#430 Add support for 'twisted' RDW headers.

AbsaOSS · Oct 26, 2021 · ebe07c7 · ebe07c7
1 parent 7c8270c
commit ebe07c7
Show file tree

Hide file tree

Showing 3 changed files with 24 additions and 19 deletions.
diff --git a/...r/src/main/scala/za/co/absa/cobrix/cobol/parser/headerparsers/RecordHeaderParserRDW.scala b/...r/src/main/scala/za/co/absa/cobrix/cobol/parser/headerparsers/RecordHeaderParserRDW.scala
@@ -65,10 +65,17 @@ class RecordHeaderParserRDW(isBigEndian: Boolean,
       RecordMetadata(-1, isValid = false)
     }
     else {
+      val useSecondHalf = header(0) == 0 && header(1) == 0 && (header(2) != 0 || header(3) != 0)
       val recordLength = if (isBigEndian) {
-        (header(1) & 0xFF) + 256 * (header(0) & 0xFF) + rdwAdjustment
+        if (useSecondHalf)
+          (header(3) & 0xFF) + 256 * (header(2) & 0xFF) + rdwAdjustment
+        else
+          (header(1) & 0xFF) + 256 * (header(0) & 0xFF) + rdwAdjustment
       } else {
-        (header(2) & 0xFF) + 256 * (header(3) & 0xFF) + rdwAdjustment
+        if (useSecondHalf)
+          (header(2) & 0xFF) + 256 * (header(3) & 0xFF) + rdwAdjustment
+        else
+          (header(0) & 0xFF) + 256 * (header(1) & 0xFF) + rdwAdjustment
       }
 
       if (recordLength > 0) {

diff --git a/...r/src/main/scala/za/co/absa/cobrix/cobol/reader/recordheader/RecordHeaderDecoderRdw.scala b/...r/src/main/scala/za/co/absa/cobrix/cobol/reader/recordheader/RecordHeaderDecoderRdw.scala
@@ -30,12 +30,17 @@ class RecordHeaderDecoderRdw(rdwParameters: RecordHeaderParameters) extends Reco
   override def getRecordLength(header: Array[Byte], offset: Long): Int = {
     validateHeader(header, offset)
 
+    val useSecondHalf = header(0) == 0 && header(0) == 0 && (header(2) != 0 || header(3) != 0)
     val recordLength = if (rdwParameters.isBigEndian) {
-      if (header(2) != 0 || header(3) != 0) reportInvalidHeaderZeros(header, offset)
-      (header(1) & 0xFF) + 256 * (header(0) & 0xFF) + rdwParameters.adjustment
+      if (useSecondHalf)
+        (header(3) & 0xFF) + 256 * (header(2) & 0xFF) + rdwParameters.adjustment
+      else
+        (header(1) & 0xFF) + 256 * (header(0) & 0xFF) + rdwParameters.adjustment
     } else {
-      if (header(0) != 0 || header(1) != 0) reportInvalidHeaderZeros(header, offset)
-      (header(2) & 0xFF) + 256 * (header(3) & 0xFF) + rdwParameters.adjustment
+      if (useSecondHalf)
+        (header(2) & 0xFF) + 256 * (header(3) & 0xFF) + rdwParameters.adjustment
+      else
+        (header(0) & 0xFF) + 256 * (header(1) & 0xFF) + rdwParameters.adjustment
     }
 
     validateRecordLength(header, offset, recordLength)

diff --git a/.../test/scala/za/co/absa/cobrix/cobol/reader/recordheader/RecordHeaderDecoderRdwSuite.scala b/.../test/scala/za/co/absa/cobrix/cobol/reader/recordheader/RecordHeaderDecoderRdwSuite.scala
@@ -84,32 +84,25 @@ class RecordHeaderDecoderRdwSuite extends WordSpec {
       assert(ex.getMessage.contains("The length of RDW headers is unexpected. Expected: 4, got 5. Header: 0,0,2,0,0, offset: 123."))
     }
 
-    "fail when big-endian header is used for little-endian headers" in {
+    "read big-endian headers even when a little-endian mode is used" in {
       val rhd = new RecordHeaderDecoderRdw(RecordHeaderParametersFactory.getDummyRecordHeaderParameters(false, 0))
 
+      val len = rhd.getRecordLength(Array[Byte](0, 1, 0, 0), 0)
 
-      val ex = intercept[IllegalStateException] {
-        rhd.getRecordLength(Array[Byte](0, 1, 0, 0), 234)
-      }
-
-      assert(ex.getMessage.contains("RDW headers contain non-zero values where zeros are expected (check 'rdw_big_endian' flag"))
+      assert(len == 256)
     }
 
-    "fail when little-endian header is used for big-endian headers" in {
+    "read little-endian headers even when a big-endian mode is used" in {
       val rhd = new RecordHeaderDecoderRdw(RecordHeaderParametersFactory.getDummyRecordHeaderParameters(true, 0))
 
+      val len = rhd.getRecordLength(Array[Byte](0, 0, 0, 1), 0)
 
-      val ex = intercept[IllegalStateException] {
-        rhd.getRecordLength(Array[Byte](0, 0, 0, 1), 234)
-      }
-
-      assert(ex.getMessage.contains("RDW headers contain non-zero values where zeros are expected (check 'rdw_big_endian' flag"))
+      assert(len == 1)
     }
 
     "fail when record size is incorrect" in {
       val rhd = new RecordHeaderDecoderRdw(RecordHeaderParametersFactory.getDummyRecordHeaderParameters(true, -10))
 
-
       val ex = intercept[IllegalStateException] {
         rhd.getRecordLength(Array[Byte](0, 1, 0, 0), 234)
       }