-- --
-- --------------------------------------------------------------------------------
-- --  FILE:  decoder.lua
-- --  DESCRIPTION:  protoc-gen-lua
-- --      Google's Protocol Buffers project, ported to lua.
-- --      https://code.google.com/p/protoc-gen-lua/
-- --
-- --      Copyright (c) 2010 , 林卓毅 (Zhuoyi Lin) netsnail@gmail.com
-- --      All rights reserved.
-- --
-- --      Use, modification and distribution are subject to the "New BSD License"
-- --      as listed at <url: http://www.opensource.org/licenses/bsd-license.php >.
-- --
-- --  COMPANY:  NetEase
-- --  CREATED:  2010年07月29日 19时30分51秒 CST
-- --------------------------------------------------------------------------------
-- --
-- local string = string
-- local table = table
-- local assert = assert
-- local ipairs = ipairs
-- local error = error
-- local print = print

-- local pb = require "pb"
-- local encoder = require "protobuf.encoder"
-- local wire_format = require "protobuf.wire_format"
-- module "protobuf.decoder"

-- local _DecodeVarint = pb.varint_decoder
-- local _DecodeSignedVarint = pb.signed_varint_decoder

-- local _DecodeVarint32 = pb.varint_decoder
-- local _DecodeSignedVarint32 = pb.signed_varint_decoder

-- local _DecodeVarint64 = pb.varint_decoder64
-- local _DecodeSignedVarint64 = pb.signed_varint_decoder64

-- ReadTag = pb.read_tag

-- local function _SimpleDecoder(wire_type, decode_value)
--     return function(field_number, is_repeated, is_packed, key, new_default)
--         if is_packed then
--             local DecodeVarint = _DecodeVarint
--             return function (buffer, pos, pend, message, field_dict)
--                 local value = field_dict[key]
--                 if value == nil then
--                     value = new_default(message)
--                     field_dict[key] = value
--                 end
--                 local endpoint
--                 endpoint, pos = DecodeVarint(buffer, pos)
--                 endpoint = endpoint + pos
--                 if endpoint > pend then
--                     LogError('Truncated message.')
--                 end
--                 local element
--                 while pos < endpoint do
--                     element, pos = decode_value(buffer, pos)
--                     value[#value + 1] = element
--                 end
--                 if pos > endpoint then
--                     value:remove(#value)
--                     LogError('Packed element was truncated.')
--                 end
--                 return pos
--             end
--         elseif is_repeated then
--             local tag_bytes = encoder.TagBytes(field_number, wire_type)
--             local tag_len = #tag_bytes
--             local sub = string.sub
--             return function(buffer, pos, pend, message, field_dict)
--                 local value = field_dict[key]
--                 if value == nil then
--                     value = new_default(message)
--                     field_dict[key] = value
--                 end
--                 while 1 do
--                     local element, new_pos = decode_value(buffer, pos)
--                     value:append(element)
--                     pos = new_pos + tag_len
--                     if sub(buffer, new_pos+1, pos) ~= tag_bytes or new_pos >= pend then
--                         if new_pos > pend then
--                             LogError('Truncated message.')
--                         end
--                         return new_pos
--                     end
--                 end
--             end
--         else
--             return function (buffer, pos, pend, message, field_dict)
--                 field_dict[key], pos = decode_value(buffer, pos)
--                 if pos > pend then
--                     field_dict[key] = nil
--                     LogError('Truncated message.')
--                 end
--                 return pos
--             end
--         end
--     end
-- end

-- local function _ModifiedDecoder(wire_type, decode_value, modify_value)
--     local InnerDecode = function (buffer, pos)
--         local result, new_pos = decode_value(buffer, pos)
--         return modify_value(result), new_pos
--     end
--     return _SimpleDecoder(wire_type, InnerDecode)
-- end

-- local function _StructPackDecoder(wire_type, value_size, format)
--     local struct_unpack = pb.struct_unpack

--     function InnerDecode(buffer, pos)
--         local new_pos = pos + value_size
--         local result = struct_unpack(format, buffer, pos)
--         return result, new_pos
--     end
--     return _SimpleDecoder(wire_type, InnerDecode)
-- end

