osd-contiki/apps/json/jsonparse.c

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/*
* Copyright (c) 2011-2012, Swedish Institute of Computer Science.
* 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 Institute 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 INSTITUTE 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 INSTITUTE 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.
*
* This file is part of the Contiki operating system.
*/
#include "jsonparse.h"
#include <stdlib.h>
#include <string.h>
/*--------------------------------------------------------------------*/
static int
push(struct jsonparse_state *state, char c)
{
state->stack[state->depth] = c;
state->depth++;
state->vtype = 0;
return state->depth < JSONPARSE_MAX_DEPTH;
}
/*--------------------------------------------------------------------*/
static char
pop(struct jsonparse_state *state)
{
if(state->depth == 0) {
return JSON_TYPE_ERROR;
}
state->depth--;
return state->stack[state->depth];
}
/*--------------------------------------------------------------------*/
/* will pass by the value and store the start and length of the value for
atomic types */
/*--------------------------------------------------------------------*/
static void
atomic(struct jsonparse_state *state, char type)
{
char c;
state->vstart = state->pos;
state->vtype = type;
if(type == JSON_TYPE_STRING || type == JSON_TYPE_PAIR_NAME) {
while((c = state->json[state->pos++]) && c != '"') {
if(c == '\\') {
state->pos++; /* skip current char */
}
}
state->vlen = state->pos - state->vstart - 1;
} else if(type == JSON_TYPE_NUMBER) {
do {
c = state->json[state->pos];
if((c < '0' || c > '9') && c != '.') {
c = 0;
} else {
state->pos++;
}
} while(c);
/* need to back one step since first char is already gone */
state->vstart--;
state->vlen = state->pos - state->vstart;
}
/* no other types for now... */
}
/*--------------------------------------------------------------------*/
static void
skip_ws(struct jsonparse_state *state)
{
char c;
while(state->pos < state->len &&
((c = state->json[state->pos]) == ' ' || c == '\n')) {
state->pos++;
}
}
/*--------------------------------------------------------------------*/
void
jsonparse_setup(struct jsonparse_state *state, const char *json, int len)
{
state->json = json;
state->len = len;
state->pos = 0;
state->depth = 0;
state->error = 0;
state->stack[0] = 0;
}
/*--------------------------------------------------------------------*/
int
jsonparse_next(struct jsonparse_state *state)
{
char c;
char s;
skip_ws(state);
c = state->json[state->pos];
s = jsonparse_get_type(state);
state->pos++;
switch(c) {
case '{':
push(state, c);
return c;
case '}':
if(s == ':' && state->vtype != 0) {
/* printf("Popping vtype: '%c'\n", state->vtype); */
pop(state);
s = jsonparse_get_type(state);
}
if(s == '{') {
pop(state);
} else {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
return c;
case ']':
if(s == '[') {
pop(state);
} else {
state->error = JSON_ERROR_UNEXPECTED_END_OF_ARRAY;
return JSON_TYPE_ERROR;
}
return c;
case ':':
push(state, c);
return c;
case ',':
/* if x:y ... , */
if(s == ':' && state->vtype != 0) {
pop(state);
} else if(s == '[') {
/* ok! */
} else {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
return c;
case '"':
if(s == '{' || s == '[' || s == ':') {
atomic(state, c = (s == '{' ? JSON_TYPE_PAIR_NAME : c));
} else {
state->error = JSON_ERROR_UNEXPECTED_STRING;
return JSON_TYPE_ERROR;
}
return c;
case '[':
if(s == '{' || s == '[' || s == ':') {
push(state, c);
} else {
state->error = JSON_ERROR_UNEXPECTED_ARRAY;
return JSON_TYPE_ERROR;
}
return c;
default:
if(s == ':' || s == '[') {
if(c <= '9' && c >= '0') {
atomic(state, JSON_TYPE_NUMBER);
return JSON_TYPE_NUMBER;
}
}
}
return 0;
}
/*--------------------------------------------------------------------*/
/* get the json value of the current position
* works only on "atomic" values such as string, number, null, false, true
*/
/*--------------------------------------------------------------------*/
int
jsonparse_copy_value(struct jsonparse_state *state, char *str, int size)
{
int i;
if(state->vtype == 0) {
return 0;
}
size = size <= state->vlen ? (size - 1) : state->vlen;
for(i = 0; i < size; i++) {
str[i] = state->json[state->vstart + i];
}
str[i] = 0;
return state->vtype;
}
/*--------------------------------------------------------------------*/
int
jsonparse_get_value_as_int(struct jsonparse_state *state)
{
if(state->vtype != JSON_TYPE_NUMBER) {
return 0;
}
return atoi(&state->json[state->vstart]);
}
/*--------------------------------------------------------------------*/
long
jsonparse_get_value_as_long(struct jsonparse_state *state)
{
if(state->vtype != JSON_TYPE_NUMBER) {
return 0;
}
return atol(&state->json[state->vstart]);
}
/*--------------------------------------------------------------------*/
/* strcmp - assume no strange chars that needs to be stuffed in string... */
/*--------------------------------------------------------------------*/
int
jsonparse_strcmp_value(struct jsonparse_state *state, const char *str)
{
if(state->vtype == 0) {
return -1;
}
return strncmp(str, &state->json[state->vstart], state->vlen);
}
/*--------------------------------------------------------------------*/
int
jsonparse_get_len(struct jsonparse_state *state)
{
return state->vlen;
}
/*--------------------------------------------------------------------*/
int
jsonparse_get_type(struct jsonparse_state *state)
{
if(state->depth == 0) {
return 0;
}
return state->stack[state->depth - 1];
}
/*--------------------------------------------------------------------*/
int
jsonparse_has_next(struct jsonparse_state *state)
{
return state->pos < state->len;
}
/*--------------------------------------------------------------------*/