Treat bom-only CSV file as empty

[KengoTODA]

Hello, thanks for making your awesome product open and contribution-welcome! 🙌

Today I found that the CSV file that contains only BOM is NOT treated as empty; It should return listOf() but it doesn't.
Here I want to suggest a small change to fix this issue, could you check it when you have time?

Thanks in advance! 👋

[KengoTODA]

This implementation does not care in which line we found the BOM.
In other words, if second line contains BOM, this implementation treats the line as empty and return null.

I think this is enough for this class, but if necessary it is possible to add private var isFirstLine: Boolean to return null only when we read the first line.

diff --git a/src/commonMain/kotlin/com/github/doyaaaaaken/kotlincsv/client/BufferedLineReader.kt b/src/commonMain/kotlin/com/github/doyaaaaaken/kotlincsv/client/BufferedLineReader.kt
index beee976..4251199 100644
--- a/src/commonMain/kotlin/com/github/doyaaaaaken/kotlincsv/client/BufferedLineReader.kt
+++ b/src/commonMain/kotlin/com/github/doyaaaaaken/kotlincsv/client/BufferedLineReader.kt
@@ -6,6 +6,8 @@ package com.github.doyaaaaaken.kotlincsv.client
 internal class BufferedLineReader(
     private val br: Reader
 ) {
+    private var isFirstLine: Boolean = true
+
     companion object {
         private val BOM = '\uFEFF'
     }
@@ -16,7 +18,8 @@ internal class BufferedLineReader(
             val c = br.read()
 
             if (c == -1) {
-                if (sb.isEmpty() || (sb.length == 1 && sb[0] == BOM)) {
+                if (sb.isEmpty() || (isFirstLine && sb.length == 1 && sb[0] == BOM)) {
+                    isFirstLine = false
                     return null
                 } else {
                     break
@@ -43,6 +46,7 @@ internal class BufferedLineReader(
                 break
             }
         } while (true)
+        isFirstLine = false
         return sb.toString()
     }
 

[doyaaaaaken]

This implementation does not care in which line we found the BOM.

I agree with this policy.

[doyaaaaaken]

Hi @KengoTODA, thank you for your first contribution! 😄

I completely agree with your proposal!
I have made a few comments, please check them out.

[doyaaaaaken]

The code below seems to better grasp the intent.
this.isEmpty() || (this.length == 1 && this[0] == BOM)

[KengoTODA]

I prefer it too, but CodeFactor did not like it so I fixed it as 5231efb 😇

[doyaaaaaken]

Oh... 😇 OK, Let's leave it as is!

[doyaaaaaken]

Thanks for contribution! Released on v1.7.0.