Field Block

A definition language for buffer parsing.

Usage

Adding this crate to a project:

bash cargo add field_block

Defining fields for a buffer:

```rust fn getblock() -> Block { let mut block = Block::new(); block.addfield( Name::FixedVarInt, // Def::VarInt(U64::Fixed(0xdeadbeef)), ); block.addfield( Name::VarInt, // Def::VarInt(U64::Var), ); block.addfield( Name::BytesFixedLen, // Def::Bytes(Len::Fixed(1)), ); block.addfield( Name::BytesVarLen, // Def::Bytes(Len::Var), ); block.addfield( Name::FixedBytes, // Def::FixedBytes(vec![0xba, 0xad, 0xf0, 0x0d]), ); block }

[derive(Debug, PartialEq, Eq, Hash, Clone)]

enum Name { FixedVarInt, VarInt, BytesFixedLen, BytesVarLen, FixedBytes, }

impl FieldName for Name {} ```

Encoding a buffer:

```rust let block = get_block();

let mut values = HashMap::new(); values.insert(Name::VarInt, Val::VarInt(0x1234)); let vec = vec![1]; values.insert(Name::BytesFixedLen, Val::Bytes(&vec)); let vec = vec![1, 2, 3]; values.insert(Name::BytesVarLen, Val::Bytes(&vec));

let mut vec = vec![0; 1024];

let end = block.to_bytes(&values, &mut vec).unwrap(); ```

Decoding a buffer:

```rust let block = get_block();

let vec = vec![0 | 0xc0, 0, 0, 0, 0xde, 0xad, 0xbe, 0xef, 0x12 | 0x40, 0x34, 1, 3, 1, 2, 3, 0xba, 0xad, 0xf0, 0x0d];

let mut values = HashMap::new();

let end = block.to_values(&vec, &mut values).unwrap();

let ValInfo { value, pos } = values.get(&Name::VarInt).unwrap(); let value = value.varint().unwrap();

println!("Field VarInt has a value {} at pos {}", value, pos); ```

See unit tests for examples.