contiki/apps/json/jsonparse.c
Jeff Kent 7dc1581631 jsonparse: multiple improvements
* input string now can be any json value type
* syntax handling completed
* stack is now used more efficiently for objects
* implemented atomic values true, false, and null
* jsonparse_copy_value now handles escapes
2015-12-28 09:47:12 -06:00

350 lines
10 KiB
C

/*
* 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 void
modify(struct jsonparse_state *state, char c)
{
if(state->depth > 0) {
state->stack[state->depth - 1] = c;
}
}
/*--------------------------------------------------------------------*/
static char
pop(struct jsonparse_state *state)
{
if(state->depth == 0) {
return JSON_TYPE_ERROR;
}
state->depth--;
state->vtype = state->stack[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 char
atomic(struct jsonparse_state *state, char type)
{
char c;
const char *str;
int len;
state->vstart = state->pos;
if(type == JSON_TYPE_STRING || type == JSON_TYPE_PAIR_NAME) {
while((c = state->json[state->pos++]) && c != '"') {
if(c == '\\') {
state->pos++; /* skip current char */
}
}
if (c != '"') {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
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;
} else if(type == JSON_TYPE_NULL || type == JSON_TYPE_TRUE || type == JSON_TYPE_FALSE) {
state->vstart--;
switch (type) {
case JSON_TYPE_NULL: str = "null"; break;
case JSON_TYPE_TRUE: str = "true"; break;
case JSON_TYPE_FALSE: str = "false"; break;
default: str = ""; break;
}
while ((c = state->json[state->pos]) && c != ' ' && c != ',' && c != ']' && c != '}') {
state->pos++;
}
state->vlen = state->pos - state->vstart;
len = strlen(str);
len = state->vlen > len ? state->vlen : len;
if (strncmp(str, &state->json[state->vstart], len) != 0) {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
}
state->vtype = type;
return state->vtype;
}
/*--------------------------------------------------------------------*/
static void
skip_ws(struct jsonparse_state *state)
{
char c;
while(state->pos < state->len &&
((c = state->json[state->pos]) == ' ' || c == '\n')) {
state->pos++;
}
}
/*--------------------------------------------------------------------*/
static int
is_atomic(struct jsonparse_state *state)
{
char v = state->vtype;
if(v == 'N' || v == '"' || v == '0' || v == 'n' || v == 't' || v == 'f') {
return 1;
} else {
return 0;
}
}
/*--------------------------------------------------------------------*/
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->vtype = 0;
state->stack[0] = 0;
}
/*--------------------------------------------------------------------*/
int
jsonparse_next(struct jsonparse_state *state)
{
char c;
char s;
char v;
skip_ws(state);
c = state->json[state->pos];
s = jsonparse_get_type(state);
v = state->vtype;
state->pos++;
switch(c) {
case '{':
if((s == 0 && v == 0) || s == '[' || s == ':') {
push(state, c);
} else {
state->error = JSON_ERROR_UNEXPECTED_OBJECT;
return JSON_TYPE_ERROR;
}
return c;
case '}':
if((s == ':' && v != ',' && v != 0 ) || (s == '{' && v == 0)) {
pop(state);
} else {
state->error = JSON_ERROR_UNEXPECTED_END_OF_OBJECT;
return JSON_TYPE_ERROR;
}
return c;
case ']':
if(s == '[' && v != ',') {
pop(state);
} else {
state->error = JSON_ERROR_UNEXPECTED_END_OF_ARRAY;
return JSON_TYPE_ERROR;
}
return c;
case ':':
if(s == '{' && v == 'N') {
modify(state, ':');
state->vtype = 0;
} else {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
return jsonparse_next(state);
case ',':
if(s == ':' && v != 0) {
modify(state, '{');
state->vtype = c;
} else if(s == '[') {
state->vtype = c;
} else {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
return c;
case '"':
if((s == 0 && v == 0) || s == '{' || s == '[' || s == ':') {
return 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 == 0 && v == 0) || s == '[' || s == ':') {
push(state, c);
} else {
state->error = JSON_ERROR_UNEXPECTED_ARRAY;
return JSON_TYPE_ERROR;
}
return c;
case 0:
if(v == 0 || state->depth > 0) {
state->error = JSON_ERROR_SYNTAX;
}
return JSON_TYPE_ERROR;
default:
if(s == 0 || s == ':' || s == '[') {
if (v != 0 && v != ',') {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
if(c == '-' || (c <= '9' && c >= '0')) {
return atomic(state, JSON_TYPE_NUMBER);
} else if(c == 'n') {
return atomic(state, JSON_TYPE_NULL);
} else if(c == 't') {
return atomic(state, JSON_TYPE_TRUE);
} else if(c == 'f') {
return atomic(state, JSON_TYPE_FALSE);
} else {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
} else if(s == '{') {
state->error = JSON_ERROR_SYNTAX;
return JSON_TYPE_ERROR;
}
}
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, o;
char c;
if(!is_atomic(state)) {
return 0;
}
for(i = 0, o = 0; i < state->vlen && o < size - 1; i++) {
c = state->json[state->vstart + i];
if(c == '\\') {
i++;
switch(state->json[state->vstart + i]) {
case '"': str[o++] = '"'; break;
case '\\': str[o++] = '\\'; break;
case '/': str[o++] = '/'; break;
case 'b': str[o++] = '\b'; break;
case 'f': str[o++] = '\f'; break;
case 'n': str[o++] = '\n'; break;
case 'r': str[o++] = '\r'; break;
case 't': str[o++] = '\t'; break;
}
continue;
}
str[o++] = c;
}
str[o] = 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(!is_atomic(state)) {
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;
}
/*--------------------------------------------------------------------*/