Momentum-Apps/jsmn/jsmn.c

/*
 * MIT License
 *
 * Copyright (c) 2010 Serge Zaitsev
 *
 * [License text continues...]
 */

#include <jsmn/jsmn.h>
#include <stdlib.h>
#include <string.h>

/**
 * Allocates a fresh unused token from the token pool.
 */
static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser, jsmntok_t *tokens,
                                   const size_t num_tokens)
{
    jsmntok_t *tok;

    if (parser->toknext >= num_tokens)
    {
        return NULL;
    }
    tok = &tokens[parser->toknext++];
    tok->start = tok->end = -1;
    tok->size = 0;
#ifdef JSMN_PARENT_LINKS
    tok->parent = -1;
#endif
    return tok;
}

/**
 * Fills token type and boundaries.
 */
static void jsmn_fill_token(jsmntok_t *token, const jsmntype_t type,
                            const int start, const int end)
{
    token->type = type;
    token->start = start;
    token->end = end;
    token->size = 0;
}

/**
 * Fills next available token with JSON primitive.
 */
static int jsmn_parse_primitive(jsmn_parser *parser, const char *js,
                                const size_t len, jsmntok_t *tokens,
                                const size_t num_tokens)
{
    jsmntok_t *token;
    int start;

    start = parser->pos;

    for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++)
    {
        switch (js[parser->pos])
        {
#ifndef JSMN_STRICT
        /* In strict mode primitive must be followed by "," or "}" or "]" */
        case ':':
#endif
        case '\t':
        case '\r':
        case '\n':
        case ' ':
        case ',':
        case ']':
        case '}':
            goto found;
        default:
            /* to quiet a warning from gcc*/
            break;
        }
        if (js[parser->pos] < 32 || js[parser->pos] >= 127)
        {
            parser->pos = start;
            return JSMN_ERROR_INVAL;
        }
    }
#ifdef JSMN_STRICT
    /* In strict mode primitive must be followed by a comma/object/array */
    parser->pos = start;
    return JSMN_ERROR_PART;
#endif

found:
    if (tokens == NULL)
    {
        parser->pos--;
        return 0;
    }
    token = jsmn_alloc_token(parser, tokens, num_tokens);
    if (token == NULL)
    {
        parser->pos = start;
        return JSMN_ERROR_NOMEM;
    }
    jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
#ifdef JSMN_PARENT_LINKS
    token->parent = parser->toksuper;
#endif
    parser->pos--;
    return 0;
}

/**
 * Fills next token with JSON string.
 */
static int jsmn_parse_string(jsmn_parser *parser, const char *js,
                             const size_t len, jsmntok_t *tokens,
                             const size_t num_tokens)
{
    jsmntok_t *token;

    int start = parser->pos;

    /* Skip starting quote */
    parser->pos++;

    for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++)
    {
        char c = js[parser->pos];

        /* Quote: end of string */
        if (c == '\"')
        {
            if (tokens == NULL)
            {
                return 0;
            }
            token = jsmn_alloc_token(parser, tokens, num_tokens);
            if (token == NULL)
            {
                parser->pos = start;
                return JSMN_ERROR_NOMEM;
            }
            jsmn_fill_token(token, JSMN_STRING, start + 1, parser->pos);
#ifdef JSMN_PARENT_LINKS
            token->parent = parser->toksuper;
#endif
            return 0;
        }

        /* Backslash: Quoted symbol expected */
        if (c == '\\' && parser->pos + 1 < len)
        {
            int i;
            parser->pos++;
            switch (js[parser->pos])
            {
            /* Allowed escaped symbols */
            case '\"':
            case '/':
            case '\\':
            case 'b':
            case 'f':
            case 'r':
            case 'n':
            case 't':
                break;
            /* Allows escaped symbol \uXXXX */
            case 'u':
                parser->pos++;
                for (i = 0; i < 4 && parser->pos < len && js[parser->pos] != '\0'; i++)
                {
                    /* If it isn't a hex character we have an error */
                    if (!((js[parser->pos] >= 48 && js[parser->pos] <= 57) || /* 0-9 */
                          (js[parser->pos] >= 65 && js[parser->pos] <= 70) || /* A-F */
                          (js[parser->pos] >= 97 && js[parser->pos] <= 102)))
                    { /* a-f */
                        parser->pos = start;
                        return JSMN_ERROR_INVAL;
                    }
                    parser->pos++;
                }
                parser->pos--;
                break;
            /* Unexpected symbol */
            default:
                parser->pos = start;
                return JSMN_ERROR_INVAL;
            }
        }
    }
    parser->pos = start;
    return JSMN_ERROR_PART;
}

