NiftiExtension: Create a NIfTI Extension

In neuroim2: Data Structures for Brain Imaging Data

Create a NIfTI Extension

Description

Constructor function for creating a NiftiExtension-class object with proper padding to ensure the size is a multiple of 16 bytes.

Usage

NiftiExtension(ecode, data)

Arguments

ecode	Integer extension code. See NiftiExtensionCodes for known codes. Common values: 4 (AFNI), 6 (comment), 32 (CIFTI).
data	The extension data. Can be: A character string (will be converted to raw with null terminator) A raw vector (used as-is)

Details

The function automatically handles padding to ensure the total extension size (esize) is a multiple of 16 bytes, as required by the NIfTI specification. The esize includes the 8-byte header (esize + ecode fields).

Value

A NiftiExtension-class object.

See Also

NiftiExtension-class, NiftiExtensionCodes

Examples

# Create a comment extension
ext <- NiftiExtension(ecode = 6L, data = "This is a comment")
ext@ecode
ext@esize

# Create an AFNI extension with XML data
afni_xml <- '<?xml version="1.0"?><AFNI_attributes></AFNI_attributes>'
afni_ext <- NiftiExtension(ecode = 4L, data = afni_xml)

neuroim2 documentation built on April 16, 2026, 5:07 p.m.