Fix casting errors in client-cli

client-cli can produce casting errors if the numbers given as
command-line arguments are negative. With this commit, the code
now checks if the arguments are negative, and if so, prints an
error message and exits.

Signed-off-by: Michael L. Szulczewski <[email protected]>

src/uhs/client/client-cli.cpp

@@ -28,8 +28,25 @@ auto mint_command(cbdc::client& client, const std::vector<std::string>& args)
         return false;
     }
 
-    const auto n_outputs = std::stoull(args[5]);
-    const auto output_val = std::stoul(args[6]);
+    const auto n_outputs_arg_idx = 5;
+    const std::string& n_outputs_arg = args[n_outputs_arg_idx];
+    std::wstring::size_type idx_first_non_whitespace
+        = n_outputs_arg.find_first_not_of(' ');
+    if(n_outputs_arg[idx_first_non_whitespace] == '-') {
+        std::cerr << "The requsted number of UTXOs cannot be negative."
+                  << std::endl;
+        return false;
+    }
+    const auto n_outputs = std::stoull(n_outputs_arg);
+
+    const auto output_val_arg_idx = 6;
+    const std::string& output_val_arg = args[output_val_arg_idx];
+    idx_first_non_whitespace = output_val_arg.find_first_not_of(' ');
+    if(output_val_arg[idx_first_non_whitespace] == '-') {
+        std::cerr << "The UTXO values cannot be negative." << std::endl;
+        return false;
+    }
+    const auto output_val = std::stoul(output_val_arg);
 
     const auto mint_tx
         = client.mint(n_outputs, static_cast<uint32_t>(output_val));
@@ -103,11 +120,20 @@ auto send_command(cbdc::client& client, const std::vector<std::string>& args)
         return false;
     }
 
-    const auto value = std::stoul(args[5]);
+    const auto value_arg_idx = 5;
+    const std::string& value_arg = args[value_arg_idx];
+    std::wstring::size_type idx_first_non_whitespace
+        = value_arg.find_first_not_of(' ');
+    if(value_arg[idx_first_non_whitespace] == '-') {
+        std::cerr << "The amount of currency to send cannot be negative."
+                  << std::endl;
+        return false;
+    }
+    const auto value = std::stoul(value_arg);
     static constexpr auto address_arg_idx = 6;
     auto pubkey = decode_address(args[address_arg_idx]);
     if(!pubkey.has_value()) {
-        std::cout << "Could not decode address" << std::endl;
+        std::cout << "Could not decode address." << std::endl;
         return false;
     }
 
@@ -130,8 +156,24 @@ auto fan_command(cbdc::client& client, const std::vector<std::string>& args)
         return false;
     }
 
-    const auto value = std::stoul(args[6]);
-    const auto count = std::stoul(args[5]);
+    const auto value_arg_idx = 6;
+    const std::string& value_arg = args[value_arg_idx];
+    std::wstring::size_type idx_first_non_whitespace
+        = value_arg.find_first_not_of(' ');
+    if(value_arg[idx_first_non_whitespace] == '-') {
+        std::cerr << "The value cannot be negative." << std::endl;
+        return false;
+    }
+    const auto value = std::stoul(value_arg);
+
+    const auto count_arg_idx = 5;
+    const std::string& count_arg = args[count_arg_idx];
+    idx_first_non_whitespace = count_arg.find_first_not_of(' ');
+    if(count_arg[idx_first_non_whitespace] == '-') {
+        std::cerr << "The count cannot be negative." << std::endl;
+        return false;
+    }
+    const auto count = std::stoul(count_arg);
 
     static constexpr auto address_arg_idx = 7;
     auto pubkey = decode_address(args[address_arg_idx]);