mirror of https://gitee.com/openkylin/qemu.git
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/*
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* Helpers for getting linearized buffers from iov / filling buffers into iovs
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*
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* Copyright IBM, Corp. 2007, 2008
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* Copyright (C) 2010 Red Hat, Inc.
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*
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* Author(s):
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* Anthony Liguori <aliguori@us.ibm.com>
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* Amit Shah <amit.shah@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include "iov.h"
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size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
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const void *buf, size_t iov_off, size_t size)
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{
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size_t iovec_off, buf_off;
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unsigned int i;
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iovec_off = 0;
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buf_off = 0;
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for (i = 0; i < iov_cnt && size; i++) {
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if (iov_off < (iovec_off + iov[i].iov_len)) {
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size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off, size);
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memcpy(iov[i].iov_base + (iov_off - iovec_off), buf + buf_off, len);
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buf_off += len;
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iov_off += len;
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size -= len;
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}
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iovec_off += iov[i].iov_len;
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}
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return buf_off;
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}
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size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
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void *buf, size_t iov_off, size_t size)
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{
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uint8_t *ptr;
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size_t iovec_off, buf_off;
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unsigned int i;
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ptr = buf;
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iovec_off = 0;
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buf_off = 0;
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for (i = 0; i < iov_cnt && size; i++) {
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if (iov_off < (iovec_off + iov[i].iov_len)) {
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size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size);
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memcpy(ptr + buf_off, iov[i].iov_base + (iov_off - iovec_off), len);
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buf_off += len;
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iov_off += len;
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size -= len;
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}
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iovec_off += iov[i].iov_len;
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}
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return buf_off;
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}
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size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
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{
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size_t len;
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unsigned int i;
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len = 0;
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for (i = 0; i < iov_cnt; i++) {
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len += iov[i].iov_len;
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}
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return len;
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}
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