1 files changed, 34 insertions, 0 deletions
diff --git a/lib/rainbows/response/range.rb b/lib/rainbows/response/range.rb
new file mode 100644
index 0000000..4c0d4a1
--- /dev/null
+++ b/lib/rainbows/response/range.rb
@@ -0,0 +1,34 @@
+# -*- encoding: binary -*-
+# :enddoc:
+module Rainbows::Response::Range
+  HTTP_RANGE = 'HTTP_RANGE'
+  Content_Range = 'Content-Range'.freeze
+  Content_Length = 'Content-Length'.freeze
+
+  # This does not support multipart responses (does anybody actually
+  # use those?) +headers+ is always a Rack::Utils::HeaderHash
+  def parse_range(env, status, headers)
+    if 200 == status.to_i &&
+        (clen = headers[Content_Length]) &&
+        /\Abytes=(\d+-\d*|\d*-\d+)\z/ =~ env[HTTP_RANGE]
+      a, b = $1.split(/-/)
+      clen = clen.to_i
+      if b.nil? # bytes=M-
+        offset = a.to_i
+        count = clen - offset
+      elsif a.empty? # bytes=-N
+        offset = clen - b.to_i
+        count = clen - offset
+      else  # bytes=M-N
+        offset = a.to_i
+        count = b.to_i + 1 - offset
+      end
+      raise Rainbows::Response416 if count <= 0 || offset >= clen
+      count = clen if count > clen
+      headers[Content_Length] = count.to_s
+      headers[Content_Range] = "bytes #{offset}-#{offset+count-1}/#{clen}"
+      [ status, offset, count ]
+    end
+    # nil if no status
+  end
+end