// Copyright (C) 2011 Milo Yip
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#ifndef RAPIDJSON_FILEREADSTREAM_H_
#define RAPIDJSON_FILEREADSTREAM_H_

#include "rapidjson.h"
#include <cstdio>

namespace rapidjson {

//! File byte stream for input using fread().
/*!
    \note implements Stream concept
*/
	class FileReadStream {
	public:
		typedef char Ch;    //!< Character type (byte).

		//! Constructor.
		/*!
			\param fp File pointer opened for read.
			\param buffer user-supplied buffer.
			\param bufferSize size of buffer in bytes. Must >=4 bytes.
		*/
		FileReadStream(FILE *fp, char *buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0),
		                                                            current_(buffer_), readCount_(0), count_(0), eof_(false) {
			RAPIDJSON_ASSERT(fp_ != 0);
			RAPIDJSON_ASSERT(bufferSize >= 4);
			Read();
		}

		Ch Peek() const { return *current_; }

		Ch Take() {
			Ch c = *current_;
			Read();
			return c;
		}

		size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); }

		// Not implemented
		void Put(Ch) { RAPIDJSON_ASSERT(false); }

		void Flush() { RAPIDJSON_ASSERT(false); }

		Ch *PutBegin() {
			RAPIDJSON_ASSERT(false);
			return 0;
		}

		size_t PutEnd(Ch *) {
			RAPIDJSON_ASSERT(false);
			return 0;
		}

		// For encoding detection only.
		const Ch *Peek4() const {
			return (current_ + 4 <= bufferLast_) ? current_ : 0;
		}

	private:
		void Read() {
			if (current_ < bufferLast_)
				++current_;
			else if (!eof_) {
				count_ += readCount_;
				readCount_ = fread(buffer_, 1, bufferSize_, fp_);
				bufferLast_ = buffer_ + readCount_ - 1;
				current_ = buffer_;

				if (readCount_ < bufferSize_) {
					buffer_[readCount_] = '\0';
					++bufferLast_;
					eof_ = true;
				}
			}
		}

		FILE *fp_;
		Ch *buffer_;
		size_t bufferSize_;
		Ch *bufferLast_;
		Ch *current_;
		size_t readCount_;
		size_t count_;  //!< Number of characters read
		bool eof_;
	};

} // namespace rapidjson

#endif // RAPIDJSON_FILESTREAM_H_