/**
 * Create JSON parser over an array of tokens
 */
void jsmn_init(jsmn_parser *parser)
{
    parser->pos = 0;
    parser->toknext = 0;
    parser->toksuper = -1;
}

/**
 * Parse JSON string and fill tokens.
 */
int jsmn_parse(jsmn_parser *parser, const char *js, const size_t len,
               jsmntok_t *tokens, const unsigned int num_tokens)
{
    int r;
    int i;
    jsmntok_t *token;
    int count = parser->toknext;

    for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++)
    {
        char c;
        jsmntype_t type;

        c = js[parser->pos];
        switch (c)
        {
        case '{':
        case '[':
            count++;
            if (tokens == NULL)
            {
                break;
            }
            token = jsmn_alloc_token(parser, tokens, num_tokens);
            if (token == NULL)
            {
                return JSMN_ERROR_NOMEM;
            }
            if (parser->toksuper != -1)
            {
                jsmntok_t *t = &tokens[parser->toksuper];
#ifdef JSMN_STRICT
                /* In strict mode an object or array can't become a key */
                if (t->type == JSMN_OBJECT)
                {
                    return JSMN_ERROR_INVAL;
                }
#endif
                t->size++;
#ifdef JSMN_PARENT_LINKS
                token->parent = parser->toksuper;
#endif
            }
            token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
            token->start = parser->pos;
            parser->toksuper = parser->toknext - 1;
            break;
        case '}':
        case ']':
            if (tokens == NULL)
            {
                break;
            }
            type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
#ifdef JSMN_PARENT_LINKS
            if (parser->toknext < 1)
            {
                return JSMN_ERROR_INVAL;
            }
            token = &tokens[parser->toknext - 1];
            for (;;)
            {
                if (token->start != -1 && token->end == -1)
                {
                    if (token->type != type)
                    {
                        return JSMN_ERROR_INVAL;
                    }
                    token->end = parser->pos + 1;
                    parser->toksuper = token->parent;
                    break;
                }
                if (token->parent == -1)
                {
                    if (token->type != type || parser->toksuper == -1)
                    {
                        return JSMN_ERROR_INVAL;
                    }
                    break;
                }
                token = &tokens[token->parent];
            }
#else
            for (i = parser->toknext - 1; i >= 0; i--)
            {
                token = &tokens[i];
                if (token->start != -1 && token->end == -1)
                {
                    if (token->type != type)
                    {
                        return JSMN_ERROR_INVAL;
                    }
                    parser->toksuper = -1;
                    token->end = parser->pos + 1;
                    break;
                }
            }
            /* Error if unmatched closing bracket */
            if (i == -1)
            {
                return JSMN_ERROR_INVAL;
            }
            for (; i >= 0; i--)
            {
                token = &tokens[i];
                if (token->start != -1 && token->end == -1)
                {
                    parser->toksuper = i;
                    break;
                }
            }
#endif
            break;
        case '\"':
            r = jsmn_parse_string(parser, js, len, tokens, num_tokens);
            if (r < 0)
            {
                return r;
            }
            count++;
            if (parser->toksuper != -1 && tokens != NULL)
            {
                tokens[parser->toksuper].size++;
            }
            break;
        case '\t':
        case '\r':
        case '\n':
        case ' ':
            break;
        case ':':
            parser->toksuper = parser->toknext - 1;
            break;
        case ',':
            if (tokens != NULL && parser->toksuper != -1 &&
                tokens[parser->toksuper].type != JSMN_ARRAY &&
                tokens[parser->toksuper].type != JSMN_OBJECT)
            {
#ifdef JSMN_PARENT_LINKS
                parser->toksuper = tokens[parser->toksuper].parent;
#else
                for (i = parser->toknext - 1; i >= 0; i--)
                {
                    if (tokens[i].type == JSMN_ARRAY || tokens[i].type == JSMN_OBJECT)
                    {
                        if (tokens[i].start != -1 && tokens[i].end == -1)
                        {
                            parser->toksuper = i;
                            break;
                        }
                    }
                }
#endif
            }
            break;
#ifdef JSMN_STRICT
        /* In strict mode primitives are: numbers and booleans */
        case '-':
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
        case 't':
        case 'f':
        case 'n':
            /* And they must not be keys of the object */
            if (tokens != NULL && parser->toksuper != -1)
            {
                const jsmntok_t *t = &tokens[parser->toksuper];
                if (t->type == JSMN_OBJECT ||
                    (t->type == JSMN_STRING && t->size != 0))
                {
                    return JSMN_ERROR_INVAL;
                }
            }
#else
        /* In non-strict mode every unquoted value is a primitive */
        default:
#endif
            r = jsmn_parse_primitive(parser, js, len, tokens, num_tokens);
            if (r < 0)
            {
                return r;
            }
            count++;
            if (parser->toksuper != -1 && tokens != NULL)
            {
                tokens[parser->toksuper].size++;
            }
            break;

