FourBitArray.cpp

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//
//  FourBitArray.cpp
//  hog2 glut
//
//  Created by Nathan Sturtevant on 4/8/13.
//  Copyright (c) 2013 University of Denver. All rights reserved.
//
 
#include <stdio.h>
#include <string.h>
#include "FourBitArray.h"
#include <string.h>
#include <cinttypes>
 
//      uint8_t *mem;
//      uint64_t entries;
 
FourBitArray::FourBitArray(uint64_t numEntries)
{
        mem = 0;
        Resize(numEntries);
}
 
FourBitArray::~FourBitArray()
{
        delete [] mem;
}
 
void FourBitArray::FillMax()
{
        memset(mem, 0xFF, (entries+1)/2);
}
 
void FourBitArray::Clear()
{
        memset(mem, 0x0, (entries+1)/2);
}
 
void FourBitArray::Resize(uint64_t newMaxEntries)
{
        entries = newMaxEntries; // 4 bit entries
        newMaxEntries = (newMaxEntries+1)/2; // bytes
        delete [] mem;
        mem = new uint8_t[newMaxEntries];
}
 
uint64_t FourBitArray::Size() const
{
        return entries;
}
 
uint8_t FourBitArray::Get(uint64_t index) const
{
        uint8_t val = mem[index/2];
        if (index&1)
        {
                return val>>4;
        }
        return val&0xF;
}
 
void FourBitArray::Set(uint64_t index, uint8_t val)
{
        if (index&1)
        {
                mem[index/2] = (mem[index/2]&0xF)|(val<<4);
        }
        else {
                mem[index/2] = (mem[index/2]&0xF0)|val;
        }
}
 
void FourBitArray::Write(const char *file)
{
        FILE *f = fopen(file, "w+");
        fprintf(f, "%" PRId64 "\n", entries);
        fwrite(mem, sizeof(uint8_t), (entries+1)/2, f);
        fclose(f);
}
 
void FourBitArray::Read(const char *file)
{
        FILE *f = fopen(file, "r");
        fscanf(f, "%" PRId64 "\n", &entries);
        Resize(entries);
        fread(mem, sizeof(uint8_t), (entries+1)/2, f);
        fclose(f);
}