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Docs /
Fuels Rs /
Codec /
Decoding

Icon LinkDecoding

Be sure to read the prerequisites to decoding.
Decoding is done via the ABIDecoder Icon Link: 
use fuels::{
    core::{
        codec::ABIDecoder,
        traits::{Parameterize, Tokenizable},
    },
    macros::{Parameterize, Tokenizable},
    types::Token,
};
 
#[derive(Parameterize, Tokenizable)]
struct MyStruct {
    field: u64,
}
 
let bytes: &[u8] = &[0, 0, 0, 0, 0, 0, 0, 101];
 
let token: Token = ABIDecoder::default().decode(&MyStruct::param_type(), bytes)?;
 
let _: MyStruct = MyStruct::from_token(token)?;
First into a Token Icon Link, then via the Tokenizable Icon Link trait, into the desired type.
If the type came from abigen! (or uses the ::fuels::macros::TryFrom Icon Link derivation) then you can also use try_into to convert bytes into a type that implements both Parameterize Icon Link and Tokenizable Icon Link: 
use fuels::macros::{Parameterize, Tokenizable, TryFrom};
 
#[derive(Parameterize, Tokenizable, TryFrom)]
struct MyStruct {
    field: u64,
}
 
let bytes: &[u8] = &[0, 0, 0, 0, 0, 0, 0, 101];
 
let _: MyStruct = bytes.try_into()?;
Under the hood, try_from_bytes Icon Link is being called, which does what the preceding example did.

Icon LinkConfiguring the decoder

The decoder can be configured to limit its resource expenditure: 
 
use fuels::core::codec::ABIDecoder;
 
ABIDecoder::new(DecoderConfig {
    max_depth: 5,
    max_tokens: 100,
});
For an explanation of each configuration value visit the DecoderConfig.
The default values for the DecoderConfig are: 
impl Default for DecoderConfig {
    fn default() -> Self {
        Self {
            max_depth: 45,
            max_tokens: 10_000,
        }
    }
}

Icon LinkConfiguring the decoder for contract/script calls

You can also configure the decoder used to decode the return value of the contract method: 
let _ = contract_instance
    .methods()
    .initialize_counter(42)
    .with_decoder_config(DecoderConfig {
        max_depth: 10,
        max_tokens: 20_00,
    })
    .call()
    .await?;
The same method is available for script calls.