Skip to content

Moved magic nums to a const #354

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Mothergoose31 wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Moved magic nums to a const #354

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
5e9895d
Updated Dicom header ints to const
Mothergoose31 Jul 16, 2025
a619114
Updated Dicom header ints to const
Mothergoose31 Jul 16, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 12 additions & 3 deletions read.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,15 @@ import (
"golang.org/x/exp/constraints"
)

// DicomPreamble = empty padding at start of file
// DicomMagicWord = 4-byte "DICM" identifier
// DicomHeaderOffset = skip to actual data
const (
DicomPreambleSize = 128
DicomMagicWordSize = 4
DicomHeaderOffset = DicomPreambleSize + DicomMagicWordSize
)

var (
// ErrorOWRequiresEvenVL indicates that an element with VR=OW had a not even
// value length which is not allowed.
Expand Down Expand Up @@ -158,11 +167,11 @@ func (r *reader) readValue(t tag.Tag, vr string, vl uint32, isImplicit bool, d *
// This should only be called once per DICOM at the start of parsing.
func (r *reader) readHeader() ([]*Element, error) {
// Check for Preamble (128 bytes) + magic word (4 bytes).
data, err := r.rawReader.Peek(128 + 4)
data, err := r.rawReader.Peek(DicomPreambleSize + DicomMagicWordSize)
if err != nil {
return nil, fmt.Errorf("error reading DICOM header preamble: %w", err)
}
if string(data[128:]) != magicWord {
if string(data[DicomPreambleSize:]) != magicWord {
// If magic word is not at byte offset 128 this is a non-standard
// non-compliant DICOM. We try to read this DICOM in a compatibility
// mode, where we rewind to position 0 and blindly attempt to parse
Expand All @@ -171,7 +180,7 @@ func (r *reader) readHeader() ([]*Element, error) {
return nil, nil
}

err = r.rawReader.Skip(128 + 4) // skip preamble + magic word
err = r.rawReader.Skip(DicomPreambleSize + DicomMagicWordSize) // skip preamble + magic word
if err != nil {
return nil, err
}
Expand Down