42 lines
1 KiB
C
42 lines
1 KiB
C
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#ifndef REF_COUNTED_H
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#define REF_COUNTED_H
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#include "mbed.h"
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/**
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* Base class for payload for ref-counted objects. Used by ManagedString and MicroBitImage.
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* There is no constructor, as this struct is typically malloc()ed.
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*/
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struct RefCounted
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{
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public:
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/**
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* Number of outstanding references. Should never be zero (object should be deleted then).
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* When it's set to 0xffff, it means the object sits in flash and should not be counted.
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*/
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uint16_t refcnt;
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/**
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* For strings this is length. For images this is both width and length (8 bit each).
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* A value of 0xffff indicates that this is in fact an instance of VirtualRefCounted
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* and therefore when the reference count reaches zero, the virtual destructor
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* should be called.
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*/
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union {
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uint16_t size;
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struct {
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uint8_t width;
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uint8_t height;
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};
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};
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/** Increment reference count. */
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void incr();
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/** Decrement reference count. */
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void decr();
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};
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#endif
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