/**************************************************************************** * net/iob/iob_copyout.c * * Copyright (C) 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 NuttX 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #if defined(CONFIG_DEBUG_FEATURES) && defined(CONFIG_IOB_DEBUG) /* Force debug output (from this file only) */ # undef CONFIG_DEBUG_NET # define CONFIG_DEBUG_NET 1 #endif #include #include #include #include #include "iob.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifndef MIN # define MIN(a,b) ((a) < (b) ? (a) : (b)) #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: iob_copyout * * Description: * Copy data 'len' bytes of data into the user buffer starting at 'offset' * in the I/O buffer, returning that actual number of bytes copied out. * ****************************************************************************/ int iob_copyout(FAR uint8_t *dest, FAR const struct iob_s *iob, unsigned int len, unsigned int offset) { FAR const uint8_t *src; unsigned int ncopy; unsigned int avail; unsigned int remaining; /* Skip to the I/O buffer containing the offset */ while (offset >= iob->io_len) { offset -= iob->io_len; iob = iob->io_flink; if (iob == NULL) { /* We have no requested data in iob chain */ return 0; } } /* Then loop until all of the I/O data is copied to the user buffer */ remaining = len; while (iob && remaining > 0) { /* Get the source I/O buffer offset address and the amount of data * available from that address. */ src = &iob->io_data[iob->io_offset + offset]; avail = iob->io_len - offset; /* Copy the from the I/O buffer in to the user buffer */ ncopy = MIN(avail, remaining); memcpy(dest, src, ncopy); /* Adjust the total length of the copy and the destination address in * the user buffer. */ remaining -= ncopy; dest += ncopy; /* Skip to the next I/O buffer in the chain */ iob = iob->io_flink; offset = 0; } return len - remaining; }