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nes-proj/os/services/lwm2m/lwm2m-json.c

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/*
* Copyright (c) 2016, Eistec AB.
* All rights reserved.
*
* 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 of the copyright holder 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 HOLDER 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 HOLDER 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.
*/
/**
* \addtogroup lwm2m
* @{
*/
/**
* \file
* Implementation of the Contiki OMA LWM2M JSON writer
* \author
* Joakim Nohlgård <joakim.nohlgard@eistec.se>
* Joakim Eriksson <joakime@sics.se> added JSON reader parts
*/
#include "lwm2m-object.h"
#include "lwm2m-json.h"
#include "lwm2m-plain-text.h"
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <inttypes.h>
/* Log configuration */
#include "coap-log.h"
#define LOG_MODULE "lwm2m-json"
#define LOG_LEVEL LOG_LEVEL_NONE
/*---------------------------------------------------------------------------*/
/* {"e":[{"n":"111/1","v":123},{"n":"111/2","v":42}]} */
/* Begin String */
#define T_NONE 0
#define T_STRING_B 1
#define T_STRING 2
#define T_NAME 4
#define T_VNUM 5
#define T_OBJ 6
#define T_VAL 7
/* Simlified JSON style reader for reading in values from a LWM2M JSON
string */
int
lwm2m_json_next_token(lwm2m_context_t *ctx, struct json_data *json)
{
int pos = ctx->inbuf->pos;
uint8_t type = T_NONE;
uint8_t vpos_start = 0;
uint8_t vpos_end = 0;
uint8_t cont;
uint8_t wscount = 0;
json->name_len = 0;
json->value_len = 0;
cont = 1;
/* We will be either at start, or at a specific position */
while(pos < ctx->inbuf->size && cont) {
uint8_t c = ctx->inbuf->buffer[pos++];
switch(c) {
case '{': type = T_OBJ; break;
case '}':
case ',':
if(type == T_VAL || type == T_STRING) {
json->value = &ctx->inbuf->buffer[vpos_start];
json->value_len = vpos_end - vpos_start - wscount;
type = T_NONE;
cont = 0;
}
wscount = 0;
break;
case '\\':
/* stuffing */
if(pos < ctx->inbuf->size) {
pos++;
vpos_end = pos;
}
break;
case '"':
if(type == T_STRING_B) {
type = T_STRING;
vpos_end = pos - 1;
wscount = 0;
} else {
type = T_STRING_B;
vpos_start = pos;
}
break;
case ':':
if(type == T_STRING) {
json->name = &ctx->inbuf->buffer[vpos_start];
json->name_len = vpos_end - vpos_start;
vpos_start = vpos_end = pos;
type = T_VAL;
} else {
/* Could be in string or at illegal pos */
if(type != T_STRING_B) {
LOG_DBG("ERROR - illegal ':'\n");
}
}
break;
/* ignore whitespace */
case ' ':
case '\n':
case '\t':
if(type != T_STRING_B) {
if(vpos_start == pos - 1) {
vpos_start = pos;
} else {
wscount++;
}
}
default:
vpos_end = pos;
}
}
if(cont == 0 && pos < ctx->inbuf->size) {
ctx->inbuf->pos = pos;
}
/* OK if cont == 0 othewise we failed */
return cont == 0 && pos < ctx->inbuf->size;
}
/*---------------------------------------------------------------------------*/
static size_t
init_write(lwm2m_context_t *ctx)
{
int len = snprintf((char *)&ctx->outbuf->buffer[ctx->outbuf->len],
ctx->outbuf->size - ctx->outbuf->len, "{\"bn\":\"/%u/%u/\",\"e\":[",
ctx->object_id, ctx->object_instance_id);
ctx->writer_flags = 0; /* set flags to zero */
if((len < 0) || (len >= ctx->outbuf->size)) {
return 0;
}
return len;
}
/*---------------------------------------------------------------------------*/
static size_t
end_write(lwm2m_context_t *ctx)
{
int len = snprintf((char *)&ctx->outbuf->buffer[ctx->outbuf->len],
ctx->outbuf->size - ctx->outbuf->len, "]}");
if((len < 0) || (len >= ctx->outbuf->size - ctx->outbuf->len)) {
return 0;
}
return len;
}
/*---------------------------------------------------------------------------*/
static size_t
enter_sub(lwm2m_context_t *ctx)
{
/* set some flags in state */
LOG_DBG("Enter sub-resource rsc=%d\n", ctx->resource_id);
ctx->writer_flags |= WRITER_RESOURCE_INSTANCE;
return 0;
}
/*---------------------------------------------------------------------------*/
static size_t
exit_sub(lwm2m_context_t *ctx)
{
/* clear out state info */
LOG_DBG("Exit sub-resource rsc=%d\n", ctx->resource_id);
ctx->writer_flags &= ~WRITER_RESOURCE_INSTANCE;
return 0;
}
/*---------------------------------------------------------------------------*/
