73 lines
1.3 KiB
C++
73 lines
1.3 KiB
C++
#ifndef __PRODOS_BITMAP_H__
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#define __PRODOS_BITMAP_H__
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#include <stdint.h>
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namespace ProDOS {
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class Bitmap {
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public:
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Bitmap(unsigned blocks);
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~Bitmap();
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bool blockFree(unsigned block) const;
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bool markBlock(unsigned block, bool inUse);
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unsigned blocks() const;
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unsigned bitmapBlocks() const;
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unsigned freeBlocks() const;
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int firstFreeBlock(unsigned startingBlock = 0) const;
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int countUnusedBlocks(unsigned startingBlock = 0, unsigned maxSearch = -1) const;
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int freeBlock(unsigned count = 1) const;
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private:
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static unsigned BlockMask(unsigned block);
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static unsigned BlockIndex(unsigned block);
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unsigned _blocks;
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unsigned _freeBlocks;
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unsigned _bitmapSize;
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uint8_t *_bitmap;
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};
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inline unsigned Bitmap::blocks() const
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{
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return _blocks;
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}
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inline unsigned Bitmap::freeBlocks() const
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{
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return _blocks;
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}
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inline unsigned Bitmap::bitmapBlocks() const
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{
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return _bitmapSize >> 12;
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}
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inline unsigned Bitmap::BlockMask(unsigned block)
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{
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return 0x80 >> (block & 0x07);
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}
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inline unsigned Bitmap::BlockIndex(unsigned block)
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{
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return block >> 3;
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}
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inline bool Bitmap::blockFree(unsigned block) const
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{
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if (block >= _blocks) return false;
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return (_bitmap[BlockIndex(block)] & BlockMask(block)) != 0;
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}
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} // namespace
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#endif
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