Struct TagsStore

pub struct TagsStore { /* private fields */ }

A registry that maintains mappings between CBOR tags, their human-readable names, and optional summarizers.

The TagsStore is the primary implementation of the TagsStoreTrait, providing a bidirectional mapping between CBOR tag values (numbers) and their human-readable names. It also supports registering custom summarizers for specific tags.

Use Cases

The TagsStore serves several important purposes:

1. Readability: Converting numeric tags to meaningful names in diagnostic output
2. Consistency: Ensuring consistent tag usage throughout an application
3. Documentation: Providing a central registry of all tags used in a system
4. Customization: Supporting custom summarization of tagged values

Features

• Bidirectional lookup between tag values and names
• Prevention of duplicate registrations with conflicting names
• Optional registration of custom summarizers for specific tags
• Default implementation for an empty registry

Examples

Basic usage

use dcbor::prelude::*;

// Create a new TagsStore with a set of predefined tags
let mut tags = TagsStore::new([
    Tag::new(1, "date".to_string()),
    Tag::new(2, "positive_bignum".to_string()),
    Tag::new(3, "negative_bignum".to_string())
]);

// Look up a tag by its value
let date_tag = tags.tag_for_value(1).unwrap();
assert_eq!(date_tag.name().unwrap(), "date");

// Look up a tag name by value
let name = tags.name_for_value(2);
assert_eq!(name, "positive_bignum");

// Look up a tag by its name
let neg_tag = tags.tag_for_name("negative_bignum").unwrap();
assert_eq!(neg_tag.value(), 3);

Adding summarizers

use dcbor::prelude::*;
use std::sync::Arc;

// Create an empty tags store
let mut tags = TagsStore::default();

// Register a tag
tags.insert(Tag::new(1, "date".to_string()));

// Add a summarizer for the date tag
tags.set_summarizer(1, Arc::new(|cbor| {
    // Try to convert CBOR to f64 for timestamp formatting
    let timestamp: f64 = cbor.clone().try_into().unwrap_or(0.0);
    Ok(format!("Timestamp: {}", timestamp))
}));

// Later, this summarizer can be retrieved and used
let date_summarizer = tags.summarizer(1);
assert!(date_summarizer.is_some());

Implementation Notes

The TagsStore prevents registering the same tag value with different names, which helps maintain consistency in CBOR tag usage. Attempting to register a tag value that already exists with a different name will panic.

Implementations

impl TagsStore

pub fn new<T>(tags: T) -> Self

where T: IntoIterator<Item = Tag>,

pub fn insert(&mut self, tag: Tag)

pub fn insert_all(&mut self, tags: Vec<Tag>)

pub fn set_summarizer(&mut self, tag: TagValue, summarizer: CBORSummarizer)

Trait Implementations

impl Clone for TagsStore

fn clone(&self) -> TagsStore

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for TagsStore

fn default() -> Self

Returns the “default value” for a type.

impl TagsStoreTrait for TagsStore

fn assigned_name_for_tag(&self, tag: &Tag) -> Option<String>

fn name_for_tag(&self, tag: &Tag) -> String

fn tag_for_name(&self, name: &str) -> Option<Tag>

fn tag_for_value(&self, value: u64) -> Option<Tag>

fn name_for_value(&self, value: u64) -> String

fn summarizer(&self, tag: TagValue) -> Option<&CBORSummarizer>

fn name_for_tag_opt<T>(tag: &Tag, tags: Option<&T>) -> String

where T: TagsStoreTrait, Self: Sized,