#ifdef JSMN_STRICT
        /* Unexpected char in strict mode */
        default:
            return JSMN_ERROR_INVAL;
#endif
        }
    }

    if (tokens != NULL)
    {
        for (i = parser->toknext - 1; i >= 0; i--)
        {
            /* Unmatched opened object or array */
            if (tokens[i].start != -1 && tokens[i].end == -1)
            {
                return JSMN_ERROR_PART;
            }
        }
    }

    return count;
}

// Helper function to create a JSON object
char *jsmn(const char *key, const char *value)
{
    int length = strlen(key) + strlen(value) + 8;         // Calculate required length
    char *result = (char *)malloc(length * sizeof(char)); // Allocate memory
    if (result == NULL)
    {
        return NULL; // Handle memory allocation failure
    }
    snprintf(result, length, "{\"%s\":\"%s\"}", key, value);
    return result; // Caller is responsible for freeing this memory
}

// Helper function to compare JSON keys
int jsoneq(const char *json, jsmntok_t *tok, const char *s)
{
    if (tok->type == JSMN_STRING && (int)strlen(s) == tok->end - tok->start &&
        strncmp(json + tok->start, s, tok->end - tok->start) == 0)
    {
        return 0;
    }
    return -1;
}

// Return the value of the key in the JSON data
char *get_json_value(char *key, char *json_data, uint32_t max_tokens)
{
    // Parse the JSON feed
    if (json_data != NULL)
    {
        jsmn_parser parser;
        jsmn_init(&parser);

        // Allocate tokens array on the heap
        jsmntok_t *tokens = malloc(sizeof(jsmntok_t) * max_tokens);
        if (tokens == NULL)
        {
            FURI_LOG_E("JSMM.H", "Failed to allocate memory for JSON tokens.");
            return NULL;
        }

        int ret = jsmn_parse(&parser, json_data, strlen(json_data), tokens, max_tokens);
        if (ret < 0)
        {
            // Handle parsing errors
            FURI_LOG_E("JSMM.H", "Failed to parse JSON: %d", ret);
            free(tokens);
            return NULL;
        }

        // Ensure that the root element is an object
        if (ret < 1 || tokens[0].type != JSMN_OBJECT)
        {
            FURI_LOG_E("JSMM.H", "Root element is not an object.");
            free(tokens);
            return NULL;
        }

