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#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "../websocksy.h"
static ssize_t json_length(char* data, size_t length);
static ssize_t json_length_string(char* data, size_t length);
static ssize_t json_length_array(char* data, size_t length){
size_t current_offset = 1;
int64_t next_length = 0;
if(!length){
return 0;
}
if(data[0] != '['){
return -1;
}
do{
//skip whitespace
for(; current_offset < length && isspace(data[current_offset]); current_offset++){
}
//empty array
if(!next_length && data[current_offset] == ']'){
break;
}
//get length
next_length = json_length(data + current_offset, length - current_offset);
if(next_length <= 0){
return next_length;
}
current_offset += next_length;
//check for end or ,
for(; current_offset < length && isspace(data[current_offset]); current_offset++){
}
//the ordering matters, check for complete array before checking for eod
if(data[current_offset] == ']'){
break;
}
if(current_offset >= length){
return 0;
}
if(data[current_offset] != ','){
break;
}
current_offset++;
} while(current_offset < length);
if(data[current_offset] == ']'){
return current_offset + 1;
}
return -1;
}
static ssize_t json_length_object(char* data, size_t length){
size_t current_offset = 1;
int64_t next_length = 0;
if(!length){
return 0;
}
if(data[0] != '{'){
return -1;
}
do{
//skip whitespace
for(; current_offset < length && isspace(data[current_offset]); current_offset++){
}
//empty object
if(!next_length && data[current_offset] == '}'){
break;
}
//get key string length
next_length = json_length_string(data + current_offset, length - current_offset);
if(next_length <= 0){
return next_length;
}
current_offset += next_length;
//find colon
for(; current_offset < length && isspace(data[current_offset]); current_offset++){
}
if(current_offset >= length - 1){ //need one more character
return 0;
}
else if(data[current_offset] != ':'){
return -1;
}
current_offset++;
//get value length
next_length = json_length(data + current_offset, length - current_offset);
if(next_length <= 0){
return next_length;
}
current_offset += next_length;
//check for end or ,
for(; current_offset < length && isspace(data[current_offset]); current_offset++){
}
//the ordering matters, check for complete object before checking for eod
if(data[current_offset] == '}'){
break;
}
if(current_offset >= length){
return 0;
}
if(data[current_offset] != ','){
break;
}
current_offset++;
} while(current_offset < length);
if(data[current_offset] == '}'){
return current_offset + 1;
}
return -1;
}
static ssize_t json_length_string(char* data, size_t length){
size_t string_length = 0;
if(!length){
return 0;
}
if(data[0] != '"'){
return -1;
}
//find terminating quotation mark not preceded by escape
for(string_length = 1; string_length < length
&& isprint(data[string_length])
&& (data[string_length] != '"' || data[string_length - 1] == '\\'); string_length++){
}
//complete string found
if(data[string_length] == '"' && data[string_length - 1] != '\\'){
return string_length + 1;
}
//still missing data
if(string_length >= length){
return 0;
}
//anything else
return -1;
}
static ssize_t json_length_value(char* data, size_t length){
size_t value_length = 0;
if(!length){
return 0;
}
if(data[0] == '-' || isdigit(data[0])){
//a number consisting of [minus] int [.int] [eE[+-]]
//terminator (comma, space, eod, eoa, eoo)
//since this is not a full parser, just ensure all characters are from that general set...
for(value_length = 1; value_length < length &&
(isdigit(data[value_length])
|| data[value_length] == '+'
|| data[value_length] == '-'
|| data[value_length] == '.'
|| tolower(data[value_length]) == 'e'); value_length++){
}
if(data[value_length] == ','
|| data[value_length] == ' '
|| data[value_length] == '}'
|| data[value_length] == ']'){
return value_length;
}
if(value_length >= length){
if(data[value_length - 1] == '.'
|| tolower(data[value_length - 1]) == 'e'
|| data[value_length - 1] == '-'
|| data[value_length - 1] == '+'){
return 0;
}
//numbers can be a value on their own...
return value_length;
}
}
//match complete values
if(length >= 4 && !strncmp(data, "null", 4)){
return 4;
}
else if(length >= 4 && !strncmp(data, "true", 4)){
return 4;
}
else if(length >= 5 && !strncmp(data, "false", 5)){
return 5;
}
//match prefix values
if(length < 4 && !strncmp(data, "null", length)){
return 0;
}
else if(length < 4 && !strncmp(data, "true", length)){
return 0;
}
else if(length < 5 && !strncmp(data, "false", length)){
return 0;
}
//invalid value
return -1;
}
static ssize_t json_length(char* data, size_t length){
size_t total_length = 0, current_offset = 0;
ssize_t rv = 0;
if(!length){
return 0;
}
//advance to the first non-blank
for(current_offset = 0; current_offset < length && isspace(data[current_offset]); current_offset++){
}
switch(data[current_offset]){
case '[':
rv = json_length_array(data + current_offset, length - current_offset);
break;
case '{':
rv = json_length_object(data + current_offset, length - current_offset);
break;
case '"':
rv = json_length_string(data + current_offset, length - current_offset);
break;
default:
//false null true
//0-9 | - -> number
rv = json_length_value(data + current_offset, length - current_offset);
break;
}
if(rv <= 0){
return rv;
}
return current_offset + rv;
}
static int64_t framing_json(uint8_t* data, size_t length, size_t last_read, ws_operation* opcode, void** framing_data, const char* config){
ssize_t data_length = json_length(data, length);
if(data_length > 0){
*opcode = ws_frame_text;
return data_length;
}
//incomplete
else if(data_length == 0){
return 0;
}
//failed to parse as json, just dump it
else{
return length;
}
}
static void __attribute__((constructor)) init(){
core_register_framing("json", framing_json);
}
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