# Packet Definition Parser

Fast XML-like parser for binary packet structures with versioning and conditional fields.

## Basic Syntax

```xml
<packet name="PacketName">
	<version number="1">
		<i32 name="player_id">
		<str16 name="player_name">
		<color name="skin_color">
	</version>
</packet>
```

## Field Types

| Type | Size | Description |
|------|------|-------------|
| `i8`, `i16`, `i32`, `i64` | 1-8 bytes | Unsigned integers |
| `si8`, `si16`, `si32`, `si64` | 1-8 bytes | Signed integers |
| `f32`, `f64` | 4-8 bytes | Floating point |
| `str8`, `str16`, `str32` | Variable | Length-prefixed strings |
| `char` | Fixed | Fixed-size byte array |
| `color` | 3 bytes | RGB color (r,g,b) |
| `equip` | 8 bytes | Equipment item |
| `array` | Variable | Array of substructures |

## Multiple Field Names

```xml
<i32 name="player_id,account_id">
<f32 name="pos_x,pos_y,pos_z">
```

## Conditional Fields

```xml
<str16 name="guild_name" if="flag:has_guild">
<i8 name="enhancement" if="item_type!=0">
<color name="aura" if="special_flags&0x01">
```

### Condition Types
- `flag:name` - Flag is set
- `!flag:name` - Flag not set  
- `var:name` - Variable exists
- `!var:name` - Variable doesn't exist
- `field>=value` - Comparison operators: `>=`, `<=`, `>`, `<`, `==`, `!=`
- `field&0x01` - Bitwise AND

## Arrays

```xml
<i8 name="item_count">
<array name="items" count="var:item_count">
	<substruct>
		<i32 name="item_id">
		<str16 name="item_name">
	</substruct>
</array>
```

## Reusable Substructs

```xml
<substruct name="ItemInfo">
	<i32 name="item_id">
	<str16 name="item_name">
</substruct>

<packet name="Inventory">
	<version number="1">
		<i8 name="count">
		<array name="items" count="var:count" substruct="ItemInfo">
	</version>
</packet>
```

## Field Attributes

- `name="field1,field2"` - Field name(s)
- `if="condition"` - Conditional parsing
- `size="10"` - Fixed array size for `char` type
- `count="var:name"` - Array size variable
- `substruct="Name"` - Reference to substruct

## Multiple Versions

```xml
<packet name="PlayerInfo">
	<version number="1">
		<i32 name="id">
		<str16 name="name">
	</version>
	<version number="562">
		<i32 name="id">
		<str16 name="name">
		<color name="skin_color">
	</version>
</packet>
```

## Comments

```xml
<!-- This is a comment -->
<packet name="Test"> <!-- Inline comment -->
	<version number="1">
		<i32 name="id"> <!-- Field comment -->
	</version>
</packet>
```

## Usage

```go
import "eq2emu/internal/parser"

// Parse PML content
packets, err := parser.Parse(pmlContent)
if err != nil {
	log.Fatal(err)
}

// Get packet definition
packet := packets["PacketName"]

// Parse binary data
result, err := packet.Parse(data, version, flags)
```