Files
OpenSK/libraries/cbor/examples/cbor.rs
David Drysdale 0287a09573 cbor: allow user to control nesting (#329)
* cbor: allow user to control nesting

 - Make the default read/write entrypoints allow infinite nesting.
 - Add {read,write}_nested() entrypoints that allow the crate user to
   control the depth of nesting that's allowed.
 - Along the way, convert the write[_nested] variants to return a
   `Result<(), EncoderError>` rather than a bool.  This exposes
   more failure information (and forces the caller to take notice
   of those tailures), and allows use of the ? operator.

* fixup: transmute error

Co-authored-by: kaczmarczyck <43844792+kaczmarczyck@users.noreply.github.com>
2021-06-18 19:39:54 +02:00

91 lines
3.0 KiB
Rust

// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////
//! Example program demonstrating cbor usage.
extern crate alloc;
use sk_cbor::values::{SimpleValue, Value};
use sk_cbor::{cbor_array, cbor_bytes, cbor_map, cbor_null, cbor_true};
fn hexify(data: &[u8]) -> String {
let mut s = String::new();
for b in data {
s.push_str(&format!("{:02x}", b));
}
s
}
fn main() {
// Build a CBOR object with various different types included. Note that this
// object is not built in canonical order.
let manual_object = Value::Map(vec![
(
Value::Unsigned(1),
Value::Array(vec![Value::Unsigned(2), Value::Unsigned(3)]),
),
(
Value::TextString("tstr".to_owned()),
Value::ByteString(vec![1, 2, 3]),
),
(Value::Negative(-2), Value::Simple(SimpleValue::NullValue)),
(Value::Unsigned(3), Value::Simple(SimpleValue::TrueValue)),
]);
// Build the same object using the crate's convenience macros.
let macro_object = cbor_map! {
1 => cbor_array![2, 3],
"tstr" => cbor_bytes!(vec![1, 2, 3]),
-2 => cbor_null!(),
3 => cbor_true!(),
};
assert_eq!(manual_object, macro_object);
println!("Object {:?}", manual_object);
// Serialize to bytes.
let mut manual_data = vec![];
sk_cbor::writer::write(manual_object, &mut manual_data).unwrap();
let hex_manual_data = hexify(&manual_data);
let mut macro_data = vec![];
sk_cbor::writer::write(macro_object, &mut macro_data).unwrap();
let hex_macro_data = hexify(&macro_data);
assert_eq!(hex_manual_data, hex_macro_data);
// Serialized version is in canonical order.
println!("Serializes to {}", hex_manual_data);
assert_eq!(
hex_manual_data,
concat!(
"a4", // 4-map
"01", // int(1) =>
"820203", // 2-array [2, 3],
"03", // int(3) =>
"f5", // true,
"21", // nint(-2) =>
"f6", // null,
"6474737472", // 4-tstr "tstr" =>
"43010203" // 3-bstr
)
);
// Convert back to an object. This is different than the original object,
// because the map is now in canonical order.
let recovered_object = sk_cbor::reader::read(&manual_data).unwrap();
println!("Deserializes to {:?}", recovered_object);
}