Radoub Formats BIF

BIF Format

BIF files are binary archives containing game resources.

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Overview

BIF (Binary Interleaved File) archives store the actual resource data indexed by KEY files. They contain two types of resources: variable-size resources (most common) and fixed-size resources (used for tiles).

Common Files: nwn_base.bif, xp1.bif, textures01.bif

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Binary Layout

Header (20 bytes)

Offset	Size	Type	Description
0	4	char[4]	FileType ("BIFF")
4	4	char[4]	Version ("V1 ")
8	4	uint32	VariableResourceCount
12	4	uint32	FixedResourceCount
16	4	uint32	VariableTableOffset

Fixed table follows variable table.

Variable Resource Entry (16 bytes)

Offset	Size	Type	Description
0	4	uint32	Id (matches ResId from KEY)
4	4	uint32	Offset (to resource data)
8	4	uint32	FileSize
12	4	uint32	ResourceType

Fixed Resource Entry (20 bytes)

Offset	Size	Type	Description
0	4	uint32	Id
4	4	uint32	Offset
8	4	uint32	PartCount
12	4	uint32	PartSize
16	4	uint32	ResourceType

Total size = PartCount * PartSize

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Resource Extraction Flow

flowchart TB
    Start[Extract Resource] --> GetIndex[Get variable table index from KEY]
    GetIndex --> ReadEntry[Read variable resource entry]
    ReadEntry --> SeekOffset[Seek to Offset in BIF]
    SeekOffset --> ReadData[Read FileSize bytes]
    ReadData --> Return[Return resource data]

Loading

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Usage in Radoub.Formats

Basic Reading

using Radoub.Formats.Bif;

// Read BIF file (keeps buffer for extraction)
var bif = BifReader.Read(@"data\nwn_base.bif", keepBuffer: true);

Console.WriteLine($"Variable resources: {bif.VariableResources.Count}");
Console.WriteLine($"Fixed resources: {bif.FixedResources.Count}");

// Extract resource by index
byte[]? data = bif.ExtractVariableResource(123);

// Or by resource object
var resource = bif.GetVariableResource(123);
if (resource != null)
{
    data = bif.ExtractVariableResource(resource);
}

Combined KEY/BIF Usage

using Radoub.Formats.Key;
using Radoub.Formats.Bif;

var key = KeyReader.Read("nwn_base.key");
var entry = key.FindResource("mydialog", ResourceTypes.Dlg);

if (entry != null)
{
    var bifEntry = key.GetBifForResource(entry);
    var bif = BifReader.Read(bifEntry.Filename);
    byte[]? data = bif.ExtractVariableResource(entry.VariableTableIndex);
}

Memory Management

// Don't keep buffer if only reading metadata
var bif = BifReader.Read("large.bif", keepBuffer: false);
// bif.ExtractVariableResource() will return null

// Keep buffer for extraction (default)
var bif = BifReader.Read("data.bif", keepBuffer: true);
// bif.ExtractVariableResource() works

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Implementation Notes

Id Field

The variable resource Id contains:

• Top 12 bits: BIF index (must match KEY)
• Bottom 20 bits: Index within this BIF's variable table

int variableTableIndex = (int)(id & 0xFFFFF);

Large Files

BIF files can be hundreds of MB. The keepBuffer parameter controls whether the entire file is kept in memory:

• true (default): Keep buffer for fast extraction
• false: Release after parsing metadata

For very large BIFs, consider using GameResourceResolver which handles caching automatically.

Fixed Resources

Fixed resources are primarily used for tileset data. Most tools only need variable resources.

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Page freshness: 2025-12-15