73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
/*
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* Copyright (c) 2014 Travis Geiselbrecht
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*
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* Use of this source code is governed by a MIT-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/MIT
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*/
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#include <lk/err.h>
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#include <lk/debug.h>
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#include <assert.h>
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#include <string.h>
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#include <sys/types.h>
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#include <iovec.h>
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#define LOCAL_TRACE 0
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/*
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* Calc total size of iovec buffers
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*/
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ssize_t iovec_size (const iovec_t *iov, uint iov_cnt) {
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if (!iov)
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return (ssize_t) ERR_INVALID_ARGS;
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size_t c = 0;
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for (uint i = 0; i < iov_cnt; i++, iov++) {
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c += iov->iov_len;
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}
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return (ssize_t) c;
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}
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/*
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* Copy out portion of iovec started from given position
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* into single buffer
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*/
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ssize_t iovec_to_membuf (uint8_t *buf, uint buf_len, const iovec_t *iov, uint iov_cnt, uint iov_pos) {
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uint buf_pos = 0;
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if (!buf || !iov)
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return (ssize_t) ERR_INVALID_ARGS;
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/* for all iovec */
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for (uint i = 0; i < iov_cnt; i++, iov++) {
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if (iov_pos >= iov->iov_len) {
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iov_pos -= iov->iov_len; /* skip whole chunks */
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continue;
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}
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/* calc number of bytes left in current iov */
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size_t to_copy = (size_t) (iov->iov_len - iov_pos);
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/* limit it to number of bytes left in buffer */
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if (to_copy > buf_len)
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to_copy = buf_len;
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/* copy data out */
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memcpy (buf + buf_pos, (uint8_t *)iov->iov_base + iov_pos, to_copy);
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/* advance in buffer position */
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buf_pos += to_copy;
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buf_len -= to_copy;
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/* check if we need to copy more data */
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if (buf_len == 0)
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break;
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iov_pos = 0; /* it is only possible to have fully copied iovec here */
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}
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return (ssize_t) buf_pos;
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}
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