Fix error handling in sam_read1 and sam_itr_next callbacks

Author: kojix2

lib/hts/bam/mpileup.rb

@@ -88,16 +88,11 @@ def initialize(inputs, region: nil, beg: nil, end_: nil, maxcnt: nil, overlaps:
           hts_fp     = data.get_pointer(0 * ptr_size)
           hdr_struct = data.get_pointer(1 * ptr_size)
           itr        = data.get_pointer(2 * ptr_size)
+          # HTSlib contract: return same as sam_itr_next/sam_read1 (>= 0 on success, -1 on EOF, < -1 on error)
           if itr && !itr.null?
-            r = HTS::LibHTS.sam_itr_next(hts_fp, itr, b)
-            if r >= 0
-              0
-            else
-              (r == -1 ? -1 : -2)
-            end
+            HTS::LibHTS.sam_itr_next(hts_fp, itr, b)
           else
-            r = HTS::LibHTS.sam_read1(hts_fp, hdr_struct, b)
-            r == -1 ? -1 : 0
+            HTS::LibHTS.sam_read1(hts_fp, hdr_struct, b)
           end
         end
 

lib/hts/bam/pileup.rb

@@ -116,19 +116,13 @@ def initialize(bam, region: nil, beg: nil, end_: nil, maxcnt: nil)
 
         @cb = if itr_local && !itr_local.null?
                 FFI::Function.new(:int, %i[pointer pointer]) do |_data, b|
-                  # HTSlib contract: sam_itr_next returns >= 0 on success, -1 on EOF, < -1 on error.
-                  r = HTS::LibHTS.sam_itr_next(hts_fp, itr_local, b)
-                  if r >= 0
-                    0
-                  else
-                    (r == -1 ? -1 : -2)
-                  end
+                  # HTSlib contract: return same as sam_itr_next (>= 0 on success, -1 on EOF, < -1 on error)
+                  HTS::LibHTS.sam_itr_next(hts_fp, itr_local, b)
                 end
               else
                 FFI::Function.new(:int, %i[pointer pointer]) do |_data, b|
-                  # HTSlib contract: sam_read1 returns >= 0 on success, -1 on EOF/error.
-                  r = HTS::LibHTS.sam_read1(hts_fp, hdr_struct, b)
-                  r == -1 ? -1 : 0
+                  # HTSlib contract: return same as sam_read1 (>= 0 on success, -1 on EOF, < -1 on error)
+                  HTS::LibHTS.sam_read1(hts_fp, hdr_struct, b)
                 end
               end