337 lines
8.7 KiB
C
337 lines
8.7 KiB
C
/*
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* Copyright (c) 2015-2018, Yanzi Networks AB.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \addtogroup lwm2m
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* @{
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*
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*/
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/**
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* \file
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* Implementation of the Contiki OMA LWM2M TLV
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* \author
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* Joakim Eriksson <joakime@sics.se>
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* Niclas Finne <nfi@sics.se>
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*/
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#include <string.h>
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#include <stdint.h>
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#include "lwm2m-tlv.h"
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/* Log configuration */
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#include "coap-log.h"
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#define LOG_MODULE "lwm2m-tlv"
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#define LOG_LEVEL LOG_LEVEL_NONE
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/*---------------------------------------------------------------------------*/
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static inline uint8_t
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get_len_type(const lwm2m_tlv_t *tlv)
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{
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if(tlv->length < 8) {
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return 0;
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} else if(tlv->length < 256) {
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return 1;
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} else if(tlv->length < 0x10000) {
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return 2;
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} else {
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return 3;
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}
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}
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/*---------------------------------------------------------------------------*/
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size_t
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lwm2m_tlv_read(lwm2m_tlv_t *tlv, const uint8_t *buffer, size_t len)
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{
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uint8_t len_type;
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uint8_t len_pos = 1;
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size_t tlv_len;
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tlv->type = (buffer[0] >> 6) & 3;
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len_type = (buffer[0] >> 3) & 3;
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len_pos = 1 + (((buffer[0] & (1 << 5)) != 0) ? 2 : 1);
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tlv->id = buffer[1];
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/* if len_pos is larger than two it means that there is more ID to read */
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if(len_pos > 2) {
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tlv->id = (tlv->id << 8) + buffer[2];
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}
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if(len_type == 0) {
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tlv_len = buffer[0] & 7;
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} else {
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/* read the length */
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tlv_len = 0;
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while(len_type > 0) {
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tlv_len = tlv_len << 8 | buffer[len_pos++];
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len_type--;
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}
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}
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/* and read out the data??? */
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tlv->length = tlv_len;
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tlv->value = &buffer[len_pos];
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return len_pos + tlv_len;
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}
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/*---------------------------------------------------------------------------*/
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size_t
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lwm2m_tlv_get_size(const lwm2m_tlv_t *tlv)
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{
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size_t size;
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/* first hdr + len size */
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size = 1 + get_len_type(tlv);
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/* id size */
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size += (tlv->id > 255) ? 2 : 1;
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/* and the length */
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size += tlv->length;
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return size;
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}
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/*---------------------------------------------------------------------------*/
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/* If the tlv->value is NULL - only the header will be generated - useful for
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* large strings or opaque streaming (block transfer)
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*/
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size_t
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lwm2m_tlv_write(const lwm2m_tlv_t *tlv, uint8_t *buffer, size_t buffersize)
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{
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int pos;
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uint8_t len_type;
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/* len type is the same as number of bytes required for length */
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len_type = get_len_type(tlv);
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pos = 1 + len_type;
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/* ensure that we do not write too much */
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if(tlv->value != NULL && buffersize < tlv->length + pos) {
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LOG_WARN("Could not write the TLV - buffer overflow.\n");
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return 0;
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}
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if(buffersize < pos + 2) {
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return 0;
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}
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/* first type byte in TLV header */
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buffer[0] = (tlv->type << 6) |
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(tlv->id > 255 ? (1 << 5) : 0) |
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(len_type << 3) |
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(len_type == 0 ? tlv->length : 0);
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pos = 1;
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/* The ID */
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if(tlv->id > 255) {
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buffer[pos++] = (tlv->id >> 8) & 0xff;
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}
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buffer[pos++] = tlv->id & 0xff;
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/* Add length if needed - unrolled loop ? */
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if(len_type > 2) {
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buffer[pos++] = (tlv->length >> 16) & 0xff;
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}
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if(len_type > 1) {
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buffer[pos++] = (tlv->length >> 8) & 0xff;
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}
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if(len_type > 0) {
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buffer[pos++] = tlv->length & 0xff;
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}
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/* finally add the value */
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if(tlv->value != NULL && tlv->length > 0) {
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memcpy(&buffer[pos], tlv->value, tlv->length);
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}
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if(LOG_DBG_ENABLED) {
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int i;
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LOG_DBG("TLV: ");
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for(i = 0; i < pos + ((tlv->value != NULL) ? tlv->length : 0); i++) {
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LOG_DBG_("%02x", buffer[i]);
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}
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LOG_DBG_("\n");
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}
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return pos + ((tlv->value != NULL) ? tlv->length : 0);
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}
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/*---------------------------------------------------------------------------*/
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int32_t
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lwm2m_tlv_get_int32(const lwm2m_tlv_t *tlv)
