Handle empty lines in parsecsv

Closes #8365

lib/pure/parsecsv.nim

@@ -170,6 +170,9 @@ proc readRow*(my: var CsvParser, columns = 0): bool =
   ## Blank lines are skipped.
   var col = 0 # current column
   let oldpos = my.bufpos
+  while my.buf[my.bufpos] == '\c' or my.buf[my.bufpos] == '\l':
+    # skip initial empty lines
+    inc(my.bufpos)
   while my.buf[my.bufpos] != '\0':
     let oldlen = my.row.len
     if oldlen < col+1:
@@ -235,7 +238,7 @@ when isMainModule:
   import os
   import strutils
   block: # Tests for reading the header row
-    let content = "One,Two,Three,Four\n1,2,3,4\n10,20,30,40,\n100,200,300,400\n"
+    let content = "\nOne,Two,Three,Four\n1,2,3,4\n10,20,30,40,\n100,200,300,400\n"
     writeFile("temp.csv", content)
 
     var p: CsvParser