-- local function _Boolean(value)
--     return value ~= 0
-- end

-- Int32Decoder = _SimpleDecoder(wire_format.WIRETYPE_VARINT, _DecodeSignedVarint32)
-- EnumDecoder = Int32Decoder

-- Int64Decoder = _SimpleDecoder(wire_format.WIRETYPE_VARINT, _DecodeSignedVarint64)

-- UInt32Decoder = _SimpleDecoder(wire_format.WIRETYPE_VARINT, _DecodeVarint32)
-- UInt64Decoder = _SimpleDecoder(wire_format.WIRETYPE_VARINT, _DecodeVarint64)

-- SInt32Decoder = _ModifiedDecoder(wire_format.WIRETYPE_VARINT, _DecodeVarint32, wire_format.ZigZagDecode32)
-- SInt64Decoder = _ModifiedDecoder(wire_format.WIRETYPE_VARINT, _DecodeVarint64, wire_format.ZigZagDecode64)

-- Fixed32Decoder  = _StructPackDecoder(wire_format.WIRETYPE_FIXED32, 4, string.byte('I'))
-- Fixed64Decoder  = _StructPackDecoder(wire_format.WIRETYPE_FIXED64, 8, string.byte('Q'))
-- SFixed32Decoder = _StructPackDecoder(wire_format.WIRETYPE_FIXED32, 4, string.byte('i'))
-- SFixed64Decoder = _StructPackDecoder(wire_format.WIRETYPE_FIXED64, 8, string.byte('q'))
-- FloatDecoder    = _StructPackDecoder(wire_format.WIRETYPE_FIXED32, 4, string.byte('f'))
-- DoubleDecoder   = _StructPackDecoder(wire_format.WIRETYPE_FIXED64, 8, string.byte('d'))


-- BoolDecoder = _ModifiedDecoder(wire_format.WIRETYPE_VARINT, _DecodeVarint, _Boolean)


-- function StringDecoder(field_number, is_repeated, is_packed, key, new_default)
--     local DecodeVarint = _DecodeVarint
--     local sub = string.sub
--     --    local unicode = unicode
--     assert(not is_packed)
--     if is_repeated then
--         local tag_bytes = encoder.TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
--         local tag_len = #tag_bytes
--         return function (buffer, pos, pend, message, field_dict)
--             local value = field_dict[key]
--             if value == nil then
--                 value = new_default(message)
--                 field_dict[key] = value
--             end
--             while 1 do
--                 local size, new_pos
--                 size, pos = DecodeVarint(buffer, pos)
--                 new_pos = pos + size
--                 if new_pos > pend then
--                     LogError('Truncated string.')
--                 end
--                 value:append(sub(buffer, pos+1, new_pos))
--                 pos = new_pos + tag_len
--                 if sub(buffer, new_pos + 1, pos) ~= tag_bytes or new_pos == pend then
--                     return new_pos
--                 end
--             end
--         end
--     else
--         return function (buffer, pos, pend, message, field_dict)
--             local size, new_pos
--             size, pos = DecodeVarint(buffer, pos)
--             new_pos = pos + size
--             if new_pos > pend then
--                 LogError('Truncated string.')
--             end
--             field_dict[key] = sub(buffer, pos + 1, new_pos)
--             return new_pos
--         end
--     end
-- end

-- function BytesDecoder(field_number, is_repeated, is_packed, key, new_default)
--     local DecodeVarint = _DecodeVarint
--     local sub = string.sub
--     assert(not is_packed)
--     if is_repeated then
--         local tag_bytes = encoder.TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
--         local tag_len = #tag_bytes
--         return function (buffer, pos, pend, message, field_dict)
--             local value = field_dict[key]
--             if value == nil then
--                 value = new_default(message)
--                 field_dict[key] = value
--             end
--             while 1 do
--                 local size, new_pos
--                 size, pos = DecodeVarint(buffer, pos)
--                 new_pos = pos + size
--                 if new_pos > pend then
--                     LogError('Truncated string.')
--                 end
--                 value:append(sub(buffer, pos + 1, new_pos))
--                 pos = new_pos + tag_len
--                 if sub(buffer, new_pos + 1, pos) ~= tag_bytes or new_pos == pend then
--                     return new_pos
--                 end
--             end
--         end
--     else
--         return function(buffer, pos, pend, message, field_dict)
--             local size, new_pos
--             size, pos = DecodeVarint(buffer, pos)
--             new_pos = pos + size
--             if new_pos > pend then
--                 LogError('Truncated string.')
--             end
--             field_dict[key] = sub(buffer, pos + 1, new_pos)
--             return new_pos
--         end
--     end
-- end

