[git/git.git] / commit-slab.h

#ifndef COMMIT_SLAB_H
#define COMMIT_SLAB_H

/*
 * define_commit_slab(slabname, elemtype) creates boilerplate code to define
 * a new struct (struct slabname) that is used to associate a piece of data
 * of elemtype to commits, and a few functions to use that struct.
 *
 * After including this header file, using:
 *
 * define_commit_slab(indegee, int);
 *
 * will let you call the following functions:
 *
 * - int *indegree_at(struct indegree *, struct commit *);
 *
 *   This function locates the data associated with the given commit in
 *   the indegree slab, and returns the pointer to it.
 *
 * - void init_indegree(struct indegree *);
 *   void init_indegree_with_stride(struct indegree *, int);
 *
 *   Initializes the indegree slab that associates an array of integers
 *   to each commit. 'stride' specifies how big each array is.  The slab
 *   that is initialized by the variant without "_with_stride" associates
 *   each commit with an array of one integer.
 *
 * - void clear_indegree(struct indegree *);
 *
 *   Empties the slab.  The slab can be reused with the same stride
 *   without calling init_indegree() again or can be reconfigured to a
 *   different stride by calling init_indegree_with_stride().
 *
 *   Call this function before the slab falls out of scope to avoid
 *   leaking memory.
 */

/* allocate ~512kB at once, allowing for malloc overhead */
#ifndef COMMIT_SLAB_SIZE
#define COMMIT_SLAB_SIZE (512*1024-32)
#endif

#define define_commit_slab(slabname, elemtype) 				\
									\
struct slabname {							\
	unsigned slab_size;						\
	unsigned stride;						\
	unsigned slab_count;						\
	elemtype **slab;						\
};									\
static int stat_ ##slabname## realloc;					\
									\
static void init_ ##slabname## _with_stride(struct slabname *s,		\
					    unsigned stride)		\
{									\
	unsigned int elem_size;						\
	if (!stride)							\
		stride = 1;						\
	s->stride = stride;						\
	elem_size = sizeof(elemtype) * stride;				\
	s->slab_size = COMMIT_SLAB_SIZE / elem_size;			\
	s->slab_count = 0;						\
	s->slab = NULL;							\
}									\
									\
static void init_ ##slabname(struct slabname *s)			\
{									\
	init_ ##slabname## _with_stride(s, 1);				\
}									\
									\
static void clear_ ##slabname(struct slabname *s)			\
{									\
	int i;								\
	for (i = 0; i < s->slab_count; i++)				\
		free(s->slab[i]);					\
	s->slab_count = 0;						\
	free(s->slab);							\
	s->slab = NULL;							\
}									\
									\
static elemtype *slabname## _at(struct slabname *s,			\
				const struct commit *c)			\
{									\
	int nth_slab, nth_slot;						\
									\
	nth_slab = c->index / s->slab_size;				\
	nth_slot = c->index % s->slab_size;				\
									\
	if (s->slab_count <= nth_slab) {				\
		int i;							\
		s->slab = xrealloc(s->slab,				\
				   (nth_slab + 1) * sizeof(s->slab));	\
		stat_ ##slabname## realloc++;				\
		for (i = s->slab_count; i <= nth_slab; i++)		\
			s->slab[i] = NULL;				\
		s->slab_count = nth_slab + 1;				\
	}								\
	if (!s->slab[nth_slab])						\
		s->slab[nth_slab] = xcalloc(s->slab_size,		\
					    sizeof(**s->slab) * s->stride);		\
	return &s->slab[nth_slab][nth_slot * s->stride];				\
}									\
									\
static int stat_ ##slabname## realloc

