swap_handle_get_printable_amount()

ledger-secure-sdk/lib_standard_app/swap_entrypoints.h

/* This handle is called when the Exchange application wants to format for
 * display an amount + ticker of a currency known by this application
 *
 * If the formatting succeeds, result is set to the formatted string. Otherwise
 * it is set to '\0'.
 */
void swap_handle_get_printable_amount(get_printable_amount_parameters_t *params);

ledger-secure-sdk/lib_standard_app/swap_lib_calls.h

typedef struct get_printable_amount_parameters_s {
    // INPUTS //
    // Additional data when dealing with tokens
    // Content is coin application specific
    uint8_t *coin_configuration;
    uint8_t  coin_configuration_length;

    // Raw amount in big number format
    uint8_t *amount;
    uint8_t  amount_length;

    // Set to true if the amount to format is the fee of the swap.
    bool is_fee;

    // OUTPUT //
    // Set to the formatted string if the formatting succeeds. 0 otherwise.
    char printable_amount[MAX_PRINTABLE_AMOUNT_SIZE];
} get_printable_amount_parameters_t;

---

Example of handle implementation in Solana

app-solana/src/swap/handle_get_printable_amount.c

#include "handle_get_printable_amount.h"
#include "swap_lib_calls.h"
#include "swap_utils.h"
#include "utils.h"
#include "sol/printer.h"
#include "swap_common.h"

void swap_handle_get_printable_amount(get_printable_amount_parameters_t *params) {
    PRINTF("Inside Solana swap_handle_get_printable_amount\n");
    MEMCLEAR(params->printable_amount);

    uint64_t amount;
    if (!swap_str_to_u64(params->amount, params->amount_length, &amount)) {
        PRINTF("Amount is too big\n");
        return;
    }

    // Fees are displayed normally
    if (params->is_fee || params->coin_configuration == NULL) {
        PRINTF("Defaulting to native SOL amount\n");
        if (print_amount(amount, params->printable_amount, sizeof(params->printable_amount)) != 0) {
            PRINTF("print_amount failed\n");
            return;
        }
    } else {
        uint8_t decimals;
        char ticker[MAX_SWAP_TOKEN_LENGTH] = {0};
        if (!swap_parse_config(params->coin_configuration,
                               params->coin_configuration_length,
                               ticker,
                               sizeof(ticker),
                               &decimals)) {
            PRINTF("Fail to parse coin_configuration\n");
            return;
        }
        if (print_token_amount(amount,
                               ticker,
                               decimals,
                               params->printable_amount,
                               sizeof(params->printable_amount)) != 0) {
            PRINTF("print_amount failed\n");
            return;
        }
    }

    PRINTF("Amount %s\n", params->printable_amount);
}