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/*
* this code is taken from Michael - the qemu code is GPLv2 so I don't want
* to reuse it.
* I've adapted it to handle offsets and callback
*/
//
// iovec.c
//
// Scatter/gather utility routines
//
// Copyright (C) 2002 Michael Ringgaard. 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. Neither the name of the project 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
//
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include "vrend_iov.h"
size_t vrend_get_iovec_size(const struct iovec *iov, int iovlen) {
size_t size = 0;
while (iovlen > 0) {
size += iov->iov_len;
iov++;
iovlen--;
}
return size;
}
size_t vrend_read_from_iovec(const struct iovec *iov, int iovlen,
size_t offset,
char *buf, size_t count)
{
size_t read = 0;
size_t len;
while (count > 0 && iovlen > 0) {
if (iov->iov_len > offset) {
len = iov->iov_len - offset;
if (count < len) len = count;
memcpy(buf, (char*)iov->iov_base + offset, len);
read += len;
buf += len;
count -= len;
offset = 0;
} else {
offset -= iov->iov_len;
}
iov++;
iovlen--;
}
assert(offset == 0);
return read;
}
size_t vrend_write_to_iovec(const struct iovec *iov, int iovlen,
size_t offset, const char *buf, size_t count)
{
size_t written = 0;
size_t len;
while (count > 0 && iovlen > 0) {
if (iov->iov_len > offset) {
len = iov->iov_len - offset;
if (count < len) len = count;
memcpy((char*)iov->iov_base + offset, buf, len);
written += len;
offset = 0;
buf += len;
count -= len;
} else {
offset -= iov->iov_len;
}
iov++;
iovlen--;
}
assert(offset == 0);
return written;
}
size_t vrend_read_from_iovec_cb(const struct iovec *iov, int iovlen,
size_t offset, size_t count,
iov_cb iocb, void *cookie)
{
size_t read = 0;
size_t len;
while (count > 0 && iovlen > 0) {
if (iov->iov_len > offset) {
len = iov->iov_len - offset;
if (count < len) len = count;
(*iocb)(cookie, read, (char*)iov->iov_base + offset, len);
read += len;
count -= len;
offset = 0;
} else {
offset -= iov->iov_len;
}
iov++;
iovlen--;
}
assert(offset == 0);
return read;
}
/**
* Copy data from one iovec to another iovec.
*
* TODO: Implement iovec copy without copy to intermediate buffer.
*
* \param src_iov The source iov.
* \param src_iovlen The number of memory regions in the source iov.
* \param src_offset The byte offset in the source iov to start reading from.
* \param dst_iov The destination iov.
* \param dst_iovlen The number of memory regions in the destination iov.
* \param dst_offset The byte offset in the destination iov to start writing to.
* \param count The number of bytes to copy
* \param buf If not NULL, a pointer to a buffer of at least count size
* to use a temporary storage for the copy operation.
* \return -1 on failure, 0 on success
*/
int vrend_copy_iovec(const struct iovec *src_iov, int src_iovlen, size_t src_offset,
const struct iovec *dst_iov, int dst_iovlen, size_t dst_offset,
size_t count, char *buf)
{
int ret = 0;
bool needs_free;
size_t nread;
size_t nwritten;
if (src_iov == NULL || dst_iov == NULL)
return -1;
if (src_iov == dst_iov && src_offset == dst_offset)
return 0;
if (!buf) {
buf = malloc(count);
needs_free = true;
} else {
needs_free = false;
}
if (!buf)
return -1;
nread = vrend_read_from_iovec(src_iov, src_iovlen, src_offset, buf, count);
if (nread != count) {
ret = -1;
goto out;
}
nwritten = vrend_write_to_iovec(dst_iov, dst_iovlen, dst_offset, buf, count);
if (nwritten != count) {
ret = -1;
goto out;
}
out:
if (needs_free)
free(buf);
return ret;
}
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