telegram_parser.c

/*
 * telegram_message_parser.c
 *
 *  Created on: Nov 14, 2019
 *      Author: alapshin
 */

#include <stdio.h>
#include <stdlib.h>
#include "telegram.h"
#include "telegram_parser.h"
#include "parser/telegram_result.h"
#include "private_include/telegram_parser.h"

#define GOTO_ERR do { ESP_LOGE(__func__, "error on line %d", __LINE__); goto err_exit; } while (0)

#define JSON_MAX_TOKENS 128

static void character_replace(char *str, char in, char out)
{
    if (str == NULL)
    {
        return;
    }
    for(; *str != '\0'; str++)
    {
        if(*str != in)
        {
            continue;
        }
        *str = out;
    }
}

int compare_json_value (const char *str, const char *json, jsmntok_t *t, int i)
{
    int len_1 = strlen(str);
    int len_2 = t[i].end - t[i].start;
    return strncmp(str, json + t[i].start, (len_1 < len_2) ? len_1 : len_2);
}

int json_parse_string (char *str, int str_len, json_parser_t *parser, int index)
{
    int result = SUCCESS;
    int json_str_len = parser->t[index].end - parser->t[index].start;
    if(str_len < json_str_len)
    {
        result = TOO_LONG_STRING;
        GOTO_ERR;
    }
    strncpy(str, parser->json + parser->t[index].start, json_str_len);
err_exit:
    return result;
}

int json_parse_int(json_parser_t *parser, int index, int *val)
{
    int result = SUCCESS;
    char *endptr;
    *val = strtol(parser->json + parser->t[index].start, &endptr, 10);
    if (endptr != parser->json + parser->t[index].end)
    {
        *val = 0;
        result = PARSING_INT;
    }

    return result;
}

int json_parse_core (json_parser_t *parser, int index, void *data, int (*callback)(json_parser_t *parser, int index, void *data))
{
    int i, result = index;
    int object_parrent = parser->t[index].parent + 1;
    if (parser->t[index].type != JSMN_OBJECT)
    {
        GOTO_ERR;
    }

    for (i = index; parser->t[i].type != JSMN_UNDEFINED && i < parser->r; i++)
    {
        ESP_LOGD(__func__, "Now parsing \"%.*s\"",
                 parser->t[i].end - parser->t[i].start,
                 &parser->json[parser->t[i].start]);

        if (parser->t[i].parent != object_parrent)
        {
            continue;
        }
        result = callback(parser, i, data);
        if (result != SUCCESS)
        {
            ESP_LOGE(__func__, "Error while parsing \"%.*s\"",
                     parser->t[i].end - parser->t[i].start,
                     &parser->json[parser->t[i].start]);
            goto err_exit;
        }
    }
    result = i;

err_exit:
    return result;
}

int parse_updates_message (char *json, telegram_parsed_msg_t *message)
{
    int i = 0, result = SUCCESS;
    jsmn_parser p;
    const char *key = NULL;
    size_t key_lenght = 0;
    json_parser_t parser = {.json = json, .t = NULL, .r = 0};

    if (json == NULL)
    {
        result = GENERAL_ERROR;
        GOTO_ERR;
    }
    parser.t = calloc(sizeof(jsmntok_t), JSON_MAX_TOKENS);
    character_replace(json, '\n', ' ');
    jsmn_init(&p);
    parser.r = jsmn_parse(&p, json, strlen(json), parser.t, JSON_MAX_TOKENS);
    if (parser.r < 0)
    {
        result = PARSING_ERROR;
        GOTO_ERR;
    }

    /* Assume the top-level element is an object */
    if (parser.r < 1 || parser.t[i].type != JSMN_OBJECT)
    {
        result = PARSING_ERROR;
        GOTO_ERR;
    }

    i++;
    key = &parser.json[parser.t[i].start];
    key_lenght = parser.t[i].end - parser.t[i].start;
    if(!IS_JSON_KEY("ok"))
    {
        result = PARSING_ERROR;
        GOTO_ERR;
    }
    key = &parser.json[parser.t[i].start];
    key_lenght = parser.t[i].end - parser.t[i].start;
    if(!IS_JSON_KEY("true"))
    {
        result = PARSING_ERROR;
        GOTO_ERR;
    }
    key = &parser.json[parser.t[i].start];
    key_lenght = parser.t[i].end - parser.t[i].start;
    if(!IS_JSON_KEY("result"))
    {
        result = PARSING_ERROR;
        GOTO_ERR;
    }
    if (parser.t[i].type == JSMN_ARRAY) /* array */
    {
        i++;
    }

    if (parser.t[i].type == JSMN_UNDEFINED)
    {
        goto err_exit;
    }

    memset(message, 0x00, sizeof(*message));
    json_parse_core(&parser, i, message, json_parse_telegram_result_callback);

    result = SUCCESS;

err_exit:
    free(parser.t);
    parser.t = NULL;
    return result;
}