81 lines
1.9 KiB
C
81 lines
1.9 KiB
C
/* Philip Thrasher's Crazy Awesome Ring Buffer Macros!
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*
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* Below you will find some naughty macros for easy owning and manipulating
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* generic ring buffers. Yes, they are slightly evil in readability, but they
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* are really fast, and they work great.
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*
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* Example usage:
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*
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* #include <stdio.h>
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*
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* // So we can use this in any method, this gives us a typedef
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* // named 'intBuffer'.
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* ringBuffer_typedef(int, intBuffer);
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*
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* int main() {
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* // Declare vars.
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* intBuffer myBuffer;
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*
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* bufferInit(myBuffer,1024,int);
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*
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* // We must have the pointer. All of the macros deal with the pointer.
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* // (except for init.)
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* intBuffer* myBuffer_ptr;
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* myBuffer_ptr = &myBuffer;
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*
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* // Write two values.
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* bufferWrite(myBuffer_ptr,37);
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* bufferWrite(myBuffer_ptr,72);
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*
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* // Read a value into a local variable.
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* int first;
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* bufferRead(myBuffer_ptr,first);
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* assert(first == 37); // true
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*
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* int second;
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* bufferRead(myBuffer_ptr,second);
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* assert(second == 72); // true
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*
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* return 0;
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* }
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*
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*/
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#ifndef _ringbuffer_h
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#define _ringbuffer_h
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#define ringBuffer_typedef(T, NAME) \
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typedef struct { \
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int size; \
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int start; \
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int end; \
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T* elems; \
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} NAME
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#define bufferInit(BUF, S, T) \
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BUF.size = S+1; \
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BUF.start = 0; \
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BUF.end = 0; \
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BUF.elems = (T*)calloc(BUF.size, sizeof(T))
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#define bufferDestroy(BUF) free(BUF->elems)
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#define nextStartIndex(BUF) ((BUF->start + 1) % BUF->size)
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#define nextEndIndex(BUF) ((BUF->end + 1) % BUF->size)
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#define isBufferEmpty(BUF) (BUF->end == BUF->start)
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#define isBufferFull(BUF) (nextEndIndex(BUF) == BUF->start)
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#define bufferWrite(BUF, ELEM) \
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BUF->elems[BUF->end] = ELEM; \
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BUF->end = (BUF->end + 1) % BUF->size; \
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if (isBufferEmpty(BUF)) { \
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BUF->start = nextStartIndex(BUF); \
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}
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#define bufferRead(BUF, ELEM) \
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ELEM = BUF->elems[BUF->start]; \
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BUF->start = nextStartIndex(BUF);
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#endif
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