#endif /* COMMIT_SLAB_H */
Commit	Line	Data
a84b794a JH	1	#ifndef COMMIT_SLAB_H
	2	#define COMMIT_SLAB_H
	3
	4	/*
	5	* define_commit_slab(slabname, elemtype) creates boilerplate code to define
	6	* a new struct (struct slabname) that is used to associate a piece of data
	7	* of elemtype to commits, and a few functions to use that struct.
	8	*
	9	* After including this header file, using:
	10	*
	11	* define_commit_slab(indegee, int);
	12	*
	13	* will let you call the following functions:
	14	*
	15	* - int indegree_at(struct indegree , struct commit *);
	16	*
	17	* This function locates the data associated with the given commit in
	18	* the indegree slab, and returns the pointer to it.
	19	*
	20	* - void init_indegree(struct indegree *);
	21	* void init_indegree_with_stride(struct indegree *, int);
	22	*
	23	* Initializes the indegree slab that associates an array of integers
	24	* to each commit. 'stride' specifies how big each array is. The slab
dcbbc8fa	25	* that is initialized by the variant without "_with_stride" associates
a84b794a	26	* each commit with an array of one integer.
dcbbc8fa TR	27	*
	28	* - void clear_indegree(struct indegree *);
	29	*
	30	* Empties the slab. The slab can be reused with the same stride
	31	* without calling init_indegree() again or can be reconfigured to a
	32	* different stride by calling init_indegree_with_stride().
	33	*
	34	* Call this function before the slab falls out of scope to avoid
	35	* leaking memory.
a84b794a JH	36	*/
	37
	38	/* allocate ~512kB at once, allowing for malloc overhead */
	39	#ifndef COMMIT_SLAB_SIZE
	40	#define COMMIT_SLAB_SIZE (512*1024-32)
	41	#endif
	42
	43	#define define_commit_slab(slabname, elemtype) \
	44	\
	45	struct slabname { \
	46	unsigned slab_size; \
	47	unsigned stride; \
	48	unsigned slab_count; \
	49	elemtype **slab; \
	50	}; \
	51	static int stat_ ##slabname## realloc; \
	52	\
	53	static void init_ ##slabname## _with_stride(struct slabname *s, \
	54	unsigned stride) \
	55	{ \
	56	unsigned int elem_size; \
	57	if (!stride) \
	58	stride = 1; \
	59	s->stride = stride; \
d7a1d629	60	elem_size = sizeof(elemtype) * stride; \
a84b794a JH	61	s->slab_size = COMMIT_SLAB_SIZE / elem_size; \
	62	s->slab_count = 0; \
	63	s->slab = NULL; \
	64	} \
	65	\
	66	static void init_ ##slabname(struct slabname *s) \
	67	{ \
	68	init_ ##slabname## _with_stride(s, 1); \
	69	} \
	70	\
	71	static void clear_ ##slabname(struct slabname *s) \
	72	{ \
	73	int i; \
	74	for (i = 0; i < s->slab_count; i++) \
	75	free(s->slab[i]); \
	76	s->slab_count = 0; \
	77	free(s->slab); \
	78	s->slab = NULL; \
	79	} \
	80	\
	81	static elemtype slabname## _at(struct slabname s, \
	82	const struct commit *c) \
	83	{ \
d7a1d629	84	int nth_slab, nth_slot; \
a84b794a	85	\
d7a1d629 RJ	86	nth_slab = c->index / s->slab_size; \
d7a1d629 RJ	87	nth_slot = c->index % s->slab_size; \
a84b794a JH	88	\
	89	if (s->slab_count <= nth_slab) { \
	90	int i; \
	91	s->slab = xrealloc(s->slab, \
	92	(nth_slab + 1) * sizeof(s->slab)); \
	93	stat_ ##slabname## realloc++; \
	94	for (i = s->slab_count; i <= nth_slab; i++) \
	95	s->slab[i] = NULL; \
	96	s->slab_count = nth_slab + 1; \
	97	} \
	98	if (!s->slab[nth_slab]) \
	99	s->slab[nth_slab] = xcalloc(s->slab_size, \
d7a1d629 RJ	100	sizeof(*s->slab) s->stride); \
d7a1d629 RJ	101	return &s->slab[nth_slab][nth_slot * s->stride]; \
a84b794a JH	102	} \
	103	\
	104	static int stat_ ##slabname## realloc
	105
	106	#endif /* COMMIT_SLAB_H */