/
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if (inbuf->off != oldoff && inbuf->cb != NULL)
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(*inbuf->cb)(inbuf, oldoff, inbuf->off, inbuf->cbarg);
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if (oldoff && outbuf->cb != NULL)
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(*outbuf->cb)(outbuf, 0, oldoff, outbuf->cbarg);
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return (0);
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}
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res = evbuffer_add(outbuf, inbuf->buffer, inbuf->off);
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if (res == 0)
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evbuffer_drain(inbuf, inbuf->off);
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return (res);
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}
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int
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evbuffer_add_printf(struct evbuffer *buf, char *fmt, ...)
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{
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int res = -1;
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char *msg;
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va_list ap;
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va_start(ap, fmt);
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if (vasprintf(&msg, fmt, ap) == -1)
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goto end;
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res = strlen(msg);
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if (evbuffer_add(buf, msg, res) == -1)
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res = -1;
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free(msg);
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end:
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va_end(ap);
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return (res);
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}
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/* Reads data from an event buffer and drains the bytes read */
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int
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evbuffer_remove(struct evbuffer *buf, void *data, size_t datlen)
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{
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size_t nread = datlen;
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if (nread >= buf->off)
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nread = buf->off;
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memcpy(data, buf->buffer, nread);
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evbuffer_drain(buf, nread);
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return (nread);
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}
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/* Adds data to an event buffer */
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static inline void
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evbuffer_align(struct evbuffer *buf)
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{
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memmove(buf->orig_buffer, buf->buffer, buf->off);
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buf->buffer = buf->orig_buffer;
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buf->misalign = 0;
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}
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/* Expands the available space in the event buffer to at least datlen */
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int
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evbuffer_expand(struct evbuffer *buf, size_t datlen)
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{
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size_t need = buf->misalign + buf->off + datlen;
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/* If we can fit all the data, then we don't have to do anything */
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if (buf->totallen >= need)
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return (0);
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/*
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* If the misalignment fulfills our data needs, we just force an
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* alignment to happen. Afterwards, we have enough space.
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*/
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if (buf->misalign >= datlen) {
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evbuffer_align(buf);
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} else {
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void *newbuf;
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size_t length = buf->totallen;
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if (length < 256)
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length = 256;
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while (length < need)
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length <<= 1;
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if (buf->orig_buffer != buf->buffer)
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evbuffer_align(buf);
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if ((newbuf = realloc(buf->buffer, length)) == NULL)
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return (-1);
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buf->orig_buffer = buf->buffer = newbuf;
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buf->totallen = length;
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}
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return (0);
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}
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int
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evbuffer_add(struct evbuffer *buf, void *data, size_t datlen)
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{
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size_t need = buf->misalign + buf->off + datlen;
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size_t oldoff = buf->off;
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if (buf->totallen < need) {
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if (evbuffer_expand(buf, datlen) == -1)
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return (-1);
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}
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memcpy(buf->buffer + buf->off, data, datlen);
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buf->off += datlen;
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if (datlen && buf->cb != NULL)
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(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
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return (0);
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}
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void
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evbuffer_drain(struct evbuffer *buf, size_t len)
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{
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size_t oldoff = buf->off;
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if (len >= buf->off) {
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buf->off = 0;
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buf->buffer = buf->orig_buffer;
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buf->misalign = 0;
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goto done;
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}
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buf->buffer += len;
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buf->misalign += len;
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buf->off -= len;
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done:
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/* Tell someone about changes in this buffer */
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if (buf->off != oldoff && buf->cb != NULL)
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(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
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}
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/*
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* Reads data from a file descriptor into a buffer.
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*/
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#define EVBUFFER_MAX_READ 4096
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int
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evbuffer_read(struct evbuffer *buf, int fd, int howmuch)
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{
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u_char *p;
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size_t oldoff = buf->off;
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int n = EVBUFFER_MAX_READ;
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if (ioctl(fd, FIONREAD, &n) == -1)
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n = EVBUFFER_MAX_READ;
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if (howmuch < 0 || howmuch > n)
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howmuch = n;
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/* If we don't have FIONREAD, we might waste some space here */
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if (evbuffer_expand(buf, howmuch) == -1)
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return (-1);
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/* We can append new data at this point */
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p = buf->buffer + buf->off;
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n = read(fd, p, howmuch);
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if (n == -1)
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return (-1);
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if (n == 0)
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return (0);
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buf->off += n;
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/* Tell someone about changes in this buffer */
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if (buf->off != oldoff && buf->cb != NULL)
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(*buf->cb)(buf, oldoff, buf->off, buf->cbarg);
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return (n);
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}
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int
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evbuffer_write(struct evbuffer *buffer, int fd)
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{
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int n;
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n = write(fd, buffer->buffer, buffer->off);
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if (n == -1)
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return (-1);
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if (n == 0)
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return (0);
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evbuffer_drain(buffer, n);
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return (n);
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}
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u_char *
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evbuffer_find(struct evbuffer *buffer, u_char *what, size_t len)
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{
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size_t remain = buffer->off;
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u_char *search = buffer->buffer;
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u_char *p;
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while ((p = memchr(search, *what, remain)) != NULL && remain >= len) {
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if (memcmp(p, what, len) == 0)
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return (p);
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search = p + 1;
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remain = buffer->off - (size_t)(search - buffer->buffer);
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}
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return (NULL);
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}
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void evbuffer_setcb(struct evbuffer *buffer,
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void (*cb)(struct evbuffer *, size_t, size_t, void *),
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void *cbarg)
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{
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buffer->cb = cb;
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buffer->cbarg = cbarg;
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}
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