@ipdb/packer

Binary Structure of ipdb Data Structure

Based on the provided code, we can outline the binary representation of the ipdb data structure as follows:

Binary Structure Overview

The binary representation of the ipdb data structure mainly consists of the following parts:

Header: Contains the JSON string of metadata (meta). The header starts with a 4-byte unsigned integer (uint32) indicating the length of the JSON string, followed by the JSON string itself.

Node Chunk: Contains the node data of the IP address binary tree structure. The length of the node chunk is equal to the number of nodes multiplied by 8 (each node occupies 8 bytes). Each node is represented by two 4-byte unsigned integers (uint32), indicating the offsets of the left and right child nodes.

Loopback Chunk: A special node representing the root of the IP address range. The loopback chunk is 8 bytes long and contains two 4-byte unsigned integers (uint32), both indicating the length of the node chunk.

Data Chunk: Contains data related to IP addresses (such as geolocation information). Each element in the data chunk is a Buffer, containing the length of the data (2-byte unsigned integer, uint16) and the actual data.

Example of Binary Structure

Here is a simplified example of the binary representation of the ipdb data structure:

+-----------------+-----------------+-----------------+-----------------+
| Header Length   | Header          | Node Chunk      | Loopback Chunk  |
| (4 bytes)       | (JSON string)   | (variable size) | (8 bytes)       |
+-----------------+-----------------+-----------------+-----------------+
| Data Chunk      | Data Chunk      | ...             | ...             |
| (variable size) | (variable size) |                 |                 |
+-----------------+-----------------+-----------------+-----------------+

Node Chunk

+-----------------+-----------------+
| Left Child      | Right Child     |
| Offset (4 bytes)| Offset (4 bytes)|
+-----------------+-----------------+