File decode support

My CPP source code is encoded with GBK, is there any API to support another file encoding?

There is binding auto-generated by bindgen but got a garbled document，like this

#[doc = "�������"]
#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct CThostFtdcDepthMarketDataField {
    #[doc = "������"]
    pub TradingDay: TThostFtdcDateType,
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    pub InstrumentID: TThostFtdcInstrumentIDType,
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    pub ExchangeID: TThostFtdcExchangeIDType,
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    pub ExchangeInstID: TThostFtdcExchangeInstIDType,
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    pub LastPrice: TThostFtdcPriceType,
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    pub PreSettlementPrice: TThostFtdcPriceType,
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    pub PreClosePrice: TThostFtdcPriceType,
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    pub PreOpenInterest: TThostFtdcLargeVolumeType,
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    pub OpenPrice: TThostFtdcPriceType,
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    pub HighestPrice: TThostFtdcPriceType,
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    pub LowestPrice: TThostFtdcPriceType,
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    pub Volume: TThostFtdcVolumeType,
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    pub Turnover: TThostFtdcMoneyType,
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    pub OpenInterest: TThostFtdcLargeVolumeType,
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    pub ClosePrice: TThostFtdcPriceType,
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    pub SettlementPrice: TThostFtdcPriceType,
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    pub UpperLimitPrice: TThostFtdcPriceType,
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    pub LowerLimitPrice: TThostFtdcPriceType,
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    pub PreDelta: TThostFtdcRatioType,
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    pub CurrDelta: TThostFtdcRatioType,
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    pub UpdateTime: TThostFtdcTimeType,
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    pub UpdateMillisec: TThostFtdcMillisecType,
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    pub BidPrice1: TThostFtdcPriceType,
    #[doc = "������һ"]
    pub BidVolume1: TThostFtdcVolumeType,
    #[doc = "������һ"]
    pub AskPrice1: TThostFtdcPriceType,
    #[doc = "������һ"]
    pub AskVolume1: TThostFtdcVolumeType,
    #[doc = "����۶�"]
    pub BidPrice2: TThostFtdcPriceType,
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    pub BidVolume2: TThostFtdcVolumeType,
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    pub AskPrice2: TThostFtdcPriceType,
    #[doc = "��������"]
    pub AskVolume2: TThostFtdcVolumeType,
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    pub BidPrice3: TThostFtdcPriceType,
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    pub BidVolume3: TThostFtdcVolumeType,
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    pub AskPrice3: TThostFtdcPriceType,
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    pub AskVolume3: TThostFtdcVolumeType,
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    pub BidPrice4: TThostFtdcPriceType,
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    pub BidVolume4: TThostFtdcVolumeType,
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    pub AskPrice4: TThostFtdcPriceType,
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    pub AskVolume4: TThostFtdcVolumeType,
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    pub BidPrice5: TThostFtdcPriceType,
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    pub BidVolume5: TThostFtdcVolumeType,
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    pub AskPrice5: TThostFtdcPriceType,
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    pub AskVolume5: TThostFtdcVolumeType,
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    pub AveragePrice: TThostFtdcPriceType,
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    pub ActionDay: TThostFtdcDateType,
}

the header file encode with "GBK"

///深度行情
struct CThostFtdcDepthMarketDataField
{
	///交易日
	TThostFtdcDateType	TradingDay;
	///合约代码
	TThostFtdcInstrumentIDType	InstrumentID;
	///交易所代码
	TThostFtdcExchangeIDType	ExchangeID;
	///合约在交易所的代码
	TThostFtdcExchangeInstIDType	ExchangeInstID;
	///最新价
	TThostFtdcPriceType	LastPrice;
	///上次结算价
	TThostFtdcPriceType	PreSettlementPrice;
	///昨收盘
	TThostFtdcPriceType	PreClosePrice;
	///昨持仓量
	TThostFtdcLargeVolumeType	PreOpenInterest;
	///今开盘
	TThostFtdcPriceType	OpenPrice;
	///最高价
	TThostFtdcPriceType	HighestPrice;
	///最低价
	TThostFtdcPriceType	LowestPrice;
	///数量
	TThostFtdcVolumeType	Volume;
	///成交金额
	TThostFtdcMoneyType	Turnover;
	///持仓量
	TThostFtdcLargeVolumeType	OpenInterest;
	///今收盘
	TThostFtdcPriceType	ClosePrice;
	///本次结算价
	TThostFtdcPriceType	SettlementPrice;
	///涨停板价
	TThostFtdcPriceType	UpperLimitPrice;
	///跌停板价
	TThostFtdcPriceType	LowerLimitPrice;
	///昨虚实度
	TThostFtdcRatioType	PreDelta;
	///今虚实度
	TThostFtdcRatioType	CurrDelta;
	///最后修改时间
	TThostFtdcTimeType	UpdateTime;
	///最后修改毫秒
	TThostFtdcMillisecType	UpdateMillisec;
	///申买价一
	TThostFtdcPriceType	BidPrice1;
	///申买量一
	TThostFtdcVolumeType	BidVolume1;
	///申卖价一
	TThostFtdcPriceType	AskPrice1;
	///申卖量一
	TThostFtdcVolumeType	AskVolume1;
	///申买价二
	TThostFtdcPriceType	BidPrice2;
	///申买量二
	TThostFtdcVolumeType	BidVolume2;
	///申卖价二
	TThostFtdcPriceType	AskPrice2;
	///申卖量二
	TThostFtdcVolumeType	AskVolume2;
	///申买价三
	TThostFtdcPriceType	BidPrice3;
	///申买量三
	TThostFtdcVolumeType	BidVolume3;
	///申卖价三
	TThostFtdcPriceType	AskPrice3;
	///申卖量三
	TThostFtdcVolumeType	AskVolume3;
	///申买价四
	TThostFtdcPriceType	BidPrice4;
	///申买量四
	TThostFtdcVolumeType	BidVolume4;
	///申卖价四
	TThostFtdcPriceType	AskPrice4;
	///申卖量四
	TThostFtdcVolumeType	AskVolume4;
	///申买价五
	TThostFtdcPriceType	BidPrice5;
	///申买量五
	TThostFtdcVolumeType	BidVolume5;
	///申卖价五
	TThostFtdcPriceType	AskPrice5;
	///申卖量五
	TThostFtdcVolumeType	AskVolume5;
	///当日均价
	TThostFtdcPriceType	AveragePrice;
	///业务日期
	TThostFtdcDateType	ActionDay;
};

The issue names no repository files or tests; it provides a GBK-encoded C++ header and garbled bindgen output as the reproduction. Start by locating bindgen's header-decoding entry point and any existing encoding-related tests, then determine the supported API and add coverage showing that the generated documentation preserves the source text.