# Trie Parser

Almost all of Pronghorn’s string manipulation utilizes a [bitwise trie](https://en.wikipedia.org/wiki/Trie). It is called the `TrieParser` and is used in route matching, JSON parsing, HTTP header parsing, and much more.

Utilize the TrieParser for fast parsing and matching in your Pronghorn projects.

### Example <a href="#example" id="example"></a>

```java
// Define a tag. This number is an ID used to associate with certain matches. Make sure this is unique.
final int tagIndex = 120;

// Create a new TrieParser
TrieParser map = new TrieParser();

// Define your matches here
// Use %b for bytes and strings
map.setUTF8Value("<strong>%b</strong>", tagIndex);

// Create a new reader. Since we already know all of our content, make sure to set alwaysCompletePayloads to true
TrieParserReader reader = new TrieParserReader(true);

// Our example string. Since it has to be in bytes, use CharSequenceToUTF8Local to convert to a String.
CharSequenceToUTF8Local.get().convert("Wow, it is a beautiful day <strong>today</strong>!").parseSetup(reader);

// This will store the output
StringBuilder tag = new StringBuilder();

// Now do the actual parsing. Make sure we have content and check if we found our tagIndex
while (TrieParserReader.parseHasContent(reader)) {
	long val = TrieParserReader.parseNext(reader, map); // The ID the parser found

	// The parser found our index
	if(val == tagIndex) {
		// Capture it and output it to the StringBuilder
		TrieParserReader.capturedFieldBytesAsUTF8(reader, 0, tag);
	} else {
		// Skip over anything else
		TrieParserReader.parseSkipOne(reader);
	}
}

System.out.println("This is what's inside the strong tag: " + tag);
```

### Supported Types <a href="#supported-types" id="supported-types"></a>

| Name                    | Description                                                                                     | Example |
| ----------------------- | ----------------------------------------------------------------------------------------------- | ------- |
| Optional Signed Integer | Optional signed int, if absent returns zero                                                     | `%o`    |
| Signed Integer          | Signed Integer (may be hex if starts with 0x)                                                   | `%i`    |
| Unsigned Integer        | Unsigned Integer (may be hex if starts with 0x)                                                 | `%u`    |
| Signed Hex              | Signed Integer (may skip prefix 0x, assumed to be hex)                                          | `%I`    |
| Unsigned Hex            | Unsigned Integer (may skip prefix 0x, assumed to be hex)                                        | `%U`    |
| Decimal                 | If value is found after dot, capture it. Otherwise, a 0 is captured.                            | `%i%.`  |
| Rational                | If value is found after dot, capture it. Otherwise, a 0 is captured. Always after i, dot, or u. | `%i%/`  |
| Bytes/String            | Captures bytes and Strings                                                                      | `%b`    |


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