| // Copyright 2016 The Fuchsia Authors |
| // Copyright (c) 2014 Travis Geiselbrecht |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #include <iovec.h> |
| |
| #include <assert.h> |
| #include <debug.h> |
| #include <err.h> |
| #include <string.h> |
| #include <sys/types.h> |
| |
| #define LOCAL_TRACE 0 |
| |
| /* |
| * Calc total size of iovec buffers |
| */ |
| ssize_t iovec_size(const iovec_t* iov, uint iov_cnt) { |
| if (!iov) { |
| return (ssize_t)ZX_ERR_INVALID_ARGS; |
| } |
| |
| size_t c = 0; |
| for (uint i = 0; i < iov_cnt; i++, iov++) { |
| c += iov->iov_len; |
| } |
| return (ssize_t)c; |
| } |
| |
| /* |
| * Copy out portion of iovec started from given position |
| * into single buffer |
| */ |
| ssize_t iovec_to_membuf(uint8_t* buf, uint buf_len, const iovec_t* iov, uint iov_cnt, uint iov_pos) { |
| uint buf_pos = 0; |
| |
| if (!buf || !iov) { |
| return (ssize_t)ZX_ERR_INVALID_ARGS; |
| } |
| |
| /* for all iovec */ |
| for (uint i = 0; i < iov_cnt; i++, iov++) { |
| |
| if (iov_pos >= iov->iov_len) { |
| iov_pos -= iov->iov_len; /* skip whole chunks */ |
| continue; |
| } |
| |
| /* calc number of bytes left in current iov */ |
| size_t to_copy = (size_t)(iov->iov_len - iov_pos); |
| |
| /* limit it to number of bytes left in buffer */ |
| if (to_copy > buf_len) { |
| to_copy = buf_len; |
| } |
| |
| /* copy data out */ |
| memcpy(buf + buf_pos, (uint8_t*)iov->iov_base + iov_pos, to_copy); |
| |
| /* advance in buffer position */ |
| buf_pos += to_copy; |
| buf_len -= to_copy; |
| |
| /* check if we need to copy more data */ |
| if (buf_len == 0) { |
| break; |
| } |
| |
| iov_pos = 0; /* it is only possible to have fully copied iovec here */ |
| } |
| |
| return (ssize_t)buf_pos; |
| } |