overwriting a cbor map field result even though field is not decoded

[ziv123]

hello Nordic

i am using ncs 2.8.0 with nrf52832 and mrf52840

i am decoding a cbor file with the 'zcbor_map_decode_bulk'

LOG_INF("in func decode config - val_9 %d", result->val_9_placeholder);

    ZCBOR_STATE_D(zsd, 2, config_file, config_file_len, 1, 0);
    struct zcbor_map_decode_key_val map_key_decode[] = {
        ZCBOR_MAP_DECODE_KEY_DECODER("..", zcbor_int32_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", my_implementation_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", my_implementation_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", my_implementation_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", my_implementation_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", my_implementation_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", zcbor_bool_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", zcbor_bool_decode, &result->..),
        ZCBOR_MAP_DECODE_KEY_DECODER("val_9", zcbor_bool_decode, &result->val_9_placeholder),
        ZCBOR_MAP_DECODE_KEY_DECODER("..", zcbor_int32_decode, &result->battery_capacity),
    };

    int rc = zcbor_map_decode_bulk(zsd, map_key_decode, ARRAY_SIZE(map_key_decode), &decoded);

LOG_INF("decode config - val_9 %d, rc %d", result->val_9_placeholder, rc);

the 'my_implementation_decode' is just a function that has map with all zcbor_decode.h function calls and the same 'zcbor_map_decode_bulk' at the end.

for some reason the value of the result->val9_placeholder changes from the default '1' it was before decoding, to '0' after, though there is no field 'val_9' in the cbor file i am decoding 

and following the 'zcbor_map_decode_bulk' function, with log prints, shows that the val_9 never goes through  

dptr->decoder(zsd, dptr->value_ptr) ... it does not pass the condition 

if (key.len == dptr->key.len && memcmp(key.value, dptr->key.value, key.len) == 0)

any idea why the result->val9_placeholder  is changed anyway ?

p.s. it does not happen when there is a shorter cbor with less fields (the cbor with issues is 246 bytes, and the small cbor is 178) 

hope to read from you soon

best regards

ZIv 

[ziv123]

the problem is that values of smaller size like uint8_t or uint16_t in the map, when decoded using zcbor_uint32_decode, cause over run of the other bytes, cause the function does a memset for 0 in the size of uint32 (4 bytes) so the values after the uint8_t, or uint16_t overrun with '0', if they are found in the cbor then they get new vals but else they get a '0'

anyways, the solution use zcbor_uint_decode api .. which also gets the size of the value in bytes .. the problem is that the macro does not get another value so i had to create a wrapper for that function  like so:

static bool augu_uint16_decode(zcbor_state_t *state, uint16_t *result)
{
    return zcbor_uint_decode(state, result, sizeof(uint16_t));
}

static bool augu_uint8_decode(zcbor_state_t *state, uint8_t *result)
{
    return zcbor_uint_decode(state, result, sizeof(uint8_t));
}

best regards

Ziv