98 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			C
		
	
	
			
		
		
	
	
			98 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			C
		
	
	
| #ifndef COMMIT_SLAB_H
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| #define COMMIT_SLAB_H
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| 
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| /*
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|  * define_commit_slab(slabname, elemtype) creates boilerplate code to define
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|  * a new struct (struct slabname) that is used to associate a piece of data
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|  * of elemtype to commits, and a few functions to use that struct.
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|  *
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|  * After including this header file, using:
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|  *
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|  * define_commit_slab(indegee, int);
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|  *
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|  * will let you call the following functions:
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|  *
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|  * - int *indegree_at(struct indegree *, struct commit *);
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|  *
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|  *   This function locates the data associated with the given commit in
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|  *   the indegree slab, and returns the pointer to it.
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|  *
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|  * - void init_indegree(struct indegree *);
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|  *   void init_indegree_with_stride(struct indegree *, int);
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|  *
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|  *   Initializes the indegree slab that associates an array of integers
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|  *   to each commit. 'stride' specifies how big each array is.  The slab
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|  *   that id initialied by the variant without "_with_stride" associates
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|  *   each commit with an array of one integer.
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|  */
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| 
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| /* allocate ~512kB at once, allowing for malloc overhead */
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| #ifndef COMMIT_SLAB_SIZE
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| #define COMMIT_SLAB_SIZE (512*1024-32)
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| #endif
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| 
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| #define define_commit_slab(slabname, elemtype) 				\
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| 									\
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| struct slabname {							\
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| 	unsigned slab_size;						\
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| 	unsigned stride;						\
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| 	unsigned slab_count;						\
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| 	elemtype **slab;						\
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| };									\
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| static int stat_ ##slabname## realloc;					\
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| 									\
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| static void init_ ##slabname## _with_stride(struct slabname *s,		\
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| 					    unsigned stride)		\
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| {									\
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| 	unsigned int elem_size;						\
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| 	if (!stride)							\
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| 		stride = 1;						\
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| 	s->stride = stride;						\
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| 	elem_size = sizeof(elemtype) * stride;				\
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| 	s->slab_size = COMMIT_SLAB_SIZE / elem_size;			\
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| 	s->slab_count = 0;						\
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| 	s->slab = NULL;							\
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| }									\
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| 									\
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| static void init_ ##slabname(struct slabname *s)			\
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| {									\
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| 	init_ ##slabname## _with_stride(s, 1);				\
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| }									\
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| 									\
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| static void clear_ ##slabname(struct slabname *s)			\
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| {									\
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| 	int i;								\
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| 	for (i = 0; i < s->slab_count; i++)				\
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| 		free(s->slab[i]);					\
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| 	s->slab_count = 0;						\
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| 	free(s->slab);							\
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| 	s->slab = NULL;							\
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| }									\
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| 									\
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| static elemtype *slabname## _at(struct slabname *s,			\
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| 				const struct commit *c)			\
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| {									\
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| 	int nth_slab, nth_slot;						\
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| 									\
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| 	nth_slab = c->index / s->slab_size;				\
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| 	nth_slot = c->index % s->slab_size;				\
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| 									\
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| 	if (s->slab_count <= nth_slab) {				\
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| 		int i;							\
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| 		s->slab = xrealloc(s->slab,				\
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| 				   (nth_slab + 1) * sizeof(s->slab));	\
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| 		stat_ ##slabname## realloc++;				\
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| 		for (i = s->slab_count; i <= nth_slab; i++)		\
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| 			s->slab[i] = NULL;				\
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| 		s->slab_count = nth_slab + 1;				\
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| 	}								\
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| 	if (!s->slab[nth_slab])						\
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| 		s->slab[nth_slab] = xcalloc(s->slab_size,		\
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| 					    sizeof(**s->slab) * s->stride);		\
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| 	return &s->slab[nth_slab][nth_slot * s->stride];				\
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| }									\
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| 									\
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| static int stat_ ##slabname## realloc
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| 
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| #endif /* COMMIT_SLAB_H */
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