feat(makernote): add Canon MakerNote parser (MNI-2)

api_integration_test.go

@@ -305,6 +305,42 @@ func TestIntegration_CR2(t *testing.T) {
 				{Name: "JPEGInterchangeFormatLength", Value: uint32(13120)},
 			},
 		},
+		{
+			Name:          "Canon",
+			ExactTagCount: 28, // Canon EOS-1Ds Mark II MakerNote
+			Tags: []imxtest.TagExpectation{
+				// Core Canon tags
+				{Name: "CameraSettings1"},
+				{Name: "FocalLength"},
+				{Name: "FlashInfo"},
+				{Name: "CameraSettings2"},
+				{Name: "ImageType"},
+				{Name: "FirmwareVersion"},
+				{Name: "OwnerName"},
+				{Name: "SerialNumber"},
+				{Name: "CameraInfo"},
+				{Name: "CustomFunctions"},
+				{Name: "ModelID"},
+				{Name: "AFInfo"},
+				{Name: "ColorInfo"},
+				{Name: "VRDOffset"},
+				{Name: "SensorInfo"},
+				{Name: "ColorData"},
+				{Name: "CRWParam"},
+				{Name: "ColorInfo2"},
+				// Unknown/undocumented tags (identified by hex code)
+				{Name: "0x0013"},
+				{Name: "0x0015"},
+				{Name: "0x0019"},
+				{Name: "0x0083"},
+				{Name: "0x0091"},
+				{Name: "0x0092"},
+				{Name: "0x0093"},
+				{Name: "0x0094"},
+				{Name: "0x00AA"},
+				{Name: "0x4004"},
+			},
+		},
 	})
 	if result.Failed() {
 		for _, err := range result.Errors {

internal/parser/tiff/ifd.go

@@ -3,6 +3,7 @@ package tiff
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"strings"
 
 	imxbin "github.com/gomantics/imx/internal/binary"
@@ -11,7 +12,7 @@ import (
 )
 
 // parseIFD parses an IFD at the given offset
-func (p *Parser) parseIFD(r *imxbin.Reader, offset int64, dirName string, iccDirs, iptcDirs, xmpDirs *[]parser.Directory, sharedParseErr *parser.ParseError) (*parser.Directory, *parser.ParseError, []SubIFD, uint16) {
+func (p *Parser) parseIFD(r *imxbin.Reader, fileReader io.ReaderAt, offset int64, dirName string, iccDirs, iptcDirs, xmpDirs, makernoteDirs *[]parser.Directory, sharedParseErr *parser.ParseError) (*parser.Directory, *parser.ParseError, []SubIFD, uint16) {
 	var parseErr *parser.ParseError
 	if sharedParseErr != nil {
 		// Use shared error accumulator for multi-IFD parsing
@@ -60,6 +61,8 @@ func (p *Parser) parseIFD(r *imxbin.Reader, offset int64, dirName string, iccDir
 			p.handleIPTC(r, entry, parseErr, iptcDirs)
 		case TagXMP:
 			p.handleXMP(r, entry, parseErr, xmpDirs)
+		case TagMakerNote:
+			p.handleMakerNote(r, fileReader, entry, &dir.Tags, parseErr, makernoteDirs)
 		default:
 			// Regular tag
 			tag, err := p.parseTag(r, entry, dirName)
@@ -516,6 +519,59 @@ func (p *Parser) handleXMP(r *imxbin.Reader, entry *IFDEntry, parseErr *parser.P
 	}
 }
 
+// handleMakerNote handles MakerNote tag (tag 0x927C)
+// MakerNote contains manufacturer-specific metadata in various formats.
+// The raw MakerNote data is always returned as a tag in ExifIFD.
+// When a manufacturer handler is registered and parses successfully,
+// the parsed tags are also returned in a separate manufacturer directory.
+func (p *Parser) handleMakerNote(r *imxbin.Reader, fileReader io.ReaderAt, entry *IFDEntry, dirTags *[]parser.Tag, parseErr *parser.ParseError, makernoteDirs *[]parser.Directory) {
+	// Read MakerNote data
+	makerNoteOffset := int64(entry.ValueOffset)
+	data, err := r.ReadBytes(makerNoteOffset, int(entry.Count))
+	if err != nil {
+		parseErr.Add(fmt.Errorf("failed to read MakerNote data at offset %d: %w", makerNoteOffset, err))
+		return
+	}
+
+	// Always add raw MakerNote tag for backward compatibility
+	*dirTags = append(*dirTags, parser.Tag{
+		ID:       parser.TagID("ExifIFD:0x927C"),
+		Name:     "MakerNote",
+		Value:    data,
+		DataType: "UNDEFINED",
+	})
+
+	// If no registry, we're done
+	if p.makernote == nil {
+		return
+	}
+
+	// Try to detect and parse manufacturer-specific format
+	handler, cfg := p.makernote.Detect(data)
+	if handler == nil {
+		// Unknown manufacturer - raw tag already added above
+		return
+	}
+
+	// Parse manufacturer-specific tags
+	// exifBase is 0 for standard TIFF files (TIFF header at file start)
+	// TODO: For JPEG files, this would need to be the APP1 EXIF header offset
+	exifBase := int64(0)
+
+	tags, mnErr := handler.Parse(fileReader, makerNoteOffset, exifBase, cfg)
+	if mnErr != nil {
+		parseErr.Merge(mnErr)
+	}
+
+	// Create directory for MakerNote tags if any were parsed
+	if len(tags) > 0 {
+		*makernoteDirs = append(*makernoteDirs, parser.Directory{
+			Name: handler.Manufacturer(),
+			Tags: tags,
+		})
+	}
+}
+
 // handleSubIFDs handles SubIFDs tag (tag 0x014A)
 // SubIFDs contain an array of offsets to sub-IFDs for preview/RAW image data
 func (p *Parser) handleSubIFDs(r *imxbin.Reader, entry *IFDEntry, subIFDs *[]SubIFD, parseErr *parser.ParseError) {

internal/parser/tiff/ifd_test.go

@@ -163,8 +163,9 @@ func TestParser_parseIFD(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			reader := imxbin.NewReader(bytes.NewReader(tt.data), order)
-			var iccDirs, iptcDirs, xmpDirs []parser.Directory
+			fileReader := bytes.NewReader(tt.data)
+			reader := imxbin.NewReader(fileReader, order)
+			var iccDirs, iptcDirs, xmpDirs, makernoteDirs []parser.Directory
 
 			// Test both with shared error and without
 			var parseErr *parser.ParseError
@@ -174,7 +175,7 @@ func TestParser_parseIFD(t *testing.T) {
 			} else {
 				parseErr = parser.NewParseError()
 			}
-			dir, _, subIFDs, numEntries := p.parseIFD(reader, 0, "IFD0", &iccDirs, &iptcDirs, &xmpDirs, parseErr)
+			dir, _, subIFDs, numEntries := p.parseIFD(reader, fileReader, 0, "IFD0", &iccDirs, &iptcDirs, &xmpDirs, &makernoteDirs, parseErr)
 
 			if (dir != nil) != tt.wantDir {
 				t.Errorf("dir = %v, wantDir %v", dir != nil, tt.wantDir)