Add strings example

main.c

@@ -1,13 +1,35 @@
 #include <stdlib.h>
-
+#include <stdio.h>
 #include "bdk_ffi.h"
 
 int main (int argc, char const * const argv[])
 {
-    Point_t * a = new_point(84,45);
-    Point_t * b = new_point(0.0,39.0);
-    Point_t * m = mid_point(a, b);
-    print_point(m);
-    print_point(NULL);
+
+    char const * string1 = "string1";
+    char const * string2 = "string2";
+    char * string3 = concat_string(string1, string2);
+    
+    print_string(string3);
+    print_string(string3);
+    free_string(string3);
+
+    //Point_t a = new_point(84,45);
+    //Point_t b = new_point(0,39);
+    //Point_t m = mid_point(a, b);
+    //print_point(m);
+    
+    //char const * name = "test_wallet";
+    //char const * desc = "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/0/*)";
+    //char const * change = "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/1/*)";
+    
+    //printf("wallet name: %s\n", name);
+    //printf("descriptor: %s\n", desc);
+    //printf("change descriptor: %s\n", change);
+    //WalletPtr_t * wallet = new_wallet(name, desc, change);
+    //sync_wallet(wallet);
+    
+    //char const * address = new_address(wallet);
+    //printf("new address: %s\n", address);
+        
     return EXIT_SUCCESS;
 }

src/lib.rs

@@ -1,10 +1,41 @@
-use ::safer_ffi::prelude::*;
+#![deny(unsafe_code)] /* No `unsafe` needed! */
+
+//use ::safer_ffi::prelude::*;
 use bdk::bitcoin::network::constants::Network::Testnet;
 use bdk::blockchain::{ElectrumBlockchain, log_progress};
 use bdk::electrum_client::Client;
 use bdk::sled;
 use bdk::sled::Tree;
 use bdk::Wallet;
+use bdk::wallet::AddressIndex::New;
+use safer_ffi::char_p::{char_p_ref, char_p_boxed};
+use ::safer_ffi::prelude::*;
+
+/// Concatenate two input UTF-8 (_e.g._, ASCII) strings.
+///
+/// \remark The returned string must be freed with `rust_free_string`
+#[ffi_export]
+fn concat_string<'a>(fst: char_p_ref<'a>, snd: char_p_ref<'a>)
+           -> char_p_boxed
+{
+    let fst = fst.to_str(); // : &'_ str
+    let snd = snd.to_str(); // : &'_ str
+    let ccat = format!("{}{}", fst, snd).try_into().unwrap(); 
+    ccat
+}
+
+#[ffi_export]
+fn print_string (string: char_p_ref)
+{
+    println!("{}", string);
+}
+
+/// Frees a Rust-allocated string.
+#[ffi_export]
+fn free_string (string: char_p_boxed)
+{
+    drop(string)
+}
 
 /// A `struct` usable from both Rust and C
 #[derive_ReprC]
@@ -18,30 +49,28 @@ pub struct Point {
 /* Export a Rust function to the C world. */
 /// Returns the middle point of `[a, b]`.
 #[ffi_export]
-fn mid_point(a: Option<repr_c::Box<Point>>, b: Option<repr_c::Box<Point>>) -> repr_c::Box<Point> {
-    let a = a.unwrap();
-    let b = b.unwrap();
-    repr_c::Box::new(Point {
+fn mid_point(a: Point, b: Point) -> Point {
+    Point {
         x: (a.x + b.x) / 2.,
         y: (a.y + b.y) / 2.,
-    })
+    }
 }
 
 /// Pretty-prints a point using Rust's formatting logic.
 #[ffi_export]
-fn print_point(point: Option<repr_c::Box<Point>>) {
+fn print_point(point: Point) {
     println!("{:?}", point);
 }
 
 #[ffi_export]
-fn new_point(x: f64, y: f64) -> repr_c::Box<Point> {
-    repr_c::Box::new(Point { x, y })
+fn new_point(x: f64, y: f64) -> Point {
+    Point { x, y }
 }
 
-#[ffi_export]
-fn free_point(point: Option<repr_c::Box<Point>>) {
-    drop(point)
-}
+//#[ffi_export]
+//fn free_point(point: Point) {
+//    drop(point)
+//}
 
 #[derive_ReprC]
 #[ReprC::opaque]
@@ -90,11 +119,21 @@ fn new_wallet(
 
 #[ffi_export]
 fn sync_wallet( wallet: repr_c::Box<WalletPtr>) {
-    println!("before sync");
     wallet.raw.sync(log_progress(), Some(100));
     println!("after sync");
 }
 
+#[ffi_export]
+fn new_address( wallet: repr_c::Box<WalletPtr>) -> char_p::Box {
+    println!("before new_address");
+    let new_address = wallet.raw.get_address(New);
+    println!("after new_address: {:?}", new_address);
+    let new_address = new_address.unwrap();
+    let new_address = new_address.to_string();
+    println!("new address: ${}", new_address);
+    new_address.try_into().unwrap()
+}
+
 /// The following test function is necessary for the header generation.
 #[::safer_ffi::cfg_headers]
 #[test]