DiskBitFile.h

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//
//  DiskBitFile.h
//  Rubik
//
//  Created by Nathan Sturtevant on 4/5/13.
//  Copyright (c) 2013 Nathan Sturtevant. All rights reserved.
//
 
#ifndef __Rubik__DiskBitFile__
#define __Rubik__DiskBitFile__
 
#include "EnvUtil.h"
#include <iostream>
#include <cassert>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
 
//const int BITS = 4;
#define BITS 4
 
class DiskBitFile
{
public:
        DiskBitFile(const char *pre);
        ~DiskBitFile();
        void Init(const std::vector<bucketData> &buckets);
        
        // incoming offset is in entries, not bytes
        void WriteFileDepth(int bucket, int64_t offset, uint8_t value);
        int ReadFileDepth(int bucket, int64_t offset);
        void CloseReadWriteFile();
        
        uint8_t *ReadChunk(int bucket, int64_t offset, int numEntries, uint8_t *data);
        void CloseReadFile();
 
        uint64_t GetBytesRead() const { return bytesRead; }
        uint64_t GetBytesWritten() const { return bytesWritten; }
private:
        void FlushCache();
        const char *getBucketFileName(int bucket, int subBucket);
 
        // data for reading and writing depths
        FILE *outputFile;
        int outputBucket;
        int outputSubBucket;
        int64_t cacheOffset; // beginning of cache [in bytes]
        
        // data for reading chunks
        bool fileOpen;
        FILE *chunkFile;
        int64_t fileOffset;
        int64_t currBucket;
        int64_t currSubBucket;
 
        const static int subBucketBits = 30;
        const static int64_t cacheSize = 1ull<<22;//4096;//1024*512; // no problem(?) // 4 MB!
        int64_t theCacheSize;      // valid bytes in the cache
        int64_t cacheFilePosition; // current offset in file (bytes)
        bool cacheChanged;
        uint8_t cache[cacheSize];
 
        uint64_t bytesRead, bytesWritten;
        char bucketFileName[255];
        char prefix[64];
};
 
 
 
#endif