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142 lines
3.7 KiB
142 lines
3.7 KiB
/*
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* this code is taken from Michael - the qemu code is GPLv2 so I don't want
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* to reuse it.
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* I've adapted it to handle offsets and callback
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*/
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//
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// iovec.c
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//
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// Scatter/gather utility routines
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//
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// Copyright (C) 2002 Michael Ringgaard. 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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//
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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. Neither the name of the project nor the names of its contributors
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// may be used to endorse or promote products derived from this software
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// without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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// SUCH DAMAGE.
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//
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#include <assert.h>
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#include <string.h>
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#include "vrend_iov.h"
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size_t vrend_get_iovec_size(const struct iovec *iov, int iovlen) {
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size_t size = 0;
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while (iovlen > 0) {
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size += iov->iov_len;
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iov++;
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iovlen--;
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}
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return size;
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}
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size_t vrend_read_from_iovec(const struct iovec *iov, int iovlen,
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size_t offset,
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char *buf, size_t count)
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{
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size_t read = 0;
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size_t len;
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while (count > 0 && iovlen > 0) {
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if (iov->iov_len > offset) {
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len = iov->iov_len - offset;
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if (count < iov->iov_len - offset) len = count;
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memcpy(buf, (char*)iov->iov_base + offset, len);
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read += len;
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buf += len;
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count -= len;
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offset = 0;
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} else {
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offset -= iov->iov_len;
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}
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iov++;
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iovlen--;
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}
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assert(offset == 0);
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return read;
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}
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size_t vrend_write_to_iovec(const struct iovec *iov, int iovlen,
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size_t offset, const char *buf, size_t count)
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{
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size_t written = 0;
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size_t len;
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while (count > 0 && iovlen > 0) {
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if (iov->iov_len > offset) {
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len = iov->iov_len - offset;
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if (count < iov->iov_len - offset) len = count;
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memcpy((char*)iov->iov_base + offset, buf, len);
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written += len;
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offset = 0;
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buf += len;
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count -= len;
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} else {
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offset -= iov->iov_len;
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}
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iov++;
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iovlen--;
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}
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assert(offset == 0);
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return written;
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}
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size_t vrend_read_from_iovec_cb(const struct iovec *iov, int iovlen,
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size_t offset, size_t count,
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iov_cb iocb, void *cookie)
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{
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size_t read = 0;
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size_t len;
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while (count > 0 && iovlen > 0) {
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if (iov->iov_len > offset) {
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len = iov->iov_len;
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if (count < iov->iov_len - offset) len = count;
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(*iocb)(cookie, count, (char*)iov->iov_base + offset, len);
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read += len;
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count -= len;
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offset = 0;
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} else {
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offset -= iov->iov_len;
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}
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iov++;
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iovlen--;
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}
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assert(offset == 0);
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return read;
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}
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