        // Loop through the tokens to find the key
        for (int i = 1; i < ret; i++)
        {
            if (jsoneq(json_data, &tokens[i], key) == 0)
            {
                // We found the key. Now, return the associated value.
                int length = tokens[i + 1].end - tokens[i + 1].start;
                char *value = malloc(length + 1);
                if (value == NULL)
                {
                    FURI_LOG_E("JSMM.H", "Failed to allocate memory for value.");
                    free(tokens);
                    return NULL;
                }
                strncpy(value, json_data + tokens[i + 1].start, length);
                value[length] = '\0'; // Null-terminate the string

                free(tokens); // Free the token array
                return value; // Return the extracted value
            }
        }

        // Free the token array if key was not found
        free(tokens);
    }
    else
    {
        FURI_LOG_E("JSMM.H", "JSON data is NULL");
    }
    FURI_LOG_E("JSMM.H", "Failed to find the key in the JSON.");
    return NULL; // Return NULL if something goes wrong
}

// Helper function to skip a token and all its descendants.
// Returns the index of the next token after skipping this one.
// On error or out of bounds, returns -1.
static int skip_token(const jsmntok_t *tokens, int start, int total)
{
    if (start < 0 || start >= total)
        return -1;

    int i = start;
    if (tokens[i].type == JSMN_OBJECT)
    {
        // For an object: size is number of key-value pairs
        int pairs = tokens[i].size;
        i++; // move to first key-value pair
        for (int p = 0; p < pairs; p++)
        {
            // skip key (primitive/string)
            i++;
            if (i >= total)
                return -1;
            // skip value (which could be object/array and must be skipped recursively)
            i = skip_token(tokens, i, total);
            if (i == -1)
                return -1;
        }
        return i; // i is now just past the object
    }
    else if (tokens[i].type == JSMN_ARRAY)
    {
        // For an array: size is number of elements
        int elems = tokens[i].size;
        i++; // move to first element
        for (int e = 0; e < elems; e++)
        {
            i = skip_token(tokens, i, total);
            if (i == -1)
                return -1;
        }
        return i; // i is now just past the array
    }
    else
    {
        // Primitive or string token, just skip it
        return i + 1;
    }
}

// Revised get_json_array_value
char *get_json_array_value(char *key, uint32_t index, char *json_data, uint32_t max_tokens)
{
    // Always extract the full array each time from the original json_data
    char *array_str = get_json_value(key, json_data, max_tokens);
    if (array_str == NULL)
    {
        FURI_LOG_E("JSMM.H", "Failed to get array for key: %s", key);
        return NULL;
    }

    jsmn_parser parser;
    jsmn_init(&parser);

    jsmntok_t *tokens = malloc(sizeof(jsmntok_t) * max_tokens);
    if (tokens == NULL)
    {
        FURI_LOG_E("JSMM.H", "Failed to allocate memory for JSON tokens.");
        free(array_str);
        return NULL;
    }

    int ret = jsmn_parse(&parser, array_str, strlen(array_str), tokens, max_tokens);
    if (ret < 0)
    {
        FURI_LOG_E("JSMM.H", "Failed to parse JSON array: %d", ret);
        free(tokens);
        free(array_str);
        return NULL;
    }

    if (ret < 1 || tokens[0].type != JSMN_ARRAY)
    {
        FURI_LOG_E("JSMM.H", "Value for key '%s' is not an array.", key);
        free(tokens);
        free(array_str);
        return NULL;
    }

    if (index >= (uint32_t)tokens[0].size)
    {
        FURI_LOG_E("JSMM.H", "Index %lu out of bounds for array with size %u.", index, tokens[0].size);
        free(tokens);
        free(array_str);
        return NULL;
    }

    // Find the index-th element: start from token[1], which is the first element
    int elem_token = 1;
    for (uint32_t i = 0; i < index; i++)
    {
        elem_token = skip_token(tokens, elem_token, ret);
        if (elem_token == -1 || elem_token >= ret)
        {
            FURI_LOG_E("JSMM.H", "Error skipping tokens to reach element %lu.", i);
            free(tokens);
            free(array_str);
            return NULL;
        }
    }