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{
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int i;
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int32_t value = 0;
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for(i = 0; i < tlv->length; i++) {
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value = (value << 8) | tlv->value[i];
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}
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/* Ensure that we set all the bits above what we read in */
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if(tlv->value[0] & 0x80) {
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while(i < 4) {
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value = value | (0xff << (i * 8));
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i++;
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}
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}
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return value;
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}
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/*---------------------------------------------------------------------------*/
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size_t
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lwm2m_tlv_write_int32(uint8_t type, int16_t id, int32_t value, uint8_t *buffer, size_t len)
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{
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lwm2m_tlv_t tlv;
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uint8_t buf[4];
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int i;
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int v;
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int last_bit;
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LOG_DBG("Exporting int32 %d %"PRId32" ", id, value);
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v = value < 0 ? -1 : 0;
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i = 0;
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do {
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buf[3 - i] = value & 0xff;
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/* check if the last MSB indicates that we need another byte */
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last_bit = (v == 0 && (value & 0x80) > 0) || (v == -1 && (value & 0x80) == 0);
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value = value >> 8;
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i++;
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} while((value != v || last_bit) && i < 4);
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/* export INT as TLV */
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LOG_DBG("len: %d\n", i);
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tlv.type = type;
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tlv.length = i;
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tlv.value = &buf[3 - (i - 1)];
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tlv.id = id;
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return lwm2m_tlv_write(&tlv, buffer, len);
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}
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/*---------------------------------------------------------------------------*/
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/* convert fixpoint 32-bit to a IEEE Float in the byte array*/
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size_t
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lwm2m_tlv_write_float32(uint8_t type, int16_t id, int32_t value, int bits,
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uint8_t *buffer, size_t len)
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{
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int i;
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int e = 0;
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int32_t val = 0;
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int32_t v;
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uint8_t b[4];
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lwm2m_tlv_t tlv;
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v = value;
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if(v < 0) {
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v = -v;
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}
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while(v > 1) {
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val = (val >> 1);
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if (v & 1) {
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val = val | (1L << 22);
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}
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v = (v >> 1);
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e++;
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}
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LOG_DBG("Sign: %d, Fraction: %06"PRIx32" 0b", value < 0, val);
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for(i = 0; i < 23; i++) {
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LOG_DBG_("%"PRId32"", ((val >> (22 - i)) & 1));
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}
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LOG_DBG_("\nExp:%d\n", e);
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/* convert to the thing we should have */
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e = e - bits + 127;
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if(value == 0) {
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e = 0;
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}
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/* is this the right byte order? */
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b[0] = (value < 0 ? 0x80 : 0) | (e >> 1);
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b[1] = ((e & 1) << 7) | ((val >> 16) & 0x7f);
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b[2] = (val >> 8) & 0xff;
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b[3] = val & 0xff;
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LOG_DBG("B=%02x%02x%02x%02x\n", b[0], b[1], b[2], b[3]);
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/* construct the TLV */
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tlv.type = type;
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tlv.length = 4;
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tlv.value = b;
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tlv.id = id;
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return lwm2m_tlv_write(&tlv, buffer, len);
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}
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/*---------------------------------------------------------------------------*/
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/* convert float to fixpoint */
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size_t
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lwm2m_tlv_float32_to_fix(const lwm2m_tlv_t *tlv, int32_t *value, int bits)
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{
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/* TLV needs to be 4 bytes */
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int e, i;
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int32_t val;
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int sign = (tlv->value[0] & 0x80) != 0;
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e = ((tlv->value[0] << 1) & 0xff) | (tlv->value[1] >> 7);
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val = (((long)tlv->value[1] & 0x7f) << 16) | (tlv->value[2] << 8) | tlv->value[3];
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LOG_DBG("Sign: %d, Fraction: %06"PRIx32" 0b", val < 0, val);
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for(i = 0; i < 23; i++) {
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LOG_DBG_("%"PRId32"", ((val >> (22 - i)) & 1));
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}
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LOG_DBG("\nExp:%d => %d\n", e, e - 127);
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e = e - 127 + bits;
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/* e corresponds to the number of times we need to roll the number */
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LOG_DBG("Actual e=%d\n", e);
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e = e - 23;
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LOG_DBG("E after sub %d\n", e);
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val = val | 1L << 23;
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if(e > 0) {
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val = val << e;
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} else {
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val = val >> -e;
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}
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*value = sign ? -val : val;
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return 4;
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}
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/*---------------------------------------------------------------------------*/
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/** @} */
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#if 0
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int main(int argc, char *argv[])
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{
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lwm2m_tlv_t tlv;
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uint8_t data[24];
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/* Make -1 */
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tlv.length = 2;
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tlv.value = data;
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data[0] = 0x00;
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data[1] = 0x80,
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printf("TLV:%d\n", lwm2m_tlv_get_int32(&tlv));
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printf("Len: %d\n", lwm2m_tlv_write_int32(0, 1, -0x88987f, data, 24));
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}
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#endif
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