find_object_in_index

in lib/grit/git-ruby/internal/pack.rb [200:242]

• 40 lines of code
• 10 McCabe index (conditional complexity)

        def find_object_in_index(idx, sha1)
          slot = sha1.getord(0)
          return nil if !slot
          first, last = @offsets[slot,2]
          while first < last
            mid = (first + last) / 2
            if @version == 2
              midsha1 = idx[OffsetStart + (mid * SHA1Size), SHA1Size]
              cmp = midsha1 <=> sha1

              if cmp < 0
                first = mid + 1
              elsif cmp > 0
                last = mid
              else
                pos = OffsetStart + (@size * (SHA1Size + CrcSize)) + (mid * OffsetSize)
                offset = idx[pos, OffsetSize].unpack('N')[0]
                if offset & 0x80000000 > 0
                  offset &= 0x7fffffff
                  pos = OffsetStart + (@size * (SHA1Size + CrcSize + OffsetSize)) + (offset * ExtendedOffsetSize)
                  words = idx[pos, ExtendedOffsetSize].unpack('NN')
                  offset = (words[0] << 32) | words[1]
                end
                return offset
              end
            else
              midsha1 = idx[SHA1Start + mid * EntrySize,SHA1Size]
              cmp = midsha1 <=> sha1

              if cmp < 0
                first = mid + 1
              elsif cmp > 0
                last = mid
              else
                pos = OffsetStart + mid * EntrySize
                offset = idx[pos,OffsetSize].unpack('N')[0]
                return offset
              end
            end
          end
          nil
        end