feat: add WKB to EWKB conversion with SRID handling and integrate into MSSQL transformation

cmd/go_migrate/mssql-transform.go

@@ -1,5 +1,9 @@
 package main
 
+import (
+	"encoding/binary"
+)
+
 func mssqlUuidToBigEndian(mssqlUuid []byte) []byte {
 	if len(mssqlUuid) != 16 {
 		return mssqlUuid
@@ -12,3 +16,37 @@ func mssqlUuidToBigEndian(mssqlUuid []byte) []byte {
 
 	return pgUuid
 }
+
+const sridFlag = 0x20000000
+
+func wkbToEwkbWithSrid(geometry []byte, srid int) []byte {
+	if len(geometry) < 5 {
+		return geometry
+	}
+
+	var byteOrder binary.ByteOrder
+	if geometry[0] == 0 {
+		byteOrder = binary.BigEndian
+	} else {
+		byteOrder = binary.LittleEndian
+	}
+
+	wkbType := byteOrder.Uint32(geometry[1:5])
+	if wkbType&sridFlag != 0 {
+		return geometry
+	}
+
+	ewkbType := wkbType | sridFlag
+
+	result := make([]byte, len(geometry)+4)
+
+	result[0] = geometry[0]
+
+	byteOrder.PutUint32(result[1:5], ewkbType)
+
+	byteOrder.PutUint32(result[5:9], uint32(srid))
+
+	copy(result[9:], geometry[5:])
+
+	return result
+}