https://github.com/mattms/esm_reader

Extract data from Fallout 3 ESM files.
https://github.com/mattms/esm_reader

Last synced: about 1 month ago
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Extract data from Fallout 3 ESM files.

• Host: GitHub
• URL: https://github.com/mattms/esm_reader
• Owner: MattMS
• License: isc
• Created: 2015-12-22T09:18:17.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2017-01-23T09:44:18.000Z (almost 8 years ago)
• Last Synced: 2024-10-03T12:10:33.589Z (3 months ago)
• Homepage:
• Size: 127 KB
• Stars: 3
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Read Fallout 3 ESM files

**Please note:** This is a work in progress.

It is only partially implemented and barely tested.

Come back later.

This package parses the `*.esm` data files used by Fallout 3 and exposes the data as Objects via a Node.js Stream.

Another aim of this project is to provide documentation of the file format.

## Usage

Add this as a dependency to your project:

	npm install esm_reader --save

## File structure and parsers

Values are stored in [little endian](https://en.wikipedia.org/wiki/Endianness) format.

This controls the Node Buffer methods to use.

Files always start with a TES4 record.

The rest of the file is divided into groups, described next.

[parser/main.coffee.md](./parser/main.coffee.md) switches to the appropriate parser based on the current state.

### Groups

[read_group_header.coffee.md](./read_group_header.coffee.md) parses the start of each group.

The rest of the group is made up of records, described next.

### Records

[read_record_header.coffee.md](./read_record_header.coffee.md) parses the start of each record.

The rest of the record is made up of fields, described next.

### Fields

[read_field.coffee.md](./read_field.coffee.md) parses field data from a Buffer.

A field contains a 4 byte label and then 2 bytes indicating the size of the field data.

The remaining bytes store the value of the field.

Fields can contain different types of values: text, numbers, bit flags, or lists of those.

The type of the value are not described by the field, but rather determined by the labels of the group+record+field.