-- function MessageDecoder(field_number, is_repeated, is_packed, key, new_default)
--     local DecodeVarint = _DecodeVarint
--     local sub = string.sub

--     assert(not is_packed)
--     if is_repeated then
--         local tag_bytes = encoder.TagBytes(field_number, wire_format.WIRETYPE_LENGTH_DELIMITED)
--         local tag_len = #tag_bytes
--         return function (buffer, pos, pend, message, field_dict)
--             local value = field_dict[key]
--             if value == nil then
--                 value = new_default(message)
--                 field_dict[key] = value
--             end
--             while 1 do
--                 local size, new_pos
--                 size, pos = DecodeVarint(buffer, pos)
--                 new_pos = pos + size
--                 if new_pos > pend then
--                     LogError('Truncated message.')
--                 end
--                 if value:add():_InternalParse(buffer, pos, new_pos) ~= new_pos then
--                     LogError('Unexpected end-group tag.')
--                 end
--                 pos = new_pos + tag_len
--                 if sub(buffer, new_pos + 1, pos) ~= tag_bytes or new_pos == pend then
--                     return new_pos
--                 end
--             end
--         end
--     else
--         return function (buffer, pos, pend, message, field_dict)
--             local value = field_dict[key]
--             if value == nil then
--                 value = new_default(message)
--                 field_dict[key] = value
--             end
--             local size, new_pos
--             size, pos = DecodeVarint(buffer, pos)
--             new_pos = pos + size
--             if new_pos > pend then
--                 LogError('Truncated message.')
--             end
--             if value:_InternalParse(buffer, pos, new_pos) ~= new_pos then
--                 LogError('Unexpected end-group tag.')
--             end
--             return new_pos
--         end
--     end
-- end

-- function _SkipVarint(buffer, pos, pend)
--     local value
--     value, pos = _DecodeVarint(buffer, pos)
--     return pos
-- end

-- function _SkipFixed64(buffer, pos, pend)
--     pos = pos + 8
--     if pos > pend then 
--         LogError('Truncated message.')
--     end
--     return pos
-- end

-- function _SkipLengthDelimited(buffer, pos, pend)
--     local size
--     size, pos = _DecodeVarint(buffer, pos)
--     pos = pos + size
--     if pos > pend then
--         LogError('Truncated message.')
--     end
--     return pos
-- end

-- function _SkipFixed32(buffer, pos, pend)
--     pos = pos + 4
--     if pos > pend then
--         LogError('Truncated message.')
--     end
--     return pos
-- end

-- function _RaiseInvalidWireType(buffer, pos, pend)
--     LogError('Tag had invalid wire type.')
-- end

-- function _FieldSkipper()
--     WIRETYPE_TO_SKIPPER = {
--         _SkipVarint,
--         _SkipFixed64,
--         _SkipLengthDelimited,
--         _SkipGroup,
--         _EndGroup,
--         _SkipFixed32,
--         _RaiseInvalidWireType,
--         _RaiseInvalidWireType,
--     }

-- --    wiretype_mask = wire_format.TAG_TYPE_MASK
--     local ord = string.byte
--     local sub = string.sub

--     return function (buffer, pos, pend, tag_bytes)
--         local wire_type = ord(sub(tag_bytes, 1, 1)) % 8 + 1
--         return WIRETYPE_TO_SKIPPER[wire_type](buffer, pos, pend)
--     end
-- end

-- SkipField = _FieldSkipper()