    // Now elem_token should point to the token of the requested element
    jsmntok_t element = tokens[elem_token];
    int length = element.end - element.start;
    char *value = malloc(length + 1);
    if (!value)
    {
        FURI_LOG_E("JSMM.H", "Failed to allocate memory for array element.");
        free(tokens);
        free(array_str);
        return NULL;
    }

    strncpy(value, array_str + element.start, length);
    value[length] = '\0';

    free(tokens);
    free(array_str);

    return value;
}

// Revised get_json_array_values function with correct token skipping
char **get_json_array_values(char *key, char *json_data, uint32_t max_tokens, int *num_values)
{
    // Retrieve the array string for the given key
    char *array_str = get_json_value(key, json_data, max_tokens);
    if (array_str == NULL)
    {
        FURI_LOG_E("JSMM.H", "Failed to get array for key: %s", key);
        return NULL;
    }

    // Initialize the JSON parser
    jsmn_parser parser;
    jsmn_init(&parser);

    // Allocate memory for JSON tokens
    jsmntok_t *tokens = malloc(sizeof(jsmntok_t) * max_tokens); // Allocate on the heap
    if (tokens == NULL)
    {
        FURI_LOG_E("JSMM.H", "Failed to allocate memory for JSON tokens.");
        free(array_str);
        return NULL;
    }

    // Parse the JSON array
    int ret = jsmn_parse(&parser, array_str, strlen(array_str), tokens, max_tokens);
    if (ret < 0)
    {
        FURI_LOG_E("JSMM.H", "Failed to parse JSON array: %d", ret);
        free(tokens);
        free(array_str);
        return NULL;
    }

    // Ensure the root element is an array
    if (tokens[0].type != JSMN_ARRAY)
    {
        FURI_LOG_E("JSMM.H", "Value for key '%s' is not an array.", key);
        free(tokens);
        free(array_str);
        return NULL;
    }

    // Allocate memory for the array of values (maximum possible)
    int array_size = tokens[0].size;
    char **values = malloc(array_size * sizeof(char *));
    if (values == NULL)
    {
        FURI_LOG_E("JSMM.H", "Failed to allocate memory for array of values.");
        free(tokens);
        free(array_str);
        return NULL;
    }

    int actual_num_values = 0;

    // Traverse the array and extract all object values
    int current_token = 1; // Start after the array token
    for (int i = 0; i < array_size; i++)
    {
        if (current_token >= ret)
        {
            FURI_LOG_E("JSMM.H", "Unexpected end of tokens while traversing array.");
            break;
        }

        jsmntok_t element = tokens[current_token];

        if (element.type != JSMN_OBJECT)
        {
            FURI_LOG_E("JSMM.H", "Array element %d is not an object, skipping.", i);
            // Skip this element
            current_token += 1;
            continue;
        }

        int length = element.end - element.start;

        // Allocate a new string for the value and copy the data
        char *value = malloc(length + 1);
        if (value == NULL)
        {
            FURI_LOG_E("JSMM.H", "Failed to allocate memory for array element.");
            for (int j = 0; j < actual_num_values; j++)
            {
                free(values[j]);
            }
            free(values);
            free(tokens);
            free(array_str);
            return NULL;
        }

        strncpy(value, array_str + element.start, length);
        value[length] = '\0'; // Null-terminate the string

        values[actual_num_values] = value;
        actual_num_values++;

        // Skip all tokens related to this object to avoid misparsing
        current_token += 1 + (2 * element.size); // Each key-value pair consumes two tokens
    }

    *num_values = actual_num_values;

    // Reallocate the values array to actual_num_values if necessary
    if (actual_num_values < array_size)
    {
        char **reduced_values = realloc(values, actual_num_values * sizeof(char *));
        if (reduced_values != NULL)
        {
            values = reduced_values;
        }

        // Free the remaining values
        for (int i = actual_num_values; i < array_size; i++)
        {
            free(values[i]);
        }
    }

    // Clean up
    free(tokens);
    free(array_str);
    return values;
}