unikernel/duniverse/angstrom/lib/input.ml

@@ -0,0 +1,111 @@
+(*----------------------------------------------------------------------------
+    Copyright (c) 2017 Inhabited Type LLC.
+
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    3. Neither the name of the author nor the names of his contributors
+       may be used to endorse or promote products derived from this software
+       without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
+    OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+    DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
+    ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+    STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGE.
+  ----------------------------------------------------------------------------*)
+
+type t =
+  { mutable parser_committed_bytes : int
+  ; client_committed_bytes         : int
+  ; off                            : int
+  ; len                            : int
+  ; buffer                         : Bigstringaf.t
+  }
+
+let create buffer ~off ~len ~committed_bytes =
+  { parser_committed_bytes = committed_bytes
+  ; client_committed_bytes = committed_bytes
+  ; off
+  ; len
+  ; buffer }
+
+let length                 t = t.client_committed_bytes + t.len
+let client_committed_bytes t = t.client_committed_bytes
+let parser_committed_bytes t = t.parser_committed_bytes
+
+let committed_bytes_discrepancy t = t.parser_committed_bytes - t.client_committed_bytes
+let bytes_for_client_to_commit  t = committed_bytes_discrepancy t
+
+let parser_uncommitted_bytes t = t.len - bytes_for_client_to_commit t
+
+let invariant t =
+  assert (parser_committed_bytes t + parser_uncommitted_bytes t = length t);
+  assert (parser_committed_bytes t - client_committed_bytes   t = bytes_for_client_to_commit t);
+;;
+
+let offset_in_buffer t pos =
+  t.off + pos - t.client_committed_bytes
+
+let apply t pos len ~f =
+  let off = offset_in_buffer t pos in
+  f t.buffer ~off ~len
+
+let unsafe_get_char t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get t.buffer off
+
+let unsafe_get_int16_le t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get_int16_le t.buffer off
+
+let unsafe_get_int32_le t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get_int32_le t.buffer off
+
+let unsafe_get_int64_le t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get_int64_le t.buffer off
+
+let unsafe_get_int16_be t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get_int16_be t.buffer off
+
+let unsafe_get_int32_be t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get_int32_be t.buffer off
+
+let unsafe_get_int64_be t pos =
+  let off = offset_in_buffer t pos in
+  Bigstringaf.unsafe_get_int64_be t.buffer off
+
+let count_while t pos ~f =
+  let buffer = t.buffer in
+  let off    = offset_in_buffer t pos in
+  let i      = ref off in
+  let limit  = t.off + t.len in
+  while !i < limit && f (Bigstringaf.unsafe_get buffer !i) do
+    incr i
+  done;
+  !i - off
+;;
+
+let commit t pos =
+  t.parser_committed_bytes <- pos
+;;