static size_t
write_boolean(lwm2m_context_t *ctx, uint8_t *outbuf, size_t outlen,
int value)
{
char *sep = (ctx->writer_flags & WRITER_OUTPUT_VALUE) ? "," : "";
int len;
if(ctx->writer_flags & WRITER_RESOURCE_INSTANCE) {
len = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u/%u\",\"bv\":%s}", sep, ctx->resource_id, ctx->resource_instance_id, value ? "true" : "false");
} else {
len = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u\",\"bv\":%s}", sep, ctx->resource_id, value ? "true" : "false");
}
if((len < 0) || (len >= outlen)) {
return 0;
}
LOG_DBG("JSON: Write bool:%s\n", outbuf);
ctx->writer_flags |= WRITER_OUTPUT_VALUE;
return len;
}
/*---------------------------------------------------------------------------*/
static size_t
write_int(lwm2m_context_t *ctx, uint8_t *outbuf, size_t outlen,
int32_t value)
{
char *sep = (ctx->writer_flags & WRITER_OUTPUT_VALUE) ? "," : "";
int len;
if(ctx->writer_flags & WRITER_RESOURCE_INSTANCE) {
len = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u/%u\",\"v\":%"PRId32"}", sep, ctx->resource_id, ctx->resource_instance_id, value);
} else {
len = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u\",\"v\":%"PRId32"}", sep, ctx->resource_id, value);
}
if((len < 0) || (len >= outlen)) {
return 0;
}
LOG_DBG("Write int:%s\n", outbuf);
ctx->writer_flags |= WRITER_OUTPUT_VALUE;
return len;
}
/*---------------------------------------------------------------------------*/
static size_t
write_float32fix(lwm2m_context_t *ctx, uint8_t *outbuf, size_t outlen,
int32_t value, int bits)
{
char *sep = (ctx->writer_flags & WRITER_OUTPUT_VALUE) ? "," : "";
size_t len = 0;
int res;
if(ctx->writer_flags & WRITER_RESOURCE_INSTANCE) {
res = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u/%u\",\"v\":", sep, ctx->resource_id, ctx->resource_instance_id);
} else {
res = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u\",\"v\":", sep, ctx->resource_id);
}
if(res <= 0 || res >= outlen) {
return 0;
}
len += res;
outlen -= res;
res = lwm2m_plain_text_write_float32fix(&outbuf[len], outlen, value, bits);
if((res <= 0) || (res >= outlen)) {
return 0;
}
len += res;
outlen -= res;
res = snprintf((char *)&outbuf[len], outlen, "}");
if((res <= 0) || (res >= outlen)) {
return 0;
}
len += res;
ctx->writer_flags |= WRITER_OUTPUT_VALUE;
return len;
}
/*---------------------------------------------------------------------------*/
static size_t
write_string(lwm2m_context_t *ctx, uint8_t *outbuf, size_t outlen,
const char *value, size_t stringlen)
{
char *sep = (ctx->writer_flags & WRITER_OUTPUT_VALUE) ? "," : "";
size_t i;
size_t len = 0;
int res;
LOG_DBG("{\"n\":\"%u\",\"sv\":\"", ctx->resource_id);
if(ctx->writer_flags & WRITER_RESOURCE_INSTANCE) {
res = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u/%u\",\"sv\":\"", sep,
ctx->resource_id, ctx->resource_instance_id);
} else {
res = snprintf((char *)outbuf, outlen, "%s{\"n\":\"%u\",\"sv\":\"", sep,
ctx->resource_id);
}
if(res < 0 || res >= outlen) {
return 0;
}
len += res;
for (i = 0; i < stringlen && len < outlen; ++i) {
/* Escape special characters */
/* TODO: Handle UTF-8 strings */
if(value[i] < '\x20') {
LOG_DBG_("\\x%x", value[i]);
res = snprintf((char *)&outbuf[len], outlen - len, "\\x%x", value[i]);
if((res < 0) || (res >= (outlen - len))) {
return 0;
}
len += res;
continue;
} else if(value[i] == '"' || value[i] == '\\') {
LOG_DBG_("\\");
outbuf[len] = '\\';
++len;
if(len >= outlen) {
return 0;
}
}
LOG_DBG_("%c", value[i]);
outbuf[len] = value[i];
++len;
if(len >= outlen) {
return 0;
}
}
LOG_DBG_("\"}\n");
res = snprintf((char *)&outbuf[len], outlen - len, "\"}");
if((res < 0) || (res >= (outlen - len))) {
return 0;
}
LOG_DBG("JSON: Write string:%s\n", outbuf);
len += res;
ctx->writer_flags |= WRITER_OUTPUT_VALUE;
return len;
}
/*---------------------------------------------------------------------------*/
const lwm2m_writer_t lwm2m_json_writer = {
init_write,
end_write,
enter_sub,
exit_sub,
write_int,
write_string,
write_float32fix,
write_boolean
};
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
/** @} */
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